Problem statement: Developing high-value nanostructured carbon from bio-char, for electrical and natural gas energy storage, is critical to improving the economic viability of thermochemical bioenergy and biofuel conversion processes. Approach: Here we show that chemical activation, using potassium or sodium hydroxide as catalysts, converted the biochar of distiller’s dried grains with soluble into activated carbon with high surface area (> 1500 m2/g). Results: The development of porosity by chemical activation using alkali hydroxides depends on type and dosage of activation catalysts; activation temperature and atmosphere conditions. Activated carbon samples with high mesoporous volume ( 1 ml/g), and nanostructure similar to activated graphene were prepared at activation temperature (1050 °C) and KOH loading (0.05 or 0.075 mol/g biochar). Conclusion: This protocol offers the potential to use other protein rich feedstocks for preparing nanostructured carbon, containing nanostructure similar to activated graphene, as an advanced carbon material.
Polymeric carbon nitride-based photocatalysts for photoreforming of biomass d...Pawan Kumar
Photoreforming of biomass to value-added chemicals and fuels is a chemical approach to extract photosynthetically-trapped energy in complex biomolecules which otherwise disintegrate naturally in the environment. Designing precise photocatalytic materials that can selectively break the sturdy, nature-designed biomass with multiplex chemical composition/bonding and inaccessible sites is central to deploying this technology. Polymeric carbon nitride (CN) comprised of a 2D network of condensed heptazine/triazine (C6N7/C3N3) core has shown great promise for photoreforming of biomass derivatives due to intriguing physicochemical and optical properties. This review comprehensively summarizes the state-of-the-art applications of CN-based photocatalysts for the conversion of lignocellulosic biomass derivatives. Various chemical and structural modifications in CN structure such as doping, surface functionalization, hybridization entailing to higher selectivity and conversion have been discussed aiming at providing valuable guidance for future CN-based materials design.
The document discusses various applications of nanomaterials in catalysis. It begins by introducing different types of catalysts and how nanocatalysts combine advantages of homogeneous and heterogeneous systems by having a high surface area like homogeneous catalysts while also being easily separable like heterogeneous catalysts. Several examples of nanocatalyst applications are then summarized in areas like water purification, biodiesel production, drug delivery, fuel cells, environmental protection, and solar cells. The document emphasizes how nanocatalysts provide benefits like high activity, selectivity, stability, and being energy efficient.
Visible light assisted reduction of nitrobenzenes using Fe(bpy)3+2/rGOnanocom...Pawan Kumar
Visible-light-induced photocatalytic reduction of aromatic nitrobenzenes to the corresponding anilinesat room temperature using reduced graphene oxide (rGO) immobilized iron(II) bipyridine complex asphotocatalyst is described. The rGO-immobilized iron catalyst exhibited superior catalytic activity thanhomogeneous iron(II) bipyridine complex and much higher than metal free rGO photocatalysts. Theheterogeneous photocatalyst was found to be robust and could easily be recovered and reused for severalruns without any significant loss in photocatalytic activity.
Sunlight-driven water-splitting using two dimensional carbon based semiconduc...Pawan Kumar
The overwhelming challenge of depleting fossil fuels and anthropogenic carbon emissions has driven research
into alternative clean sources of energy. To achieve the goal of a carbon neutral economy, the harvesting of
sunlight by using photocatalysts to split water into hydrogen and oxygen is an expedient approach to fulfill
the energy demand in a sustainable way along with reducing the emission of greenhouse gases. Even though
the past few decades have witnessed intensive research into inorganic semiconductor photocatalysts, their
quantum efficiencies for hydrogen production from visible photons remain too low for the large scale
deployment of this technology. Visible light absorption and efficient charge separation are two key necessary
conditions for achieving the scalable production of hydrogen from water. Two-dimensional carbon based
nanoscale materials such as graphene oxide, reduced graphene oxide, carbon nitride, modified 2D carbon
frameworks and their composites have emerged as potential photocatalysts due to their astonishing
properties such as superior charge transport, tunable energy levels and bandgaps, visible light absorption,
high surface area, easy processability, quantum confinement effects, and high photocatalytic quantum yields.
The feasibility of structural and chemical modification to optimize visible light absorption and charge
separation makes carbonaceous semiconductors promising candidates to convert solar energy into chemical
energy. In the present review, we have summarized the recent advances in 2D carbonaceous photocatalysts
with respect to physicochemical and photochemical tuning for solar light mediated hydrogen evolution
Synthesis of flower-like magnetite nanoassembly: Application in the efficient...Pawan Kumar
A facile approach for the synthesis of magnetite microspheres with flower-like morphology is reported
that proceeds via the reduction of iron(III) oxide under a hydrogen atmosphere. The ensuing magnetic
catalyst is well characterized by XRD, FE-SEM, TEM, N2 adsorption-desorption isotherm, and
Mössbauer spectroscopy and explored for a simple yet efficient transfer hydrogenation reduction of a
variety of nitroarenes to respective anilines in good to excellent yields (up to 98%) employing hydrazine
hydrate. The catalyst could be easily separated at the end of a reaction using an external magnet and
can be recycled up to 10 times without any loss in catalytic activity.
Microbial Communities Involved in Methane Production from Coal Treated by Pot...CrimsonPublishersAMMS
Microbial Communities Involved in Methane Production from Coal Treated by Potassium Permanganate by Zaixing Huang in Aspects in Mining & Mineral Science
nano catalysis as a prospectus of green chemistry Ankit Grover
Nanocatalysis and green chemistry prospects.
Nanocatalysts have higher activity, selectivity, and efficiency than traditional catalysts due to their high surface area to volume ratio. They can be designed for sustainability by having properties like recyclability, durability, and cost-effectiveness. Examples discussed include gold nanoparticle catalysts for oxidation reactions and magnetically separable nanoparticle catalysts. Nanocatalyst applications highlighted are water splitting for hydrogen production and storage, and fuel cells.
Polymeric carbon nitride-based photocatalysts for photoreforming of biomass d...Pawan Kumar
Photoreforming of biomass to value-added chemicals and fuels is a chemical approach to extract photosynthetically-trapped energy in complex biomolecules which otherwise disintegrate naturally in the environment. Designing precise photocatalytic materials that can selectively break the sturdy, nature-designed biomass with multiplex chemical composition/bonding and inaccessible sites is central to deploying this technology. Polymeric carbon nitride (CN) comprised of a 2D network of condensed heptazine/triazine (C6N7/C3N3) core has shown great promise for photoreforming of biomass derivatives due to intriguing physicochemical and optical properties. This review comprehensively summarizes the state-of-the-art applications of CN-based photocatalysts for the conversion of lignocellulosic biomass derivatives. Various chemical and structural modifications in CN structure such as doping, surface functionalization, hybridization entailing to higher selectivity and conversion have been discussed aiming at providing valuable guidance for future CN-based materials design.
Polymeric carbon nitride-based photocatalysts for photoreforming of biomass d...Pawan Kumar
Photoreforming of biomass to value-added chemicals and fuels is a chemical approach to extract photosynthetically-trapped energy in complex biomolecules which otherwise disintegrate naturally in the environment. Designing precise photocatalytic materials that can selectively break the sturdy, nature-designed biomass with multiplex chemical composition/bonding and inaccessible sites is central to deploying this technology. Polymeric carbon nitride (CN) comprised of a 2D network of condensed heptazine/triazine (C6N7/C3N3) core has shown great promise for photoreforming of biomass derivatives due to intriguing physicochemical and optical properties. This review comprehensively summarizes the state-of-the-art applications of CN-based photocatalysts for the conversion of lignocellulosic biomass derivatives. Various chemical and structural modifications in CN structure such as doping, surface functionalization, hybridization entailing to higher selectivity and conversion have been discussed aiming at providing valuable guidance for future CN-based materials design.
The document discusses various applications of nanomaterials in catalysis. It begins by introducing different types of catalysts and how nanocatalysts combine advantages of homogeneous and heterogeneous systems by having a high surface area like homogeneous catalysts while also being easily separable like heterogeneous catalysts. Several examples of nanocatalyst applications are then summarized in areas like water purification, biodiesel production, drug delivery, fuel cells, environmental protection, and solar cells. The document emphasizes how nanocatalysts provide benefits like high activity, selectivity, stability, and being energy efficient.
Visible light assisted reduction of nitrobenzenes using Fe(bpy)3+2/rGOnanocom...Pawan Kumar
Visible-light-induced photocatalytic reduction of aromatic nitrobenzenes to the corresponding anilinesat room temperature using reduced graphene oxide (rGO) immobilized iron(II) bipyridine complex asphotocatalyst is described. The rGO-immobilized iron catalyst exhibited superior catalytic activity thanhomogeneous iron(II) bipyridine complex and much higher than metal free rGO photocatalysts. Theheterogeneous photocatalyst was found to be robust and could easily be recovered and reused for severalruns without any significant loss in photocatalytic activity.
Sunlight-driven water-splitting using two dimensional carbon based semiconduc...Pawan Kumar
The overwhelming challenge of depleting fossil fuels and anthropogenic carbon emissions has driven research
into alternative clean sources of energy. To achieve the goal of a carbon neutral economy, the harvesting of
sunlight by using photocatalysts to split water into hydrogen and oxygen is an expedient approach to fulfill
the energy demand in a sustainable way along with reducing the emission of greenhouse gases. Even though
the past few decades have witnessed intensive research into inorganic semiconductor photocatalysts, their
quantum efficiencies for hydrogen production from visible photons remain too low for the large scale
deployment of this technology. Visible light absorption and efficient charge separation are two key necessary
conditions for achieving the scalable production of hydrogen from water. Two-dimensional carbon based
nanoscale materials such as graphene oxide, reduced graphene oxide, carbon nitride, modified 2D carbon
frameworks and their composites have emerged as potential photocatalysts due to their astonishing
properties such as superior charge transport, tunable energy levels and bandgaps, visible light absorption,
high surface area, easy processability, quantum confinement effects, and high photocatalytic quantum yields.
The feasibility of structural and chemical modification to optimize visible light absorption and charge
separation makes carbonaceous semiconductors promising candidates to convert solar energy into chemical
energy. In the present review, we have summarized the recent advances in 2D carbonaceous photocatalysts
with respect to physicochemical and photochemical tuning for solar light mediated hydrogen evolution
Synthesis of flower-like magnetite nanoassembly: Application in the efficient...Pawan Kumar
A facile approach for the synthesis of magnetite microspheres with flower-like morphology is reported
that proceeds via the reduction of iron(III) oxide under a hydrogen atmosphere. The ensuing magnetic
catalyst is well characterized by XRD, FE-SEM, TEM, N2 adsorption-desorption isotherm, and
Mössbauer spectroscopy and explored for a simple yet efficient transfer hydrogenation reduction of a
variety of nitroarenes to respective anilines in good to excellent yields (up to 98%) employing hydrazine
hydrate. The catalyst could be easily separated at the end of a reaction using an external magnet and
can be recycled up to 10 times without any loss in catalytic activity.
Microbial Communities Involved in Methane Production from Coal Treated by Pot...CrimsonPublishersAMMS
Microbial Communities Involved in Methane Production from Coal Treated by Potassium Permanganate by Zaixing Huang in Aspects in Mining & Mineral Science
nano catalysis as a prospectus of green chemistry Ankit Grover
Nanocatalysis and green chemistry prospects.
Nanocatalysts have higher activity, selectivity, and efficiency than traditional catalysts due to their high surface area to volume ratio. They can be designed for sustainability by having properties like recyclability, durability, and cost-effectiveness. Examples discussed include gold nanoparticle catalysts for oxidation reactions and magnetically separable nanoparticle catalysts. Nanocatalyst applications highlighted are water splitting for hydrogen production and storage, and fuel cells.
Polymeric carbon nitride-based photocatalysts for photoreforming of biomass d...Pawan Kumar
Photoreforming of biomass to value-added chemicals and fuels is a chemical approach to extract photosynthetically-trapped energy in complex biomolecules which otherwise disintegrate naturally in the environment. Designing precise photocatalytic materials that can selectively break the sturdy, nature-designed biomass with multiplex chemical composition/bonding and inaccessible sites is central to deploying this technology. Polymeric carbon nitride (CN) comprised of a 2D network of condensed heptazine/triazine (C6N7/C3N3) core has shown great promise for photoreforming of biomass derivatives due to intriguing physicochemical and optical properties. This review comprehensively summarizes the state-of-the-art applications of CN-based photocatalysts for the conversion of lignocellulosic biomass derivatives. Various chemical and structural modifications in CN structure such as doping, surface functionalization, hybridization entailing to higher selectivity and conversion have been discussed aiming at providing valuable guidance for future CN-based materials design.
Catalytic cracking of polypropylene waste over zeolite betaAlexander Decker
This document summarizes a study that investigated the catalytic cracking of polypropylene (PP) waste using zeolite beta (BEA) catalysts. BEA catalysts with different Si/Al ratios were synthesized from mesoporous silica and tested for their ability to crack PP waste at various temperatures. The BEA catalyst with Si/Al ratio of 12.5 showed 95% conversion of PP waste at 400°C. Catalytic cracking led to higher conversions and more valuable products compared to thermal cracking. The used BEA catalyst could be regenerated with similar activity to the fresh catalyst.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Recovery of Lead (II) from electroplating industrial wastewater by Bio-func...Rajmohan Govindarajan
Heavy metal removal from wastewater through adsorption is more effective, eco-friendly and recyclable.
Use of activated carbon, Graphene nanosheets, nanotubes etc. have higher specific area.
Use of immobilized biomass increase the pore structure and adsorption sites areas.
Magnetic adsorption by magnetic nanoparticles are easy to separate from the treatment system.
Combining of adsorbent particle constituting magnetic particles and immobilized biomass alginated beads have advantages of increased pore structure, surface area and ability of recycling.
Optical Control of Selectivity of High Rate CO2 Photoreduction Via Interband-...Pawan Kumar
Photonic crystals consisting of TiO2 nanotube arrays (PMTiNTs) with periodically modulated diameters were fabricated using a precise charge-controlled pulsed anodization technique. The PMTiNTs were decorated with gold nanoparticles (Au NPs) to form plasmonic photonic crystal photocatalysts (Au-PMTiNTs). A systematic study of CO2 photoreduction performance on as-prepared samples was conducted using different wavelengths and illumination sequences. A remarkable selectivity of the mechanism of CO2 photoreduction could be engineered by merely varying the spectral composition of the illumination sequence. Under AM1.5 G simulated sunlight (pathway#1), the Au-PMTiNTs produced methane (302 µmol h-1) from CO2 with high selectivity (89.3%). When also illuminated by a UV-poor white lamp (pathway#2), the Au-PMTiNTs produced formaldehyde (420 µmol h-1) and carbon monoxide (323 µmol h-1) with almost no methane evolved. We confirmed the photoreduction results by 13C isotope labeling experiments using GC-MS. These results point to optical control of the selectivity of high-rate CO2 photoreduction through selection of one of two different mechanistic pathways. Pathway#1 implicates electron-hole pairs generated through interband transitions in TiO2 and Au as the primary active species responsible for reducing CO2 to methane. Pathway#2 involves excitation of both TiO2 and surface plasmons in Au. Hot electrons produced by plasmon damping and photogenerated holes in TiO2 proceed to reduce CO2 to HCHO and CO through a plasmonic Z-scheme.
Reduced graphene oxide–CuO nanocomposites for photocatalyticconversion of CO2...Pawan Kumar
tReduced graphene oxide (rGO)–copper oxide nanocomposites are prepared by covalent grafting of CuOnanorods on the rGO skeleton. Chemical and structural features of rGO–CuO nanocomposites are probedby FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO–CuO nanocomposites is exploredfor reduction of CO2into the methanol under the visible light irradiation. The breadth of CuO nanorods andthe oxidation state of Cu in the rGO–CuO/Cu2O nanocomposites are systematically varied to investigatetheir photocatalytic activities. The pristine CuO nanorods exhibited very low photocatalytic activity owingto fast recombination of charge carriers and yielded 175 mol g−1methanol, whereas rGO–Cu2O andrGO–CuO exhibited significantly improved photocatalytic activities and yielded five (862 mol g−1) andseven (1228 mol g−1) folds methanol, respectively. The superior photocatalytic activity of CuO in therGO–CuO nanocomposites was attributed to slow recombination of charge carriers and efficient transferof photo-generated electrons through the rGO skeleton. This study further excludes the use of scavengingdonor.
Pawan Homogeneous catalyst for CO2 reductionPawan Kumar
This document provides an overview of homogenous photocatalytic reduction of CO2. It discusses key topics such as what photocatalysis is, problems with CO2 reduction, classifications of photocatalysts including homogeneous and heterogeneous examples, and mechanisms of type I and type II catalysts. Molecular complexes like rhenium and ruthenium are described as promising homogeneous photocatalysts. The effects of catalyst structure, reaction conditions, and anchoring to surfaces are reviewed. Future areas of improvement include increasing turnover numbers and standardizing test conditions for fair catalyst comparisons.
Nanostructured composite materials for CO2 activationPawan Kumar
This document discusses nanostructured composite materials for CO2 activation, specifically for the photocatalytic reduction of CO2 to valuable products. It provides background on the increasing energy crisis and climate change caused by fossil fuel use. It then summarizes the basic principles and challenges of using semiconductor photocatalysts for CO2 reduction, including appropriate band gap positions and preventing electron-hole recombination. The document discusses various approaches to overcoming these challenges, such as forming heterojunction composites and using co-catalysts to facilitate charge separation and transfer.
Catalysis role in enhancement of Hydrogen Storage properties of NanomaterialsRasmeetSingh2
Rapid growth in population, increased standard of living has put the adverse effect on the environment due to the limited supply of fossil fuels, therefore the need of clean, sustainable and affordable fuel has been increased. These conditions has led to the continuous generation of H2 with very high purity over various range of pressures under mild conditions. The polymer-based organic microporous materials termed as Polymers of Intrinsic Micro porosity (PIMs) has emerged as one of selective gas separation membranes. We therefore will discuss and examine wide range of catalysts Nano-scale structure which can be subsequently used for the improvements in kinetics through Nano-scale solid state catalysis, the special properties of Nano-composites, and the role played by Nano-scale reactions.
Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C3N5 Co...Pawan Kumar
We present a potential solution to the problem of extraction of photogenerated holes from CdS nanocrystals and nanowires. The nanosheet form of C3N5 is a low-band-gap (Eg = 2.03 eV), azo-linked graphenic carbon nitride framework formed by the polymerization of melem hydrazine (MHP). C3N5 nanosheets were either wrapped around CdS nanorods (NRs) following the synthesis of pristine chalcogenide or intercalated among them by an in situ synthesis protocol to form two kinds of heterostructures, CdS-MHP and CdS-MHPINS, respectively. CdS-MHP improved the photocatalytic degradation rate of 4-nitrophenol by nearly an order of magnitude in comparison to bare CdS NRs. CdS-MHP also enhanced the sunlight-driven photocatalytic activity of bare CdS NWs for the decolorization of rhodamine B (RhB) by a remarkable 300% through the improved extraction and utilization of photogenerated holes due to surface passivation. More interestingly, CdS-MHP provided reaction pathway control over RhB degradation. In the absence of scavengers, CdS-MHP degraded RhB through the N-deethylation pathway. When either hole scavenger or electron scavenger was added to the RhB solution, the photocatalytic activity of CdS-MHP remained mostly unchanged, while the degradation mechanism shifted to the chromophore cleavage (cycloreversion) pathway. We investigated the optoelectronic properties of CdS-C3N5 heterojunctions using density functional theory (DFT) simulations, finite difference time domain (FDTD) simulations, time-resolved terahertz spectroscopy (TRTS), and photoconductivity measurements. TRTS indicated high carrier mobilities >450 cm2 V–1 s–1 and carrier relaxation times >60 ps for CdS-MHP, while CdS-MHPINS exhibited much lower mobilities <150 cm2 V–1 s–1 and short carrier relaxation times <20 ps. Hysteresis in the photoconductive J–V characteristics of CdS NWs disappeared in CdS-MHP, confirming surface passivation. Dispersion-corrected DFT simulations indicated a delocalized HOMO and a LUMO localized on C3N5 in CdS-MHP. C3N5, with its extended π-conjugation and low band gap, can function as a shuttle to extract carriers and excitons in nanostructured heterojunctions, and enhance performance in optoelectronic devices. Our results demonstrate how carrier dynamics in core–shell heterostructures can be manipulated to achieve control over the reaction mechanism in photocatalysis.
Synthesis and Characterization of Zinc Phthalocyanine-Cellulose Nanocrystal (...Pawan Kumar
We report highly fluorescent cellulose nanocrystals (CNCs) formed by conjugating a carboxylated zinc phthalocyanine (ZnPc) to two different types of CNCs. The conjugated nanocrystals (henceforth called ZnPc@CNCs) were bright green in color and exhibited absorption and emission maxima at ∼690 and ∼715 nm, respectively. The esterification protocol employed to covalently bind carboxylated ZnPc to surface hydroxyl group rich CNCs was expected to result in a monolayer of ZnPc on the surface of the CNCs. However, dynamic light scattering (DLS) studies indicated a large increase in the hydrodynamic radius of CNCs following conjugation to ZnPc, which suggests the binding of multiple ZnPc molecular layers on the CNC surface. This binding could be through co-facial π-stacking of ZnPc, where ZnPc metallophthalocyanine rings are horizontal to the CNC surface. The other possible binding mode would give rise to conjugated systems where ZnPc metallophthalocyanine rings are oriented vertically on the CNC surface. Density functional theory based calculations showed stable geometry following the conjugation protocol that involved covalently attached ester bond formation. The conjugates demonstrated superior performance for potential sensing applications through higher photoluminescence quenching capabilities compared to pristine ZnPc.
Water-splitting photoelectrodes consisting of heterojunctions of carbon nitri...Pawan Kumar
Quinary and senary non-stoichiometric double perovskites such as Ba2Ca0.66Nb1.34−xFexO6−δ (BCNF) have been utilized for gas sensing, solid oxide fuel cells and thermochemical CO2 reduction. Herein, we examined their potential as narrow bandgap semiconductors for use in solar energy harvesting. A cobalt co-doped BCNF, Ba2Ca0.66Nb0.68Fe0.33Co0.33O6−δ (BCNFCo), exhibited an optical absorption edge at ∼800 nm, p-type conduction and a distinct photoresponse up to 640 nm while demonstrating high thermochemical stability. A nanocomposite of BCNFCo and g-C3N4 (CN) was prepared via a facile solvent-assisted exfoliation/blending approach using dichlorobenzene and glycerol at a moderate temperature. The exfoliation of g-C3N4 followed by wrapping on perovskite established an effective heterojunction between the materials for charge separation. The conjugated 2D sheets of CN enabled better charge migration resulting in increased photoelectrochemical performance. A blend composed of 40 wt% perovskites and CN performed optimally, whilst achieving a photocurrent density as high as 1.5 mA cm−2 for sunlight-driven water-splitting with a Faradaic efficiency as high as ∼88%.
The document discusses nanocatalysis, which involves using nanotechnology products as catalysts (called nanocatalysts). It describes the history and introduction of nanocatalysis, benefits of nanocatalysts, methods of synthesizing nanocatalysts both homogenously and heterogeneously, types of nanocatalysts, how catalytic activity depends on properties like composition and environment, applications in industries like petroleum refining and pharmaceuticals, and concludes that nanocatalysts offer opportunities to meet future demands through their high activity and selectivity.
2014_Nguyen et al._The Journal of Supercritical FluidsHuyen Lyckeskog
This document describes a study that developed a pilot plant to catalytically convert LignoBoost Kraft lignin into bio-oil and chemicals using near-critical water. The conversion took place continuously in a fixed-bed catalytic reactor filled with ZrO2 pellets at 350°C and 25 MPa. Lignin was dispersed in an aqueous solution containing K2CO3 and phenol. The products consisted of an aqueous phase containing phenolic chemicals and a bio-oil with higher heating value than the lignin feed. Preliminary results showed that increasing the K2CO3 content increased the yield of 1-ring aromatic compounds from 17% to 27% based on dry lignin.
Final Report (Graphene supported platinum nanoparticles) (1)Sridharan Thirumalai
This document is a student project report on platinum-graphene nanocomposites as electrocatalysts in PEM fuel cells. It was submitted by T.V. Sridharan to Professor Manoj Neergat at the Indian Institute of Technology, Bombay under his supervision. The report describes the synthesis of Pt/rGO nanocomposites using a modified polyol method, and their physical and electrochemical characterization. TEM analysis showed the successful deposition of platinum nanoparticles on graphene oxide sheets. Electrochemical experiments found the Pt/rGO composite had a higher effective surface area than Pt/C, but similar activity for the oxygen reduction reaction. Further research is needed to fully realize graphene's potential as
Abstract— The content of the heavy metal cadmium (Cd) which is excessive in the soil could affects on the soil and plants health. The aim of this descriptive study was to investigate the ability of selected indigenous plants in stabilizing Cd. The study was conducted at an agricultural production center in Batu City, East Java, Indonesia. There were two stages of this study, namely: (1) analysis of nutrient and heavy metal contamination, and (2) phytoremediation experiment by using five types of indigenous plants. The experiment was arranged in completely randomized design (CRD) with three replications. Once the plants were harvested, the plant materials then were analyzed the heavy metal content remaining in the soil and absorbed by the plants. The heavy metal content analysis used AAS (Atomic Absorption Spectrometry). Subsequently, the analysis result data were calculated for the bio-concentration factor (BCF) and heavy metal reduction. The initial content of heavy metal Cd in the soil prior phytoremediation had passed the threshold value (2.26 mg kg-1). The five indigenous plants tested on the contaminated soil showed a good growth pattern, especially in the fourth week after planting. The average ability of this selected plant to reduce heavy metals Cd was up to 71.2%. The reductions of heavy metals Cd obtained by each plant were Vetiveria zizanioides (71.2%), Eleusine indica, L. (58.9%), Ageratum conyzoides L. (52.2%), Euphorbia hirta (51.8%) and Chromolaena odorata (22.1%).
This summarizes a document describing research on using boron-doped diamond (BDD) electrochemical reactors to treat polluted waters. Key points:
1) BDD electrodes have been used in various bench-scale electrochemical reactors, including undivided flow cells and trickle tower reactors, to degrade organic pollutants via electrochemical oxidation.
2) The BDD surface generates reactive oxygen species like hydroxyl radicals that can fully mineralize organic contaminants into CO2 and water. Operating parameters like current density and flow rate influence degradation rates.
3) Studies show these BDD reactors can achieve high removals of chemical oxygen demand (COD) and total organic carbon (TOC) for
Heterostructured nanocomposite tin phthalocyanine@mesoporous ceria (SnPc@CeO2...Pawan Kumar
Heterostructured tin phthalocyanine supported to mesoporous ceria was synthesized and used a
photocatalyst for CO2 reduction under visible light. The photoreduction CO2 activities of the
heterostructures were investigated in the presence of triethylamine as sacrificial agent. The developed
photocatalyst exhibited high catalytic activity for photoreduction of CO2 and after 24 hours of visible
light irradiation 2342 mmol g1 cat of methanol (fMeOH ¼ 0.0223 or 2.23%) and 840 mmol g1 cat of CO
(fCO ¼ 0.0026 or 0.26%) were obtained as the major reaction products. The methanol formation rate
(RMeOH) and CO formation rate (RCO) was found to be 97.5 mmol h1 g1 cat and 35.0 mmol h1 g1 cat
respectively. While under the identical experimental conditions mesoporous ceria (meso-CeO2) gave
only 316 mmol g1 cat of methanol (fMeOH ¼ 0.003 or 0.30%) and 126 mmol g1 cat CO (fCO ¼ 0.0004
or 0.04%) with product formation rate RMeOH ¼ 13.2 mmol h1 g1 cat and RCO ¼ 5.3 mmol h1 g1 cat.
Furthermore, the recovered catalyst showed consistent catalytic activity for at least five runs without any
significant loss in product yields
Energy level tuning of cd se colloidal quantum dots in ternary 0d 2d-2d cdse ...Journal Papers
This document summarizes the energy level tuning of CdSe colloidal quantum dots (QDs) in a ternary 0D-2D-2D CdSe QD/B-rGO/O-gC3N4 photocatalyst system for enhanced hydrogen generation. Specifically, it discusses how the use of different thiol capping ligands on CdSe QDs results in shifts in the QD energy levels and band gaps. These ligand-specific CdSe QDs then exhibit trends in photocatalytic performance consistent with their respective measured energy and gap levels. Furthermore, it describes how an optimized CdSe QD is incorporated into a ternary composite with B-rGO and O-g
Design, Performance Evaluation and Synthesis of Sulfonated Carbon Based Catal...ijtsrd
Microcrystalline cellulose can be converted into valuable products such as glucose via hydrolysis reaction at mild condition using sulfonated carbon catalyst. A sulfonated carbon material was prepared by carbonization of bamboo sawdust followed by sulfonation. Prepared catalyst was studied for its ability to catalyze microcrystalline cellulose yield via hydrolysis reaction. Three carbon based catalysts at three different temperatures 400, 450 and 500 were prepared. The sulfonated catalysts were characterized using the following analyses elemental analysis, total acid density, FT IR, SEM and XRD. Based on the above characterization results, sulfonated carbon prepared at 500 and sulfonated via ultra sonication was found to have a higher acid density that is suitable to catalyze the hydrolysis reaction. The first step in the catalyst development approach was to increase the hydrolysis reaction by employing a stronger sulfonation procedure during catalyst preparation. The total acid density obtained for sulfonated carbon catalyst at 500 was 4.16 mmol g which significantly increases glucose yield. According to the FTIR analysis the sulfonated bio char contained sulfonic, carboxylic, and phenolic groups, which are responsible for the exhibited high catalytic performance during hydrolysis of cellulose. The yield of glucose obtained was 60.5 at 149.0°C in 8hour reaction time. Kefyalew H/Mariam | Bayisa Dame | Beteley Tekola "Design, Performance Evaluation and Synthesis of Sulfonated Carbon Based Catalyst for Hydrolysis of Microcrystalline Cellulose" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-1 , December 2020, URL: https://www.ijtsrd.com/papers/ijtsrd38100.pdf Paper URL : https://www.ijtsrd.com/engineering/chemical-engineering/38100/design-performance-evaluation-and-synthesis-of-sulfonated-carbon-based-catalyst-for-hydrolysis-of-microcrystalline-cellulose/kefyalew-hmariam
Photo-assisted oxidation of thiols to disulfides using cobalt ‘‘Nanorust’’ un...Pawan Kumar
Heterogeneous ‘‘Nanorust’’ containing cobalt oxide has been developed for the visible light assisted
oxidation of thiols to disulfides using molecular oxygen as an oxidant under alkaline free conditions and
therefore more environmentally friendly. Pyrolysis of heterogenized tetrasulfonated cobalt(II) phthalocyanine
(CoPcS) supported on mesoporous ceria (CeO2) transforms it into a novel heterogeneous ‘‘Nanorust’’
containing CoOx-C,N@CeO2 which exhibited higher catalytic activity than the homogeneous CoPcS as well
as the ceria immobilized CoPcS catalyst. Importantly, these catalysts could easily be recovered and recycled
for several runs, which makes the process greener and cost-effective.
Slow Pyrolysis of Corncobs for Biochar as a Possible Alternative to Graphene ...Alexander Lau
The document examines using slow pyrolysis of corncobs to produce biochar as a potential alternative to graphene, as biochar shows similarities to graphene in properties like optical absorption when analyzed using UV-Vis spectroscopy. Various pyrolysis temperatures were tested and results showed that biochar yield and carbon content peaked at around 300-400°C, while chemical activation changed the pore structure of biochar to potentially mimic graphene. In conclusion, biochar shows potential as a graphene alternative but requires further analysis and thin film fabrication studies.
Catalytic cracking of polypropylene waste over zeolite betaAlexander Decker
This document summarizes a study that investigated the catalytic cracking of polypropylene (PP) waste using zeolite beta (BEA) catalysts. BEA catalysts with different Si/Al ratios were synthesized from mesoporous silica and tested for their ability to crack PP waste at various temperatures. The BEA catalyst with Si/Al ratio of 12.5 showed 95% conversion of PP waste at 400°C. Catalytic cracking led to higher conversions and more valuable products compared to thermal cracking. The used BEA catalyst could be regenerated with similar activity to the fresh catalyst.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Recovery of Lead (II) from electroplating industrial wastewater by Bio-func...Rajmohan Govindarajan
Heavy metal removal from wastewater through adsorption is more effective, eco-friendly and recyclable.
Use of activated carbon, Graphene nanosheets, nanotubes etc. have higher specific area.
Use of immobilized biomass increase the pore structure and adsorption sites areas.
Magnetic adsorption by magnetic nanoparticles are easy to separate from the treatment system.
Combining of adsorbent particle constituting magnetic particles and immobilized biomass alginated beads have advantages of increased pore structure, surface area and ability of recycling.
Optical Control of Selectivity of High Rate CO2 Photoreduction Via Interband-...Pawan Kumar
Photonic crystals consisting of TiO2 nanotube arrays (PMTiNTs) with periodically modulated diameters were fabricated using a precise charge-controlled pulsed anodization technique. The PMTiNTs were decorated with gold nanoparticles (Au NPs) to form plasmonic photonic crystal photocatalysts (Au-PMTiNTs). A systematic study of CO2 photoreduction performance on as-prepared samples was conducted using different wavelengths and illumination sequences. A remarkable selectivity of the mechanism of CO2 photoreduction could be engineered by merely varying the spectral composition of the illumination sequence. Under AM1.5 G simulated sunlight (pathway#1), the Au-PMTiNTs produced methane (302 µmol h-1) from CO2 with high selectivity (89.3%). When also illuminated by a UV-poor white lamp (pathway#2), the Au-PMTiNTs produced formaldehyde (420 µmol h-1) and carbon monoxide (323 µmol h-1) with almost no methane evolved. We confirmed the photoreduction results by 13C isotope labeling experiments using GC-MS. These results point to optical control of the selectivity of high-rate CO2 photoreduction through selection of one of two different mechanistic pathways. Pathway#1 implicates electron-hole pairs generated through interband transitions in TiO2 and Au as the primary active species responsible for reducing CO2 to methane. Pathway#2 involves excitation of both TiO2 and surface plasmons in Au. Hot electrons produced by plasmon damping and photogenerated holes in TiO2 proceed to reduce CO2 to HCHO and CO through a plasmonic Z-scheme.
Reduced graphene oxide–CuO nanocomposites for photocatalyticconversion of CO2...Pawan Kumar
tReduced graphene oxide (rGO)–copper oxide nanocomposites are prepared by covalent grafting of CuOnanorods on the rGO skeleton. Chemical and structural features of rGO–CuO nanocomposites are probedby FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO–CuO nanocomposites is exploredfor reduction of CO2into the methanol under the visible light irradiation. The breadth of CuO nanorods andthe oxidation state of Cu in the rGO–CuO/Cu2O nanocomposites are systematically varied to investigatetheir photocatalytic activities. The pristine CuO nanorods exhibited very low photocatalytic activity owingto fast recombination of charge carriers and yielded 175 mol g−1methanol, whereas rGO–Cu2O andrGO–CuO exhibited significantly improved photocatalytic activities and yielded five (862 mol g−1) andseven (1228 mol g−1) folds methanol, respectively. The superior photocatalytic activity of CuO in therGO–CuO nanocomposites was attributed to slow recombination of charge carriers and efficient transferof photo-generated electrons through the rGO skeleton. This study further excludes the use of scavengingdonor.
Pawan Homogeneous catalyst for CO2 reductionPawan Kumar
This document provides an overview of homogenous photocatalytic reduction of CO2. It discusses key topics such as what photocatalysis is, problems with CO2 reduction, classifications of photocatalysts including homogeneous and heterogeneous examples, and mechanisms of type I and type II catalysts. Molecular complexes like rhenium and ruthenium are described as promising homogeneous photocatalysts. The effects of catalyst structure, reaction conditions, and anchoring to surfaces are reviewed. Future areas of improvement include increasing turnover numbers and standardizing test conditions for fair catalyst comparisons.
Nanostructured composite materials for CO2 activationPawan Kumar
This document discusses nanostructured composite materials for CO2 activation, specifically for the photocatalytic reduction of CO2 to valuable products. It provides background on the increasing energy crisis and climate change caused by fossil fuel use. It then summarizes the basic principles and challenges of using semiconductor photocatalysts for CO2 reduction, including appropriate band gap positions and preventing electron-hole recombination. The document discusses various approaches to overcoming these challenges, such as forming heterojunction composites and using co-catalysts to facilitate charge separation and transfer.
Catalysis role in enhancement of Hydrogen Storage properties of NanomaterialsRasmeetSingh2
Rapid growth in population, increased standard of living has put the adverse effect on the environment due to the limited supply of fossil fuels, therefore the need of clean, sustainable and affordable fuel has been increased. These conditions has led to the continuous generation of H2 with very high purity over various range of pressures under mild conditions. The polymer-based organic microporous materials termed as Polymers of Intrinsic Micro porosity (PIMs) has emerged as one of selective gas separation membranes. We therefore will discuss and examine wide range of catalysts Nano-scale structure which can be subsequently used for the improvements in kinetics through Nano-scale solid state catalysis, the special properties of Nano-composites, and the role played by Nano-scale reactions.
Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C3N5 Co...Pawan Kumar
We present a potential solution to the problem of extraction of photogenerated holes from CdS nanocrystals and nanowires. The nanosheet form of C3N5 is a low-band-gap (Eg = 2.03 eV), azo-linked graphenic carbon nitride framework formed by the polymerization of melem hydrazine (MHP). C3N5 nanosheets were either wrapped around CdS nanorods (NRs) following the synthesis of pristine chalcogenide or intercalated among them by an in situ synthesis protocol to form two kinds of heterostructures, CdS-MHP and CdS-MHPINS, respectively. CdS-MHP improved the photocatalytic degradation rate of 4-nitrophenol by nearly an order of magnitude in comparison to bare CdS NRs. CdS-MHP also enhanced the sunlight-driven photocatalytic activity of bare CdS NWs for the decolorization of rhodamine B (RhB) by a remarkable 300% through the improved extraction and utilization of photogenerated holes due to surface passivation. More interestingly, CdS-MHP provided reaction pathway control over RhB degradation. In the absence of scavengers, CdS-MHP degraded RhB through the N-deethylation pathway. When either hole scavenger or electron scavenger was added to the RhB solution, the photocatalytic activity of CdS-MHP remained mostly unchanged, while the degradation mechanism shifted to the chromophore cleavage (cycloreversion) pathway. We investigated the optoelectronic properties of CdS-C3N5 heterojunctions using density functional theory (DFT) simulations, finite difference time domain (FDTD) simulations, time-resolved terahertz spectroscopy (TRTS), and photoconductivity measurements. TRTS indicated high carrier mobilities >450 cm2 V–1 s–1 and carrier relaxation times >60 ps for CdS-MHP, while CdS-MHPINS exhibited much lower mobilities <150 cm2 V–1 s–1 and short carrier relaxation times <20 ps. Hysteresis in the photoconductive J–V characteristics of CdS NWs disappeared in CdS-MHP, confirming surface passivation. Dispersion-corrected DFT simulations indicated a delocalized HOMO and a LUMO localized on C3N5 in CdS-MHP. C3N5, with its extended π-conjugation and low band gap, can function as a shuttle to extract carriers and excitons in nanostructured heterojunctions, and enhance performance in optoelectronic devices. Our results demonstrate how carrier dynamics in core–shell heterostructures can be manipulated to achieve control over the reaction mechanism in photocatalysis.
Synthesis and Characterization of Zinc Phthalocyanine-Cellulose Nanocrystal (...Pawan Kumar
We report highly fluorescent cellulose nanocrystals (CNCs) formed by conjugating a carboxylated zinc phthalocyanine (ZnPc) to two different types of CNCs. The conjugated nanocrystals (henceforth called ZnPc@CNCs) were bright green in color and exhibited absorption and emission maxima at ∼690 and ∼715 nm, respectively. The esterification protocol employed to covalently bind carboxylated ZnPc to surface hydroxyl group rich CNCs was expected to result in a monolayer of ZnPc on the surface of the CNCs. However, dynamic light scattering (DLS) studies indicated a large increase in the hydrodynamic radius of CNCs following conjugation to ZnPc, which suggests the binding of multiple ZnPc molecular layers on the CNC surface. This binding could be through co-facial π-stacking of ZnPc, where ZnPc metallophthalocyanine rings are horizontal to the CNC surface. The other possible binding mode would give rise to conjugated systems where ZnPc metallophthalocyanine rings are oriented vertically on the CNC surface. Density functional theory based calculations showed stable geometry following the conjugation protocol that involved covalently attached ester bond formation. The conjugates demonstrated superior performance for potential sensing applications through higher photoluminescence quenching capabilities compared to pristine ZnPc.
Water-splitting photoelectrodes consisting of heterojunctions of carbon nitri...Pawan Kumar
Quinary and senary non-stoichiometric double perovskites such as Ba2Ca0.66Nb1.34−xFexO6−δ (BCNF) have been utilized for gas sensing, solid oxide fuel cells and thermochemical CO2 reduction. Herein, we examined their potential as narrow bandgap semiconductors for use in solar energy harvesting. A cobalt co-doped BCNF, Ba2Ca0.66Nb0.68Fe0.33Co0.33O6−δ (BCNFCo), exhibited an optical absorption edge at ∼800 nm, p-type conduction and a distinct photoresponse up to 640 nm while demonstrating high thermochemical stability. A nanocomposite of BCNFCo and g-C3N4 (CN) was prepared via a facile solvent-assisted exfoliation/blending approach using dichlorobenzene and glycerol at a moderate temperature. The exfoliation of g-C3N4 followed by wrapping on perovskite established an effective heterojunction between the materials for charge separation. The conjugated 2D sheets of CN enabled better charge migration resulting in increased photoelectrochemical performance. A blend composed of 40 wt% perovskites and CN performed optimally, whilst achieving a photocurrent density as high as 1.5 mA cm−2 for sunlight-driven water-splitting with a Faradaic efficiency as high as ∼88%.
The document discusses nanocatalysis, which involves using nanotechnology products as catalysts (called nanocatalysts). It describes the history and introduction of nanocatalysis, benefits of nanocatalysts, methods of synthesizing nanocatalysts both homogenously and heterogeneously, types of nanocatalysts, how catalytic activity depends on properties like composition and environment, applications in industries like petroleum refining and pharmaceuticals, and concludes that nanocatalysts offer opportunities to meet future demands through their high activity and selectivity.
2014_Nguyen et al._The Journal of Supercritical FluidsHuyen Lyckeskog
This document describes a study that developed a pilot plant to catalytically convert LignoBoost Kraft lignin into bio-oil and chemicals using near-critical water. The conversion took place continuously in a fixed-bed catalytic reactor filled with ZrO2 pellets at 350°C and 25 MPa. Lignin was dispersed in an aqueous solution containing K2CO3 and phenol. The products consisted of an aqueous phase containing phenolic chemicals and a bio-oil with higher heating value than the lignin feed. Preliminary results showed that increasing the K2CO3 content increased the yield of 1-ring aromatic compounds from 17% to 27% based on dry lignin.
Final Report (Graphene supported platinum nanoparticles) (1)Sridharan Thirumalai
This document is a student project report on platinum-graphene nanocomposites as electrocatalysts in PEM fuel cells. It was submitted by T.V. Sridharan to Professor Manoj Neergat at the Indian Institute of Technology, Bombay under his supervision. The report describes the synthesis of Pt/rGO nanocomposites using a modified polyol method, and their physical and electrochemical characterization. TEM analysis showed the successful deposition of platinum nanoparticles on graphene oxide sheets. Electrochemical experiments found the Pt/rGO composite had a higher effective surface area than Pt/C, but similar activity for the oxygen reduction reaction. Further research is needed to fully realize graphene's potential as
Abstract— The content of the heavy metal cadmium (Cd) which is excessive in the soil could affects on the soil and plants health. The aim of this descriptive study was to investigate the ability of selected indigenous plants in stabilizing Cd. The study was conducted at an agricultural production center in Batu City, East Java, Indonesia. There were two stages of this study, namely: (1) analysis of nutrient and heavy metal contamination, and (2) phytoremediation experiment by using five types of indigenous plants. The experiment was arranged in completely randomized design (CRD) with three replications. Once the plants were harvested, the plant materials then were analyzed the heavy metal content remaining in the soil and absorbed by the plants. The heavy metal content analysis used AAS (Atomic Absorption Spectrometry). Subsequently, the analysis result data were calculated for the bio-concentration factor (BCF) and heavy metal reduction. The initial content of heavy metal Cd in the soil prior phytoremediation had passed the threshold value (2.26 mg kg-1). The five indigenous plants tested on the contaminated soil showed a good growth pattern, especially in the fourth week after planting. The average ability of this selected plant to reduce heavy metals Cd was up to 71.2%. The reductions of heavy metals Cd obtained by each plant were Vetiveria zizanioides (71.2%), Eleusine indica, L. (58.9%), Ageratum conyzoides L. (52.2%), Euphorbia hirta (51.8%) and Chromolaena odorata (22.1%).
This summarizes a document describing research on using boron-doped diamond (BDD) electrochemical reactors to treat polluted waters. Key points:
1) BDD electrodes have been used in various bench-scale electrochemical reactors, including undivided flow cells and trickle tower reactors, to degrade organic pollutants via electrochemical oxidation.
2) The BDD surface generates reactive oxygen species like hydroxyl radicals that can fully mineralize organic contaminants into CO2 and water. Operating parameters like current density and flow rate influence degradation rates.
3) Studies show these BDD reactors can achieve high removals of chemical oxygen demand (COD) and total organic carbon (TOC) for
Heterostructured nanocomposite tin phthalocyanine@mesoporous ceria (SnPc@CeO2...Pawan Kumar
Heterostructured tin phthalocyanine supported to mesoporous ceria was synthesized and used a
photocatalyst for CO2 reduction under visible light. The photoreduction CO2 activities of the
heterostructures were investigated in the presence of triethylamine as sacrificial agent. The developed
photocatalyst exhibited high catalytic activity for photoreduction of CO2 and after 24 hours of visible
light irradiation 2342 mmol g1 cat of methanol (fMeOH ¼ 0.0223 or 2.23%) and 840 mmol g1 cat of CO
(fCO ¼ 0.0026 or 0.26%) were obtained as the major reaction products. The methanol formation rate
(RMeOH) and CO formation rate (RCO) was found to be 97.5 mmol h1 g1 cat and 35.0 mmol h1 g1 cat
respectively. While under the identical experimental conditions mesoporous ceria (meso-CeO2) gave
only 316 mmol g1 cat of methanol (fMeOH ¼ 0.003 or 0.30%) and 126 mmol g1 cat CO (fCO ¼ 0.0004
or 0.04%) with product formation rate RMeOH ¼ 13.2 mmol h1 g1 cat and RCO ¼ 5.3 mmol h1 g1 cat.
Furthermore, the recovered catalyst showed consistent catalytic activity for at least five runs without any
significant loss in product yields
Energy level tuning of cd se colloidal quantum dots in ternary 0d 2d-2d cdse ...Journal Papers
This document summarizes the energy level tuning of CdSe colloidal quantum dots (QDs) in a ternary 0D-2D-2D CdSe QD/B-rGO/O-gC3N4 photocatalyst system for enhanced hydrogen generation. Specifically, it discusses how the use of different thiol capping ligands on CdSe QDs results in shifts in the QD energy levels and band gaps. These ligand-specific CdSe QDs then exhibit trends in photocatalytic performance consistent with their respective measured energy and gap levels. Furthermore, it describes how an optimized CdSe QD is incorporated into a ternary composite with B-rGO and O-g
Design, Performance Evaluation and Synthesis of Sulfonated Carbon Based Catal...ijtsrd
Microcrystalline cellulose can be converted into valuable products such as glucose via hydrolysis reaction at mild condition using sulfonated carbon catalyst. A sulfonated carbon material was prepared by carbonization of bamboo sawdust followed by sulfonation. Prepared catalyst was studied for its ability to catalyze microcrystalline cellulose yield via hydrolysis reaction. Three carbon based catalysts at three different temperatures 400, 450 and 500 were prepared. The sulfonated catalysts were characterized using the following analyses elemental analysis, total acid density, FT IR, SEM and XRD. Based on the above characterization results, sulfonated carbon prepared at 500 and sulfonated via ultra sonication was found to have a higher acid density that is suitable to catalyze the hydrolysis reaction. The first step in the catalyst development approach was to increase the hydrolysis reaction by employing a stronger sulfonation procedure during catalyst preparation. The total acid density obtained for sulfonated carbon catalyst at 500 was 4.16 mmol g which significantly increases glucose yield. According to the FTIR analysis the sulfonated bio char contained sulfonic, carboxylic, and phenolic groups, which are responsible for the exhibited high catalytic performance during hydrolysis of cellulose. The yield of glucose obtained was 60.5 at 149.0°C in 8hour reaction time. Kefyalew H/Mariam | Bayisa Dame | Beteley Tekola "Design, Performance Evaluation and Synthesis of Sulfonated Carbon Based Catalyst for Hydrolysis of Microcrystalline Cellulose" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-1 , December 2020, URL: https://www.ijtsrd.com/papers/ijtsrd38100.pdf Paper URL : https://www.ijtsrd.com/engineering/chemical-engineering/38100/design-performance-evaluation-and-synthesis-of-sulfonated-carbon-based-catalyst-for-hydrolysis-of-microcrystalline-cellulose/kefyalew-hmariam
Photo-assisted oxidation of thiols to disulfides using cobalt ‘‘Nanorust’’ un...Pawan Kumar
Heterogeneous ‘‘Nanorust’’ containing cobalt oxide has been developed for the visible light assisted
oxidation of thiols to disulfides using molecular oxygen as an oxidant under alkaline free conditions and
therefore more environmentally friendly. Pyrolysis of heterogenized tetrasulfonated cobalt(II) phthalocyanine
(CoPcS) supported on mesoporous ceria (CeO2) transforms it into a novel heterogeneous ‘‘Nanorust’’
containing CoOx-C,N@CeO2 which exhibited higher catalytic activity than the homogeneous CoPcS as well
as the ceria immobilized CoPcS catalyst. Importantly, these catalysts could easily be recovered and recycled
for several runs, which makes the process greener and cost-effective.
Slow Pyrolysis of Corncobs for Biochar as a Possible Alternative to Graphene ...Alexander Lau
The document examines using slow pyrolysis of corncobs to produce biochar as a potential alternative to graphene, as biochar shows similarities to graphene in properties like optical absorption when analyzed using UV-Vis spectroscopy. Various pyrolysis temperatures were tested and results showed that biochar yield and carbon content peaked at around 300-400°C, while chemical activation changed the pore structure of biochar to potentially mimic graphene. In conclusion, biochar shows potential as a graphene alternative but requires further analysis and thin film fabrication studies.
This document summarizes Carlos Loyola's presentation on biochar synthesis and its use in soil amendment and biotrickling filters. The presentation covered isolating soil bacteria that can solubilize phosphates, experimental setup to study the effect of bacterial consortia and biochar on phosphorus uptake by plants, characterization of biochars produced from different biomass at various temperatures, and potential use of biochar and avocado seeds as support materials in biotrickling filters.
The document summarizes an initiative by an exciting startup company that deals with developing and marketing biotic fertilizer made from biochar. Biochar is a carbon-rich charcoal produced from plant waste through pyrolysis, a process of heating biomass in the absence of oxygen. The company plans to target farmers and agricultural corporations by providing a first-of-its-kind, natural fertilizer in India at affordable prices. It projects increasing sales and profits over three years through establishing production machines, acquiring biotic waste, and implementing marketing and distribution networks.
Ceramic materials can be classified according to their type, function, or microstructure. They have properties including high strength and stiffness, resistance to heat and corrosion, and hardness. Important ceramic materials include structural ceramics, refractories, abrasives, cements, glasses, advanced ceramics, and magnetic and electronic ceramics.
Carbon nanotubes have unique electrical, mechanical, and thermal properties that make them promising for a variety of applications. They have very high tensile strength and thermal conductivity. Their properties depend on their geometry, with single-walled nanotubes being metallic or semiconducting depending on their structure. Common synthesis methods include arc discharge, laser ablation, and chemical vapor deposition. Raman spectroscopy is useful for characterizing carbon nanotubes and can determine their diameter and identify defects. Potential applications of carbon nanotubes include use in electronics, gas sensors, field emission displays, and energy storage.
The document discusses the carbon, nitrogen, and phosphorus cycles, explaining how each element cycles through the environment and is used by organisms. It also describes how human activities like burning fossil fuels, agriculture, and deforestation are disrupting these natural cycles and releasing excess carbon, nitrogen, and phosphorus into the environment, leading to issues like global warming, acid rain, and pollution of waterways.
EU-OSHA. European Agency for Safety and Health at Work.
The huge scope, novelty, excitement about promised benefits coupled with the uncertainty and low current level of understanding in a rapidly changing scientific field poses significant challenges for risk communication on ENM to workplaces.
• Risk communication strategies need to handle these uncertainties and to be able to adapt to facilitate reframing and redefining of the issues as they change with the emergence of new ENM and scientific knowledge.
• Because there is as yet no outright rejection of nanotechnology, policy- makers have the opportunity to define how to frame communication on ENM to promote a sensible risk management. Once this frame has been found it needs to be used consistently among stakeholders.
• In order to ensure long-term success of risk communication initiatives to workplaces, these should inform decisions that employers make about workplaces and support them in implementing adequate prevention measures; and empower individual workers to exert personal control over their own situations and environments
Celebrity PR involves managing all aspects of a celebrity's public image including their appearances, statements, dress code and behavior. Various tactics are used including press releases, interviews, publicity stunts, social media, charity work and branching out into other ventures like restaurants, clothing lines or politics. Reality television and guest roles help further promote celebrities, and strong social media use was key to Brand Obama's PR success.
The document summarizes the manufacturing process of ceramic tiles. Raw materials like clay, silica, and talc are ground into a slurry using a continuous ball mill. The slurry is spray dried into a fine powder and stored in silos. The powder is pressed into tiles using hydraulic presses and dried. Tiles are glazed, printed, and fired in a roller kiln to increase strength. The finished tiles are sorted, packaged, and shipped for use in floors, walls, roofs, and ceilings.
This document summarizes the history and development of ceramic materials used in dentistry over the past 200+ years. It traces the evolution from early porcelain dentures in the late 18th century to modern all-ceramic systems using lithium disilicate, zirconia and CAD/CAM technologies. The key properties of esthetics, biocompatibility, strength and preservation of tooth structure are discussed for different ceramic types. Clinical indications and considerations are provided to help practitioners select the best ceramic material for a given case.
The document summarizes the operations of a financial institute, using IDBI Bank as a case study. It discusses the inputs, processes, and outputs of IDBI's operations. The main inputs are deposits from customers including fixed deposits, current deposits, and savings deposits. The processes include activities like check clearance, account management, and advertising. The outputs are loans, financial services, and security of savings instruments provided to customers.
Applications of nanomaterials in food and cosmeticAnkita Jagtap
This document discusses applications of nanomaterials in food and cosmetics. It begins by defining nanomaterials as materials with at least one dimension between 1-100 nanometers. It describes how nanomaterials are synthesized using bottom-up or top-down methods and lists some common types including carbon-based, metal-based, and dendrimers. The document notes that nanomaterials can be engineered to have specific properties and outlines properties of nanomaterials related to their size, shape, and surface chemistry. It states that nanomaterials find applications in food such as supplements or additives to improve texture, appearance and shelf-life, and in cosmetics to deliver active ingredients and UV protection.
This document reviews nanotoxicology and the toxicity of nanomaterials. It defines nanomaterials and nanotoxicology, and discusses the subdisciplines of toxicology. Nanotoxicology studies the toxicity of nanomaterials, which exhibit unique properties and potential health effects compared to larger materials due to their nanoscale size and large surface area. Some reasons for nanoparticle toxicity include increased reactivity due to quantum effects and adherence to tissues. The document discusses experiments showing carbon nanomaterials impairing mobility and causing death in fruit flies, as well as spreading between flies. It notes both inorganic and organic nanoparticles can have toxic effects and emphasizes the need for further research to develop nanomaterials with minimal adverse impacts.
Nanomaterials are commonly defined as materials with at least one dimension measuring less than 100 nanometers. They can exist in single, spherical, tubular, or irregular shapes in one, two, or three dimensions. Nanomaterials are important because their ultra-small size enables benefits like transparency in coatings and high strength with minimal material. Their large surface area enhances reactivity, strength, and electrical properties compared to larger particles of the same composition. Nanomaterials are created through top-down methods like grinding or bottom-up sol-gel processes and have applications in ceramics, semiconductors, powders, and thin films due to their unique mechanical, electrical, and optical properties at the nanoscale.
The document discusses various characterization techniques used to analyze nanomaterials. It begins by providing historical context on the origins of nanotechnology and then describes several microscopy and spectroscopy methods. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, small angle X-ray scattering, and scanning probe microscopy are some of the key techniques explained in the document.
This document provides an overview of nanomaterials and carbon nanotubes. It discusses how nanomaterials are materials with sizes between 1 to 100 nm that exhibit unique properties. Carbon nanotubes are nanomaterials made of rolled graphene sheets that have excellent mechanical and electrical properties. The document outlines several methods for synthesizing carbon nanotubes including high pressure carbon monoxide deposition and chemical vapor deposition. It then discusses important properties and applications of carbon nanotubes such as their strength, conductivity, and use as reinforcements in composites.
This document discusses types of mechanisms obtained through inversion of a single kinematic chain. It describes four bar chain mechanisms that have all four turning pairs, single slider crank chains that have three turning pairs and one sliding pair, and double slider mechanisms that have two turning pairs and two sliding pairs. Examples are given for each type of mechanism along with their purposes.
The document discusses surface modification of nanoparticles to improve their properties and applications. Surface modification can make nanoparticles more hydrophilic, hydrophobic, conductive or anticorrosive. Functionalizing nanoparticle surfaces is necessary to optimize properties for use in various fields like engineering, medicine and biology. Common modification techniques discussed are NMR, FTIR, RAMAN spectroscopy, and TEM imaging. Surface modification can improve nanoparticle dispersion, enhance coatings for scratch/corrosion resistance, and develop transparent, wear resistant or superhydrophobic coatings.
all ceramic materials- Dr Rasleen SabharwalRas Sabharwal
This document provides an overview of all ceramic materials used in dentistry. It begins with an introduction to dental ceramics and their advantages over other materials. The document then covers the history, composition, properties and classification of different ceramic materials. It describes various strengthening methods for ceramics including residual stresses, dispersion of crystalline phases, and thermal compatibility. The document outlines production techniques for conventional powder slurry ceramics, castable ceramics, machinable ceramics, infiltrated ceramics, and zirconia-based systems.
This study examined the bioregeneration of granular activated carbon (GAC) contaminated with hydrocarbon using Pseudomonas putida bacteria. The rate of bioregeneration was analyzed by varying the volume of bacteria from 10-40ml and the temperature from 25-45°C over 21 days. Increasing the bacteria volume and temperature both increased the rate of bioregeneration. The highest regeneration efficiency occurred with 40ml of bacteria at 40°C, as increasing temperature further to 45°C did not provide additional benefit. Characterization of the GAC before and after regeneration showed that its properties were largely preserved through the bioregeneration process.
Experimental Studies on Bioregeneration of Activated Carbon Contaminated With...IOSR Journals
The document summarizes an experimental study on bioregenerating activated carbon contaminated with hydrocarbons. The researchers characterized virgin and regenerated activated carbon and found the regeneration process maintained the carbon's key properties. They conducted experiments regenerating contaminated carbon using different volumes of Pseudomonas Putida bacteria and temperatures. Increasing bacteria volume and temperature both increased regeneration rates by reducing total hydrocarbon content more quickly. The optimal conditions were 30-40ml of bacteria at 35-40°C, providing effective regeneration while remaining economical.
The characteristic of pelleted broiler litter biochar derived from pilot scal...Alexander Decker
This document summarizes a study that compared the characteristics of biochar produced from pelleted broiler litter using two different pyrolysis methods. Biochar was produced using a pilot-scale pyrolysis reactor (PBLBP) and a 200-liter oil drum kiln (PBLBO) at 500°C for 5 hours. Testing found that PBLBO had a higher surface area, total pore volume, and content of phosphorus, potassium, calcium, magnesium, organic matter, and cation exchange capacity compared to PBLBP. However, PBLBP had a higher nitrogen and moisture content. No heavy metals were detected in either biochar. The study concludes that biochar produced in the 200-liter oil drum kiln
This document describes a study on producing activated carbon from agricultural waste. Researchers tested two types of agricultural waste - rice husk and paper mill waste - as precursors for activated carbon production. They characterized the wastes using CHNS elemental analysis and proximate analysis to determine which was superior. Paper mill waste was found to be a better precursor. It was chemically activated using zinc chloride, potassium hydroxide, and potassium chloride. The researchers optimized production conditions and characterized the activated carbon produced in terms of iodine value, yield percentage, apparent density, ash content, and moisture content. The activated carbon with the highest iodine value of 764.80 mg/g was produced using zinc chloride as the activating agent.
Microwave-Assisted hydrothermal carbonization and characterization of Amazoni...perrrrojosesoto
Microwave-Assisted hydrothermal carbonization and characterization of Amazonian biomass as an activated carbon for methane adsorption - ScienceDirect.pdf
This document summarizes a study on producing granular activated carbon from activated sludge. Activated sludge was obtained from a dairy wastewater treatment plant and chemically activated using sulfuric acid. The resulting activated carbon was characterized based on its physical properties, structure, and ability to adsorb pesticides. Testing showed the activated carbon had a high surface area of 580 m2/g and effectively adsorbed pesticides, fitting the BET adsorption model well. The maximum pesticide adsorption capacity was 110 mg/g at pH 3. Activated sludge is shown to be a promising low-cost precursor for producing activated carbon.
This document describes a study that aimed to select Spirulina strains with high CO2 fixation capabilities for large-scale cultivation. Nine Spirulina species were screened in column bioreactors with 10% CO2 addition. Strains 208 and 220 were selected and optimized in 4 m2 raceway ponds for pH, dissolved inorganic carbon, and phosphate levels. The optimized conditions were then used to cultivate the two strains on a large scale of 605 m2 raceway ponds aerated with purified CO2 from a coal plant, achieving daily biomass production of up to 18.7 and 13.2 g/m2.
Gasification the Flexible Answer to Biomass Conversionbigterguy
Gasification is a process that converts biomass into syngas (CO, H2, CO2) at high temperatures. This allows biomass to be more easily handled and converted into liquid fuels and chemicals through established processes. However, biomass gasification faces challenges like tar production and high oxygen content requiring more energy to remove. While some biomass gasification projects have begun, many have faced operating or funding difficulties. Gasification may be more economically viable when producing higher value chemicals rather than fuels alone.
Biomass gasification for hydrogen productionMd Tanvir Alam
Biomass gasification can be used to produce hydrogen fuel through thermal conversion processes. Gasification involves heating biomass with limited oxygen to produce syngas containing hydrogen, carbon monoxide, and other gases. Several pathways exist to convert biomass to hydrogen through gasification. Research has demonstrated hydrogen yields of up to 60% by volume from biomass gasification using fluidized beds and catalysts. Economic analyses show biomass gasification can competitively produce hydrogen compared to natural gas reforming. With environmental and economic benefits, biomass gasification is a promising option for renewable hydrogen production.
PRESENTATION ON PLANT DESIGN FOR MANUFACTURING OF HYDROGENPriyam Jyoti Borah
Steam reforming or steam methane reforming is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen production.The reaction is conducted in a reformer vessel where a high pressure mixture of steam and methane are put into contact with a nickel catalyst. Catalysts with high surface-area-to-volume ratio are preferred because of diffusion limitations due to high operating temperature. Examples of catalyst shapes used are spoked wheels, gear wheels, and rings with holes. Additionally, these shapes have a low pressure drop which is advantageous for this application.
Hydrogen generation by cascading hydrothermal liquefaction of cotton with pho...Richa Tungal
This document describes a novel integrated process for enhanced hydrogen generation from biomass. The process involves two steps: 1) Hydrothermal liquefaction of biomass at 250°C in the presence of a nickel catalyst produces a biocrude containing carboxylic acids as well as hydrogen gas, though hydrogen yields are low. 2) Solar photocatalytic reforming of the biocrude using a platinum-coated titanium dioxide catalyst generates additional hydrogen, with hydrogen yields up to 17.82% higher than hydrothermal liquefaction alone. The integrated hydrothermal liquefaction and photocatalytic reforming process has potential for improved hydrogen production from biomass.
The document discusses bio-energy generation from food waste through hydrothermal liquefaction. It begins by introducing the process of hydrothermal liquefaction, which converts wet biomass into bio-oil under moderate temperature and high pressure, mimicking natural fossil fuel formation. It then discusses how food waste can be converted into energy through various waste-to-energy techniques, focusing on hydrothermal liquefaction. Hydrothermal liquefaction holds advantages as it can process high-moisture feedstocks like food waste to produce bio-oil with energy densities similar to coal, potentially offsetting the need for fossil fuels.
Effect Of Curing Temperature And Curing Hours On The Properties Of Geo-Polyme...ijceronline
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Carbon Materials from High Ash Bio-char: A Nanostructure Similar to Activated Graphene
1. 2013 American Transactions on Engineering & Applied Sciences.
American Transactions on
Engineering & Applied Sciences
http://TuEngr.com/ATEAS, http://Get.to/Research
Carbon Materials from High Ash Bio-char:
A Nanostructure Similar to Activated Graphene
Gu, Zhengrong a*; Wang, Xiaomin a
a
Agricultural and Biosystems Engineering Department, South Dakota State University
SAE 221, Box 2120, 1400 North Campus Drive, Brookings SD 57007, USA
ARTICLEINFO A B S T RA C T
Article history: Problem statement: Developing high-value nanostructured
Received August 25, 2012
Received in revised form October carbon from bio-char, for electrical and natural gas energy storage, is
08, 2012 critical to improving the economic viability of thermochemical
Accepted 12 October 2012 bioenergy and biofuel conversion processes. Approach: We show
Available online
20 November 2012 chemical activation, using potassium or sodium hydroxide as
Keywords: catalysts, converted the biochar of distiller’s dried grains with soluble
Activation; into activated carbon with high surface area (> 1500 m2/g). Results:
Biochar; The development of porosity by chemical activation using alkali
Activated carbon; hydroxides depends on type and dosage of activation catalysts;
Grapheme; activation temperature and atmosphere conditions. Activated carbon
Mesopore; samples with high mesoporous volume (>1 ml/g), and nanostructure
Hierarchical. similar to activated graphene were prepared at activation temperature
(1050 °C) and KOH loading (0.05 or 0.075 mol/g biochar).
Conclusion: This protocol offers the potential to use other protein
rich feedstocks for preparing nanostructured carbon, containing
nanostructure similar to activated graphene, as an advanced carbon
material.
2013 Am. Trans. Eng. Appl. Sci.
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
Zhengrong.gu@sdstate.edu, 2013. American Transactions on Engineering & Applied
Sciences. Volume 2 No.1 ISSN 2229-1652 eISSN 2229-1660 Online Available at
15
http://TuEngr.com/ATEAS/V02/015-035.pdf
2. 1. Introduction
Renewable lignocellulosic biomass, such as native grasses, as well as agricultural crop
residues including corn stover, can be converted to drop-in biofuels through thermochemical
processes. Because of the lower reaction time and fewer pretreatment requirements,
thermochemical processes are more efficient than bio-chemical/biological processes. All
thermochemical bioenergy conversion processes, including gasification, hydrothermal pyrolysis,
fast pyrolysis and slow pyrolysis, generate a solid co-product called bio-char. The bio-char
generated from fast pyrolysis has a significantly higher ash content than charcoal obtained through
traditional carbonization processes. So far, bio-char generated in thermochemical conversion has
only been used as a soil amendment or low grade fuel (Brewer et al. 2008; Wang et al. 2009), which
inherently limits the market demand for this type of char. Therefore, developing high-value
co-products from bio-char is necessary to improve the economic sustainability and viability of
thermochemical bioenergy and biofuel conversion processes.
Activated carbon is one possible high-value co-product ($1100 US/ton in 2007) with demands
growing 9% annually through 2017 (Marsh and Rodriguez-Reinoso 2006; GIA 2012). In the
activated carbon industry, physical activation by using gasifying agents, carbon dioxide and water
vapor (either singly or together) and chemical activation by using potassium/sodium hydroxides or
their carbonates are well established for activation of pyrolyzed biomass (charcoal or bio-char)
from woody biomass such as coconut shell or hardwood. In research, bio-char from fast pyrolysis
of wood, or corn cob containing less than 20% ash, has been successfully converted to activated
carbon with surface area >1000 m2/g through physical activation with CO2 (Zhang et al. 2004), and
chemical/catalytic activation with KOH (Azargohar and Dalai 2008), while most fast pyrolysis
bio-char, from herbaceous biomass, were only successfully upgraded to activated carbon with low
surface area (around 600 m2/g) with physical activation (Zhang et al. 2004; Lima et al. 2010).
However, dehydrating agents, such as ZnCl2 and H3PO4, are not suitable for activation of
carbonized feedstock (Marsh and Rodriguez-Reinoso 2008; Gu et al. 2008) such as bio-char
(results not reported here).
Currently, high surface (>2000 m2/g) activated carbon, from sustainable resources, is
attracting more attention because of a fast growing market for electrical energy and natural gas
16 Zhengrong Gu and Xiaomin Wang
3. storage. Likewise, activated carbon with high surface area (>2000 m2/g) has been prepared
successfully from herbaceous biomass such as peanut shell (Ioannidou and Zabaniotou 2007), rice
husk /straw (Zhang et al. 2009), sewage sludge (Lillo-Rodenas et al. 2008), corn cob (Aworn et al.
2009), using NaOH, KOH or carbonates of alkali metals as activation agents. However, bio-char,
after recovering biofuel or bioenergy, is different from biomass. The much higher mineral (ash)
content in these bio-chars creates a significantly different challenge for preparing high quality
activated carbon. In most herbaceous bio-char, major ash components are silica or silicate
derivatives followed by oxides of alkalis (Brewer et al. 2008). Soluble ash components (e.g.,
carbonates and oxides of alkali metals, alkali earth metals and oxides of transition metals) in
herbaceous bio-chars are particularly effective positive catalysts for gasification of carbon using
steam or carbon dioxide (Marsh and Rodriguez-Reinoso 2008; Gu et al. 2008). For example, only
trace (about 1% wt) alkali and alkali earth metal oxidants in bio-chars catalyze combustion reaction
with steam or oxygen 10 times faster (Matsumoto et al. 2010), while insoluble silica ash
components in biomass or high ash bio-char has been used as a natural template for controlling the
pore structure of activated carbon in chemical activation catalyzed by hydroxide or carbonates of
alkali metal (Yeletsky et al. 2009).
Corn ethanol is the major biofuel in USA, which generate distiller’s dried grains with solubles
(DDGS) as major co-product. DDGS, containing mainly protein, fiber and fat, is generally used
as an additive for animal feeds. DDGS was also used as potential energy sources for producing
bio-oil with about 67% heating value of gasoline through thermochemical processes (Lei et al.
2011), which also generated 20~30% bio-char containing around 50% ash and minerals. Bio-char
of DDGS is far different from the char of other biomass such as crops residues and energy crops.
Although high surface area activated carbon has been prepared from bread yeast residues using
alkali metal carbonates as activation agents (Urabe et al. 2008), bio-char of DDGS, after biooil
recovery, has not been utilized in carbon materials preparation.
In this study, bio-char from DDGS after pyrolysis, which was a co-product produced by
thermochemical processing designed for maximum bioenergy production, was collected and
chemically activated using KOH and NaOH as catalysts. Activated carbon samples were
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
Zhengrong.gu@sdstate.edu, 2013. American Transactions on Engineering & Applied
Sciences. Volume 2 No.1 ISSN 2229-1652 eISSN 2229-1660 Online Available at
17
http://TuEngr.com/ATEAS/V02/015-035.pdf
4. characterized using different analytic approaches (e.g., Scanning Electron Microscopy (SEM),
Raman Spectroscopy, N2 isothermal adsorption, and XRD and TEM). This study aimed to
evaluate impact of activation parameters, (i.e., catalysts type, ratio of base to char, atmosphere
during activation, and temperature) on properties of generated activated carbon.
2. Materials and Experimental Methodology
2.1 Materials
Bio-char of DDGS was used as feeding material for activation. This bio-char was produced
from biomass using pyrolysis process. See the compositions and properties of the bio-char listed in
Table 1. Table 2 gives Mineral ash composition in bio-char of DDGS.
Table 1: Compositions and properties of bio-char sample.
Ash%dry Density surface
Volatile Moisture N%
Biomass C% dry C/N (575 C for (apparen area
% dry % dry
24 hr) t) m2/g
DDGS 9.3 4.4 8.27 60.73 7.27 47.42 0.36 7.77
Table 2: Mineral ash composition in bio-char of DDGS.
Mineral Ca P K Na Mg Fe S
% in ash 28 8 2 2 2 15 1.5
2.2 Activation
NaOH and KOH were used as catalysts for chemical activation in N2 inert atmosphere.
Bio-char samples were mixed with solution of catalysts and dried in a conventional oven at 120 °C
overnight. These dried mixtures were further dried at 400 °C in a muffle furnace (chamber is
15*15*22 cm) in N2 atmosphere (N2 flow is 500 ml/min) for more than 2 hours to remove crystal
water. Then, activation was carried out at specific temperatures for a certain amount of time. After
specified activation time, activated samples were cooled within muffle furnace in same N2
atmosphere. The control experiments without N2 flow were also tested with a KOH catalyst.
After activation, activated carbon samples were washed with 0.1 mol/L HCl at 100 °C with
condensing, then washed with DI water to pH 7 and dried at 105 C overnight under vacuum.
18 Zhengrong Gu and Xiaomin Wang
5. A B
C D
NaOH 950 C KOH 950 C KOH 1050 C KOH 950 C no N2
Figure 1: Catalysts load and activation.
A: Surface Area, B: Micropore Volume, C: Mesopore Volume, D: Total Pore Volume
2.3 Analytical methods for bio-char and activated carbon samples
Isotherm adsorption of N2 at 77K was carried out using Surface Area and Pore Size analyzers
(one ASAP 2010 Micropore analyzer). The specific surface areas were calculated using the
Brunauer–Emmett–Teller (BET) equation. The total pore volumes were obtained at relative
pressure 0.99 P0. The micropore volume was estimated using t-plot method, while mesopore
volume and the pore size distribution were determined by the NLDFT analysis for carbon with slit
pore model (Micromeritics Inc.) based on the N2 isotherm adsorption data.
The methylene blue adsorption was analyzed according to standard protocol described in
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
Zhengrong.gu@sdstate.edu, 2013. American Transactions on Engineering & Applied
Sciences. Volume 2 No.1 ISSN 2229-1652 eISSN 2229-1660 Online Available at
19
http://TuEngr.com/ATEAS/V02/015-035.pdf
6. reference (Marsh and Rodriguez-Reinoso 2008; Gu et al. 2008). For brief, specific volume
methylene blue solution 1.5 g/L in phosphate buffer (3.6 g KH2PO4 and 14.3 g Na2HPO4 in 1 L
water, pH=7, no titration is permitted) was added to 0.1 g dried activated carbon (>90% pass 200
mesh or 71um screen) and incubated for 10 minutes on shaker (275 rpm) at 25 C. The slurry was
centrifuged at 5000 rpm for 5 minutes and filtrate with filter paper. The clarified sample was
quantified with spectrophotometer at 665 nm (1cm cuvette). If the Ab of light was the same as
CuSO4 solution (2.4g CuSO4.5H2O in 100 ml water), the specific volume of methylene blue was
used to calculated adsorption amount. If the Ab of light was higher than CuSO4 solution, the
methylene blue solution volume was reduced and the assay was redone.
Mineral composition in carbon samples were identified and quantified with inductively
coupled plasma–atomic emission spectrometry (ICP-AES Varian 735-ES). The structure of
activated carbon was also characterized with Raman Spectrum (Horiba LABRam confocal Raman
microscope) at room temperature, using an excitation wavelength at 532 nm from a diode pumped
solid-state laser, as well as TEM (Hitachi H-7000 FA) and XRD (Rigaku D/Max Ultima).
A B
Supplement Figure 1:
A: Methylene blue Adsorption and Surface Area, B: Methylene blue Adsorption and Pore Volume.
20 Zhengrong Gu and Xiaomin Wang
7. 3. Results and Discussion
3.1 Bio-char properties
The ash content of DDGS bio-char used in this project is higher than 45%wt, while its BET
surface area is less than 10 m2/g. After activation, the apparent bulk density of activated carbon is
around 0.2 g/cm3 as same as activated carbon from coal using KOH at the same molar ratio to char.
3.2 Impact of activation parameters
For both activation catalysts, the dosage of the activating agent changed the surface area of the
activated carbons derived from DDGS bio-char. For activation with KOH at 950 °C, the BET
surface area increased with the increase in the dosage of KOH, until the molar/mass ratio of
base/bio-char reached 0.075, and then decreased slightly; while BET surface area just fluctuated
around 2500 m2/g for activation using KOH at 1050 °C. For activation with NaOH at 950 °C, BET
surface area increased with the increase in the dosage of the catalyst (Figure 1A). Microporous
volume also heavily depends on temperature and catalysts loading, (i.e., increased with dosage of
KOH and NaOH), until the molar/mass ratio of base/bio-char reached 0.075 at 950 °C. But at
1050 °C, microporous volume decreased heavily at high KOH loading (> 0.05 mol/g) (Figure 1B).
However, the total pore volume and mesopore volume increased with dosage of catalysts (Figure
1C&D).
Those results could be explained according to mechanism of base activation (Alcañiz-Monge
and Illán-Gómez 2008; Lillo-Rodenas et al. 2003); the carbon burnoff increased with catalyst
loading and temperature (Figure 2A) because reactions between carbon and sodium or potassium
hydroxide are more favored at higher temperatures and high activation agent loading. Therefore,
the BET surface area increased with carbon burnoff until around 40% (Figure 2B). However,
further increasing KOH loading caused more severe burnoff of the surface carbon atoms through
carbon gasification reactions with activation agent KOH and activation products, such as K2CO3,
K2O, CO2 and H2O, as well as lead to a decrease of the surface area of the porous carbon and
damaged the structures of micropores. As the result, micropore volume increased slightly to <40%
carbon loss (Figure 2C) then decreased with further carbon burnoff, while meso and total pore
volume increased with carbon burnoff. Additionally, the carbon loss or burnoff increased sharply
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
Zhengrong.gu@sdstate.edu, 2013. American Transactions on Engineering & Applied
Sciences. Volume 2 No.1 ISSN 2229-1652 eISSN 2229-1660 Online Available at
21
http://TuEngr.com/ATEAS/V02/015-035.pdf
8. when the ratio of KOH/bio-char increased from 0.075 to 1 mol/g because gasification of carbon
with KOH is a self-catalytic reaction catalyzed by KOH. Furthermore, the reaction rates of all of
those reactions were faster at higher temperatures. As a result, the activation at a temperature of
1050 °C generated higher specific surface area at lower KOH loading (i.e., 0.015 and 0.025 mol
KOH/g bio-char), while causing a lower specific surface area at higher KOH loading (i.e., 0.05 and
0.075 mol KOH/g bio-char) (Figure 1A). Activated carbon with less micropores as well as higher
percentage of mesopore was obtained at higher KOH dosage and temperature (Figure 1C&D),
which are attributed to predominating of pore widening at higher base loading (Alcañiz-Monge and
Illán-Gómez 2008; Lillo-Rodenas et al. 2003) and gasification on the external surface of the carbon
which destroy the porous structure. This result was also verified by pore size distribution obtained
through NLDFT analysis for isothermal N2 adsorption data with slit pore model (Fig 3A, B and C).
Pore size increased with KOH/NaOH dosage and temperature. It was noteworthy that activated
carbon samples, catalyzed using NaOH, showed lower specific surface area and porous volume
than samples prepared with KOH at the same temperature and molar dosage (Figure 1). This is
similar to results obtained in activation of low rank coal (Alcañiz-Monge and Illán-Gómez 2008;
Lillo-Rodenas et al. 2003) and lignin (Fierro et al. 2007) with NaOH and KOH, because KOH is a
stronger oxidant and dehydrator than NaOH, (i.e., KOH begins reacting with not completely
carbonized carbon at 400 °C, which is lower than NaOH at ~570 °C). The Bio-char of the DDGS
used in this project is similar to low grade coal containing high amounts of nitrogen, as well as
significant hydrogen and oxygen.
Furthermore, activated carbons prepared at 1050 °C with KOH loading at 0.05 or 0.075mol/g
or synthesized at 950 °C with higher KOH (i.e., 0.1 mol/g) loading showed nitrogen isothermal
adsorption similar to activated graphene (Zhu et al. 2011), which also showed the hysteresis loop
between adsorption and desorption isotherms (Figure 4A&B), as the evidence for the existence of
slit mesopores (Figure 3 A&B) between graphene nanosheets (Zhu et al. 2011). In this research,
mesopore structure was also shown through methylene blue adsorption analysis (Supplement
Figure 1). However, methylene blue adsorption depends more on surface area and total pore
volume due to its molecular size (1.43 nm × 0.61 nm × 0.4 nm). Therefore, in contrast to ASTM
methods, methylene blue adsorption is a useful method for estimating activation efficiency, surface
area, and total pore volume, but is not an accurate tool to quantify or estimate mesoporous pore
volume.
22 Zhengrong Gu and Xiaomin Wang
9. A B
NaOH KOH 950 C KOH 1050 C KOH 950 C no N2 Estimated
C
Figure 2: Carbon burnoff and activation
A: Catalysts load and Carbon Burnoff
B: Surface Area and Carbon Burnoff
C: Pore Volume Carbon Burnoff.
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
Zhengrong.gu@sdstate.edu, 2013. American Transactions on Engineering & Applied
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10. A
B
Figure 3. Pore Distrubution for Activated Carbon from DDGS Biochar
A: KOH 950 °C, B: KOH 1050 °C
24 Zhengrong Gu and Xiaomin Wang
11. C
D
Figure 3 (continued): Pore Distrubution for Activated Carbon from DDGS Biochar
C: NaOH 950 °C, D: KOH 950 °C without N2 flow.
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
Zhengrong.gu@sdstate.edu, 2013. American Transactions on Engineering & Applied
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12. A B
C
Figure 4. N2 isothermal for Activated Carbon from DDGS Biochar
A: KOH 950, B: KOH 1050, C: NaOH 950.
Experimental results also showed the significant impact of nitrogen flow on activation at
950 °C using KOH as a catalyst; without nitrogen flow, the surface area and pore volume are
significantly lower, even lower than activation using NaOH as catalyst with nitrogen flow (Figure
1A). However, the carbon yield was higher without nitrogen flow (Figure 2A). According to
published reports of the activation mechanism in KOH or NaOH activation, nitrogen flow can
remove gas products generated during activation, including inhibitive products such as H2 and CO,
as well as reduce potential activation agents such as vapor of hydroxides, steam and CO2
(Alcañiz-Monge and Illán-Gómez 2008; Lillo-Rodenas et al. 2003; Fierro et al. 2007). Therefore,
without nitrogen flow, the atmosphere in closed chamber became H2 and CO rich, which inhibited
further activation reactions between carbon and hydroxide catalysts.
26 Zhengrong Gu and Xiaomin Wang
13. 3.3 Activation mechanism of high ash bio-char
On the other hand, in chemical activation with KOH or NaOH, the activation mechanisms to
generate porous structure are complicated. If all porous structure was caused by carbon gasification,
according to the stoichiometry of gasification reactions listed below, the carbon burnoff should
increase linearly with catalysts loading. However, the burnoff of carbon was significantly lower
than calculated value at higher catalysts dosage, which is estimated according to mechanism listed
in below (Figure 2A). Therefore, the activation mechanism with NaOH/KOH is not only due to
gasification of carbon through reaction with catalysts and derivative product (reactions 1-6), but
also due to intercalation, which must play an important role on nano-porous structure formation. A
similar result was also verified by Alcañiz-Monge and Illán-Gómez (2008), where carbon,
activated with NaOH, showed a much higher surface area and pore volume than carbon activated
with steam or CO2 at comparable carbon burnoff because of the intercalation/de-intercalation of
metallic generated during activation.
4MeOH + –CH2 Me2CO3 + Me2O + 3H2, (1)
6MeOH + C Me + H2 + Me2CO3, (2)
Me2CO3 Me2O + CO2, (3)
4MeOH + C 4Me + CO2 + H2O, (4)
Me2O + C 2Me + CO, (5)
Me2CO3 + 2C 2Me + 3CO, (6)
Where Me is alkaline metal element, such as Na and K.
Besides reactions involving carbon and intercalation, the reaction among ash components with
catalysts are significant for forming porous structure. For example, after activation, specific
surface area of carbon samples, activated with NaOH at 0.025mol/g, was only around 300m2/g
before ash removal, while surface area of activated carbon samples increased to more than 1500
m2/g after further ash removal, i.e. water washing followed by HCl washing to remove soluble
compounds. Furthermore, specific surface area of control samples after heat treatment and ash
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14. removal without activation agent was only 30m2/g.
According to the results obtained in this research, the activation of bio-char with alkaline
hydroxide includes multiple processes: dehydration and dehydrogenation of non-carbonized
components; gasification of carbon with catalysts and derivative product; intercalation of metallic
species. In addition, soluble compounds, formed through reaction among ash components with
catalysts, are templates for forming porous structure after dissolving in washing steps. As a result,
the development of porosity in bio-char by chemical activation using alkali hydroxides depends on
several interrelated parameters: ash compositions and distribution in bio-char; initial porous
structure of bio-char; type and dosage of activation catalysts; activation temperature; time;
atmosphere conditions.
A B
Figure 5. A: Raman of Activated carbon, B: XRD of Activated carbon
3.4 Activated graphene similar structure in nanostructured activated carbon
It is also noteworthy that DDGS bio-char based nanostructured activated carbon is different
from traditional activated carbon. The most important difference is that nanostructured activated
carbons, prepared at 1050 °C with KOH dosage at 0.05 or 0.075 mol/g or at 950 °C with KOH
loading 0.1 mol/g, showed significant slit mesopores structure (Figure 3 A&B). The Raman
spectrum of the activated carbons, based on DDGS bio-char, also exhibited two peaks at 1580/cm
(G band) and 1360/cm (D band). Both G and D bands are generally caused by sp2-bonded carbon.
The D-band is usually related to the existence of disordered turbostratic/defective and
non-graphitic carbon, while the G-band, as the graphitic band, corresponds to an intermolecular
28 Zhengrong Gu and Xiaomin Wang
15. A B
C D
Figure 6: TEM of Activated carbon from DDGS biochar (KOH 0.075 1050 °C).
A: TEM at 300 nm, B: TEM at 100 nm,
C: TEM at 20 nm, D: TEM of commercial activated carbon at 50 nm
A B
Figure7. SEM image of biochar and activated carbon from DDGS
A: Biochar of DDGS B: Activated carbon (KOH 0.075, 1050 °C)
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
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16. shear vibration of carbon atoms between individual C-layers (Oskar et al. 2005). In the present
work, the Raman spectrum result showed characters corresponding to individual graphene
nanosheet structure, and the disordered and imperfect structures of carbon materials in the
activated carbon respectively. In addition, it is noteworthy that the Id/Ig of activated carbon,
activated with KOH at 1050 °C is 1.06 (Figure 5A), is similar to the value reported for activated
graphene (Zhu et al. 2011). The XRD result of the activated sample (Figure 5B) also showed
similarity to activated graphene (Zhu et al. 2011); there are no peaks related to carbon crystal
structures. This result is consistent with the observations from TEM. The high-resolution TEM
image clearly shows the micro-graphene structure within the activated carbon materials based on
DDGS bio-char. Furthermore, different from traditional activated carbon (Figure 6D), distinct
domains of graphene sheets or layers structure are observed in the TEM images (Figure 6 A&B).
The metrical thickness value is around 0.4 nm, which is close to the theoretical value (0.34 nm) of
single-layer graphene (Figure 6C). As a result, single graphite or graphene layer is obtained from
DDGS bio-char after activation with KOH. This observation was not expected, even X-ray
scattering already showed the existence of turbostratic disordered graphene stacks embedded in
amorphous phases in bio-char, which is generated from pyrolysis processes of lignocellulosic
biomass (Oskar et al. 2005; Keiluweit et al. 2010). Although the micropores in activated carbon
are formed through random cross-linking of graphene micro-sheets in the porous carbon,
individual graphene nanosheets do not exist in general activated carbon (Figure 6D) or bio-char
(Marsh and Rodriguez-Reinoso 2006; Malard et al 2009). In addition, KOH activation resulted in
layers carbon structure from DDGS bio-char particles (Figure 7A & B).
Therefore, the mechanism to form graphene structure in activated carbon, which is produced
from bio-char of DDGS with KOH activation, needs further investigation. On the other hand,
carbon materials with structure similar to graphene or oxidized graphitic sheets have been
synthesized from biobased organic compound using mesopore silicate or silica as templates
(Clippel et al. 2011). The graphene-like conductive carbonaceous structure, supported on silica or
silicates was obtained from pyrolysis, at 800°C in N2 without reducing agents, of compounds
containing clay or sepiolite and carbon precursor such as sucrose, caramel or gelatin, while only
aggregates of graphene sheets were produced without porous silicate supports (Eduardo et al. 2011;
30 Zhengrong Gu and Xiaomin Wang
17. Gmez-Avils et al. 2007). Furthermore, N-doped carbonaceous porous nano-sheets had been
synthesized from collagen cross-linked gel after pyrolysis in nitrogen atmosphere (Lee et al. 2011).
According to these reported results and samples obtained in our lab, protein rich precursors (i.e.,
DDGS and high ash content in DDGS’s bio-char) are possible major factors in forming activated
graphene like structure in prepared activated carbon samples.
Until now, graphene is generally produced from graphite through a similar method (i.e.,
breaking graphite into oxidized graphite nanosheets with strong acid and strong oxidants), which
was developed by Hummers and Offeman (1958), after that oxidized graphite nanosheets are
dispersed by ultrasonic stirring and reduced to graphene with hydrazine, hydrogen, or
electrochemical reduction (Regis et al. 2010). Although graphite based graphene has been
manufactured in pilot scale (i.e., 10 ton/year with lower cost approaches), the price is still
prohibitively high (more than $ 200/kg, XGScience Inc) for a large scale application (Segal 2009).
On the other hand, bottom-up approaches to direct synthesis graphene nanosheets from organic
compounds, such as solvent-thermochemical reduction of organic compounds with metal sodium
(Choucair et al. 2009), are still in early stages and limited by conversion ratio and costs.
4. Conclusion
We prepared a super activated carbon that has a nanostructure similar to activated graphene
and potentially offers a lower cost substitute for the advanced carbon materials currently derived
from graphene or activated graphene. According to Raman, TEM and XRD and N2 isothermal
adsorption results, the nanostructure similar to activated graphene was domain portion in the
overall structure, which was also verified by energy storage capacity of the carbon materials.
Especially as an advanced carbon material, the super activated carbon with graphene-like
nanosheets has excellent potential as high capacity anode materials for lithium batteries or
supercapacitors (Gerard and Tarun 2011) and as adsorbents for natural gas or hydrogen storage.
Our super-capacitor, using 6mol/L KOH as electrolyte and electrodes composed of activated
carbon prepared with KOH (0.075 mol/g) activation at 1050 °C, showed stable high reversible
capacity (i.e., 270 F/g at constant currents 1A/g), while the capacity is 160 F/g at constant currents
*Corresponding Author Zhengrong Gu, Tel: 605-688-5372, Email:
Zhengrong.gu@sdstate.edu, 2013. American Transactions on Engineering & Applied
Sciences. Volume 2 No.1 ISSN 2229-1652 eISSN 2229-1660 Online Available at
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18. 1A/g using organic electrolytes i.e., 1 mol/L TEA BF4 in acetonitrile (results not discussed here).
5. Acknowledgement
This research is funded by project “DEVELOPMENT OF HIGH VALUE CARBON BASED
ADSORBENTS FROM THERMOCHEMICALLY PRODUCED BIOCHAR” 2011-67009-20030
USDA-NIFA Agriculture and Food Research Initiative Sustainable Bioenergy Program.
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Dr. Zhengrong Gu is an Assistant Professor in the Department of Agricultural and Biosystems
Engineering at South Dakota State University (SDSU). Currently, Dr. Gu is a PI of the USDA (NIFA)
project that focusing on innovative carbon materials from thermochemically generated biochar. Dr. Gu
has more than 15 year experience in carbon materials preparation and application. Dr. Gu has
published one textbook of “Activated Carbon” in 2008.
Ms. Xiaomin Wang is a Research Associate in Agricultural and Biosystems Engineering Dept. at
SDSU. She is working on carbon materials preparation with chemical activation, microwave and
hydrothermal pathways as well as ultrasonic treatment in the project funded by USDA.
Peer Review: This article has been internationally peer-reviewed and accepted for
publication according to the guidelines given at the journal’s website.
34 Zhengrong Gu and Xiaomin Wang