Polyethersulfone (PES) is a polymeric permeable material used in ultrafiltration (UF)
membranes due to its high thermomechanical and chemical stability. The hydrophobic nature of
PES membranes renders them prone to fouling and restricts the practical applications of PES in the
fabrication of water treatment membranes. The present study demonstrates a non-solvent-induced
phase separation (NIPS) approach to modifying PES membranes with different concentrations of
discrete TiO2 nanotubes (TNTs). Zeta potential and contact angle measurements showed enhanced
hydrophilicity and surface negative charge in TNTs/PES nanocomposite membranes compared to
unmodified PES membranes. To discern the antifouling and permeation properties of the TNTs/PES
membranes, steam assisted gravity drainage (SAGD) wastewater obtained from the Athabasca oil
sands of Alberta was used. The TiO2 modified polymer nanocomposite membranes resulted in a
higher organic matter rejection and water flux than the unmodified PES membrane. The addition of
discrete TNTs at 1 wt% afforded maximum water flux (82 L/m2 h at 40 psi), organic matter rejection
(53.9%), and antifouling properties (29% improvement in comparison to pristine PES membrane).
An enhancement in fouling resistance of TNTs/PES nanocomposite membranes was observed in
flux recovery ratio experiments.
This document summarizes a study that examined using micro zeolite combined with coagulants and coagulant aids to treat stabilized landfill leachate. The study tested different dosages of polyaluminum chloride (PAC), alum, and ferric chloride combined with micro zeolite and a polymer. The micro zeolite was tested at different particle sizes. The combination of PAC and micro zeolite achieved the highest removal rates for suspended solids (99.7%), color (96%), chemical oxygen demand (76%), and ammoniacal nitrogen (68%) with a settling time of 30 minutes.
Resistance of Superhydrophobic Surface-Functionalized TiO2 Nanotubes to Corro...Pawan Kumar
The availability of robust superhydrophobic materials with the ability to withstand harsh environments are in high demand for many applications. In this study, we have presented a simple method to fabricate superhydrophobic materials from TiO 2 nanotube arrays (TNTAs) and investigated the resilience of the materials when they are subjected to harsh conditions such as intense cavitation upon ultrasonication, corrosion in saline water, water-jet impact, and abrasion. The TNTAs were prepared by anodization of Ti foil in buffered aqueous electrolyte containing fluoride ions. The hydrophilic TNTAs were functionalized with octadecylphosphonic acid (ODPA) or 1H, 1H′, 2H, 2H′-perfluorodecyl phosphonic acid (PFDPA) to form a self-assembled monolayer on the TNTA surface to produce superhydrophobic [email protected] or [email protected] surfaces. The superhydrophobic [email protected] and [email protected] have contact angles of 156.0±1.5 and 168±1.5, and contact angle hysteresis of 3.0 and 0.8, respectively. The superhydrophobic [email protected] and [email protected] were subjected to ultrasonication, corrosion in saline water, and water-jet impact and abrasion, and the resilience of the systems was characterized by electrochemical impedance spectroscopy (EIS), contact angle (CA) measurements, diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), and field-emission scanning electron microscopy (FESEM). The results presented here show that superhydrophobic [email protected] and [email protected] are robust and resilient under the harsh conditions studied in this work, and indicate the potential of these materials …
This document reviews the use of nanotechnology for waste water treatment. It discusses how nanoparticles have a high surface area and unique properties that allow them to efficiently remove toxins, microbes, and other contaminants from water. Various nanomaterials can be used, including metal nanoparticles, carbon nanomaterials, zeolites, and dendrimers. The document summarizes recent research on nanostructured catalytic membranes, nanosorbents, nanocatalysts, bioactive nanoparticles, biomimetic membranes, and molecularly imprinted polymers for applications in water treatment. Nanotechnology approaches provide efficient, precise, and scalable ways to treat waste water with benefits like lower costs and energy usage compared to conventional methods. However, more research is
An experimental study on the effect of alkali treatment on properties of kena...eSAT Journals
Abstract Kenaf fibers are coming into interest to use in reinforced concrete elements in recent years due to its attractive properties such as non-abrasive, lightweight and renewable. However, the properties of kenaf fiber such as high moisture absorption and weak in interfacial adhesion make the use of kenaf fiber in reinforced concrete elements become less attractive. Alkali treatment is one of the best used chemical treatment for natural fibers. It help to increase the fiber surface roughness by chemically modify and clean the fiber surface. The purpose of this research is to do a fundamental study on the effects of alkali solutions to the kenaf fiber. There are a lot of researchers conducted study on the effects of different concentrations of NaOH on kenaf fiber. However, there is no information about the study of alkali treatment of kenaf fiber with different pH. Therefore, this study seeks to determine the effects of alkali pH on the properties of kenaf fiber. By theoretically, the pH of concrete is around 13, so it is important to have a better understanding on the effects of alkaline to the kenaf fiber especially pH 13. The finding of the research can help to develop an effective use of fiber in cementitious materials. The problem of water absorption of kenaf fiber could appear if fibers are directly introduced in concrete. For these reasons, in this study, different pH of NaOH ( pH 8 to 14) were used and the effects on the colour of fiber, weight loss and water absorption of treated kenaf fibers were evaluated. Keywords: Kenaf fiber; Natural fiber; Alkali treatment; Weight loss; Water absorption
IRJET - Potential Impact of Nanoclay on the Atterberg Limits of Clayey SoilIRJET Journal
This document discusses research into the potential impact of adding montmorillonite nanoclay on the Atterberg limits of clayey soil. The researchers obtained a kaolinite clay soil and montmorillonite nanoclay to test. Varying amounts of nanoclay from 0.2% to 3.5% by mass were added to the soil. Testing found that the liquid limit and plastic limit increased with nanoclay content up to 2%, while the plasticity index decreased. This was due to the nanoclay absorbing water and filling pores between clay particles. The nanoclay thus had the potential to stabilize the soil through stronger bonding of particles.
IRJET- Reuse of Plastics in Soil Bricks Substituting Traditional BricksIRJET Journal
The document discusses the reuse of plastic waste in manufacturing soil bricks as an alternative to traditional clay bricks. Plastic waste is a growing problem as plastics do not degrade naturally. The study aims to use waste plastics to create bricks that can be used in construction. Bricks were created with different ratios of plastic and soil. Testing showed plastic-soil bricks with 1% plastic and 2% soil had a compressive strength of 5.12 N/mm2, meeting standards and higher than traditional clay bricks. Water absorption was also lower for plastic bricks compared to clay. The study concludes plastic bricks can help reduce waste while providing a construction material that meets standards.
The document describes various steps in the production of aggregates for concrete:
1) Quarrying of raw materials
2) Hauling and stockpiling of raw materials
3) Crushing, screening, and washing to produce the final product
4) Stockpiling of finished aggregates to prevent mixing
5) Delivery of aggregates to construction sites
It also discusses testing aggregates to check for impurities and harmful substances, which can negatively impact the properties of concrete. Two methods described to test for alkali-aggregate reaction are petrographic analysis and following the risk assessment guidelines in CSA standard A23.2-27A.
This document reviews advances in membrane distillation technology for water desalination and purification. It discusses the fundamental heat and mass transfer processes in membrane distillation, recent developments in membrane materials and module designs, as well as applications and economics. Key configurations of membrane distillation include direct contact, air gap, vacuum, and sweep gas membrane distillation. While membrane distillation was introduced in the 1960s, limitations in membrane technology and economics previously hindered widespread adoption; however, new membrane materials and improved understanding of mass and heat transfer principles have renewed interest in membrane distillation in recent decades.
This document summarizes a study that examined using micro zeolite combined with coagulants and coagulant aids to treat stabilized landfill leachate. The study tested different dosages of polyaluminum chloride (PAC), alum, and ferric chloride combined with micro zeolite and a polymer. The micro zeolite was tested at different particle sizes. The combination of PAC and micro zeolite achieved the highest removal rates for suspended solids (99.7%), color (96%), chemical oxygen demand (76%), and ammoniacal nitrogen (68%) with a settling time of 30 minutes.
Resistance of Superhydrophobic Surface-Functionalized TiO2 Nanotubes to Corro...Pawan Kumar
The availability of robust superhydrophobic materials with the ability to withstand harsh environments are in high demand for many applications. In this study, we have presented a simple method to fabricate superhydrophobic materials from TiO 2 nanotube arrays (TNTAs) and investigated the resilience of the materials when they are subjected to harsh conditions such as intense cavitation upon ultrasonication, corrosion in saline water, water-jet impact, and abrasion. The TNTAs were prepared by anodization of Ti foil in buffered aqueous electrolyte containing fluoride ions. The hydrophilic TNTAs were functionalized with octadecylphosphonic acid (ODPA) or 1H, 1H′, 2H, 2H′-perfluorodecyl phosphonic acid (PFDPA) to form a self-assembled monolayer on the TNTA surface to produce superhydrophobic [email protected] or [email protected] surfaces. The superhydrophobic [email protected] and [email protected] have contact angles of 156.0±1.5 and 168±1.5, and contact angle hysteresis of 3.0 and 0.8, respectively. The superhydrophobic [email protected] and [email protected] were subjected to ultrasonication, corrosion in saline water, and water-jet impact and abrasion, and the resilience of the systems was characterized by electrochemical impedance spectroscopy (EIS), contact angle (CA) measurements, diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), and field-emission scanning electron microscopy (FESEM). The results presented here show that superhydrophobic [email protected] and [email protected] are robust and resilient under the harsh conditions studied in this work, and indicate the potential of these materials …
This document reviews the use of nanotechnology for waste water treatment. It discusses how nanoparticles have a high surface area and unique properties that allow them to efficiently remove toxins, microbes, and other contaminants from water. Various nanomaterials can be used, including metal nanoparticles, carbon nanomaterials, zeolites, and dendrimers. The document summarizes recent research on nanostructured catalytic membranes, nanosorbents, nanocatalysts, bioactive nanoparticles, biomimetic membranes, and molecularly imprinted polymers for applications in water treatment. Nanotechnology approaches provide efficient, precise, and scalable ways to treat waste water with benefits like lower costs and energy usage compared to conventional methods. However, more research is
An experimental study on the effect of alkali treatment on properties of kena...eSAT Journals
Abstract Kenaf fibers are coming into interest to use in reinforced concrete elements in recent years due to its attractive properties such as non-abrasive, lightweight and renewable. However, the properties of kenaf fiber such as high moisture absorption and weak in interfacial adhesion make the use of kenaf fiber in reinforced concrete elements become less attractive. Alkali treatment is one of the best used chemical treatment for natural fibers. It help to increase the fiber surface roughness by chemically modify and clean the fiber surface. The purpose of this research is to do a fundamental study on the effects of alkali solutions to the kenaf fiber. There are a lot of researchers conducted study on the effects of different concentrations of NaOH on kenaf fiber. However, there is no information about the study of alkali treatment of kenaf fiber with different pH. Therefore, this study seeks to determine the effects of alkali pH on the properties of kenaf fiber. By theoretically, the pH of concrete is around 13, so it is important to have a better understanding on the effects of alkaline to the kenaf fiber especially pH 13. The finding of the research can help to develop an effective use of fiber in cementitious materials. The problem of water absorption of kenaf fiber could appear if fibers are directly introduced in concrete. For these reasons, in this study, different pH of NaOH ( pH 8 to 14) were used and the effects on the colour of fiber, weight loss and water absorption of treated kenaf fibers were evaluated. Keywords: Kenaf fiber; Natural fiber; Alkali treatment; Weight loss; Water absorption
IRJET - Potential Impact of Nanoclay on the Atterberg Limits of Clayey SoilIRJET Journal
This document discusses research into the potential impact of adding montmorillonite nanoclay on the Atterberg limits of clayey soil. The researchers obtained a kaolinite clay soil and montmorillonite nanoclay to test. Varying amounts of nanoclay from 0.2% to 3.5% by mass were added to the soil. Testing found that the liquid limit and plastic limit increased with nanoclay content up to 2%, while the plasticity index decreased. This was due to the nanoclay absorbing water and filling pores between clay particles. The nanoclay thus had the potential to stabilize the soil through stronger bonding of particles.
IRJET- Reuse of Plastics in Soil Bricks Substituting Traditional BricksIRJET Journal
The document discusses the reuse of plastic waste in manufacturing soil bricks as an alternative to traditional clay bricks. Plastic waste is a growing problem as plastics do not degrade naturally. The study aims to use waste plastics to create bricks that can be used in construction. Bricks were created with different ratios of plastic and soil. Testing showed plastic-soil bricks with 1% plastic and 2% soil had a compressive strength of 5.12 N/mm2, meeting standards and higher than traditional clay bricks. Water absorption was also lower for plastic bricks compared to clay. The study concludes plastic bricks can help reduce waste while providing a construction material that meets standards.
The document describes various steps in the production of aggregates for concrete:
1) Quarrying of raw materials
2) Hauling and stockpiling of raw materials
3) Crushing, screening, and washing to produce the final product
4) Stockpiling of finished aggregates to prevent mixing
5) Delivery of aggregates to construction sites
It also discusses testing aggregates to check for impurities and harmful substances, which can negatively impact the properties of concrete. Two methods described to test for alkali-aggregate reaction are petrographic analysis and following the risk assessment guidelines in CSA standard A23.2-27A.
This document reviews advances in membrane distillation technology for water desalination and purification. It discusses the fundamental heat and mass transfer processes in membrane distillation, recent developments in membrane materials and module designs, as well as applications and economics. Key configurations of membrane distillation include direct contact, air gap, vacuum, and sweep gas membrane distillation. While membrane distillation was introduced in the 1960s, limitations in membrane technology and economics previously hindered widespread adoption; however, new membrane materials and improved understanding of mass and heat transfer principles have renewed interest in membrane distillation in recent decades.
Nano porous membranes for water purification by shrinath ghadgeShrinath Ghadge
Continuous population growth and urbanization as well as rapid industrialization, causing huge contamination of potable water or underground water, has been a serious concern all over the world. Due to incompetency of conventional water purification technologies to deliver complete pollutants free water at an economical price, a high performance, cost-effective and environmentally acceptable separation system is an urgent need which should not only remove macro-, micro- and nano-pollutants but also desalinate water to a significant extent. In this milieu, nanotechnology based carbon nanotube (CNT) membranes have shown impressive breakthroughs towards water purification as compared to existing energy intensive water purification systems and thus, this technology has immense potential for large scale commercial water purification in a cost effective manner.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This presentation summarizes research on mesoporous materials for drug delivery systems. Mesoporous materials were first developed in 1990 and have large surface areas and tunable pore sizes, making them useful for controlled drug release. The presentation discusses different types of nano drug delivery systems and classifications of mesoporous materials based on pore size and framework. It also outlines the sol-gel process and properties of mesoporous silica nanoparticles. Finally, potential applications are mentioned in pharmaceuticals, biomedical, chemical catalysis, and sensors.
This document discusses a study on the influence of continuous plastic fiber reinforcement arrangements in concrete. Concrete beams were reinforced using two different fiber arrangements: short, discontinuous recycled PET fibers (SFRC), and a novel arrangement using continuous recycled PET fibers as long as the beams (CFRC). The mechanical behavior of samples from both arrangements was evaluated through bending tests. Results showed the continuous fiber reinforcement performed better, with CFRC samples experiencing a 150% increase in maximum load compared to SFRC samples. Characterization of the recycled PET fibers included FTIR, DSC, and tensile tests to analyze the fibers structurally and mechanically before use in concrete mixtures.
The Impacts of Cement Dust Deposits on Soil Available MicronutrientsEditor IJCATR
The impact of cement dust deposits on soils micronutrient around Ashaka cement factory, Nigeria was evaluated by
determining available micronutrient elements in 68 soil samples and some crop plant stalks using acid extraction and atomic absorption
spectrophotometric methods. Soil samples collected in a radius of 6Km from a 0 – 30cm depth and analysed indicated mean
concentrations of 215.30gKg-1 Fe, 7.96 gKg-1 Zn, 0.33 gKg-1 Cu, 80.79 gKg-1 Mn, 2.05 gKg-1 Ni, and 26.91 gKg-1 Co. The concentration
of each element in the soil varies in a decreasing order with increasing distance away from the cement factory and generally occurring
above background levels (Zn, Mn, Ni). The metals in the crop plants were higher than normal levels with sorghum concentrating more
metals than millet, suggesting a reflection of the soil metal concentrations and this might be due to the presence of available mobile
elements and the slightly acidic nature of the soil outside the factory
Mechanical Properties of Concrete with Marine Sand as Partial Replacement of ...IJERA Editor
The process of depleting sources of natural aggregates challenges the production of technically and
environmentally adequate concrete. Alternative material from marine sources is good enough for the
replacement of fine aggregate in the concrete. The material was stockpiled in the open air and no washing,
drying or decontamination process was carried out. Physical and chemical properties of DMS material were
determined. All the materials used in the concrete were selected and tested as per the standard procedures of the
Indian standards. A unique design mix will be done based on the entire material test results. Different mixtures
were produced using DMS in different proportions from 15% to 100% as per the finalized trial of the design
mix. The concrete were submitted to compressive strength testsafter 7, 28 and 90 days of moist curing, as well
as flexure and splitting tensile strength tests for M-25 grade.
This document presents the minor project of synthesizing Fe-Co MCM-41 catalyst for the preparation of carbon nanotubes by catalytic chemical vapor deposition. The objective is to achieve a high purity and performance catalyst by synthesizing Fe-Co MCM-41 with varying molar ratios of Fe and Co to silicon. The catalyst will be characterized using XRD and FT-IR. Synthesis of Fe, Co, and Fe-Co MCM-41 is described along with future work to improve yield and prevent impurities.
PDC Analysis of LLDPE-NR Nanocomposite for Effect of Moisture Absorption IJECEIAES
The properties of insulation have been improved by many research and the ability of nanocomposite material that composes the characteristic of improving electrical performance due to the addition of nanofiller into the based material gets serious attention. Polarization and Depolarization Current (PDC) measurement that has the ability to assess the condition of HV insulations with the initial periods after a DC step voltage application was favoured compared to other non-destructive monitoring techniques. This paper presents the works on moisture absorption in LLDPE-NR nanocomposite with different amount and percentage of nanofillers. The study of PDC level of the LLDPE-NR compound, filled with different amount of SiO 2 , TiO and MMT nanofiller using Polarization and Depolarization Current (PDC) measurement technique is the main objective of this research. These results show that sample A1 has the lowest polarization current value and sample B5 has the lowest depolarization current value.
Diffusion Studies of Nanofibril Reinforced Unsaturated Polyester NanocompositesIRJESJOURNAL
ABSTRACT: This work deals with the water sorption characteristics of isorananofibril reinforced polyester composites with special reference to filler loading as well as temperature. It was found that, the neat polyester resin shows high water absorption at room temperature. The reduction of water absorption of INF filled composites is due to the improved inter-facial adhesion, which prevents the easy penetration of water molecules in the nanofibril composite. The formation of fibrous network of cellulose nanofibrils with the polyester matrix also prevents the swelling of the composite and thus reduces the water penetration. At 90 ˚C, after the initial capillary uptake of water, as the INF loading increases the water uptake also increases. This is due to the hydrophilic character of INF. At higher temperature, the composite lost all its hydrogen bonding interactions and the neat polyester shows lower water uptake. The mechanism of diffusion was analysed and the effect of INF on the sorption kinetics was studied. Parameters like diffusion, sorption and permeability coefficients of the composites were determined.
Investigation Review of Self Curing Concrete Experiment ResultsIRJET Journal
This document summarizes an investigation into the physical properties of self-curing concrete using different admixtures. The study tested concrete with lightweight aggregates (LECA) ranging from 0-20% by volume and polyethylene glycol ranging from 1-3% by weight of cement. Tests measured volumetric water absorption, water permeability, water sorptivity, and mass loss at 28 days. Results showed LECA up to 15% and polyethylene glycol at 2% improved properties by retaining more moisture for hydration. Higher cement content, lower water-cement ratio, and addition of silica fume also improved durability. The study concluded self-curing agents along with silica fume can enhance physical properties of concrete compared to
POLYMER NANOCOMPOSITE ARE THE FUTURE for packaging industriesPrajwal Ghadekar
Flexible packaging consumption’s rapid growth represents a $38 billion market in the global Community. As the demand in the industry continues to rise at an average of 3.5% each year, flexible materials need to meet and exceed the high expectations of consumers And the stressors of the supply chain. Increased competition between suppliers Along with government regulations translates into innovations in films that enhance product and Package performance as well as address worldwide concerns with packaging waste.
One such innovation is polymer nanocomposite technology which holds the key to future Advances in flexible packaging. According to Aaron Brody in a December, 2003 Food Technology article, “…Nano composites appear capable of approaching the elusive goal of converting plastic into a superbarrier—the equivalent of glass or metal—without upsetting regulators” (Brody, 2003). This paper will discuss how nanocomposites are made and the growth of nanocomposite materials as a function of their numerous advantages in the packaging industry today and in the future.
This document reviews piezodialysis (PD), a process for removing salt from water using charge mosaic membranes. It discusses how early PD membranes were made by embedding ion exchange resins in polymer matrices, but had poor performance due to imperfect membrane structures. More recent approaches to creating charge mosaic membranes include stacking alternating cation and anion exchange membranes, using block copolymers containing both cation and anion exchange groups, and blending polymers with ion exchange functionality. However, the ideal membrane structure that can achieve the predicted high performance of PD through efficient salt transport while limiting water transport has yet to be realized.
Influence of alkaline substances (carbonates and bicarbonates of sodium) in w...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This document describes a new method for producing stable carbon nanotube (CNT) aerogels with high electrical conductivity and porosity. The method involves:
1) Forming a chemically cross-linked gel of CNTs in solution using a chemical cross-linker.
2) Drying the gel using supercritical CO2 to produce an aerogel without shrinkage.
3) Thermally annealing the aerogel in air, which improves electrical conductivity, mechanical stability, surface area, and porosity by reopening pores.
The resulting annealed CNT aerogels are highly porous (>99%), electrically conductive (1-2 S/cm), and have a large specific surface area (590
The document discusses the use of nanobioremediation to clean up environmental pollution. It proposes using genetic engineering and nanoparticles to enhance the ability of microorganisms to remediate contaminants. Key points:
1) Nanoparticles and genetic engineering can be used to modify microbial cells to increase their ability to degrade various pollutants like heavy metals and organic compounds through increased enzyme production and substrate specificity.
2) Immobilizing microbial cells and enzymes onto nanoparticles increases their stability and reusability, improving bioremediation efficiency.
3) A radioresistant bacterium, Deinococcus radiodurans, has been genetically engineered to remediate multiple contaminants found in radioactive waste, providing a
A designed surface modification to disperse silica powder into polyurethaneTrang Le
This document describes a method for modifying silica powder nanoparticles through surface grafting of polyurethane (PU) oligomers or short chains to improve dispersion in PU matrices. Silica particles were first modified with 3-isocyanatepropyltriethoxysilane to introduce isocyanate groups on the surface. Further surface-initiated condensation reactions were carried out in steps using diols, triols and diisocyanates to graft PU oligomers of varying lengths. Characterization techniques confirmed grafting and showed the surface density of initial isocyanate groups could be controlled. Hybrid films with modified silica particles dispersed in PU matrices showed improved optical, thermal and mechanical properties compared to films with unmodified particles
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
IRJET- Multi Layered Soil Column Analysis for WastewaterIRJET Journal
This document summarizes a study that analyzed the effectiveness of using a multi-layered soil column system to treat domestic wastewater. The system consists of layers of soil, charcoal, sawdust and iron scraps placed in acrylic tubes. Greywater is passed through the layers, where various physical, chemical and biological processes help treat pollutants. Key pollutants like BOD, COD, nutrients and microbes are reduced as the greywater percolates through the soil mixture and permeable filter layers. The document describes the experimental setup, materials used, treatment mechanisms involved and design of the soil column apparatus used in the study.
The availability of robust superhydrophobic materials with the ability to withstand harsh environments are in high demand for many applications. In this study, we have presented a simple method to fabricate superhydrophobic materials from TiO2 nanotube arrays (TNTAs) and
investigated the resilience of the materials when they are subjected to harsh conditions such as
intense cavitation upon ultrasonication, corrosion in saline water, water-jet impact, and abrasion. The TNTAs were prepared by anodization of Ti foil in buffered aqueous electrolyte containing fluoride ions. The hydrophilic TNTAs were functionalized with octadecylphosphonic acid (ODPA) or
1H, 1H0, 2H, 2H0-perfluorodecyl phosphonic acid (PFDPA) to form a self-assembled monolayer
on the TNTA surface to produce superhydrophobic ODPA@TNTA or PFDPA@TNTA surfaces.
The superhydrophobic ODPA@TNTA and PFDPA@TNTA have contact angles of 156.0+-1.5 and 168+- 1.5, and contact angle hysteresis of 3.0 and 0.8, respectively. The superhydrophobic
ODPA@TNTA and PFDPA@TNTA were subjected to ultrasonication, corrosion in saline water, and water-jet impact and abrasion, and the resilience of the systems was characterized by electrochemical impedance spectroscopy (EIS), contact angle (CA) measurements, diffuse reflectance
Fourier transform infrared spectroscopy (DRIFTS), and field-emission scanning electron microscopy (FESEM). The results presented here show that superhydrophobic ODPA@TNTA and PFDPA@TNTA are robust and resilient under the harsh conditions studied in this work, and indicate the potential of
these materials to be deployed in practical applications.
Investigation Of Hydrogen Production By Using Composite Membrane (Nafion/Zro2...IJERA Editor
In the present study, Composite materials based on perfluorinated cation-exchange membrane incorporating particles of Zirconium and Nafion is synthesized .With this membrane the performance of the electrolysis cell improved considerably at room temperature and atmospheric pressure. In addition, by using catalysts and membranes, the performance of this Composite membrane is studied by varying voltage range with respect to hydrogen yield and at current density 0.1, 0.2, 0.3, 0.4, and 0.5(A cm-2), With a Nafion 115 membrane as a reference electrolyte. Experiments have shown that 99.9% purity of hydrogen Gas is evolved The physicochemical properties of the composite membranes such as thermogravimetric analyzer (TGA), Scanning Electron Microscope (SEM), XRD (X-ray powder diffraction), Fourier transform infrared spectroscopyand and Ion Exchange Capacity is determined. The fabricated composite membranes have shown the significant improvement of all tested properties compared to that of pure Nafion membrane.
Ceramic membrane coating with graphene oxide for tannery wastewater treatmenthunypink
The document summarizes a study on using a graphene oxide coated ceramic membrane for treating tannery wastewater. Key points:
- Tannery wastewater is highly contaminated and poses risks to the environment. A ceramic membrane was coated with graphene oxide using dip coating to treat this wastewater.
- Experiments were conducted at different pressures from 0.7 to 3 bar to evaluate the coated membrane's rejection of contaminants like total solids, salts, and conductivity.
- Results showed the coating improved the membrane's rejection performance. Rejection percentages increased for parameters like total solids, dissolved solids, suspended solids, salinity and conductivity compared to an uncoated membrane.
This document describes the development of a novel carbon nanotube decorated poly(arylene ether nitrile) nanofibrous composite absorbent for efficient removal of methylene blue and congo red dyes. The absorbent was fabricated through decoration of acidified multi-walled carbon nanotubes onto a polydopamine-modified poly(arylene ether nitrile) nanofibrous membrane, followed by co-deposition of tannic acid and carboxylated chitosan. Characterization showed the absorbent had an average pore diameter of 19.21 nm. Adsorption tests found it could achieve maximum capacities of 633 and 589 mg/g for methylene blue and congo red
Nano porous membranes for water purification by shrinath ghadgeShrinath Ghadge
Continuous population growth and urbanization as well as rapid industrialization, causing huge contamination of potable water or underground water, has been a serious concern all over the world. Due to incompetency of conventional water purification technologies to deliver complete pollutants free water at an economical price, a high performance, cost-effective and environmentally acceptable separation system is an urgent need which should not only remove macro-, micro- and nano-pollutants but also desalinate water to a significant extent. In this milieu, nanotechnology based carbon nanotube (CNT) membranes have shown impressive breakthroughs towards water purification as compared to existing energy intensive water purification systems and thus, this technology has immense potential for large scale commercial water purification in a cost effective manner.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This presentation summarizes research on mesoporous materials for drug delivery systems. Mesoporous materials were first developed in 1990 and have large surface areas and tunable pore sizes, making them useful for controlled drug release. The presentation discusses different types of nano drug delivery systems and classifications of mesoporous materials based on pore size and framework. It also outlines the sol-gel process and properties of mesoporous silica nanoparticles. Finally, potential applications are mentioned in pharmaceuticals, biomedical, chemical catalysis, and sensors.
This document discusses a study on the influence of continuous plastic fiber reinforcement arrangements in concrete. Concrete beams were reinforced using two different fiber arrangements: short, discontinuous recycled PET fibers (SFRC), and a novel arrangement using continuous recycled PET fibers as long as the beams (CFRC). The mechanical behavior of samples from both arrangements was evaluated through bending tests. Results showed the continuous fiber reinforcement performed better, with CFRC samples experiencing a 150% increase in maximum load compared to SFRC samples. Characterization of the recycled PET fibers included FTIR, DSC, and tensile tests to analyze the fibers structurally and mechanically before use in concrete mixtures.
The Impacts of Cement Dust Deposits on Soil Available MicronutrientsEditor IJCATR
The impact of cement dust deposits on soils micronutrient around Ashaka cement factory, Nigeria was evaluated by
determining available micronutrient elements in 68 soil samples and some crop plant stalks using acid extraction and atomic absorption
spectrophotometric methods. Soil samples collected in a radius of 6Km from a 0 – 30cm depth and analysed indicated mean
concentrations of 215.30gKg-1 Fe, 7.96 gKg-1 Zn, 0.33 gKg-1 Cu, 80.79 gKg-1 Mn, 2.05 gKg-1 Ni, and 26.91 gKg-1 Co. The concentration
of each element in the soil varies in a decreasing order with increasing distance away from the cement factory and generally occurring
above background levels (Zn, Mn, Ni). The metals in the crop plants were higher than normal levels with sorghum concentrating more
metals than millet, suggesting a reflection of the soil metal concentrations and this might be due to the presence of available mobile
elements and the slightly acidic nature of the soil outside the factory
Mechanical Properties of Concrete with Marine Sand as Partial Replacement of ...IJERA Editor
The process of depleting sources of natural aggregates challenges the production of technically and
environmentally adequate concrete. Alternative material from marine sources is good enough for the
replacement of fine aggregate in the concrete. The material was stockpiled in the open air and no washing,
drying or decontamination process was carried out. Physical and chemical properties of DMS material were
determined. All the materials used in the concrete were selected and tested as per the standard procedures of the
Indian standards. A unique design mix will be done based on the entire material test results. Different mixtures
were produced using DMS in different proportions from 15% to 100% as per the finalized trial of the design
mix. The concrete were submitted to compressive strength testsafter 7, 28 and 90 days of moist curing, as well
as flexure and splitting tensile strength tests for M-25 grade.
This document presents the minor project of synthesizing Fe-Co MCM-41 catalyst for the preparation of carbon nanotubes by catalytic chemical vapor deposition. The objective is to achieve a high purity and performance catalyst by synthesizing Fe-Co MCM-41 with varying molar ratios of Fe and Co to silicon. The catalyst will be characterized using XRD and FT-IR. Synthesis of Fe, Co, and Fe-Co MCM-41 is described along with future work to improve yield and prevent impurities.
PDC Analysis of LLDPE-NR Nanocomposite for Effect of Moisture Absorption IJECEIAES
The properties of insulation have been improved by many research and the ability of nanocomposite material that composes the characteristic of improving electrical performance due to the addition of nanofiller into the based material gets serious attention. Polarization and Depolarization Current (PDC) measurement that has the ability to assess the condition of HV insulations with the initial periods after a DC step voltage application was favoured compared to other non-destructive monitoring techniques. This paper presents the works on moisture absorption in LLDPE-NR nanocomposite with different amount and percentage of nanofillers. The study of PDC level of the LLDPE-NR compound, filled with different amount of SiO 2 , TiO and MMT nanofiller using Polarization and Depolarization Current (PDC) measurement technique is the main objective of this research. These results show that sample A1 has the lowest polarization current value and sample B5 has the lowest depolarization current value.
Diffusion Studies of Nanofibril Reinforced Unsaturated Polyester NanocompositesIRJESJOURNAL
ABSTRACT: This work deals with the water sorption characteristics of isorananofibril reinforced polyester composites with special reference to filler loading as well as temperature. It was found that, the neat polyester resin shows high water absorption at room temperature. The reduction of water absorption of INF filled composites is due to the improved inter-facial adhesion, which prevents the easy penetration of water molecules in the nanofibril composite. The formation of fibrous network of cellulose nanofibrils with the polyester matrix also prevents the swelling of the composite and thus reduces the water penetration. At 90 ˚C, after the initial capillary uptake of water, as the INF loading increases the water uptake also increases. This is due to the hydrophilic character of INF. At higher temperature, the composite lost all its hydrogen bonding interactions and the neat polyester shows lower water uptake. The mechanism of diffusion was analysed and the effect of INF on the sorption kinetics was studied. Parameters like diffusion, sorption and permeability coefficients of the composites were determined.
Investigation Review of Self Curing Concrete Experiment ResultsIRJET Journal
This document summarizes an investigation into the physical properties of self-curing concrete using different admixtures. The study tested concrete with lightweight aggregates (LECA) ranging from 0-20% by volume and polyethylene glycol ranging from 1-3% by weight of cement. Tests measured volumetric water absorption, water permeability, water sorptivity, and mass loss at 28 days. Results showed LECA up to 15% and polyethylene glycol at 2% improved properties by retaining more moisture for hydration. Higher cement content, lower water-cement ratio, and addition of silica fume also improved durability. The study concluded self-curing agents along with silica fume can enhance physical properties of concrete compared to
POLYMER NANOCOMPOSITE ARE THE FUTURE for packaging industriesPrajwal Ghadekar
Flexible packaging consumption’s rapid growth represents a $38 billion market in the global Community. As the demand in the industry continues to rise at an average of 3.5% each year, flexible materials need to meet and exceed the high expectations of consumers And the stressors of the supply chain. Increased competition between suppliers Along with government regulations translates into innovations in films that enhance product and Package performance as well as address worldwide concerns with packaging waste.
One such innovation is polymer nanocomposite technology which holds the key to future Advances in flexible packaging. According to Aaron Brody in a December, 2003 Food Technology article, “…Nano composites appear capable of approaching the elusive goal of converting plastic into a superbarrier—the equivalent of glass or metal—without upsetting regulators” (Brody, 2003). This paper will discuss how nanocomposites are made and the growth of nanocomposite materials as a function of their numerous advantages in the packaging industry today and in the future.
This document reviews piezodialysis (PD), a process for removing salt from water using charge mosaic membranes. It discusses how early PD membranes were made by embedding ion exchange resins in polymer matrices, but had poor performance due to imperfect membrane structures. More recent approaches to creating charge mosaic membranes include stacking alternating cation and anion exchange membranes, using block copolymers containing both cation and anion exchange groups, and blending polymers with ion exchange functionality. However, the ideal membrane structure that can achieve the predicted high performance of PD through efficient salt transport while limiting water transport has yet to be realized.
Influence of alkaline substances (carbonates and bicarbonates of sodium) in w...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This document describes a new method for producing stable carbon nanotube (CNT) aerogels with high electrical conductivity and porosity. The method involves:
1) Forming a chemically cross-linked gel of CNTs in solution using a chemical cross-linker.
2) Drying the gel using supercritical CO2 to produce an aerogel without shrinkage.
3) Thermally annealing the aerogel in air, which improves electrical conductivity, mechanical stability, surface area, and porosity by reopening pores.
The resulting annealed CNT aerogels are highly porous (>99%), electrically conductive (1-2 S/cm), and have a large specific surface area (590
The document discusses the use of nanobioremediation to clean up environmental pollution. It proposes using genetic engineering and nanoparticles to enhance the ability of microorganisms to remediate contaminants. Key points:
1) Nanoparticles and genetic engineering can be used to modify microbial cells to increase their ability to degrade various pollutants like heavy metals and organic compounds through increased enzyme production and substrate specificity.
2) Immobilizing microbial cells and enzymes onto nanoparticles increases their stability and reusability, improving bioremediation efficiency.
3) A radioresistant bacterium, Deinococcus radiodurans, has been genetically engineered to remediate multiple contaminants found in radioactive waste, providing a
A designed surface modification to disperse silica powder into polyurethaneTrang Le
This document describes a method for modifying silica powder nanoparticles through surface grafting of polyurethane (PU) oligomers or short chains to improve dispersion in PU matrices. Silica particles were first modified with 3-isocyanatepropyltriethoxysilane to introduce isocyanate groups on the surface. Further surface-initiated condensation reactions were carried out in steps using diols, triols and diisocyanates to graft PU oligomers of varying lengths. Characterization techniques confirmed grafting and showed the surface density of initial isocyanate groups could be controlled. Hybrid films with modified silica particles dispersed in PU matrices showed improved optical, thermal and mechanical properties compared to films with unmodified particles
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
IRJET- Multi Layered Soil Column Analysis for WastewaterIRJET Journal
This document summarizes a study that analyzed the effectiveness of using a multi-layered soil column system to treat domestic wastewater. The system consists of layers of soil, charcoal, sawdust and iron scraps placed in acrylic tubes. Greywater is passed through the layers, where various physical, chemical and biological processes help treat pollutants. Key pollutants like BOD, COD, nutrients and microbes are reduced as the greywater percolates through the soil mixture and permeable filter layers. The document describes the experimental setup, materials used, treatment mechanisms involved and design of the soil column apparatus used in the study.
The availability of robust superhydrophobic materials with the ability to withstand harsh environments are in high demand for many applications. In this study, we have presented a simple method to fabricate superhydrophobic materials from TiO2 nanotube arrays (TNTAs) and
investigated the resilience of the materials when they are subjected to harsh conditions such as
intense cavitation upon ultrasonication, corrosion in saline water, water-jet impact, and abrasion. The TNTAs were prepared by anodization of Ti foil in buffered aqueous electrolyte containing fluoride ions. The hydrophilic TNTAs were functionalized with octadecylphosphonic acid (ODPA) or
1H, 1H0, 2H, 2H0-perfluorodecyl phosphonic acid (PFDPA) to form a self-assembled monolayer
on the TNTA surface to produce superhydrophobic ODPA@TNTA or PFDPA@TNTA surfaces.
The superhydrophobic ODPA@TNTA and PFDPA@TNTA have contact angles of 156.0+-1.5 and 168+- 1.5, and contact angle hysteresis of 3.0 and 0.8, respectively. The superhydrophobic
ODPA@TNTA and PFDPA@TNTA were subjected to ultrasonication, corrosion in saline water, and water-jet impact and abrasion, and the resilience of the systems was characterized by electrochemical impedance spectroscopy (EIS), contact angle (CA) measurements, diffuse reflectance
Fourier transform infrared spectroscopy (DRIFTS), and field-emission scanning electron microscopy (FESEM). The results presented here show that superhydrophobic ODPA@TNTA and PFDPA@TNTA are robust and resilient under the harsh conditions studied in this work, and indicate the potential of
these materials to be deployed in practical applications.
Investigation Of Hydrogen Production By Using Composite Membrane (Nafion/Zro2...IJERA Editor
In the present study, Composite materials based on perfluorinated cation-exchange membrane incorporating particles of Zirconium and Nafion is synthesized .With this membrane the performance of the electrolysis cell improved considerably at room temperature and atmospheric pressure. In addition, by using catalysts and membranes, the performance of this Composite membrane is studied by varying voltage range with respect to hydrogen yield and at current density 0.1, 0.2, 0.3, 0.4, and 0.5(A cm-2), With a Nafion 115 membrane as a reference electrolyte. Experiments have shown that 99.9% purity of hydrogen Gas is evolved The physicochemical properties of the composite membranes such as thermogravimetric analyzer (TGA), Scanning Electron Microscope (SEM), XRD (X-ray powder diffraction), Fourier transform infrared spectroscopyand and Ion Exchange Capacity is determined. The fabricated composite membranes have shown the significant improvement of all tested properties compared to that of pure Nafion membrane.
Ceramic membrane coating with graphene oxide for tannery wastewater treatmenthunypink
The document summarizes a study on using a graphene oxide coated ceramic membrane for treating tannery wastewater. Key points:
- Tannery wastewater is highly contaminated and poses risks to the environment. A ceramic membrane was coated with graphene oxide using dip coating to treat this wastewater.
- Experiments were conducted at different pressures from 0.7 to 3 bar to evaluate the coated membrane's rejection of contaminants like total solids, salts, and conductivity.
- Results showed the coating improved the membrane's rejection performance. Rejection percentages increased for parameters like total solids, dissolved solids, suspended solids, salinity and conductivity compared to an uncoated membrane.
This document describes the development of a novel carbon nanotube decorated poly(arylene ether nitrile) nanofibrous composite absorbent for efficient removal of methylene blue and congo red dyes. The absorbent was fabricated through decoration of acidified multi-walled carbon nanotubes onto a polydopamine-modified poly(arylene ether nitrile) nanofibrous membrane, followed by co-deposition of tannic acid and carboxylated chitosan. Characterization showed the absorbent had an average pore diameter of 19.21 nm. Adsorption tests found it could achieve maximum capacities of 633 and 589 mg/g for methylene blue and congo red
Mechanical Properties of Concrete with Marine Sand as Partial Replacement of ...IJERA Editor
The process of depleting sources of natural aggregates challenges the production of technically and
environmentally adequate concrete. Alternative material from marine sources is good enough for the
replacement of fine aggregate in the concrete. The material was stockpiled in the open air and no washing,
drying or decontamination process was carried out. Physical and chemical properties of DMS material were
determined. All the materials used in the concrete were selected and tested as per the standard procedures of the
Indian standards. A unique design mix will be done based on the entire material test results. Different mixtures
were produced using DMS in different proportions from 15% to 100% as per the finalized trial of the design
mix. The concrete were submitted to compressive strength testsafter 7, 28 and 90 days of moist curing, as well
as flexure and splitting tensile strength tests for M-25 grade.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
IRJET- Effect of Fly Ash and Nano Calcium Silicates in Clayey Soil Used as Cl...IRJET Journal
This document discusses using a mixture of locally available clayey soil, fly ash, and nano calcium silicate as a potential landfill liner material. Laboratory tests were conducted to analyze the properties of the soil mixtures with varying percentages of fly ash (2-10%) and nano calcium silicate (0.2-1%). The results found that adding 6% fly ash produced the optimum moisture content and maximum dry density for the soil. Additional tests determined that incorporating nano calcium silicate into the soil-fly ash mixture further improved strength characteristics by filling voids and promoting pozzolanic reactions. The study aims to develop an affordable landfill liner material using industrial and local waste products that meets specifications for low hydraulic conductivity and strength.
This document summarizes a study on the effect of environmental degradation on the viscoelastic response of epoxy resins modified with carbon nanotubes (CNTs) and carbon fiber reinforced plastics (CFRPs) made with the modified epoxy. CNTs were added to an epoxy resin at concentrations from 0.1-1% using high-shear mixing. The modified resin was used to make unreinforced cast specimens and CFRPs with a 0.5% CNT content. All specimens were subjected to hydrothermal conditioning. Dynamic mechanical analysis of the conditioned specimens showed degradation of properties like damping and storage modulus for the modified materials compared to unmodified controls.
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward
exploiting alternative energy resources such as solar energy. Here, we
report the successful low-cost and easily accessible synthesis of hybrid
semiconductor@TiO2 nanotube photocatalysts. In order to realize its
maximum potential in harvesting photons in the visible-light range, TiO2
nanotubes have been loaded with earth-abundant, low-band-gap fibrous
red and black phosphorus (P). Scanning electron microscopy− and
scanning transmission electron microscopy−energy-dispersive X-ray
spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV−vis measurements have been performed,
substantiating the deposition of fibrous red and black P on top and
inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular morphology of titania and a vapor-transport technique are utilized to form heterojunctions of P and
TiO2. Compared to pristine anatase 3.2 eV TiO2 nanotubes, the creation of heterojunctions in the hybrid material resulted in
1.5−2.1 eV photoelectrocatalysts. An enhanced photoelectrochemical water-splitting performance under visible light compared
with the individual components resulted for the P@TiO2 hybrids. This feature is due to synergistically improved charge
separation in the heterojunction and more effective visible-light absorption. The electronic band structure and charge-carrier
dynamics are investigated in detail using ultraviolet photoelectron spectroscopy and Kelvin probe force microscopy to elucidate
the charge-separation mechanism. A Fermi-level alignment in P@TiO2 heterojunctions leads to a more reductive flat-band
potential and a deeper valence band compared to pristine P and thus facilitates a better water-splitting performance. Our results
demonstrate effective conversion efficiencies for the nanostructured hybrids, which may enable future applications in
optoelectronic applications such as photodetectors, photovoltaics, photoelectrochemical catalysts, and sensors.
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward exploiting alternative energy resources such as solar energy. Here, we report the successful low-cost and easily accessible synthesis of hybrid semiconductor@TiO2 nanotube photocatalysts. In order to realize its maximum potential in harvesting photons in the visible-light range, TiO2 nanotubes have been loaded with earth-abundant, low-band-gap fibrous red and black phosphorus (P). Scanning electron microscopy– and scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV–vis measurements have been performed, substantiating the deposition of fibrous red and black P on top and inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular …
1. The document describes a study that developed silicone foul-release nanocomposites by incorporating Cu2O nanocubes into polydimethylsiloxane (PDMS) for use as environmentally friendly antifouling coatings.
2. A series of PDMS/Cu2O nanocube composites with different nanofiller concentrations were synthesized via solution casting and characterized. The addition of low amounts of Cu2O nanocubes improved surface properties like contact angle and surface free energy without changing bulk properties.
3. Laboratory assays showed that the nanocomposites with lower surface energy and elastic modulus exhibited less adherence of marine microfouling like bacteria and yeast over 30 days. The best
This document summarizes a research article that synthesized silicon dioxide (SiO2) nano particles using a sol-gel route. The sol-gel process involves hydrolysis and polymerization reactions of metal alkoxides or salts to form a colloidal suspension (sol) that transitions to a gel and then to an oxide network. In this study, tetrahydrofuran and silicic acid were stirred at room temperature for 60 minutes to form a gel. After drying and annealing at 400°C, SiO2 nano powders with an average particle size of ~6nm were obtained. The ratios of starting materials and calcination temperature affected the crystallite size of the particles. The study demonstrated a sol-gel method for
This document discusses a study on poly(vinyl chloride)/layered silicate nanocomposites. The study analyzed the effect of organoclay type (PGV or 1.31PS) and content on the electrical, antibacterial, and oxygen barrier properties of PVC compounds. Key findings include:
1) Dielectric properties (permittivity and loss) of PVC/1.31PS nanocomposites decreased with increasing organoclay content up to 2.5 phr, indicating improved electrical insulation properties, while PVC/PGV increased with content.
2) PVC/1.31PS (2.5 phr) showed significant resistance to Gram-positive and Gram
Vapor growth of binary and ternary phosphorusbased semiconductors into TiO2 n...Pawan Kumar
We report successful synthesis of low band gap inorganic polyphosphide and TiO2 heterostructures with
the aid of short-way transport reactions. Binary and ternary polyphosphides (NaP7, SnIP, and (CuI)3P12)
were successfully reacted and deposited into electrochemically fabricated TiO2 nanotubes. Employing
vapor phase reaction deposition, the cavities of 100 mm long TiO2 nanotubes were infiltrated;
approximately 50% of the nanotube arrays were estimated to be infiltrated in the case of NaP7. Intensive
characterization of the hybrid materials with techniques including SEM, FIB, HR-TEM, Raman
spectroscopy, XRD, and XPS proved the successful vapor phase deposition and synthesis of the
substances on and inside the nanotubes. The polyphosphide@TiO2 hybrids exhibited superior water
splitting performance compared to pristine materials and were found to be more active at higher
wavelengths. SnIP@TiO2 emerged to be the most active among the polyphosphide@TiO2 materials. The
improved photocatalytic performance might be due to Fermi level re-alignment and a lower charge
transfer resistance which facilitated better charge separation from inorganic phosphides to TiO2.
1) Nanocomposite sodalite/ceramic membranes were synthesized via a "pore-plugging" hydrothermal synthesis method for pre-combustion CO2 capture from coal-fired power plants.
2) Characterization of the membranes showed sodalite crystals embedded within the pores of the ceramic membrane support, forming a nanocomposite structure. This results in higher mechanical strength and thermal stability than conventional thin-film membranes.
3) The nanocomposite architecture also allows for defect control by limiting defects to the size of support pore openings, and protects the membrane from damage during use. This makes the membrane a promising material for high performance and cost-effective CO2 capture.
IRJET- Artificial Water Cycle using Paraffin B-WaxIRJET Journal
This document describes an experiment to artificially recreate the natural water cycle using paraffin wax to purify contaminated water. The natural water cycle involves evaporation and condensation of ocean water to distill out impurities. In this experiment, paraffin wax is used as a phase change material inside metal tubes submerged in contaminated water. As the wax melts, it absorbs heat from the sun and increases the evaporation rate of the water. The evaporated water then condenses on a transparent dome structure and is collected as purified water. The experiment was conducted on a small scale in the laboratory as a low-cost alternative to desalination plants. Further improvements could enhance heat transfer and allow application at larger scales.
IRJET- CharactCharacteristic Study on Behaviour of Integral Crystalline Water...IRJET Journal
This document discusses the use of integral crystalline waterproofing concrete where cement is partially replaced with fly ash, GGBS, silica fume, or rice husk ash along with the addition of a crystalline waterproofing agent. Compressive strength tests were performed on concrete cubes at 7, 14, and 28 days that used each replacement material at different percentages along with 2% crystalline waterproofing agent. The results showed that concrete with 10% fly ash replacement and 2% crystalline waterproofing agent had the lowest 28-day compressive strength, while concrete with 20% GGBS replacement and 2% crystalline waterproofing agent had the highest 28-day compressive strength. In conclusion, the addition of crystalline
- The document investigates the hydrogen permeation behavior and effect of annealing on palladium (Pd) and palladium-silver (Pd/Ag) composite membranes prepared by electroless plating.
- Hydrogen flux tests were conducted on the membranes at different temperatures before and after annealing at higher temperatures. The Pd membrane showed a hydrogen flux of up to 4.32E + 01 cm3cm-2min-1 at 723K, while the Pd/Ag membrane had a slightly higher flux of 4.57E + 01 cm3cm-2min-1.
- Annealing the membranes greatly enhanced the hydrogen flux, increasing it by about two-fold for both membranes.
Vapor growth of binary and ternary phosphorus-based semiconductors into TiO 2...Pawan Kumar
We report successful synthesis of low band gap inorganic polyphosphide and TiO2 heterostructures with the aid of short-way transport reactions. Binary and ternary polyphosphides (NaP7, SnIP, and (CuI)3P12) were successfully reacted and deposited into electrochemically fabricated TiO2 nanotubes. Employing vapor phase reaction deposition, the cavities of 100 μm long TiO2 nanotubes were infiltrated; approximately 50% of the nanotube arrays were estimated to be infiltrated in the case of NaP7. Intensive characterization of the hybrid materials with techniques including SEM, FIB, HR-TEM, Raman spectroscopy, XRD, and XPS proved the successful vapor phase deposition and synthesis of the substances on and inside the nanotubes. The polyphosphide@TiO2 hybrids exhibited superior water splitting performance compared to pristine materials and were found to be more active at higher wavelengths. SnIP …
Similar to Robust Polymer Nanocomposite Membranes Incorporating Discrete TiO2 Nanotubes for Water Treatment (20)
Isolated Iridium Sites on Potassium-Doped Carbon-nitride wrapped Tellurium Na...Pawan Kumar
Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by-product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium-doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible-NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core-shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X-ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.
Isolated Iridium Sites on Potassium-Doped Carbon-nitride wrapped Tellurium Na...Pawan Kumar
Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by-product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium-doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible-NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core-shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X-ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.
Isolated Iridium Sites on Potassium-Doped Carbon-nitride wrapped Tellurium Na...Pawan Kumar
Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by-product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium-doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible-NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core-shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X-ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.
Solar-Driven Cellulose Photorefining into Arabinose over Oxygen-Doped Carbon ...Pawan Kumar
Biomass photorefining is a promising strategy to address the energy crisis and transition toward carbon carbon-neutral society. Here, we demonstrate the feasibility of direct cellulose photorefining into arabinose by a rationally designed oxygen-doped polymeric carbon nitride, which generates favorable oxidative species (e.g., O2–, •OH) for selective oxidative reactions at neutral conditions. In addition, we also illustrate the mechanism of the photocatalytic cellulose to arabinose conversion by density functional theory calculations. The oxygen insertion derived from oxidative radicals at the C1 position of glucose within cellulose leads to oxidative cleavage of β-1,4 glycosidic linkages, resulting in the subsequent gluconic acid formation. The following decarboxylation process of gluconic acid via C1–C2 α-scissions, triggered by surface oxygen-doped active sites, generates arabinose and formic acid, respectively. This work not only offers a mechanistic understanding of cellulose photorefining to arabinose but also sets up an example for illuminating the path toward direct cellulose photorefining into value-added bioproducts under mild conditions.
Solar-Driven Cellulose Photorefining into Arabinose over Oxygen-Doped Carbon ...Pawan Kumar
Biomass photorefining is a promising strategy to address the energy crisis and transition toward carbon carbon-neutral society. Here, we demonstrate the feasibility of direct cellulose photorefining into arabinose by a rationally designed oxygen-doped polymeric carbon nitride, which generates favorable oxidative species (e.g., O2–, •OH) for selective oxidative reactions at neutral conditions. In addition, we also illustrate the mechanism of the photocatalytic cellulose to arabinose conversion by density functional theory calculations. The oxygen insertion derived from oxidative radicals at the C1 position of glucose within cellulose leads to oxidative cleavage of β-1,4 glycosidic linkages, resulting in the subsequent gluconic acid formation. The following decarboxylation process of gluconic acid via C1–C2 α-scissions, triggered by surface oxygen-doped active sites, generates arabinose and formic acid, respectively. This work not only offers a mechanistic understanding of cellulose photorefining to arabinose but also sets up an example for illuminating the path toward direct cellulose photorefining into value-added bioproducts under mild conditions.
Solar-Driven Cellulose Photorefining into Arabinose over Oxygen-Doped Carbon ...Pawan Kumar
Biomass photorefining is a promising strategy to address the energy crisis and transition toward carbon carbon-neutral society. Here, we demonstrate the feasibility of direct cellulose photorefining into arabinose by a rationally designed oxygen-doped polymeric carbon nitride, which generates favorable oxidative species (e.g., O2–, •OH) for selective oxidative reactions at neutral conditions. In addition, we also illustrate the mechanism of the photocatalytic cellulose to arabinose conversion by density functional theory calculations. The oxygen insertion derived from oxidative radicals at the C1 position of glucose within cellulose leads to oxidative cleavage of β-1,4 glycosidic linkages, resulting in the subsequent gluconic acid formation. The following decarboxylation process of gluconic acid via C1–C2 α-scissions, triggered by surface oxygen-doped active sites, generates arabinose and formic acid, respectively. This work not only offers a mechanistic understanding of cellulose photorefining to arabinose but also sets up an example for illuminating the path toward direct cellulose photorefining into value-added bioproducts under mild conditions.
Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single...Pawan Kumar
Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer–Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.
Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single...Pawan Kumar
Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer–Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.
Selective Cellobiose Photoreforming for Simultaneous Gluconic Acid and Syngas...Pawan Kumar
Here, we demonstrate the selective cellobiose (building block of cellulose) photoreforming for gluconic acid and syngas co-production in acidic conditions by rationally designing a bifunctional polymeric carbon nitride (CN) with potassium/sulfur co-dopant. This heteroatomic doped CN photocatalyst possesses enhanced visible light absorption, higher charge separation efficiency than pristine CN. Under acidic conditions, cellobiose is not only more efficiently hydrolyzed into glucose but also promotes the syngas and gluconic acid production. Density functional theory (DFT) calculations reveal the favorable generation of •O2− during the photocatalytic reaction, which is essential for gluconic acid production. Consequently, the fine-designed photocatalyst presents excellent cellobiose conversion (>80%) and gluconic acid selectivity (>70%) together with the co-production of syngas (~56 μmol g-1 h-1) under light illumination. The current work demonstrates the feasibility of biomass photoreforming with value-added chemicals and syngas co-production under mild condition.
Selective Cellobiose Photoreforming for Simultaneous Gluconic Acid and Syngas...Pawan Kumar
Here, we demonstrate the selective cellobiose (building block of cellulose) photoreforming for gluconic acid and syngas co-production in acidic conditions by rationally designing a bifunctional polymeric carbon nitride (CN) with potassium/sulfur co-dopant. This heteroatomic doped CN photocatalyst possesses enhanced visible light absorption, higher charge separation efficiency than pristine CN. Under acidic conditions, cellobiose is not only more efficiently hydrolyzed into glucose but also promotes the syngas and gluconic acid production. Density functional theory (DFT) calculations reveal the favorable generation of •O2− during the photocatalytic reaction, which is essential for gluconic acid production. Consequently, the fine-designed photocatalyst presents excellent cellobiose conversion (>80%) and gluconic acid selectivity (>70%) together with the co-production of syngas (~56 μmol g-1 h-1) under light illumination. The current work demonstrates the feasibility of biomass photoreforming with value-added chemicals and syngas co-production under mild condition.
Selective Cellobiose Photoreforming for Simultaneous Gluconic Acid and Syngas...Pawan Kumar
Here, we demonstrate the selective cellobiose (building block of cellulose) photoreforming for gluconic acid and syngas co-production in acidic conditions by rationally designing a bifunctional polymeric carbon nitride (CN) with potassium/sulfur co-dopant. This heteroatomic doped CN photocatalyst possesses enhanced visible light absorption, higher charge separation efficiency than pristine CN. Under acidic conditions, cellobiose is not only more efficiently hydrolyzed into glucose but also promotes the syngas and gluconic acid production. Density functional theory (DFT) calculations reveal the favorable generation of •O2− during the photocatalytic reaction, which is essential for gluconic acid production. Consequently, the fine-designed photocatalyst presents excellent cellobiose conversion (>80%) and gluconic acid selectivity (>70%) together with the co-production of syngas (~56 μmol g-1 h-1) under light illumination. The current work demonstrates the feasibility of biomass photoreforming with value-added chemicals and syngas co-production under mild condition.
Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single...Pawan Kumar
Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer–Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.
Recent advancements in tuning the electronic structures of transitional metal...Pawan Kumar
The smooth transition from finite non-renewables to renewable energy conversion technologies will require efficient electrocatalysts which can harness intermittent energies to store in the form of chemical bonds. The oxygen evolution reaction (OER) impedes the widespread usage of water electrolyzers to convert H2O into H2 and persists as a bottleneck, including other energy conversion devices with sluggish four H+/e− kinetics. In this context, designing highly active and stable catalysts capable of driving a lower overpotential in the OER to produce continuous hydrogen (H2) is a primary demanded. This chapter discussed the mechanism of the OER in conventional adsorbate oxygen and lattice oxygen participation in transition metal oxides (TMOs). Further, the influences of surface engineering, doping, and defects in the TMOs and understanding the electronic structure to screen electrodes towards the structure–activity relationship are highlighted. Specifically, the adsorption strength of O 2p is understood in detail as its binding ability over the surface of TMOs can be correlated directly to the OER activity. The iterative development of TMOs in terms of understanding electronic structural attributes is essential for the commercial deployment of energy conversion technologies. The comprehensive outlook of this chapter investigates thoroughly how TMOs can be used as significant materials for the OER in the near future.
Hole transport materials (HTMs) have a significant impact on the effectiveness of organic electronic devices; therefore, we present a molecular architecture of pyrazino[2,3-g]quinoxaline (PQ10)-based room-temperature organic liquid crystalline semiconductor (OLCS) as an alternative HTM. The PQ10 compound exhibits three different rectangular columnar (Colr) phases offering an impressive hole mobility of 8.8 × 10−3 cm2V−1s−1 which is found to be dexterous than most of existing polymeric hole transport materials. The charge transport mechanism is governed by the hole polarons hopping through H-aggregates of the PQ10 molecules and the hole mobility remains nearly constant throughout the mesophase range, but it decreases with increasing applied electric field. The current-voltage characteristics of the PQ10 have also been investigated in all three Colr phases and explained via the Poole-Frenkel conduction mechanism. The dielectric spectroscopy has been eventually carried out to understand the nature of dielectric permittivity and conductivity as a function of temperature and a correlation is established between the molecular architecture of the Colr phases and aforementioned physical properties. Solar cell simulation has been additionally performed to demonstrate that the PQ10 material can be a better choice as HTM for organic electronics and photovoltaic applications.
Multifunctional carbon nitride nanoarchitectures for catalysisPawan Kumar
Catalysis is at the heart of modern-day chemical and pharmaceutical industries, and there is an urgent demand to develop metal-free, high surface area, and efficient catalysts in a scalable, reproducible and economic manner. Amongst the ever-expanding two-dimensional materials family, carbon nitride (CN) has emerged as the most researched material for catalytic applications due to its unique molecular structure with tunable visible range band gap, surface defects, basic sites, and nitrogen functionalities. These properties also endow it with anchoring capability with a large number of catalytically active sites and provide opportunities for doping, hybridization, sensitization, etc. To make considerable progress in the use of CN as a highly effective catalyst for various applications, it is critical to have an in-depth understanding of its synthesis, structure and surface sites. The present review provides an overview of the recent advances in synthetic approaches of CN, its physicochemical properties, and band gap engineering, with a focus on its exclusive usage in a variety of catalytic reactions, including hydrogen evolution reactions, overall water splitting, water oxidation, CO2 reduction, nitrogen reduction reactions, pollutant degradation, and organocatalysis. While the structural design and band gap engineering of catalysts are elaborated, the surface chemistry is dealt with in detail to demonstrate efficient catalytic performances. Burning challenges in catalytic design and future outlook are elucidated.
Production of Renewable Fuels by the Photocatalytic Reduction of CO2 using Ma...Pawan Kumar
The photo-reductive performance of natural ilmenite was boosted and the production of renewable fuels from the reduction of CO2 was enhanced by doping the natural mineral with magnesium. The doping was achieved by high energy ball milling in the presence of MgO and Mg(NO3)2. The photo-reduction of CO2 in aqueous solution led to the evolution of H2, CH4, C2H4, and C2H6, and the insertion of Mg in the structure of ilmenite enabled increases of up to 1245% in the fuel production yield, reaching total production of 210.9 µmol h-1 gcat-1. Displacements of the conduction band to more negative potentials were evidenced for the samples doped with magnesium. Indirect effects such as increases in the valence band maximum, and the introduction of intermediate energy levels were also evidenced through the measurement of the crystallite size and the determination of the band structure of the materials. Mott-Schottky analyses of the samples showed the n-type nature of the semiconductor materials and enabled the estimation of the density of charge carriers, which strongly influenced the photocatalytic performance. The strong potential of the application of natural ilmenite in gas phase artificial photosynthesis was proved by the evaluation of CO2 reduction in gas conditions, which allowed the enhancement in the selectivity and significantly increased the production of CH4 as compared to aqueous solution, reaching an important yield of CH4 of 16.1 µmol h-1 gcat-1.
Nanoengineered Au-Carbon Nitride Interfaces Enhance PhotoCatalytic Pure Water...Pawan Kumar
Photocatalytic pure water splitting using solar energy is one of the promising routes to produce sustainable green hydrogen (H2). Tuning the interfacial active site density at catalytic heterojunctions and better light management are imperative to steer the structure-activity correlations to enhance the photo-efficiency of nanocomposite photocatalysts. Herein, we report the decoration of nitrogen defects-rich carbon nitride CN(T) with metallic Au nanostructures of different morphologies and sizes to investigate their influence on the photocatalytic hydrogen evolution reactions (HER). The CN(T)-7-NP nano-heterostructure comprises Au nanoparticles (NPs) of ~7 nm and thiourea-derived defective CN exhibits an excellent H2 production rate of 76.8 µmol g–1 h–1 from pure water under simulated AM 1.5 solar irradiation. In contrast to large-size Au nanorods, the high activity of CN(T)-7-NP was attributed to their strong localized surface plasmon resonance (LSPR) mediated visible absorption and interfacial charge separation. The surface ligands used to control Au nanostructures morphology were found to play a major role in the stabilization of NPs and improve interfacial charge transport between Au NPs and CN(T). First-principles calculations revealed that defects in CN and Au-CN interfacial sites in these nanocomposites facilitate the separation of e-/h+ pairs after light excitation and provide lower energy barrier pathways for H2 production by photocatalytic water splitting.
Nanoengineered Au-Carbon Nitride Interfaces Enhance Photo-Catalytic Pure Wate...Pawan Kumar
Photocatalytic pure water splitting using solar energy is one of the promising routes to produce sustainable green hydrogen (H2). Tuning the interfacial active site density at catalytic heterojunctions and better light management are imperative to steer the structure-activity correlations to enhance the photo-efficiency of nanocomposite photocatalysts. Herein, we report the decoration of nitrogen defects-rich carbon nitride CN(T) with metallic Au nanostructures of different morphologies and sizes to investigate their influence on the photocatalytic hydrogen evolution reactions (HER). The CN(T)-7-NP nano-heterostructure comprises Au nanoparticles (NPs) of ~7 nm and thiourea-derived defective CN exhibits an excellent H2 production rate of 76.8 µmol g–1 h–1 from pure water under simulated AM 1.5 solar irradiation. In contrast to large-size Au nanorods, the high activity of CN(T)-7-NP was attributed to their strong localized surface plasmon resonance (LSPR) mediated visible absorption and interfacial charge separation. The surface ligands used to control Au nanostructures morphology were found to play a major role in the stabilization of NPs and improve interfacial charge transport between Au NPs and CN(T). First-principles calculations revealed that defects in CN and Au-CN interfacial sites in these nanocomposites facilitate the separation of e-/h+ pairs after light excitation and provide lower energy barrier pathways for H2 production by photocatalytic water splitting.
Cooperative Copper Single Atom Catalyst in Two-dimensional Carbon Nitride for...Pawan Kumar
This document summarizes a study that investigated copper single atom catalysts supported on two-dimensional carbon nitride materials for enhancing the electrochemical reduction of carbon dioxide to methane. Specifically, copper ions were incorporated into the nanoporous structures of poly(heptazine imide) and poly(triazine imide) using a room temperature ion exchange process. This allowed for high loading densities of isolated copper sites. The proximity of copper atoms within the nanopores was found to enable cooperative catalysis that boosted the selectivity and efficiency of the multi-electron conversion of CO2 to CH4. Density functional theory calculations helped explain how the copper-copper distance and coordination environment modulated the binding of reaction intermediates. Optimized copper loading in the
Bioinspired multimetal electrocatalyst for selective methane oxidationPawan Kumar
Selective partial electrooxidation of methane (CH4) to liquid oxygenates has been a long-sought goal. However, the high activation energy of C–H bonds and competing oxygen evolution reaction limit product selectivity and reaction rates. Inspired by iron (IV)-oxo containing metalloenzymes’ functionality to activate the C–H bond, here we report on the design of a copper-iron-nickel catalyst for selective oxidation of CH4 to formate via a peroxide-assisted pathway. Each catalyst serves a specific role which is confirmed via electrochemical, in situ, and theoretical studies. A combination of electrochemical and in situ spectroelectrochemical studies revealed that H2O2 oxidation on nickel led to the formation of active oxygen species which trigger the formation of iron (IV) at low voltages. Density functional theory analysis helped reveal the role of iron (IV)-oxo species in reducing the activation energy barrier for CH4 deprotonation and the critical role of copper to suppress overoxidation. Our multimetal catalyst exhibits a formate faradaic efficiency of 42% at an applied potential of 0.9 V versus a reversible hydrogen electrode.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
Robust Polymer Nanocomposite Membranes Incorporating Discrete TiO2 Nanotubes for Water Treatment
1. Nanomaterials 2019, 9, 1186; doi:10.3390/nano9091186 www.mdpi.com/journal/nanomaterials
Article
Robust Polymer Nanocomposite Membranes
Incorporating Discrete TiO2 Nanotubes
for Water Treatment
Najia Mahdi 1, Pawan Kumar 1, Ankur Goswami 1,2, Basil Perdicakis 3,, Karthik Shankar 1,*
and Mohtada Sadrzadeh 4,*
1 Department of Electrical and Computer Engineering, University of Alberta, Edmonton,
AB T6G1H9, Canada
2 Department of Materials Science and Engineering, Indian Institute of Technology Delhi,
New Delhi 110016, India
3 Suncor Energy Inc., P.O. Box 2844, 150-6th Ave. SW, Calgary, AB T2P3E3, Canada
4 Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G1H9, Canada
* Correspondence: kshankar@ualberta.ca (K.S.); sadrzade@ualberta.ca (M.S.);
Tel.: +1-780-492-1354 (K.S.); +1-780-492-8745 (M.S.)
Received: 27 June 2019; Accepted: 13 August 2019; Published: 21 August 2019
Abstract: Polyethersulfone (PES) is a polymeric permeable material used in ultrafiltration (UF)
membranes due to its high thermomechanical and chemical stability. The hydrophobic nature of
PES membranes renders them prone to fouling and restricts the practical applications of PES in the
fabrication of water treatment membranes. The present study demonstrates a non-solvent-induced
phase separation (NIPS) approach to modifying PES membranes with different concentrations of
discrete TiO2 nanotubes (TNTs). Zeta potential and contact angle measurements showed enhanced
hydrophilicity and surface negative charge in TNTs/PES nanocomposite membranes compared to
unmodified PES membranes. To discern the antifouling and permeation properties of the TNTs/PES
membranes, steam assisted gravity drainage (SAGD) wastewater obtained from the Athabasca oil
sands of Alberta was used. The TiO2 modified polymer nanocomposite membranes resulted in a
higher organic matter rejection and water flux than the unmodified PES membrane. The addition of
discrete TNTs at 1 wt% afforded maximum water flux (82 L/m2 h at 40 psi), organic matter rejection
(53.9%), and antifouling properties (29% improvement in comparison to pristine PES membrane).
An enhancement in fouling resistance of TNTs/PES nanocomposite membranes was observed in
flux recovery ratio experiments.
Keywords: superhydrophilic nanotubes; electrochemical anodization; blend membranes;
asymmetric polysulfone
1. Introduction
Water sources, such as lakes, groundwater, and rivers, have been contaminated by industrial
waste disposal directly or indirectly [1]. The coastal areas of seas and oceans have also witnessed a
dramatic increase in contaminants [2]. The shortage of clean water continues to increase due to which
improved water usage efficiency is of paramount importance. Many industrial processes that use
steam production in boilers are completely reliant on the supply of fresh water. Therefore, it is
important to treat wastewater using energy efficient and robust techniques to ensure a continuous
supply of fresh water. Various methods have been explored for water recycling that are both more
energy efficient and environmentally sustainable [3]. Non-reactive interfacial interaction between a
solid surface and aqueous medium, i.e., sorption and filtration based on microstructure,
electrostatics, dispersion forces, etc., can be utilized for the cost-effective and facile purification of
2. Nanomaterials 2019, 9, 1186 2 of 18
water [4]. Filtration using polymeric membranes for wastewater has seen increased adoption recently
due to cost efficiency, low energy consumption, reliability, and ease of contaminant removal without
using harmful products and no phase change at room temperature operations in comparison to other
methods of water recycling [5–9].
Polymers are economical materials that can be used for large-scale membrane fabrication and
are easy to modify as needed [9–13]. Polyethersulfone (PES) is a commonly used polymeric material
for filtration applications due to its excellent thermomechanical, chemical, and contaminant
separation properties. However, the hydrophobicity of PES results in poor performance of membrane
which could hinder its anti-fouling properties negating many of its advantages during the filtration
process [12]. Such poor anti-fouling properties have a detrimental effect on the permeation properties
which causes a decrease in lifespan of the membrane resulting in an increase of operation cost [14].
Surface modified ultrafiltration (UF) membranes have been explored significantly to enhance the
anti-fouling properties of the PES membrane by increasing the hydrophilicity and decreasing the
surface charge as these parameters can have significant positive effects on the initial stages of fouling
[15,16]. A variety of methods such as chemical grafting [17], the addition of antifouling blending
materials [13], surface coating [18] and plasma treatment [19] have been explored to fabricate anti-
fouling surfaces.
Currently, much research and development are underway on the surface modification of
membranes by the incorporation of hydrophilic nanoparticles into the PES polymer to fabricate
polymer nanocomposite membranes with higher surface hydrophilicity, increased anti-fouling
properties and enhanced separation performance [20,21]. Numerous studies investigated the effect
of various nanostructures including porous nanostructures such as carbon nanotubes (CNTs),
cellulose nanocrystals, graphene oxide nanoplates, zeolites, mesoporous silica, and nonporous metal
oxide nanoparticles, such as TiO2, MgO, ZnO, Al2O3, ZrO2, Fe2O3, and SiO2, on the structural
morphology, transport properties, and surface characteristics of the fabricated nanocomposite
membranes [22–28]. Atomic layer deposition (ALD) of metal oxides on the polymeric membrane is
an approach that provides hydrophilicity and antifouling properties to the filtration membranes [29].
Yang et al. reported that ~10 nm TiO2 and SnO2-deposited via ALD on polyvinylidene fluoride
(PVDF) membranes exhibit excellent anti-crude-oil fouling performance [30].
Recently, TiO2 nanostructures have received significant attention as membrane additives due to
their stability, non-toxicity, self-cleaning ability, and natural abundance [31,32].
TiO2 nanotubes are hollow annular structures synthesized by the electrochemical anodization
process that can be tailored to have cylindrical or square pores, with tunable diameters from ~10–
1000 nm [33,34]. These nanotubes have a high effective surface area for interfacial adhesion to the
polymer due to nanoscopic wall roughness, and the availability of both inner and outer tube walls.
In the present study, the effect of incorporation of different concentrations of discrete TiO2 NTs on
the physicochemical characteristics and permeation properties of the polyethersulfone (PES)
membranes are reported. In addition, bare TiO2 nanotubes are superhydrophilic and can be rendered
superhydrophobic or amphiphobic if needed by suitable surface functionalization [35,36].
The non-solvent-induced phase separation (NIPS) method was used to fabricate TiO2 NT
incorporated PES membranes. The morphology of structures, chemical compositions and surface
properties of the synthesized membranes were investigated by field emission scanning electron
microscopy (FESEM), atomic force Microscopy (AFM), Fourier-transform infrared spectroscopy
(FTIR), surface zeta potential, and water contact angle measurements. Water flux, organic matter
rejection, and fouling resistance of the TiO2 NTs incorporated PES membranes were studied using
both real and synthetically-produced water, and were compared with unmodified PES membranes.
2. Materials and Methods
2.1. Chemical and Reagents
The ultrafiltration membranes were made using the PES polymer with a molecular weight of 58
kDa obtained from BASF (Ludwigshafen, Germany). PVP (molecular weight, MW: 360 kDa) was
3. Nanomaterials 2019, 9, 1186 3 of 18
procured from Sigma Aldrich (St. Louis, MO, USA) and used as an additive. Potassium chloride (KCl)
and N,N-dimethylacetamide (DMA) were purchased from Fisher Scientific (Waltham, MA, USA).
The discrete TiO2 NTs were synthesized using an electrochemical anodization process followed by
sonication for discretization. Diethylene glycol (DEG) and ammonium fluoride (NH4F) were
purchased from Sigma Aldrich to be used as an electrolyte in electrochemical anodization.
Octadecylphosphonic acid (ODPA) to functionalize discrete nanotubes was also indented from
Sigma Aldrich. An industrial wastewater, produced from steam-assisted gravity drainage (SAGD) in
the Athabasca oil sands industry (AB, Canada) was used for the membrane permeation and fouling
characteristics tests. The produced water is the feed water to the warm lime softener (WLS) of current
SAGD water treatment facilities.
2.2. Preparation of TiO2 NTs/PES Membranes
The preparation of TiO2 NTs/PES membranes consisted of two steps. The first step includes
synthesis of TiO2 NTs via an electrochemical anodization process in DEG based electrolyte using a
two-electrode electrochemical cell as shown in Figure 1. The synthesized TiO2 NTs on foil were
annealed in a furnace at 500 °C for 3 h followed by functionalization with 1 mM ODPA solution
overnight (Figure 2). The TiO2 NTs were discretized in 8 mL DMA using a probe sonicator. Different
concentrations of discrete NT solutions were made to test the effect of concentration of nanomaterials
on PES membrane structure and permeation properties.
The second step, which is shown in Figure 3, was to fabricate TiO2 NTs/PES nanocomposite
membranes. First, a casting solution was prepared by dissolving desired amounts of PES pellets,
discrete TiO2 NTs and PVP in DMA solvent. In this work, to produce porous polymer films,
homogeneously doped polymer solutions were prepared by mixing DMA with 14 wt% PES, 2 wt%
PVP, and various ratios of discrete TiO2 NTs to polymer (1, 0.5, and 0.25 wt%). Next, a probe sonicator
was used to disperse the discrete TiO2 NTs in DMA uniformly. PVP and PES mixture was then added
to the discrete TiO2 NT/DMA solution and stirred overnight at 100 rpm. The obtained mixture, which
is also called dope solution, was kept at room temperature for 24 h to remove air bubbles from the
casting solution and to produce a defect-free membrane. A film applicator (Gardco, MICROM II,
Pompano Beach, FL, USA) with a clearance gap of 190 μm and a casting speed of 5 mm/s was used
to cast the solution on a flat glass surface. The film was then immersed in DI water and the membrane
formation was completed after 24 h by liquid-liquid demixing.
Figure 1. Electrochemical anodization process used to form TiO2 NTs.
4. Nanomaterials 2019, 9, 1186 4 of 18
Figure 2. Discrete TiO2 NT synthesis, functionalization, and discretization methods explained.
Figure 3. Fabrication process of TiO2 NTs/PES nanocomposite membranes.
2.3. Measurements of Porosity and Pore Size
The average pore size of the membrane was measured using the following expression below
which was proposed by Guerout–Elford–Ferry [37]:
𝑟 =
(2.9 − 1.75𝜀)8𝜂𝑙𝑄
𝜀𝐴𝛥𝑃
(1)
where Q is the permeate volumetric flow rate (m3/s), η is the water viscosity which is 8.9 × 10−4 Pas at
25 °C, and ΔP is the transmembrane pressure (Pa). The applied transmembrane pressures in this
study were 10, 20, 30, and 40 psi.
Average porosity of membranes which is the ratio of total pore volume to the volume of the
membrane was calculated using the gravimetric method [18]. The following equation was used to
calculate the porosity of a membrane. To calculate the average porosity of each membrane the
measurements were repeated three times.
𝜀 =
𝑤 − 𝑤
𝐴𝑙𝜌
(2)
where w1 and w2 are mass of wet and dry membranes (g) respectively, ρ is the water density (0.997
g/cm3 at 25 °C), l is the membrane thickness (cm), and A is the surface area (cm2) of the membrane.
5. Nanomaterials 2019, 9, 1186 5 of 18
2.4. Pure Water Flux Measurement
A dead-end filtration cell setup consisted of a membrane with an area of 41.8 cm2 and a dead-
end stirred cell (Millipore Amicon Ultra, UFSC40001, Burlington, MA, USA) with a capacity of 400
mL. To monitor and record the permeate water flux over time, a digital balance (ME 4002, Mettler
Toledo, Columbus, OH, USA) connected to a computer was employed. Various transmembrane
pressures were applied using the pressurized nitrogen gas. The solution in the dead-end cell, in this
case, the deionized (DI) water was stirred at a rate of 80 rpm. The equation below was used to
calculate the water flux (J0):
𝐽 =
𝑊
𝐴𝛥𝑡
(3)
where A is the membrane effective area (m2), W is the mass of the permeate water (kg), and t is the
permeation time (h).
2.5. Fouling Tests
The fouling tests consisted of a three-step experimental procedure. The pure water flux, JW1, was
first measured. The, JWF, water flux during the filtration of WLS inlet water, was then recorded. Lastly,
the pure water filtration after hydraulic washing of the membrane surface with DI water for 15 min
was performed and the pure water flux of the cleaned membrane JW2 was measured again. Based on
these fouling tests, the fouling evaluation parameters namely total flux decline ratio (DRt), the sum
of the reversible flux decline ratio (DRr), irreversible flux decline ratio (DRir), and flux recovery ratio
(FRR) were calculated using the equations below [38]:
𝐷𝑅 = 1 −
𝐽
𝐽
(4)
𝐹𝑅𝑅 =
𝐽
𝐽
(5)
𝐷𝑅 =
(𝐽 𝐽 )
𝐽
(6)
𝐷𝑅 = 1 −
𝐽
𝐽
(7)
2.6. Total Organic Carbon Estimation
The total organic carbon (TOC) in the WLS inlet water was measured using a TOC analyzer
(Shimadzu, Kyoto, Japan, model TOC-V; detection range 3–25,000 mg/L). The TOC analyzer
measures the level of the organic contaminants or organic molecules in purified water and in this
work the concentration of organic carbon atoms covalently bonded in the organic molecules of the
PES based membranes was detected by the TOC analyzer. This parameter can be used to test the
efficiency of the treatment process. The rejection of the organic matter can also be calculated using
the measured TOC concentrations of the permeate (Cp) and feed (CF) solutions. The rejection was
calculated using the equation below:
𝑅 = 1 −
𝐶
𝐶
× 100 (8)
2.7. Chemical Composition Test (FTIR)
To verify the functionalization of titanium nanotube arrays (TNTAs) with ODPA, the IR active
vibrations were recorded on a Digilab (Varian, Palo Alto, CA, USA) FTS 7000 FT-Infrared
Spectrophotometer equipped with a UMA 600 Microscope and ZnSe ATR accessory. The sample was
6. Nanomaterials 2019, 9, 1186 6 of 18
scratched from the surface and deposited directly on the ZnSe crystal and nitrogen gas flow was
maintained through the ATR assembly. The spectra were accumulated by averaging 64 scans in the
frequency range of 850–4000 cm−1.
2.8. X-Ray Photoelectron Spectroscopy (XPS)
X-ray photoelectron spectroscopy (XPS) was used to determine the surface and subsurface (up
to ~10 nm) chemical composition and oxidation state of materials using an Axis-Ultra, Kratos
Analytical Limited instrument (Trafford Park, Manchester, UK) equipped with a monochromatic Al-
Kα source (15 kV, 50 W) with photon energy of 1486.7 eV under ultrahigh vacuum (~10−8 Torr). The
binding energy of adventitious carbons C1s peak at ≈ 284.8 eV was used as standard (carbon
correction) to assign the peak of other elements. The raw spectra in vms format were deconvoluted
into various peak components using CasaXPS software (version 2.3.22) and exported data was
plotted in origin 2018.
2.9. Surface Properties (Wettability and Surface Charge)
Surface wetting characteristics of the fabricated membranes with various concentrations of
discrete TiO2 NTs were measured using FTA-200 contact angle analyzer (First Ten Ångstroms,
Portsmouth, VA, USA). DI water was used as a drop method to measure the contact angle. The lower
the wettability of the membrane, the higher is the contact angle.
The Surpass3 zeta potential analyzer (Anton Paar GmbH, Graz, Austria) was used to analyze
the charging behavior of the membrane surface when in contact with a liquid such as DI water. The
surface zeta potential is derived from a flow of potential which arises from the interaction between
the motions of liquid relating to the solid surface. The zeta potential values were obtained using
various pH values (5, 6, 7, and 8) at 25 °C using 0.001 M KCl solution.
2.10. Membrane Morphology Study
The morphologies and cross-sections of the dried membranes were studied using the field
emission scanning electron microscopy (Hitachi S-4800 Field Emission SEM, FE-SEM, Tokyo, Japan).
The conductivity of the membranes was improved by sputtering 10 nm of gold on the surface of the
membrane using Denton Gold Sputterer Unit (for SEM). A high vacuum with 5 kV/20 μA condition
was used to image the cross-sectional structure of the prepared nanocomposite membranes.
2.11. Atomic Force Microscopy
Atomic force microscopy (AFM, Bruker, The Dimension Fast Scan Atomic Force Microscope,
Santa Barbara, CA, USA) was used to image the surface topography of the TiO2 NTs/PES
nanocomposite membrane.
3. Results
3.1. FTIR Measurement Results
A vibrational spectrum of ODPA monolayer functionalized TiO2 nanotubes was collected to
validate the successful chemical functionalization of TiO2 NTs surface with ODPA molecules (Figure
4a). The FTIR spectrum of ODPA functionalized TiO2 exhibits a characteristic IR absorption band at
2848 and 2917 cm−1 due to symmetric and anti-symmetric C–H stretching vibrations of CH2 in alkyl
chain of ODPA [35,36,39]. The IR peak at 3019 cm−1 was derived from C–H stretch of terminal methyl
(–CH3) groups. Further, the peak observed at 3320 and 1605 cm–1 was assigned to O–H stretch and
bending vibration of surface adsorbed water, respectively. Additionally, various peaks
corresponding to symmetric and asymmetric bending vibration of CH2 and CH3 groups in ODPA
were observed at 1492 cm−1 (CH2 + CH3 bend), 1450 cm−1 (CH2 in-plane bend) and 906 cm−1 (C–H out
of plane bend) confirming the presence of ODPA molecule on the surface of TiO2 nanotubes. The IR
spectrum of ODPA functionalized TNTAs in the frequency range 850–1300 cm−1 shows various IR
7. Nanomaterials 2019, 9, 1186 7 of 18
bands at 1265, 1152, 1065 and 1027 cm−1 assigned to P=O vibration, PO3 asymmetric stretch, PO3
symmetric stretch and P–O–(H) symmetric stretch respectively. The presence of these IR bands
clearly demonstrates successful chemical functionalization of TNTA with OPDA via the reaction
between the –OH group on the surface of TiO2 and the phosphonate group (–H2PO4) on ODPA to
form a phosphonate ester linkage (ROPO2–). TiO2 nanotubes were functionalized with the 18-carbon
long ODPA to improve the monodispersity of the discrete TiO2 NTs in DMA (since the long alkyl
chains prevent agglomeration of individual nanotubes). It is also well-known that
organophosphonate monolayers bind very strongly to TiO2 surfaces and are not vulnerable to
hydrolytic desorption [40].
Figure 4. (a) FTIR spectra of ODPA functionalized TiO2 NTs; (b) XPS elemental survey scan of ODPA
functionalized TiO2 nanotubes.
3.2. XPS Results
The oxidation state and surface chemical attributes of ODPA functionalized TiO2 nanotubes
were determined using X-ray photoelectron microscopy (XPS) (Figures 4b and 5a–d). The appearance
of C1s, O1s, Ti2p, P2p peaks in XPS elemental survey scan of ODPA functionalized TiO2 nanotubes
demonstrate successful functionalization of TiO2 nanotubes with carbon and phosphorous rich
organic molecules. The signal intensity of C1s peak was much higher, agreeing with a high
concentration of carbon at the surface of TiO2 due to better coverage with ODPA monolayer (Figure
5b). High-resolution XPS spectra (HR-XPS) of ODPA functionalized TiO2 nanotubes in the Ti2p
region show two peaks components located at a binding energy (BE) 458.8 and 464.6 eV, originated
due to Ti2p3/2 and Ti2p1/2 peak components of the Ti4+ state in the TiO2 crystal lattice (Figure 5a) [41].
The peak separation of 5.8 eV between Ti2p3/2 and Ti2p1/2 peaks and their respective positions validate
the O2– coordinated Ti4+ in tetragonal anatase phase TiO2 [42]. Core-level HR-XPS spectra of ODPA
8. Nanomaterials 2019, 9, 1186 8 of 18
functionalized TiO2 nanotubes in O1s region can be deconvoluted into three peak components
centered at BE ≈ 530.4, 531.5 and 532.7 eV (Figure 5b). The peak component at BE value 530.4 eV was
originated from the contribution from Ti-coordinated oxygen atoms (O2−–Ti4+ forming TiO6
octahedron) present in the crystal lattice of TiO2 and P=O of surface-adsorbed ODPA molecule while
an intense peak at BE ≈ 531.5 eV was corroborated to non-lattice adventitious oxygen atoms (–OH
groups) and P–O oxygen of ODPA molecule (Figure 5b) [35,43]. Relatively small peak component at
532.7 eV was assigned to adventitious carbon bonded oxygen atoms (C=O). Deconvoluted HR-XPS
spectra of ODPA functionalized TiO2 nanotubes in the C1s region gave two peak components, at
284.8 and 286.3 eV (Figure 5c). The major peak component at 284.8 eV originated from sp3 hybridized
carbon atoms composing the alkyl chain of ODPA while the less intense shoulder peak at 286.3 eV
was arose from the contribution of C–OH/C–P type carbon atoms [1,44]. Additionally, a single peak
at BE ≈134.1 eV, in the HR-XPS of ODPA-grafted TiO2 nanotubes in the P2p region was assigned to
phosphorous in the phosphonate group (P–O) bonded to TiO2 and confirms successful grafting of
ODPA on TiO2’s surface (Figure 5d) [45].
Figure 5. Core-level HR-XPS spectra of ODPA functionalized TiO2 nanotubes in (a) Ti2p region; (b)
O1s region; (c) C1s region; and (d) O1s region.
3.3. Surface and Cross-Section Morphology
The membranes were immersed in liquid nitrogen for a few seconds to get a clear cut before
preparing the samples for the internal cross-sectional imaging. The images of the unmodified PES
membrane and the TiO2 NTs incorporated PES membranes are presented in Figure 6 for a
comparison. The PES membranes used for microfiltration (MF) and UF purposes have a common
trait which is a porous finger-type asymmetric structure consisting of macrovoids and a top dense
skin layer [46]. Figure 6 shows this very clearly in all the membrane cross-sectional images. According
to Figure 6, the addition of discrete TiO2 NTs to the unmodified PES membrane decreased the
thickness of the membrane. However, the average skin thickness of the membranes increased as the
concentration of discrete TiO2 NTs increased. A possible explanation is that the addition of the
discrete NTs slows down the solvent/anti-solvent exchange rate in the coagulation bath and this
9. Nanomaterials 2019, 9, 1186 9 of 18
causes the formation of thinner membranes with a thicker skin layer due to the entrapment of more
discrete TiO2 NTs at the top surface during phase separation [38]. The discrete TiO2 NTs tend to
enhance thermodynamic instability of the casting solution that accelerates the exchange of solvent
and non-solvent [46]. The additional volume of TiO2 nanotubes, together with the existence of some
portion of the hollow internal nanotube that is not infiltrated by the polymer, is expected to produce
swelling of the polymer film by hydrophilic nanotubes before its solidification, thus allowing more
non-solvent to flow into the casting film during NIPS process which, in turn, tends to increase the
thickness of the membrane. However, an increase in the viscosity of the casting solution due to
addition of discrete TiO2 NTs, together with the excellent miscibility of the PDPS-coated TiO2 NTs
with PES, reversed these effects. As a result, the mutual diffusivities between non-solvent and solvent
were reduced causing a decrease in the membrane thickness.
Figure 6. The cross-sectional SEM images of pristine PES and TiO2 NTs/PES nanocomposite
membranes (a–c); pristine PES membrane (d–f); 0.25% TiO2/PES membrane (g–i); 0.5% TiO2/PES
membrane; and (j–l) 1% TiO2/PES membrane.
3.4. Atomic Force Microscopy (AFM)
Roughness is a direct metric of surface topography which can be measured with AFM.
According to the images in Figure 7, the surface roughness increased with increasing the
concentration of discrete TiO2 NTs in PES membranes. The surface roughness of pristine PES, 0.25%
TiO2/PES, 0.5% TiO2/PES, and 1% TiO2/PES were measured to be 57.1, 83.3, 121, and 133 nm,
10. Nanomaterials 2019, 9, 1186 10 of 18
respectively. The PES membrane with 1% discrete TiO2 NTs had the highest surface roughness. This
membrane also had the lowest contact angle meaning that a part of improved wettability of
nanocomposite membranes can be attributed to the increased roughness. According to the Wenzel
equation, a membrane that is slightly hydrophilic becomes more hydrophilic as the surface roughness
increases. In addition, based on Table 1, 1% TiO2/PES membrane was more negatively charged (−32.0
± 0.6 mV) which proves the intended material improvement, e.g., addition of TiO2 NTs does increases
the hydrophilicity of the membranes.
Figure 7. Topography of discrete TiO2-based PES membranes using atomic force microscopy: (a) 1%
TiO2/PES membrane; (b) 0.5% TiO2/PES membrane; (c) 0.25% TiO2/PES membrane; and (d) pristine
PES membrane.
Table 1. Surface charge/roughness of PES membranes and contact angle measurement results.
Membranes
Surface
Roughness
(nm)
Contact
Angle
Zeta Potential
(mV) at pH 5
Zeta Potential
(mV) at pH 6
Zeta Potential
(mV) at pH 7
Zeta Potential
(mV) at pH 8
Unmodified PES 57.1 65.1 ± 2 ° −24.2 ± 0.1 −26.6 ± 0.7 −27.5 ± 0.1 −28.0 ± 0.9
Unmodified TiO2
NT membrane
– 8.0 ± 2 ° −8.3 ± 0.5 −8.8 ± 0.4 −9.2 ± 0.2 −10.1 ± 0.8
PES with 0.25 wt%
TiO2 NTs
83.3 49.1 ± 1 ° −25.2 ± 0.8 −27.0 ± 0.6 −27.8 ± 0.4 −28.4 ± 0.5
PES with 0.5 wt%
TiO2 NTs
121 40.5 ± 2 ° −26.4 ± 0.7 −27.3 ± 0.4 −28.6 ± 0.6 −29.7 ± 0.8
11. Nanomaterials 2019, 9, 1186 11 of 18
PES with 1 wt%
TiO2 NTs
133 37.4 ± 1 ° −28.2 ± 1 −29.4 ± 0.4 −31.5 ± 0.3 −32.0 ± 0.6
3.5. Contact Angle Measurement Results
Water contact angle analysis is a technique to study the hydrophilic properties of synthesized
membranes. In general, a higher contact angle means that the membrane is more hydrophobic, and
a lower contact angle reveals more hydrophilicity and higher surface energy of the membrane. A
syringe which was positioned above the sample surface was used to deposit water droplets with a
volume of 1 μL and a high-resolution camera was used to capture the side image of the droplet. The
angle of the image was then analyzed using a protractor to measure the contact angles. For each
membrane, three different measurements were taken from various spots on the membrane and the
average values were reported. The contact angles of the membranes are presented in Table 1. The
contact angle of the bare PES membrane was 65 ± 2° and as the concentration of discrete TiO2 NTs
increased from 0.25% to 1%, the contact angle was observed to decrease from 49 ± 1° to 37 ± 1°. The
contact angle of the bare TiO2 NTs was measured to be 8.0 ± 2°, which is highly hydrophilic compared
to the PES membrane. The accumulation of hydrophilic discrete TiO2 NTs on the surface during phase
inversion process reduced the interface energy. Based on contact angle measurements, the addition
of discrete TiO2 NTs to PES membranes leads to the formation of more hydrophilic membranes. More
hydrophilicity of microfiltration (MF)/ultrafiltration (UF) membranes can be correlated with their
antifouling properties, as will be discussed later.
3.6. Membrane Surface Charge Results
The nature of surface charge on the membrane is a crucial parameter which governs the
hydrophilicity and longevity of the membrane. The incorporation of discrete TiO2 NTs in TiO2
NTs/PES increases the hydrophilicity due to the raising the surface free energy which concomitantly
reduces fouling of the PES membranes. The contact angle measurements and the surface charge of
the membranes are presented in Table 1. The PES polymer consists of a polyetherphenylsulfone
backbone with pendant sulfonate (–SO3H) groups and the number of sulfonic acid groups is
dependent on the degree of sulfonation. At pH values higher than the isoelectric point (IEP), the
sulfonate groups in PES polymer get dissociated into negatively charged sulfate ions. Due to low
dissociation constant (pKa), the sulfonate groups readily get dissociated in water at pH-7, which gives
them surface negative charge as observed from zeta potential measurements. In the pristine PES
material, a certain fraction of sulfonate functionalities remains undissociated due to strong hydrogen
bonding and inaccessibility of solvent. Upon the incorporation of discrete TiO2 NTs, the membrane
surface becomes more accessible to solvents which facilitates dissociation of sulfonic acid groups and
increases negative change. Additionally, the surface of TiO2 possesses plenty of hydroxyl groups (–
OH) bonded with Ti atoms. These hydroxyl groups get deprotonated at elevated pH which further
contributes to surface negative charge of the membrane. The PES membrane with 1 wt% TiO2 NTs is
the most negatively charged in this study (see Table 1), and is expected to reduce the fouling by
organic and inorganic contaminants in the water due to electrostatic repulsion [47].
3.7. Permeability of Membranes
In asymmetric membranes, there are two layers; the top dense layer which governs the
permeation properties and the bottom porous layer which provides mechanical strength. The
addition of the inorganic discrete TiO2 NTs which are polar attract the polar water molecules to the
membrane surface which leads to an improvement in pure water flux. The pure water flux graph of
pristine PES membrane and nanocomposite PES membranes with 0.25 to 1 wt% loading of discrete
TiO2 NTs, as a function transmembrane pressure is shown in Figure 8a. The hydraulic permeability
of the PES based membranes was obtained from the slopes of this figure. As can be seen in this figure,
incorporating discrete TiO2 NTs has resulted in higher water permeability than unmodified PES
membrane. The addition of more hydrophilic hydroxyl groups to the surface of the membrane
12. Nanomaterials 2019, 9, 1186 12 of 18
improved the hydrophilicity (Table 1) which also increased water permeability of the membrane [48].
The nanocomposite membrane prepared by 1 wt% discrete TiO2 NTs was found to provide the
maximum hydraulic permeability of 1.65 L/m2h(LMH)/psi. The extracted hydraulic permeability
results from Figure 8a are shown in Figure 8b. As can be seen in this figure, increasing the
concentration of discrete NTs up to 1 wt% increased the water permeability. This result can be
attributed to a remarkable increase in hydrophilicity of membranes (Table 1). In addition, the overall
thickness of membranes was reduced by the incorporation of TiO2 NTs (Figure 6), which decreased
the resistance of the membranes against water transport.
(a) (b)
Figure 8. (a) Permeation flux as a function of transmembrane pressure; and (b) hydraulic permeability
of membranes as a function of NT concentration.
3.8. Porosity and Mean Pore Radius of Membrane
The porosity (%) is the void space over the total volume of a polymer matrix and is one of the
most important properties of a polymer. The pore size and pore volume are essential parameters to
be measured prior to the application of a polymer in various fields. Porosity is measured by filling
the pores either with a liquid or gas. Following the gravimetric method [49], the wet and dry masses
of various membranes were measured, and this is shown in Table 2. The porosity of nanocomposite
membranes is shown in Figure 9. By the addition of discrete TiO2 NTs up to 1 wt%, the overall
porosity is increased. Theoretically, PVP as an additive to PES increases the thermodynamic
instability due to its non-solvent property and kinetic hindrance due to its high molecular weight. As
result, this relation between kinetic hindrance and thermodynamic enhancement of the casting
solution affects the solidified membranes’ functional and structural properties by changing the
porosity of phase inversion membranes [46,50]. The addition of hydrophilic discrete TiO2 NTs to the
polymer solution further decreases its thermodynamic stability. Addition of both PVP and discrete
TiO2 NTs results in thermodynamic variation which enhances the demixing of solution, thus leading
to the formation of more porous structures. On the other hand, an increase in the viscosity of casting
solution by the addition of TiO2 NTs can lead to the delayed demixing of solvent and non-solvent
and thus formation of denser structures. This implies the presence of an optimum loading of discrete
NTs (0.25 to 1 wt% TiO2 NTs) for improving the water flux. The increase in porosity is another
parameter that improved the water flux results as shown in Figure 8. According to Figure 9, the mean
pore size decreased, and the overall porosity increased as the percentage of discrete TiO2 NTs in
membrane increased (see Equation (1)). The reduced pore diameter can potentially improve the
separation properties of the nanocomposite membranes. As mentioned before, the separation
properties of membranes are governed by the overall porosity and the membrane thickness and the
addition of higher concentration of NTs increases both of these parameters, thus bettering the
membrane properties for water treatment applications. In the present study, the main reason for the
increase in the removal of organic matter by the addition of 1 wt% discrete TiO2 NTs, as will be
13. Nanomaterials 2019, 9, 1186 13 of 18
explained in the next section, can be due to the increase in the thickness of skin layer (FESEM images
in Figure 6).
Table 2. Measured masses of dry and wet membranes for porosity and mean pore radius.
Membrane Mass of Dry Membrane (mg) Mass of Wet Membrane (mg)
Unmodified PES 14.6 ± 1 502.1 ± 2
PES with 0.25 wt% TiO2 NTs 25.0 ± 2 557.5 ± 3
PES with 0.5 wt% TiO2 NTs 27.2 ± 2 597.2 ± 1
PES with 1 wt% TiO2 NTs 24.2 ± 2 639.2 ± 2
(a) (b)
Figure 9. (a) Porosity and (b) mean pore radius plots of various membranes.
3.9. Separation Performance of Membranes
The separation performance of nanocomposite membranes was evaluated by the filtration of
WLS feed water. Table 3 presents the organic matter rejection results. A better performance for the
removal of organic matter from oil sands produced water was observed for the nanocomposite
membranes when compared with pristine membrane. The TOC rejection increased from 11.7%
(unmodified PES membrane) to more than 50% for the 1 wt% discrete TiO2 NTs/PES nanocomposite
membrane. Based on the data presented in Figure 4 and Table 3, the addition of 1 wt% discrete TiO2
NT has maximized both water flux (82 LMH at 40 psi) and TOC rejection (53.9%). The rejection was
calculated using equation 8 in Section 2.5.
Table 3. Removal of organic matter from WLS inlet water (TOC: 500 ppm).
Permeate TOC
(mg/L)
Permeate TC
(mg/L)
Permeate IC
(mg/L)
WLS Feed Water Rejection
(%)
Bare PES 441.28 468.74 27.46 11.7
1 wt% TiO2/PES 230.70 253.80 23.10 53.9
0.5 wt% TiO2/PES 413.51 447.40 33.90 17.3
0.25 wt%
TiO2/PES
424.23 451.20 26.97 15.15
3.10. Fouling Characteristics of Membranes
14. Nanomaterials 2019, 9, 1186 14 of 18
The fouling characteristics of unmodified pristine PES membrane and discrete TiO2 NTs/PES
nanocomposite membranes during the filtration of WLS feed water are shown in Table 3. To
investigate the effect of TiO2 NTs on flux decline over time, all experiments were conducted at a
similar initial permeation flux. Additionally, in all experiments, the feed solution chemistry,
temperature, and hydrodynamic of membrane modules were kept similar. This allowed attributing
the fouling propensity of membranes to the surface properties rather than feed properties and
hydrodynamic conditions (e.g., drag force) [47,51]. The membranes were compressed at high
pressure (70 psi) before the experiments to ensure that the flux decline over time is only due to the
fouling of the membranes. At a constant initial flux, the flux decline can be attributed to the
hydrophilicity, surface charge, and roughness of the modified membranes [52].
According to the Figure 10, the flux decline of the unmodified membrane is more than the PES
membranes modified with discrete TiO2 NTs. The PES membrane with 1 wt% discrete TiO2 NTs
showed approximately 29% more water flux than the unmodified PES membrane after 20 min of
filtration. It is well known that the membranes with more negative surface charge and higher
hydrophilicity have less interaction amongst the functional dissolved organic compounds in the feed
solution and the polar groups on the membranes surface. This can be explained by formation of a
water layer on the surface of the membrane that hinders foulant attachment to the membrane surface
due to the formation of hydrogen bonds among the surface hydrophilic groups to start with. Due to
the hydrophobic nature of most organic matter in the fluids tested [51], the fouling materials are less
inclined to attach to a hydrophilic surface where there is smaller hydrophobic interaction with
membrane surface. Membrane surface roughness, characterized by AFM, also plays a significant role
in fouling. Foulant materials are entrapped in the edgy zones, behind the peaks and consequently
clog the valleys on the surface of MF/UF membranes resulting in significant decrease in permeate
flux. In this study, the combination of the hydrophilic surface of TiO2 NTs-based nanocomposite
membranes along with their high surface potential (Table 1) seem to have dominated the roughness
effect and made them less prone to fouling by dissolved organic matter, which can be beneficial for
oil sands-produced water treatment.
Figure 10. Water flux vs. time discrete TiO2 nanocomposite membranes and unmodified PES
membrane due to fouling.
The total flux decline ratio (DRt), irreversible fouling ratio (DRir), water flux recovery ratio (FRR),
and reversible fouling ratio (DRr) for the pristine PES membrane and TiO2 NTs/PES nanocomposite
15. Nanomaterials 2019, 9, 1186 15 of 18
membranes are shown in Figure 11. The membranes showed flux decline during the filtration of WLS
feed water for 20 min, which was possibly due to the existence of inorganic and organic materials on
the surface of membranes. TiO2 NTs with high surface area are great adsorbent materials that adsorb
foulants on the surface of the membrane thus decreasing the irreversible flux reduction. The DRir was
found to be 12.5%, 11%, and 15% for 1, 0.5, and 0.25 wt% TiO2 loading as compared to 18% for
unmodified PES membrane. The 1 wt% TiO2/PES membrane indicated a 9% greater flux recovery
ratio than the pristine PES membrane, suggesting an improvement in antifouling characteristics of
the unmodified membrane by the incorporation of TiO2 NTs.
Figure 11. Comparisons of fouling characteristics of unmodified PES and PES/discrete TiO2
nanocomposite membranes.
4. Conclusions
In this study, discrete TiO2 NTs with various concentrations were blended into a polymeric
membrane matrix via the NIPS technique. The surface properties of the nanocomposite membranes
such as negative surface charge and hydrophilicity have noticeably changed to be stronger. The
contact angle and zeta potential measurements showed the fabrication of more hydrophilic and
negatively charged TiO2 NTs PES nanocomposite membranes. All discrete TiO2 NTs incorporated
PES membranes showed better organic matter rejection and water flux when compared with the
pristine PES membrane. The incorporation of discrete TiO2 NTs, up to 1 wt% enhanced the water flux
due to an increase in overall porosity and hydrophilicity of the membranes. The most favorable
loading to improve both organic matter rejection and water flux was found to be 1 wt% TiO2 NTs
incorporated PES membranes which removed 53.9% of dissolved organic matter from SAGD-
produced water. The SAGD WLS feed water was used to test the fouling propensity of membranes.
The results showed that by the addition of discrete TiO2 NTs, the fouling tendency of the membranes
has hindered due to improved surface properties. Discrete TiO2 NTs at its optimal loading (1 wt%)
has provided the maximum rejection of organic matter (53.9%), water flux (82 LMH at 40 psi), and
antifouling properties (29% improvement compared to pristine PES membrane). The flux recovery
ratio (FRR) experiments have confirmed notable improvement in the antifouling property of discrete
TiO2 NTs incorporated PES membranes.
As mentioned before, one of the potential benefits of TiO2 NTs incorporated PES membranes is
their low cost compared to other nanomaterials due to their nearly endless lifetime. The low human
toxicity, and high thermal and chemical stability are also other main advantages of TiO2 NTs which
16. Nanomaterials 2019, 9, 1186 16 of 18
make them a good material in water filtration processes commercially. This membrane technology
can easily be implemented into an existing commercial production facility due to facile synthesis
methods of TiO2 NTs as well as the discrete TiO2 NTs. Since it is possible to produce discrete
nanotubes in large scale, commercial fabrication of nanotube nanocomposite PES membranes will be
an easy solution to fouling of membranes in water treatment.
Author Contributions: Conceptualization: B.P., K.S., and M.S.; methodology: N.M.; formal analysis: N.M. and
P.K.; investigation: N.M., A.G., and P.K.; writing—original draft preparation: N.M.; writing—review and
editing: P.K., K.S., and M.S.; visualization: P.K.; supervision: K.S. and M.S.; project administration: M.S.; funding
acquisition: M.S.
Funding: This research was funded by Canada’s Oil Sands Innovation Alliance (COSIA) and the Natural
Sciences and Engineering Research Council of Canada (NSERC).
Acknowledgments: N.M. thanks Behnam Khorshidi and Amin Karkooti for training her on the membrane
characterization tools.
Conflicts of Interest: The authors declare no conflict of interest. Suncor Energy Inc. and its affiliates (collectively
“Suncor”) do not make any express or implied representations or warranties as to the accuracy, timeliness, or
completeness of the statements, information, data, and content contained in this paper and any materials or
information (written or otherwise) provided in conjunction with this paper (collectively, the “Information”). The
Information has been prepared solely for informational purposes only and should not be relied upon. Suncor is
not responsible for and is hereby released from any liabilities whatsoever for any errors or omissions in the
Information and/or arising out of a person’s use of, or reliance on, the Information. The funders had no role in
the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or
in the decision to publish the results.
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