In India around 147 million hectares (Mha) of land is under degradation, this includes 94 Mha from water erosion, 16 Mha from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of factors. Even though The total land area of India is just 2.4% of the world’s land area , it ranks second in the world in farming. Agriculture employs almost 50% of the total workforce in India. So there is an increased need for monitoring and researching the various facets of land degradation. Electrokinetics is defined as the physicochemical transport of charge, action of charged particles and effects of applied electric potentials on formation and fluid transport in porous media. The utilization of electrokinetic in geotechnical engineering for dewatering, consolidation and stabilization of low permeability and to transport certain chemical species in an electrolyte system had opened new opportunities for application in geo environmental engineering. Approaching anode is one of the enhancement techniques in electrokinetic soil remediation. This technique is reported to give promising migration for heavy metals under shorter treatment time and at lower cost in comparison to normal fixed anode system. In the present study, the effectiveness of fixed anode and approaching anode techniques in electrokinetic soil remediation for lead migration under different types of wetting agents (0.01M NaNO3 and 0.1M citric acid) was investigated. Key Words: Acidification , Failure, Land Degradation, Electrokinetics
This document discusses electro kinetic geo synthetics (EKG), which combine traditional geo synthetic functions like drainage and reinforcement with electro kinetic phenomena like electro-osmosis. EKG has applications in slope stabilization, consolidation, and dewatering of sludge and mine tailings. A case study describes how EKG successfully stabilized a failing clay embankment through electro-osmotic dewatering, increasing shear strength and reducing slope movement. Analysis found the factor of safety increased after EKG treatment. EKG provides long-term stabilization and has cost and carbon footprint advantages over conventional methods.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Aluminum Oxide-Silver Nanoparticle Interfaces for Memristive ApplicationsIOSR Journals
This document summarizes a study on a nonvolatile resistive random access memory device based on the heterojunction of silver nanoparticles and aluminum oxide. The device structure consists of aluminum-aluminum oxide-silver nanoparticles-aluminum. Current-voltage measurements show the device transitions between two states in two steps - a major transition with a resistance ratio of 105 and a minor transition with a ratio of about 101. The memristor operates at low voltages with good uniformity. Scanning electron microscopy, X-ray diffraction and optical absorption characterization confirm the formation of aluminum oxide and silver nanoparticles.
This document discusses photoelectrochemical water splitting for hydrogen production. It describes the process which uses a photoelectrode to drive the oxidation of water at the anode and the concurrent reduction of protons at the cathode to produce hydrogen gas. Issues with the technology include high costs of production compared to natural gas, slow oxygen evolution kinetics, and challenges associated with transporting and storing the gases produced. The document then reviews current research trends focused on developing new photoelectrode materials like metal oxides, improving material morphologies at the nano-scale, and investigating techniques like electrospinning to produce novel structures with improved performance.
This document summarizes a presentation on misconceptions in photocatalysis given at the 15th Orientation Course on Catalysis in India in 2014. It discusses several common misconceptions in photocatalysis research, such as referring to photocatalysts as catalysts when photocatalysis involves accumulating energy rather than just lowering activation energy. It also addresses misconceptions around the role of hydroxyl radicals, use of dyes as model compounds, definitions of photocatalytic activity and synergetic effects, and mechanisms of hydrogen production via water splitting. Recommended reading materials provide further details on the topics covered.
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.
This document discusses electro kinetic geo synthetics (EKG), which combine traditional geo synthetic functions like drainage and reinforcement with electro kinetic phenomena like electro-osmosis. EKG has applications in slope stabilization, consolidation, and dewatering of sludge and mine tailings. A case study describes how EKG successfully stabilized a failing clay embankment through electro-osmotic dewatering, increasing shear strength and reducing slope movement. Analysis found the factor of safety increased after EKG treatment. EKG provides long-term stabilization and has cost and carbon footprint advantages over conventional methods.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Aluminum Oxide-Silver Nanoparticle Interfaces for Memristive ApplicationsIOSR Journals
This document summarizes a study on a nonvolatile resistive random access memory device based on the heterojunction of silver nanoparticles and aluminum oxide. The device structure consists of aluminum-aluminum oxide-silver nanoparticles-aluminum. Current-voltage measurements show the device transitions between two states in two steps - a major transition with a resistance ratio of 105 and a minor transition with a ratio of about 101. The memristor operates at low voltages with good uniformity. Scanning electron microscopy, X-ray diffraction and optical absorption characterization confirm the formation of aluminum oxide and silver nanoparticles.
This document discusses photoelectrochemical water splitting for hydrogen production. It describes the process which uses a photoelectrode to drive the oxidation of water at the anode and the concurrent reduction of protons at the cathode to produce hydrogen gas. Issues with the technology include high costs of production compared to natural gas, slow oxygen evolution kinetics, and challenges associated with transporting and storing the gases produced. The document then reviews current research trends focused on developing new photoelectrode materials like metal oxides, improving material morphologies at the nano-scale, and investigating techniques like electrospinning to produce novel structures with improved performance.
This document summarizes a presentation on misconceptions in photocatalysis given at the 15th Orientation Course on Catalysis in India in 2014. It discusses several common misconceptions in photocatalysis research, such as referring to photocatalysts as catalysts when photocatalysis involves accumulating energy rather than just lowering activation energy. It also addresses misconceptions around the role of hydroxyl radicals, use of dyes as model compounds, definitions of photocatalytic activity and synergetic effects, and mechanisms of hydrogen production via water splitting. Recommended reading materials provide further details on the topics covered.
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.
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
This document is a resume for Dr. Elena A. Guliants seeking a research or program management position involving renewable and alternative energy technologies. She has over 23 years of experience in fields such as photovoltaics, energy storage, hydrogen generation, and nanoenergetics. Her educational background includes a Ph.D. in Electrical Engineering and an M.B.A. She is fluent in English and Russian.
Flexible and Ultrasoft Inorganic 1D Semiconductor and Heterostructure Systems...Pawan Kumar
Low dimensionality and high flexibility are key demands for flexible electronic semiconductor devices. SnIP, the first atomic-scale double helical semiconductor combines structural anisotropy and robustness with exceptional electronic properties. The benefit of the double helix, combined with a diverse structure on the nanoscale, ranging from strong covalent bonding to weak van der Waals interactions, and the large structure and property anisotropy offer substantial potential for applications in energy conversion and water splitting. It represents the next logical step in downscaling the inorganic semiconductors from classical 3D systems, via 2D semiconductors like MXenes or transition metal dichalcogenides, to the first downsizeable, polymer-like atomic-scale 1D semiconductor SnIP. SnIP shows intriguing mechanical properties featuring a bulk modulus three times lower than any IV, III-V, or II-VI semiconductor. In situ bending tests substantiate that pure SnIP fibers can be bent without an effect on their bonding properties. Organic and inorganic hybrids are prepared illustrating that SnIP is a candidate to fabricate flexible 1D composites for energy conversion and water splitting applications. SnIP@C3N4 hybrid forms an unusual soft material core–shell topology with graphenic carbon nitride wrapping around SnIP. A 1D van der Waals heterostructure is formed capable of performing effective water splitting.
A review on ipce and pec measurements and materials p.basnetPradip Basnet
The slides show how to measure the photoelectrochemical (PEC) properties of a light-active photocatalyst (usually semiconductor) and current literature summary for water splitting using sunlight.
This document summarizes research on hydrogen production in Mexico. The most active area of research is biological processes, representing 40% of published papers, focusing on topics like bioreactors. The next most active area is catalysis and modified hydrogen processes from conventional sources, representing 22% of papers. Research on photocatalysis and photoelectrocatalysis focuses on developing efficient, stable, and inexpensive photocatalytic materials. Theoretical studies concentrate on optimizing reactor design and evaluating efficiencies. Electrolysis research proposes novel alloys and electrocatalysts. The review aims to assess scientific activity and advances in hydrogen production in Mexico.
The document discusses the origin of radiation-induced degradation in polymer solar cells. It finds that charge accumulation at the interface is the primary reason for degradation, affected by the donor-acceptor mixing ratio in the bulk heterojunction. In situ measurements of polymer solar cell performance and recombination lifetimes under X-ray radiation show that devices with high acceptor concentrations experience a significant decrease in open-circuit voltage and fill factor due to radiation, while devices with low acceptor concentrations are more resistant to these changes. The findings provide a quantitative understanding and physical model of the degradation mechanism.
This document summarizes the key findings from a workshop on basic research needs for solar energy utilization. It discusses how sunlight provides by far the largest source of carbon-neutral energy but is currently underutilized. The workshop identified several priority areas for basic research that could enable major advances in solar electricity and solar fuels technologies, such as developing solar cells that are 50% efficient and using artificial photosynthesis approaches to produce fuels from sunlight, water, and carbon dioxide. Further research is needed to fully harness the potential of solar energy to meet growing global energy demands in a sustainable way.
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.
Water splitting on semiconductor catalysts under visible light irradiationMuhammad Mudassir
This document discusses photocatalytic water splitting to produce hydrogen fuel using solar energy. It begins by outlining the need to find renewable hydrogen production methods, as fossil fuel reserves are depleting. It then explains that photocatalytic water splitting uses a photocatalyst to split water into hydrogen and oxygen when exposed to sunlight, providing a renewable method. However, the process is not yet highly efficient due to recombination of the photogenerated charge carriers in the photocatalyst before they can react at the surface to split water. Improving the efficiency and durability of photocatalysts remains an ongoing challenge.
Kinetic modelling of nitrate removal from aqueous solution during electrocoag...Alexander Decker
This document discusses a study that aimed to model nitrate removal from aqueous solutions using electrocoagulation. Experiments were conducted to treat a synthetic solution containing 150 mg/L of nitrate using iron electrodes under various conditions. Kinetic and adsorption models were tested to determine which best fit the nitrate removal data. The results showed pseudo-second order kinetics and the Freundlich isotherm provided the best fits. Nitrate removal efficiency increased with reaction time and current density.
This document describes a hydrometallurgical process for recovering rare earth elements from spent nickel-metal hydride batteries. The process involves three steps:
1) Leaching electrode materials from the batteries in sulfuric acid solutions using ozone as the oxidant, which achieved over 90% recovery of lanthanum, cerium, and neodymium.
2) Separating cobalt and part of the nickel from the leach solution using electrodeposition in an electrochemical reactor.
3) Precipitating the remaining rare earth elements along with the rest of the nickel by adjusting the pH of the solution.
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.
This document summarizes research on using electrodeposited manganese dioxide (MnO2) coatings on porous carbon substrates for capacitive deionization (CDI) applications. Two carbon substrates with different surface areas and morphologies were coated with MnO2 using galvanostatic and cyclic voltammetric deposition. Characterization of the coated electrodes found mixed MnO2 phases present. Testing in half-cell configurations showed that maximum ion uptake per mass was not necessarily optimal for practical CDI applications, where performance per electrode area is more important. The results suggest the structure and deposition method can impact how effectively the electrode volume participates in ion removal reactions.
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
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.
TREATING WASTE WATER USING ELECTROCOAGULATION APPROACHIAEME Publication
Performance of Electro coagulation method is evaluated by treating various
sources of water. The electrodes of stainless steel are used for arranging electrolytic
cell. The treatment efficiency is assessed by varying electrical potential and
concentration time. The parameters namely pH, Total Dissolved Solids (TDS), Total
Hardness, Electrical Conductivity, Biochemical Oxygen Demand (BOD) and
Chemical Oxygen Demand (COD) were tested and results were compared to assess
the performance of treatment process. Effects of operating parameters such as
varying electrical potential (3V-12V) and concentration time (10 minutes- 30 minutes)
were evaluated for optimum operating conditions. The result shown that identified
electrolytic arrangement is significantly efficient for treating BOD and COD when
compared to other water quality parameters especially for grey and industrial water
samples. The highest removal efficiency under optimum operating condition for COD
and BOD removal were obtained with 58% and 67% in grey water sample whereas in
industrial waste water sample, the efficiencies are 53% and 57%. Further, the study
suggested the various simulations in the operating parameters with the economic
considerations to optimize the findings and for upcoming progress in the application
of this advanced technology.
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward
exploiting alternative energy resources such as solar energy. Here, we
report the successful low-cost and easily accessible synthesis of hybrid
semiconductor@TiO2 nanotube photocatalysts. In order to realize its
maximum potential in harvesting photons in the visible-light range, TiO2
nanotubes have been loaded with earth-abundant, low-band-gap fibrous
red and black phosphorus (P). Scanning electron microscopy− and
scanning transmission electron microscopy−energy-dispersive X-ray
spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV−vis measurements have been performed,
substantiating the deposition of fibrous red and black P on top and
inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular morphology of titania and a vapor-transport technique are utilized to form heterojunctions of P and
TiO2. Compared to pristine anatase 3.2 eV TiO2 nanotubes, the creation of heterojunctions in the hybrid material resulted in
1.5−2.1 eV photoelectrocatalysts. An enhanced photoelectrochemical water-splitting performance under visible light compared
with the individual components resulted for the P@TiO2 hybrids. This feature is due to synergistically improved charge
separation in the heterojunction and more effective visible-light absorption. The electronic band structure and charge-carrier
dynamics are investigated in detail using ultraviolet photoelectron spectroscopy and Kelvin probe force microscopy to elucidate
the charge-separation mechanism. A Fermi-level alignment in P@TiO2 heterojunctions leads to a more reductive flat-band
potential and a deeper valence band compared to pristine P and thus facilitates a better water-splitting performance. Our results
demonstrate effective conversion efficiencies for the nanostructured hybrids, which may enable future applications in
optoelectronic applications such as photodetectors, photovoltaics, photoelectrochemical catalysts, and sensors.
TiO2-HfN Radial Nano-Heterojunction: A Hot Carrier Photoanode for Sunlight-Dr...Pawan Kumar
The lack of active, stable, earth-abundant, and visible-light absorbing materials to replace
plasmonic noble metals is a critical obstacle for researchers in developing highly efficient and costeffective photocatalytic systems. Herein, a core–shell nanotube catalyst was fabricated consisting of
atomic layer deposited HfN shell and anodic TiO2 support layer with full-visible regime photoactivity
for photoelectrochemical water splitting. The HfN active layer has two unique characteristics: (1) a
large bandgap between optical and acoustic phonon modes (2) and no electronic bandgap, which
allows a large population of long life-time hot carriers, which are used to enhance the photoelectrochemical performance. The photocurrent density (≈2.5 mA·cm−2 at 1 V vs. Ag/AgCl) obtained in
this study under AM 1.5G 1 Sun illumination is unprecedented, as it is superior to most existing
plasmonic noble metal-decorated catalysts and surprisingly indicates a photocurrent response that
extends to 730 nm. The result demonstrates the far-reaching application potential of replacing active
HER/HOR noble metals such as Au, Ag, Pt, Pd, etc. with low-cost plasmonic ceramics.
Electrodeposited nanostructured a-Fe2O3 thin films for solar water splitting:...North Breeze
This document describes a study on the effects of platinum (Pt) doping on the photoelectrochemical performance of nanostructured alpha-iron oxide (α-Fe2O3) thin films deposited via electrodeposition. Un-doped and Pt-doped α-Fe2O3 thin films were characterized using various techniques. The results showed that Pt doping increased the density of small nanoparticles in the films and enhanced the photocurrent density for water splitting by up to a factor of 1.4 compared to un-doped films. The highest photocurrent density of 0.56 mA/cm2 was achieved for a 3% Pt-doped film. Electrochemical impedance analysis also revealed that Pt d
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward exploiting alternative energy resources such as solar energy. Here, we report the successful low-cost and easily accessible synthesis of hybrid semiconductor@TiO2 nanotube photocatalysts. In order to realize its maximum potential in harvesting photons in the visible-light range, TiO2 nanotubes have been loaded with earth-abundant, low-band-gap fibrous red and black phosphorus (P). Scanning electron microscopy– and scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV–vis measurements have been performed, substantiating the deposition of fibrous red and black P on top and inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular …
This document summarizes electrolytic soil decontamination methods, specifically electro-osmosis and electroacoustic techniques. Electro-osmosis uses electrical currents and potentials to mobilize ionic contaminants towards electrodes for removal. Electroacoustic adds acoustic fields to further rearrange particles and enhance removal. Both have been demonstrated at lab and field scales for heavy metal removal but have limitations for non-polar compounds and low permeability soils. Costs are comparable to other in-situ techniques when conditions allow electrolytic applications.
This document summarizes an article about electrocoagulation as a novel wastewater treatment method. Electrocoagulation uses sacrificial metal anodes that corrode when electric current is applied, producing metal cations that neutralize pollutants in water. It has advantages over other methods in providing coagulants without increasing water salinity. The document discusses the mechanisms of electrocoagulation including coagulant production, pollutant destabilization, and aggregation. Key factors like electrode material, current density, and operating conditions affect the process's performance in removing various pollutants from water.
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
This document is a resume for Dr. Elena A. Guliants seeking a research or program management position involving renewable and alternative energy technologies. She has over 23 years of experience in fields such as photovoltaics, energy storage, hydrogen generation, and nanoenergetics. Her educational background includes a Ph.D. in Electrical Engineering and an M.B.A. She is fluent in English and Russian.
Flexible and Ultrasoft Inorganic 1D Semiconductor and Heterostructure Systems...Pawan Kumar
Low dimensionality and high flexibility are key demands for flexible electronic semiconductor devices. SnIP, the first atomic-scale double helical semiconductor combines structural anisotropy and robustness with exceptional electronic properties. The benefit of the double helix, combined with a diverse structure on the nanoscale, ranging from strong covalent bonding to weak van der Waals interactions, and the large structure and property anisotropy offer substantial potential for applications in energy conversion and water splitting. It represents the next logical step in downscaling the inorganic semiconductors from classical 3D systems, via 2D semiconductors like MXenes or transition metal dichalcogenides, to the first downsizeable, polymer-like atomic-scale 1D semiconductor SnIP. SnIP shows intriguing mechanical properties featuring a bulk modulus three times lower than any IV, III-V, or II-VI semiconductor. In situ bending tests substantiate that pure SnIP fibers can be bent without an effect on their bonding properties. Organic and inorganic hybrids are prepared illustrating that SnIP is a candidate to fabricate flexible 1D composites for energy conversion and water splitting applications. SnIP@C3N4 hybrid forms an unusual soft material core–shell topology with graphenic carbon nitride wrapping around SnIP. A 1D van der Waals heterostructure is formed capable of performing effective water splitting.
A review on ipce and pec measurements and materials p.basnetPradip Basnet
The slides show how to measure the photoelectrochemical (PEC) properties of a light-active photocatalyst (usually semiconductor) and current literature summary for water splitting using sunlight.
This document summarizes research on hydrogen production in Mexico. The most active area of research is biological processes, representing 40% of published papers, focusing on topics like bioreactors. The next most active area is catalysis and modified hydrogen processes from conventional sources, representing 22% of papers. Research on photocatalysis and photoelectrocatalysis focuses on developing efficient, stable, and inexpensive photocatalytic materials. Theoretical studies concentrate on optimizing reactor design and evaluating efficiencies. Electrolysis research proposes novel alloys and electrocatalysts. The review aims to assess scientific activity and advances in hydrogen production in Mexico.
The document discusses the origin of radiation-induced degradation in polymer solar cells. It finds that charge accumulation at the interface is the primary reason for degradation, affected by the donor-acceptor mixing ratio in the bulk heterojunction. In situ measurements of polymer solar cell performance and recombination lifetimes under X-ray radiation show that devices with high acceptor concentrations experience a significant decrease in open-circuit voltage and fill factor due to radiation, while devices with low acceptor concentrations are more resistant to these changes. The findings provide a quantitative understanding and physical model of the degradation mechanism.
This document summarizes the key findings from a workshop on basic research needs for solar energy utilization. It discusses how sunlight provides by far the largest source of carbon-neutral energy but is currently underutilized. The workshop identified several priority areas for basic research that could enable major advances in solar electricity and solar fuels technologies, such as developing solar cells that are 50% efficient and using artificial photosynthesis approaches to produce fuels from sunlight, water, and carbon dioxide. Further research is needed to fully harness the potential of solar energy to meet growing global energy demands in a sustainable way.
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.
Water splitting on semiconductor catalysts under visible light irradiationMuhammad Mudassir
This document discusses photocatalytic water splitting to produce hydrogen fuel using solar energy. It begins by outlining the need to find renewable hydrogen production methods, as fossil fuel reserves are depleting. It then explains that photocatalytic water splitting uses a photocatalyst to split water into hydrogen and oxygen when exposed to sunlight, providing a renewable method. However, the process is not yet highly efficient due to recombination of the photogenerated charge carriers in the photocatalyst before they can react at the surface to split water. Improving the efficiency and durability of photocatalysts remains an ongoing challenge.
Kinetic modelling of nitrate removal from aqueous solution during electrocoag...Alexander Decker
This document discusses a study that aimed to model nitrate removal from aqueous solutions using electrocoagulation. Experiments were conducted to treat a synthetic solution containing 150 mg/L of nitrate using iron electrodes under various conditions. Kinetic and adsorption models were tested to determine which best fit the nitrate removal data. The results showed pseudo-second order kinetics and the Freundlich isotherm provided the best fits. Nitrate removal efficiency increased with reaction time and current density.
This document describes a hydrometallurgical process for recovering rare earth elements from spent nickel-metal hydride batteries. The process involves three steps:
1) Leaching electrode materials from the batteries in sulfuric acid solutions using ozone as the oxidant, which achieved over 90% recovery of lanthanum, cerium, and neodymium.
2) Separating cobalt and part of the nickel from the leach solution using electrodeposition in an electrochemical reactor.
3) Precipitating the remaining rare earth elements along with the rest of the nickel by adjusting the pH of the solution.
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.
This document summarizes research on using electrodeposited manganese dioxide (MnO2) coatings on porous carbon substrates for capacitive deionization (CDI) applications. Two carbon substrates with different surface areas and morphologies were coated with MnO2 using galvanostatic and cyclic voltammetric deposition. Characterization of the coated electrodes found mixed MnO2 phases present. Testing in half-cell configurations showed that maximum ion uptake per mass was not necessarily optimal for practical CDI applications, where performance per electrode area is more important. The results suggest the structure and deposition method can impact how effectively the electrode volume participates in ion removal reactions.
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
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.
TREATING WASTE WATER USING ELECTROCOAGULATION APPROACHIAEME Publication
Performance of Electro coagulation method is evaluated by treating various
sources of water. The electrodes of stainless steel are used for arranging electrolytic
cell. The treatment efficiency is assessed by varying electrical potential and
concentration time. The parameters namely pH, Total Dissolved Solids (TDS), Total
Hardness, Electrical Conductivity, Biochemical Oxygen Demand (BOD) and
Chemical Oxygen Demand (COD) were tested and results were compared to assess
the performance of treatment process. Effects of operating parameters such as
varying electrical potential (3V-12V) and concentration time (10 minutes- 30 minutes)
were evaluated for optimum operating conditions. The result shown that identified
electrolytic arrangement is significantly efficient for treating BOD and COD when
compared to other water quality parameters especially for grey and industrial water
samples. The highest removal efficiency under optimum operating condition for COD
and BOD removal were obtained with 58% and 67% in grey water sample whereas in
industrial waste water sample, the efficiencies are 53% and 57%. Further, the study
suggested the various simulations in the operating parameters with the economic
considerations to optimize the findings and for upcoming progress in the application
of this advanced technology.
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward
exploiting alternative energy resources such as solar energy. Here, we
report the successful low-cost and easily accessible synthesis of hybrid
semiconductor@TiO2 nanotube photocatalysts. In order to realize its
maximum potential in harvesting photons in the visible-light range, TiO2
nanotubes have been loaded with earth-abundant, low-band-gap fibrous
red and black phosphorus (P). Scanning electron microscopy− and
scanning transmission electron microscopy−energy-dispersive X-ray
spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV−vis measurements have been performed,
substantiating the deposition of fibrous red and black P on top and
inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular morphology of titania and a vapor-transport technique are utilized to form heterojunctions of P and
TiO2. Compared to pristine anatase 3.2 eV TiO2 nanotubes, the creation of heterojunctions in the hybrid material resulted in
1.5−2.1 eV photoelectrocatalysts. An enhanced photoelectrochemical water-splitting performance under visible light compared
with the individual components resulted for the P@TiO2 hybrids. This feature is due to synergistically improved charge
separation in the heterojunction and more effective visible-light absorption. The electronic band structure and charge-carrier
dynamics are investigated in detail using ultraviolet photoelectron spectroscopy and Kelvin probe force microscopy to elucidate
the charge-separation mechanism. A Fermi-level alignment in P@TiO2 heterojunctions leads to a more reductive flat-band
potential and a deeper valence band compared to pristine P and thus facilitates a better water-splitting performance. Our results
demonstrate effective conversion efficiencies for the nanostructured hybrids, which may enable future applications in
optoelectronic applications such as photodetectors, photovoltaics, photoelectrochemical catalysts, and sensors.
TiO2-HfN Radial Nano-Heterojunction: A Hot Carrier Photoanode for Sunlight-Dr...Pawan Kumar
The lack of active, stable, earth-abundant, and visible-light absorbing materials to replace
plasmonic noble metals is a critical obstacle for researchers in developing highly efficient and costeffective photocatalytic systems. Herein, a core–shell nanotube catalyst was fabricated consisting of
atomic layer deposited HfN shell and anodic TiO2 support layer with full-visible regime photoactivity
for photoelectrochemical water splitting. The HfN active layer has two unique characteristics: (1) a
large bandgap between optical and acoustic phonon modes (2) and no electronic bandgap, which
allows a large population of long life-time hot carriers, which are used to enhance the photoelectrochemical performance. The photocurrent density (≈2.5 mA·cm−2 at 1 V vs. Ag/AgCl) obtained in
this study under AM 1.5G 1 Sun illumination is unprecedented, as it is superior to most existing
plasmonic noble metal-decorated catalysts and surprisingly indicates a photocurrent response that
extends to 730 nm. The result demonstrates the far-reaching application potential of replacing active
HER/HOR noble metals such as Au, Ag, Pt, Pd, etc. with low-cost plasmonic ceramics.
Electrodeposited nanostructured a-Fe2O3 thin films for solar water splitting:...North Breeze
This document describes a study on the effects of platinum (Pt) doping on the photoelectrochemical performance of nanostructured alpha-iron oxide (α-Fe2O3) thin films deposited via electrodeposition. Un-doped and Pt-doped α-Fe2O3 thin films were characterized using various techniques. The results showed that Pt doping increased the density of small nanoparticles in the films and enhanced the photocurrent density for water splitting by up to a factor of 1.4 compared to un-doped films. The highest photocurrent density of 0.56 mA/cm2 was achieved for a 3% Pt-doped film. Electrochemical impedance analysis also revealed that Pt d
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward exploiting alternative energy resources such as solar energy. Here, we report the successful low-cost and easily accessible synthesis of hybrid semiconductor@TiO2 nanotube photocatalysts. In order to realize its maximum potential in harvesting photons in the visible-light range, TiO2 nanotubes have been loaded with earth-abundant, low-band-gap fibrous red and black phosphorus (P). Scanning electron microscopy– and scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV–vis measurements have been performed, substantiating the deposition of fibrous red and black P on top and inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular …
This document summarizes electrolytic soil decontamination methods, specifically electro-osmosis and electroacoustic techniques. Electro-osmosis uses electrical currents and potentials to mobilize ionic contaminants towards electrodes for removal. Electroacoustic adds acoustic fields to further rearrange particles and enhance removal. Both have been demonstrated at lab and field scales for heavy metal removal but have limitations for non-polar compounds and low permeability soils. Costs are comparable to other in-situ techniques when conditions allow electrolytic applications.
This document summarizes an article about electrocoagulation as a novel wastewater treatment method. Electrocoagulation uses sacrificial metal anodes that corrode when electric current is applied, producing metal cations that neutralize pollutants in water. It has advantages over other methods in providing coagulants without increasing water salinity. The document discusses the mechanisms of electrocoagulation including coagulant production, pollutant destabilization, and aggregation. Key factors like electrode material, current density, and operating conditions affect the process's performance in removing various pollutants from water.
IRJET- COD Removal by Electro-CoagulationIRJET Journal
This document summarizes research on using electro-coagulation to remove COD (chemical oxygen demand) from textile wastewater. It discusses how textile dyeing and processing produces large volumes of wastewater high in COD, color, and other pollutants. A study was conducted using a continuous plug flow reactor with iron electrodes to optimize parameters like voltage, detention time and energy usage for COD removal. Experiments were performed on wastewater from the Sanganer industrial area in India. The results showed electro-coagulation can effectively remove COD and has good treatment economics and effectiveness for textile wastewater.
This document discusses the removal of heavy metals from water using nano metal oxides. It introduces heavy metals as relatively high density metals that are toxic, like lead, arsenic, cadmium and mercury. Heavy metals accumulate in organisms and can be harmful. Nano metal oxides like ZnO are effective at removing heavy metals from water through adsorption and photocatalysis mechanisms involving the absorption of light and production of electron-hole pairs on the nanoparticle surface. This allows for the reduction of heavy metals or reaction with electron acceptors. Nano metal oxides provide an efficient and low-cost approach for heavy metal removal through these photocatalytic processes.
Recent advancements in tuning the electronic structures of transitional metal...Pawan Kumar
The smooth transition from finite non-renewables to renewable energy conversion technologies will require efficient electrocatalysts which can harness intermittent energies to store in the form of chemical bonds. The oxygen evolution reaction (OER) impedes the widespread usage of water electrolyzers to convert H2O into H2 and persists as a bottleneck, including other energy conversion devices with sluggish four H+/e− kinetics. In this context, designing highly active and stable catalysts capable of driving a lower overpotential in the OER to produce continuous hydrogen (H2) is a primary demanded. This chapter discussed the mechanism of the OER in conventional adsorbate oxygen and lattice oxygen participation in transition metal oxides (TMOs). Further, the influences of surface engineering, doping, and defects in the TMOs and understanding the electronic structure to screen electrodes towards the structure–activity relationship are highlighted. Specifically, the adsorption strength of O 2p is understood in detail as its binding ability over the surface of TMOs can be correlated directly to the OER activity. The iterative development of TMOs in terms of understanding electronic structural attributes is essential for the commercial deployment of energy conversion technologies. The comprehensive outlook of this chapter investigates thoroughly how TMOs can be used as significant materials for the OER in the near future.
This document summarizes various electrochemical waste water treatment methods. It discusses separation methods like electrodeionization (EDI), capacitive deionization (CDI), electroflotation, and electrodialysis. It also covers conversion methods such as electrochemical oxidation and reduction. Combined methods like electrocoagulation, electroflotation coagulation, and photoelectrocatalysis are also summarized. The document concludes that electrochemical methods provide efficient, economical, and controllable waste water treatment through separation, conversion and combined techniques. Key advantages include removal of organic matter, heavy metals, and particles in a cost-effective manner while also extracting pure metals and organic pollutants from waste water.
1) Geoelectric energy is a new source of electrical energy produced naturally from radioactive decay in the Earth's crust or artificially from nuclear waste decay.
2) This energy can be harnessed using solar cells to convert radiation into electricity or by installing converters in deep repositories where nuclear waste is stored.
3) Storing nuclear waste in areas with organic waste and complex hydrocarbons can safely protect repositories by converting radiation into fuels and gases while preventing earthquakes.
Electrochemical treatment of hazardous organic pollutants – a status reviewAlexander Decker
This document provides a status review of electrochemical treatment methods for hazardous organic pollutants. It discusses two main electrochemical treatment methods: electrocoagulation and electrochemical incineration. Electrocoagulation utilizes a sacrificial anode like aluminum or iron to generate metal ions that form hydroxide flocs, which can adsorb and remove organic pollutants. Electrochemical incineration, also known as electrochemical advanced oxidation, generates hydroxyl radicals at the anode that mineralize pollutants into carbon dioxide, water and inorganic ions. The choice of anode material is important for this process, with boron-doped diamond electrodes being well-suited due to their ability to maximize hydroxyl
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
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.
Remediation technologies for heavy metal contaminated groundwaterSoumyadeep Mukherjee
This document summarizes 35 approaches for remediating heavy metal contaminated groundwater. The approaches are classified into three categories: chemical, biochemical/biological/biosorption, and physico-chemical treatment processes. Selection of a suitable technology depends on the complex soil chemistry and aquifer characteristics at a contaminated site. Recently, iron-based technologies, microbial remediation, biological sulphate reduction, and various adsorbents have played effective remediation roles. Technologies using natural chemistry, bioremediation and biosorption are recommended where applicable due to sustainability concerns. Multiple techniques may work together synergistically at some sites.
This document discusses spinel ferrite magnetic nanoparticles as an alternative for wastewater treatment. It begins with an introduction explaining the global challenges of water pollution and scarcity. It then provides details on conventional wastewater treatment methods and their limitations. The document introduces nanotechnology as a promising new approach, specifically highlighting photocatalysis, nanofiltration, and nanoadsorbents using magnetic nanoparticles. It focuses on the properties of spinel ferrite nanoparticles that make them well-suited for wastewater remediation applications like adsorption and magnetic separation.
Photosyntheis in a test tube-Dye sensitized solar cells (USPseminar)Atul Raturi
Dye-sensitized solar cells (DSSCs) mimic the process of photosynthesis by using a photosensitive dye to absorb sunlight and a nanocrystalline semiconductor to transport electrons, achieving efficiencies over 10%. DSSCs could provide low-cost solar power for the billions lacking electricity, especially in remote Pacific islands vulnerable to climate change. By emulating natural photosynthesis, DSSCs represent an example of biomimicry and have potential for widespread commercial production of affordable renewable energy.
The document discusses the history and evolution of electrodeionization (EDI) technology. EDI was originally developed in the 1950s to overcome concentration polarization limitations of traditional electrodialysis by filling the spaces between ion-selective membranes with ion exchange resins. This allowed EDI to effectively treat more dilute solutions. Since its commercial introduction over 16 years ago, EDI technology has matured through improvements in manufacturing techniques and membrane materials, driving increased acceptance and lower costs. EDI is now available from multiple suppliers and used in various industries beyond its original use in pharmaceutical water treatment.
Analysis and assessment of essential toxic heavy metals, ph andAlexander Decker
This document summarizes a study that analyzed heavy metal contamination in river banks and adjacent agricultural soils along a 48 km section of the Ishaqi River in Iraq. Samples were taken from 10 sites and analyzed for zinc, copper, manganese, iron, cobalt, nickel, chromium, cadmium, vanadium and lead using atomic absorption spectrophotometry. Results showed higher concentrations of most metals in river banks compared to soils. Nickel, zinc, manganese and iron exceeded permissible levels in both river banks and soils. The highest metal concentrations were found at sites near residential and industrial areas, indicating pollution from waste discharges.
E-Waste: Recovery of Precious Materials and Minimization of Environmental Imp...CrimsonpublishersEAES
E-Waste: Recovery of Precious Materials and Minimization of Environmental Impact by Separating Toxic Metals by RK Singhal* in Environmental Analysis & Ecology Studies
Removal of Lead Ion Using Maize Cob as a BioadsorbentIJERA Editor
The intensification of industrial activity and environmental stress greatly contributes to the significant rise of
heavy metal pollution in water resources making threats on terrestrial and aquatic life. The toxicity of metal
pollution is slow and interminable, as these metal ions are non bio-degradable. The most appropriate solution for
controlling the biogeochemistry of metal contaminants is sorption technique, to produce high quality treated
effluents from polluted wastewater. Maize cob readily available was used as sorbent for the removal of lead ions
from aqueous media. Adsorption studies were performed by batch experiments as a function of process
parameters such as sorption 500ppm,2.5g, 400minutes, 400 rpm and 5 PH. Concentration, Dosage, time, rpm,
and pH. I have found that the optimized parameters are Freundlich model fits best with the experimental
equilibrium data among the three tested adsorption isotherm models. The kinetic data correlated well with the
Lagergren first order kinetic model for the adsorption studies of lead using maize cob. It was concluded that
adsorbent prepared from maize cob as to be a favorable adsorbent and easily available to remove the heavy
metal lead (II) is 95 % and can be used for the treatment of heavy metals in wastewater.
Nuclear hazards from soil contamination can have significant health and environmental impacts. Radioactive materials from nuclear power plants and waste can spread through fallout and enter the food chain. Proper management and disposal of nuclear waste is important to isolate radioactive materials and prevent harmful exposure. In case of a nuclear accident, immediate evacuation from the area and avoiding direct contact with radiation is crucial until it can be contained and the contaminated site cleaned up.
Electrokinetic remediation of the pollutantsAnup Kumar
This document discusses electrokinetic remediation as a technique for removing organic and inorganic pollutants from soil. It provides details on the components of an electrokinetic remediation system and the transport mechanisms involved. Several types of electrokinetic remediation techniques are described, including direct electrokinetic remediation, and techniques combined with Fenton reactions, surfactants, biological processes, and ultrasonication. Case studies demonstrating the application and effectiveness of these techniques in removing various pollutants like atrazine, 2,4-DNT, diuron, and creosote from contaminated soils are also summarized.
COMPLAINTS AND APPEALS in Research examples from abroadtp jayamohan
The document discusses several topics related to research misconduct allegations and whistleblowing. It provides guidance for complainants on carefully preparing allegations, protections for complainants, and reporting allegations to the appropriate institutional official. It also discusses cases where whistleblowers uncovered misconduct through diligent analysis of data, but faced resistance, and a case where a complainant was found to have defamed and invaded the privacy of the researcher through improper public disclosure of unproven allegations.
There are several ways to identify research gaps including reviewing literature, discussions with colleagues, reviewing digital platforms, analyzing issues raised by organizations, examining highly cited research, and questioning aspects of previous research works. Some challenges in identifying gaps are the large number of unsolved issues to analyze, unorganized literature reviews, hesitation to question existing works, and lack of skills like curiosity and imagination.
prevention of flood using reataining walltp jayamohan
This document discusses the application of a retaining wall with a relief shelf for flood control in Kuttanad, Kerala. Kuttanad frequently experiences severe flooding, with water levels rising over 5 feet in many areas. The study aims to analyze how incorporating a retaining wall with a relief shelf can help control floods in the region. Retaining walls are commonly used in engineering, but adding a relief shelf can increase the stability of taller walls by decreasing lateral earth pressures. The document provides background on retaining walls and discusses software used for the finite element analysis. It also lists several references on retaining wall design and the impacts of flooding in Kuttanad.
This document discusses flood modelling and prediction in Kerala using GIS and remote sensing. It provides background on Kerala's geography and climate, which causes frequent flooding. It then describes how GIS and remote sensing tools like digital elevation models, land use data, and rainfall data can be used as inputs to model flood inundation areas and predict future flooding. The outputs of these models, like flood extent maps, can help with disaster management and planning flood prevention measures.
This document provides an overview of a project report on designing a multi-storied reinforced concrete building using ETABS software. The objectives are to analyze, design, and detail the structural components of the building. The methodology involves preparing CAD drawings, calculating loads, analyzing the structure, and designing and detailing structural elements. The building to be designed is a residential building with ground + 5 floors located in Chalikkavattom. Loads like dead, live, wind, and seismic loads will be calculated according to Indian codes and applied in the ETABS analysis model.
This document provides an overview of berth development projects at several ports. It discusses the scope of improving existing berths at Morehead Port in North Carolina and the Panama Canal by strengthening structures, increasing dredge depth, and adding new finger piers for larger ships. It also reviews a project to monitor lateral soil movement during dredging near berths constructed with diaphragm walls and piles at Jawaharlal Nehru Port in Mumbai. Geotechnical site investigations including testing were important for understanding soil conditions and designing stable berth structures.
This document discusses precautions taken for concreting in sub-zero temperatures. It recommends selecting cement that hydrates fast to generate early heat, using admixtures like calcium chloride or sodium chloride to lower the freezing point of water and accelerate hydration, insulating concrete to preserve heat during curing, and employing air entraining agents to increase durability against frost damage by modifying the pore structure. Heating materials like aggregates and mixing water is also suggested to maintain the concrete above freezing during the pre-hardening period.
The document contains floor plans for a two story building. The ground floor includes a 5x4 verandah, 3x4.2 store, 5x3 dining area, 4x2 car porch, 4x5 living room, 4x2 kitchen, and 1.8x4.2 toilet. The first floor contains a master bedroom, work area, two bedrooms, two toilets, and windows and doors labeled on the plans. Dimensions are provided for all rooms and building elements in meters. The plans were created by student Gayathry.T.J with roll number 27.
This engineering drawing shows elevation section A-A with various dimensions in meters. It includes dimensions for the overall height of 2.9 meters and widths of 0.12, 0.9, 1.2, 0.45 and 0.45 meters. Smaller dimensions shown are 0.1, 1.38, 0.13 and 0.6 meters.
The document contains a floor plan layout for a house with dimensions for various rooms and features. It includes a kitchen, two bedrooms, a dining/living area, verandah, toilet, and car porch. The bedrooms are labeled Bedroom-1 and Bedroom-2 and measure 3x4 meters and 4x5.3 meters respectively. An index provides labels and dimensions for doors, windows, and ventilators used in the plan.
Internship front pages (3 files merged)tp jayamohan
This report summarizes the internship of the author at a construction site in South Kalamassery, Ernakulam. The five-day internship involved observing the reinforcement and concreting of the basement slab, and formwork of retaining walls. The project site is a five-story residential and commercial building. On the first day, reinforcement was placed for the basement slab. On the second day, the basement slab was concreted. The last two days focused on the formwork of retaining walls. The report also discusses soil testing, foundation design using a reinforced concrete raft, and concrete mixing and placement.
1. Water resources are essential for development but face increasing challenges from climate change, demand, and sedimentation. Reservoirs constructed on rivers are prone to sedimentation over time, reducing their storage capacity.
2. Sedimentation in reservoirs occurs as sediment particles from the watershed settle in the reservoir due to decreased flow speeds. This reduces the reservoir's storage potential and can impact downstream soil fertility and biodiversity. Assessing sedimentation is important for reservoir management.
3. Remote sensing techniques provide an alternative method for assessing reservoir sedimentation that is more expedient and efficient than traditional surveys. Satellite imagery can be used to measure changes in reservoir water spreads at different elevations over time, indicating loss of storage capacity
William John Macquorn Rankine, (born July 5, 1820, Edinburgh, Scot.—died Dec. 24, 1872, Glasgow), Scottish engineer and physicist and one of the founders of the science of thermodynamics, particularly in reference to steam-engine theory.
Trained as a civil engineer under Sir John Benjamin MacNeill, Rankine was appointed to the Queen Victoria chair of civil engineering and mechanics at the University of Glasgow (1855). One of Rankine’s first scientific works, a paper on fatigue in metals of railway axles (1843), led to new methods of construction. His Manual of Applied Mechanics (1858) was of considerable help to designing engineers and architects. His classic Manual of the Steam Engine and Other Prime Movers (1859) was the first attempt at a systematic treatment of steam-engine theory. Rankine worked out a thermodynamic cycle of events (the so-called Rankine cycle) used as a standard for the performance of steam-power installations in which a condensable vapour provides the working fluid.
William John Macquorn Rankine, (born July 5, 1820, Edinburgh, Scot.—died Dec. 24, 1872, Glasgow), Scottish engineer and physicist and one of the founders of the science of thermodynamics, particularly in reference to steam-engine theory.
Trained as a civil engineer under Sir John Benjamin MacNeill, Rankine was appointed to the Queen Victoria chair of civil engineering and mechanics at the University of Glasgow (1855). One of Rankine’s first scientific works, a paper on fatigue in metals of railway axles (1843), led to new methods of construction. His Manual of Applied Mechanics (1858) was of considerable help to designing engineers and architects. His classic Manual of the Steam Engine and Other Prime Movers (1859) was the first attempt at a systematic treatment of steam-engine theory. Rankine worked out a thermodynamic cycle of events (the so-called Rankine cycle) used as a standard for the performance of steam-power installations in which a condensable vapour provides the working fluid.
Utilization of jarosite generated from leadtp jayamohan
Large quantities of industrial waste by-products are produced in India by different type of industries viz. Jarosite, Jarofix, Copper slag, Zinc slag, Red mud, Steel slag and Coal ash. For many years these materials were considered as waste and were dumped haphazardly near the producing plants. Efforts are being carried out by research studies to utilize these materials in embankment, sub base and base layers of road construction. Experimental studies have been also carried out to investigate their feasibility as an additive in cement concrete. Jarosite material is produced during extraction of zinc ore concentrate by hydrometallurgy operation. When zinc ore concentrate is roasted at 9000 C and subjected to leaching, Jarosite is formed as a waste material. The Jarosite material is mixed with 2 % lime and 10 % cement and transported to the disposal area as a Jarofix material.
Tall structures are ;
Flexible, low in damping, slender and light in weight.
Sensitive to dynamic wind loads.
Adversely affect the serviceability and occupant comfort.
Oscillations are observed in the along-wind and crosswind directions and in torsional mode.
Behaviour of wind response is largely determined by building shapes.
Aerodynamic optimization of building shapes is the most efficient way to achieve wind resistant design.
In ancient China, tall buildings appear to be those of traditional pagodas.
Abrasive jet micro-machining (AJM), in which abrasive parti-cles are accelerated by air and directed toward a target, has beenused to make components for micro-electromechanical (MEMS) and micro-fluidic capillary electrophoresis devices . One ofthe disadvantages of AJM is that the compressed air jet used topropel the erodent particles diverges significantly after the noz-zle exit, increasing the size of the blast zone and the width of thesmallest channel or hole that can be machined without the use of a patterned erosion-resistant mask that defines the micro-featureedges . Abrasive slurry jet micro-machining (ASJM) is similar to AJM except that pressurized water, instead of air, is used to accel-erate the suspended abrasive particles such as garnet or alumina(Al2O3). In both AJM and ASJM, the material removal occurs by ero-sion. However, for the same jet dimension and flow speed, slurryjets have a much lower divergence angle than air jets , allow-ing for the micro-machining of small features without the use ofpatterned masks.
This document discusses a novel direct-injection system for 2-stroke engines that uses LPG as fuel. It aims to increase fuel efficiency by reducing fuel spillage and fresh charge losses. CFD simulations analyze different injector positions and their effects. Graphs of mass flow rate and combustion chamber pressure show the best position is at the transfer port. Emission levels are also studied and compared to a conventional engine. The ignition system is recommended to use a fast-response inductive ignition to suit the direct-injection setup, though it can still work with the existing ignition.
This document discusses dynamic analysis of soil structure interaction on gravity dams. It first provides background on dynamic analysis and how the behavior of dams is influenced by foundation conditions. It then reviews literature showing that considering soil stiffness, mass, and soil-structure interaction leads to higher displacements and stresses in dams compared to models without these factors. The document outlines a methodology to model different soil types, analyze soil-structure interaction, and conduct dynamic analysis. It provides a time schedule and expected outcomes of discovering displacement based on soil-structure interaction and seismic response of the structure. Finally, it lists references on this topic.
• Considering soil-structure interaction makes a structure more flexible and thus, increasing the natural period of the structure compared to the corresponding rigidly supported structure
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Software Engineering and Project Management - Software Testing + Agile Method...Prakhyath Rai
Software Testing: A Strategic Approach to Software Testing, Strategic Issues, Test Strategies for Conventional Software, Test Strategies for Object -Oriented Software, Validation Testing, System Testing, The Art of Debugging.
Agile Methodology: Before Agile – Waterfall, Agile Development.
VARIABLE FREQUENCY DRIVE. VFDs are widely used in industrial applications for...PIMR BHOPAL
Variable frequency drive .A Variable Frequency Drive (VFD) is an electronic device used to control the speed and torque of an electric motor by varying the frequency and voltage of its power supply. VFDs are widely used in industrial applications for motor control, providing significant energy savings and precise motor operation.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELijaia
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
IEEE Aerospace and Electronic Systems Society as a Graduate Student Member
Electro
1. 1
Electrokinetic Soil Remediation
GAYATHRY T J
M-Tech Second Semester in Geotechnical Engineering
School of Engineering, CUSAT
npspark17@gmail.com
Abstract
In India around 147 million hectares (Mha) of land is under degradation, this includes 94 Mha from water erosion, 16 Mha
from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of
factors. Even though The total land area of India is just 2.4% of the world’s land area , it ranks second in the world in farming.
Agriculture employs almost 50% of the total workforce in India. So there is an increased need for monitoring and researching
the various facets of land degradation. Electrokinetics is defined as the physicochemical transport of charge, action of charged
particles and effects of applied electric potentials on formation and fluid transport in porous media. The utilization of
electrokinetic in geotechnical engineering for dewatering, consolidation and stabilization of low permeability and to transport
certain chemical species in an electrolyte system had opened new opportunities for application in geo environmental
engineering. Approaching anode is one of the enhancement techniques in electrokinetic soil remediation. This technique is
reported to give promising migration for heavy metals under shorter treatment time and at lower cost in comparison to normal
fixed anode system. In the present study, the effectiveness of fixed anode and approaching anode techniques in electrokinetic
soil remediation for lead migration under different types of wetting agents (0.01M NaNO3 and 0.1M citric acid) was
investigated.
Key Words: Acidification , Failure, Land Degradation, Electrokinetics
I. INTRODUCTION
Due to rapid industrialization and
urbanization, soils are increasingly getting
polluted. Many industries are generating
wastes which contain heavy metals.
Nowadays, industries are practicing open
dumping, since it is an economical means
of waste disposal. Waste, which contains
heavy metal, either in liquid or solid form,
will pollute soil and ground water, when it
gets disposed off to the soil. It has become
a major social issue. So removal of heavy
metal from soil or decontamination of soil
is now gaining importance.
Heavy metals consist of group of metals
and metalloids. Their atomic density is
more than 5 times that of water. Heavy
metal contamination of soil is a common
occurrence in industrial areas and in areas
with high traffic volume. Heavy metal
contamination of soil occurs during mining,
manufacturing and the use of synthetic
products such as pesticides, paints,
batteries, industrial waste and land
application of industrial or domestic sludge.
The density of heavy metal is more than 5
g/cm3. Most common problem causing
heavy metals are Lead, Mercury, Cadmium,
Arsenic, etc. Other problems associated
with heavy metals is, it is non-
biodegradable. Unlike carbon based
molecules, it remains in the soil for decades
(Giannis et al., 2009). So it is important to
have an effective and economical soil
remediation technique.
A number of technologies have been
developed in response to address increasing
environmental problems. Over the past few
decades, electrokinetic (EK) remediation
has been demonstrated to be one of the most
effective methods for in situ or ex situ soil
decontamination. Numerous EK
remediation investigations have shown
success in degrading soil contaminants and
removing heavy metals.
II. ELECTROKINETIC
REMEDIATION
Electrokinetics is defined as the
physicochemical transport of charge, action
2. 2
of charged particles and effects of applied
electric potentials on formation and fluid
transport in porous media. The utilization of
electrokinetic in geotechnical engineering
for dewatering, consolidation and
stabilization of low permeability and to
transport certain chemical species in an
electrolyte system had opened new
opportunities for application in geo
environmental engineering. Recently the
electrical treatment technique has been
applied to in-situ remediation, which was
used to clean up contaminated sites
containing heavy metals and hydrocarbons.
The idea of electrokinetic remediation
started in the 1980s after it was noticed that
water transported by electroosmosis
contained high amounts of heavy metals
and other chemical species.
III.COMPONENTS OF THE
ELECTROLYTIC PROCESS
The main components of the electrolytic
process are:
1) Electrolyte: is a substance that
dissociates in solution into positive and
negative ions to produce an electrically
conductive medium.
2) Electrolysis: the passage of an electric
current through an electrolyte decomposing
it in the process: negative ions (anions) are
attracted to the anode, where they are
oxidized (lose electrons). Positive ions
(cations) are attracted to the cathode, where
they are reduced (gain electrons).
3) Electrolytic Cell: a cell containing an
electrolyte through which an externally
generated electric current is passed by a
system of electrodes in order to produce an
electrochemical reaction.
4) Electrode: Any terminal by which an
electric current passes in or out of an
electrolytic cell. The anode is the positive
electrode and the cathode is the negative
electrode.
5) Electrokinetics: is the movement of
water (electroosmosis), ions and polar
molecules (electromigration), and charged
solid particles (electrophoresis) relative to
one another between two electrodes under
the action of an applied direct electric
current.
Figure1: Electrolytic cell
Electrokinetic process is a soil remediation
method which uses electricity as driving
force for contaminant transport in the soil.
Figure2: Schematic diagram of in-situ
electrokinetic remediation system
This process is initiated by applying low
magnitude direct current from the
electrodes injected into the soil. During
electrokinetic process, electrolysis occurs
in both anode and cathode chambers which
produce H+ and OH-, respectively. Due to
the potential difference between the
electrodes, H+ and OH- transport to the
respective electrode and these are named as
3. 3
acid front and base front. The major
contaminant transport mechanisms under
an induced electric potential are:
(1) Electroosmosis – bulk movement of
pore fluid through the electrical double
layer in clayey soils, generally occurring
from anode to cathode;
(2) Electromigration – transport of ions and
ion complexes within the pore fluid towards
oppositely charged electrodes;
(3) Electrophoresis – transport of charged
colloids, micelles, bacterial cells, etc.
within the pore fluid towards oppositely
charged electrodes; and
(4) Diffusion – transport of chemicals due
to concentration gradients
These forces are responsible for
contaminants removal from the soil,
whereby the contaminants are concentrated
in the electrolyte chambers or enriched in a
smaller soil volume.
In the EK remediation process, electrode
reactions take place on the surface to
generate protons (H+) and hydroxyl (OH−)
at the anode and the cathode, respectively.
The concentration of these ions near the
electrodes creates an acid front that moves
from anode to cathode and a basic front that
moves the other way. At the same time, the
generation of OH− ions at the cathode leads
to the precipitation of the heavy metals,
called the focusing effect. This is the main
barrier to electrokinetic remediation of
heavy- metal contaminated soils (Lu et al.
2012). Many studies have been performed
with the aim to control the soil pH and
enhance the capability of electrokinetic
remediation for heavy-metal removal.
Measures include adding strong
complexing agents such as ethylene
diamine tetra acetic acid (EDTA) into soil
(Ottosen et al. 2005) and using ion-
exchange membranes (IEM) to control the
pH and zeta potential (Amrate et al. 2006).
Electrokinetic remediation technology can
be used for the in-situ treatment of
contaminated sites. It consists of drilling
wells (drains or trenches) in which
electrodes are installed and then applying a
very low direct current electric potential.
Pumping and conditioning systems may be
needed at the electrodes depending on the
site conditions. Similarly, electrokinetic
treatment may be accomplished ex-situ by
using specially designed above-ground
reactors. Generally, the contaminants
accumulated at the electrodes are removed
by either adsorption onto the electrodes or
withdrawal followed by treatment.
IV. ADVANTAGES OF ER
Electrokinetic remediation offers the
following advantages as compared to
conventional remediation methods:
(1) Simplicity – requires simple equipment;
(2) Safety – the personnel or the public in
the vicinity are not exposed to
contaminants;
(3) Wide range of contaminated media –
can be used for soils, sludge, sediments, and
groundwater (particularly well-suited for
low-permeability clays and heterogeneous
soil deposits within the vadose zone where
conventional remedial methods have
proven to be ineffective or expensive);
(4) Wide range of contaminants – can be
used for metals, organic compounds,
radionuclide, or a combination of these
contaminants;
(5) Flexibility – can be used as an insitu or
ex-situ remediation system, and it can be
easily integrated with other remediation
technologies such as bioremediation; and
(6) Cost effectiveness- requires low
electrical energy (relative to other thermal
technologies) leading to lower overall cost.
V. FACTORS THAT AFFECT THE
ELECTROKINETIC SOIL
REMEDIATION TECHNIQUE
4. 4
A number of factors determine the direction
and extent of the migration of the
contaminant. Such factors include: the type
and structure of the soil, applied current
density, sample conditioning and the
electrode material.
1. Soil Type and Physical Properties
According to Acar (1992), there should not
be any technical restriction on the type of
soil to be cleaned. However, metal
contaminant mobility and transport
efficiencies depend heavily on the physical
properties of the soil and environmental
variables. Soils with fine particles (<100
gm) are more reactive and have a higher
specific surface area than coarser material.
As a result, the fine fraction of a soil often
contains the majority of the contamination.
The distribution of particle sizes with which
a metal contaminant is associated can
therefore determine the effectiveness of the
technology.
2. Voltage and Current Levels
The electric current intensities used in most
studies are of the order of a few tens of
milliamperes per square centimeter.
Although a high current intensity can
generate more acid and increase the rate of
transport to facilitate the contaminant
removal process, it increases power
consumption tremendously as power
consumption is proportional to the square
of electric current. An electric current
density in the range of 1-10 A/rn2 has been
demonstrated to be the most efficient for the
process (Alshawabkeh et al 1999).
However, appropriate selection of electric
current density and electric field strength
Depends on the electrochemical properties
of the soil to be treated in particular the
electric conductivity. The higher the
electric conductivity of the soil is, the
higher the required electric current density
will need to maintain the electric field
strength required. An optimum electric
current density or electric field strength
should be selected based on soil properties,
electrode spacing, and time requirements of
the process.
3. Enhancement
In some cases, an acid front may not be able
to develop by electrokinetic processes
because of the high acid/base buffer
capacity of the soil and reverse
electroosmotic flow,
i.e., from the cathode toward the anode.
Under these circumstances and in order to
promote solubilization and transport of the
metallic species, enhancement agents may
be needed.
Different schemes have been proposed and
evaluated to enhance transport and
extraction of cationic species under a DC
electric field and to prevent the formation
of immobile precipitates. To neutralize the
hydroxyl ions generated by electrolytic
reduction of water, acids such as acetic
acid, hydrochloric acid may be introduced
at the cathode. Chelating or complexing
agents, such as citric acid and ethylene
diamine tetra acetic acid (EDTA), have also
been demonstrated to be feasible for the
extraction of different types of metal
contaminants from fine-gained soils. The
choice of enhancement agent is
contaminant specific. If the primary
function of the enhancement agent is to
desorb the contaminant from the soil
particle surface, the sorption characteristics
of the contaminant on the soil particle
surface in the presence of the enhancement
agent as a function of the value of pH must
be carefully studied. This is because the
presence of the enhancement agent can
change the sorption characteristics
completely.
4. Electrode Material and Spacing
To prevent dissolution of the electrode and
generation of undesirable corrosion
products during electrolysis, chemically
inert and electrically conducting materials
such as graphite, coated titanium, or
platinum should be used. Important
Considerations for the choice of electrode
material are:
5. 5
a) Electrical conduction properties of the
material
b) Availability of the material
c) Ease of fabrication to the form required
for the process
d) Ease of installation in the field
e) Material, fabrication, and installation
costs
Regardless of the material selected for the
electrode, the electrode has to be installed
properly in the field so that it can make
good electrical contact with the subsurface.
Moreover, the design must make provisions
to facilitate exchange of solution with the
subsurface through the electrode. When
selecting spacing between electrodes,
issues of costs and processing time need to
be considered. Larger electrode spacing
will reduce the number of boreholes and
installation costs, but will increase the
processing time required and operation
costs.
VI.COMPARISON OF FIXED
ANODE AND APPROACHING
ANODE TECHNIQUES
Usually, the EK process is operated with
one fixed anode (FA). An enhanced EK
method with approaching anodes (AAs) is
believed to strengthen the remediation
effect. Compared with other remediation
methods, this study speculates that if the
area of the focusing effect can be migrated
towards the cathode in a step-by-step
manner with approaching anodes (AAs),
more heavy metal ions will be precipitated
in a narrow area and extracted from the
contaminated soil (Li et al. 2012b), which
will improve the removal of ions in the
remediation of soils. It may hugely save
remediation time and energy. Approaching
electrode can be categorized into two types,
namely approaching anode and
approaching cathode. This technique
involves sequential switching of either
anode (approaching anode) or cathode
(approaching cathode) close to the other
fixed electrode during electrokinetic
process. This can provide progressive soil
conditioning while compressing the
undesired pH region, which can further
enhance the desorption of heavy metal ions
while reducing the focusing effect for better
electromigration. From the cost aspect,
approaching electrode is reported to
provide saving in energy consumption and
treatment time by 16-44% and 20-40%,
respectively. These advantages generally
improve the feasibility of electrokinetic
process in soil remediation. To date,
approaching electrode technique is mainly
studied for remediating single-
contaminated soil such as Cr (Li et al.
2012), Cd (Shen et al. 2007) and Pb (Zhang
et al. 2014), Hg (Shen et al. 2009) and
fluorine (Zhou et al. 2014) and the results
are promising. However, it is noted that the
investigation of approaching electrode
assisted electrokinetic process in treating
co- contaminated soil is scarce, especially
for the metals that have opposite charge.
This is important as electro migration
would concentrate both metal cations and
anions in cathode and anode regions,
respectively, which fails the purpose of
contaminated soil volume reduction.
Figure3: General diagram for approaching
anode electrokinetic process with a total
treatment time of 5t
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