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Arup K Sengupta - One of the best experts on this subject based on the ideXlab platform.
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Arsenic Removal from groundwater and its safe containment in a rural environment validation of a sustainable approach
Environmental Science & Technology, 2008Co-Authors: Sudipta Sarkar, Lee Blaney, Anirban Gupta, Debabrata Ghosh, Arup K SenguptaAbstract:Of all the naturally occurring groundwater contaminants, Arsenic is by far the most toxic. Any large-scale treatment strategy to remove Arsenic from groundwater must take into consideration safe containment of the Arsenic removed with no adverse ecological impact. Currently, 175 well-head community-based Arsenic Removal units are in operation in remote villages of the Indian subcontinent. Approximately 150,000 villagers collect Arsenic-safe potable water everyday from these units. The continued safe operation of these units has amply demonstrated that use of regenerable Arsenic-selective adsorbents is quite viable in remote locations. Upon exhaustion, the adsorbents are regenerated in a central facility by a few trained villagers and reused. The process of regeneration reduces the volume of disposable Arsenic-laden solids by nearly 2 orders of magnitude. Finally, the Arsenic-laden solids are contained on well-aerated coarse-sand filters with minimum Arsenic leaching. This disposal technique is scientifically more appropriate than dumping Arsenic-loaded adsorbents in the reducing environment of landfills as currently practiced in developed countries including the United States.
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use of arsenxnp a hybrid anion exchanger for Arsenic Removal in remote villages in the indian subcontinent
Reactive & Functional Polymers, 2007Co-Authors: Sudipta Sarkar, Lee Blaney, Anirban Gupta, Debabrata Ghosh, Arup K SenguptaAbstract:Abstract Many of the Arsenic Removal units operating in remote villages of West Bengal, India now use a hybrid anion exchanger (HAIX) which are essentially spherical anion exchange resin beads containing dispersed nanoparticles of hydrated ferric oxide (HFO). HAIX, now commercially available as ArsenX np , offers a very high selectivity for sorption of oxyanions of Arsenic due to the Donnan membrane effect. The sorption columns used in the field for Removal of Arsenic are either single column or split-column design. The sorption columns allow flow of atmospheric oxygen, thereby promoting oxidation of dissolved Fe(II) species of Arsenic-contaminated raw water to insoluble Fe(III) oxides or HFO particulates. Apart from the usual role played by the sorbents like ArsenX np or activated alumina towards Arsenic Removal, HFO particulates also aid in the treatment process. Each unit is attached to a hand-pump driven well and capable of providing Arsenic-safe water to three hundred (300) households or approximately one thousand villagers. No chemical addition, pH adjustment or electricity is required to run these units. On average, every unit runs for more than 20,000 bed volumes before a breakthrough of 50 μg/L of Arsenic, the maximum contaminant level in drinking water in India, is reached. In addition to Arsenic Removal, significant iron Removal is also achieved throughout the run. Upon exhaustion, the media is withdrawn and taken to a central regeneration facility where 2% NaCl and 2% NaOH solution are used for regeneration. Subsequently, the regenerated resin is reloaded into the well-head sorption column. Following regeneration, the spent solutions, containing high Arsenic concentration, are transformed into solids residuals and contained in a way to avoid any significant Arsenic leaching. Laboratory investigations confirmed that the regenerated ArsenX np is amenable to reuse for multiple cycles without any significant loss in capacity.
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Arsenic Removal using polymer supported hydrated iron iii oxide nanoparticles role of donnan membrane effect
Environmental Science & Technology, 2005Co-Authors: Luis Cumbal, Arup K SenguptaAbstract:The conditions leading to the Donnan membrane equilibrium arise from the inability of ions to diffuse out from one phase in a heterogeneous system. In a polymeric cation exchanger, negatively charged sulfonic acid groups are covalently attached to the polymer chains, and thus, they cannot permeate out of the polymer phase. Conversely, a polymeric anion exchanger contains a high concentration of non-diffusible positively charged quaternary ammonium functional groups. It is well-established that submicron or nanoscale hydrated iron(III) oxide (HFO) particles exhibit high sorption affinity toward both arsenates and arsenites. In this study, commercially available cation and anion exchangers were used as host materials for dispersing HFO nanoparticles within the polymer phase using a technique previously developed. The resulting polymeric/inorganic hybrid sorbent particles were subsequently used for Arsenic Removal in the laboratory. The most significant finding of the study is that the anion exchanger as a s...
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well head Arsenic Removal units in remote villages of indian subcontinent field results and performance evaluation
Water Research, 2005Co-Authors: Sudipta Sarkar, John E Greenleaf, Anirban Gupta, Ranjan K Biswas, Arun K Deb, Arup K SenguptaAbstract:Abstract Since 1997, over 135 well-head Arsenic Removal units have been installed in remote villages in the Indian state of West Bengal bordering Bangladesh. Every component of the Arsenic Removal treatment system including activated alumina sorbent is procured indigenously. Each unit serves approximately 200–300 households and contains about 100 L of activated alumina. No chemical addition, pH adjustment or electricity is required for operating these units. The Arsenic concentration in the influent varies from around 100 μg/L to greater than 500 μg/L. In the treated water, Arsenic concentration is consistently below 50 μg/L. The units are capable of removing both arsenites and arsenates from the contaminated groundwater for several months, often exceeding 10,000 bed volumes. In the top portion of the column, the dissolved iron present in ground water is oxidized by atmospheric oxygen into hydrated Fe(III) oxides or HFO particles which in turn selectively bind both As(III) and As(V). Upon exhaustion, these units are regenerated by caustic soda solution followed by acid wash. The Arsenic-laden spent regenerant is converted into a small volume sludge (less than 500 g) and contained over a coarse sand filter in the same premise requiring no disposal. Many units have been operating for several years without any significant operational difficulty. The treated water is used for drinking and cooking. Most importantly, the villagers are responsible for the day to day operation and the upkeep of the units.
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Arsenic Removal using a polymeric inorganic hybrid sorbent
Water Research, 2003Co-Authors: Matthew J Demarco, Arup K Sengupta, John E GreenleafAbstract:Abstract A fixed-bed sorption process can be very effective in removing trace concentrations of Arsenic from contaminated groundwater provided: the sorbent is very selective toward both As(III) and As(V) species; the influent and treated water do not warrant any additional pre- or post- treatment; pH and composition of the raw water with respect to other electrolytes remain unchanged besides Arsenic Removal, and the sorbent is durable with excellent attrition resistance properties. In addition, the sorbent should be amenable to efficient regeneration for multiple reuse. This study reports the results of an extensive investigation pertaining to Arsenic Removal properties of a polymeric/inorganic hybrid sorbent. Each hybrid sorbent particle is essentially a spherical macroporous cation exchanger bead within which agglomerates of nanoscale hydrated Fe oxide (HFO) particles have been uniformly and irreversibly dispersed using a simple chemical–thermal treatment. The new sorbent, referred to as hybrid ion exchanger or HIX, combines excellent mechanical and hydraulic properties of spherical polymeric beads with selective As(III) and As(V) sorption properties of HFO nanoparticles at circum-neutral pH. Comparison of the results of fixed-bed column runs between the new sorbent and the polymeric anion exchanger confirmed that both As(V) and As(III) were removed very selectively with HIX. Equally important, no pH adjustment, pre- or post-treatment was warranted. Besides the absence of Arsenic, the treated water composition was identical to that of influent water. HIX was amenable to efficient in situ regeneration with caustic soda and could subsequently be brought into service following a short rinse with carbon dioxide sparged water. During fixed-bed column runs, intraparticle diffusion was identified as the primary rate-limiting step for both As(III) and As(V) sorption. Repeated use of the same HIX particles during various laboratory investigations provided strong evidence that the new sorbent possesses excellent attrition resistance properties and retains its Arsenic Removal capacity over cycles.
Charles U Pittman - One of the best experts on this subject based on the ideXlab platform.
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Arsenic Removal from water wastewater using adsorbents a critical review
Journal of Hazardous Materials, 2007Co-Authors: Dinesh Mohan, Charles U PittmanAbstract:Arsenic's history in science, medicine and technology has been overshadowed by its notoriety as a poison in homicides. Arsenic is viewed as being synonymous with toxicity. Dangerous Arsenic concentrations in natural waters is now a worldwide problem and often referred to as a 20th-21st century calamity. High Arsenic concentrations have been reported recently from the USA, China, Chile, Bangladesh, Taiwan, Mexico, Argentina, Poland, Canada, Hungary, Japan and India. Among 21 countries in different parts of the world affected by groundwater Arsenic contamination, the largest population at risk is in Bangladesh followed by West Bengal in India. Existing overviews of Arsenic Removal include technologies that have traditionally been used (oxidation, precipitation/coagulation/membrane separation) with far less attention paid to adsorption. No previous review is available where readers can get an overview of the sorption capacities of both available and developed sorbents used for Arsenic remediation together with the traditional remediation methods. We have incorporated most of the valuable available literature on Arsenic remediation by adsorption ( approximately 600 references). Existing purification methods for drinking water; wastewater; industrial effluents, and technological solutions for Arsenic have been listed. Arsenic sorption by commercially available carbons and other low-cost adsorbents are surveyed and critically reviewed and their sorption efficiencies are compared. Arsenic adsorption behavior in presence of other impurities has been discussed. Some commercially available adsorbents are also surveyed. An extensive table summarizes the sorption capacities of various adsorbents. Some low-cost adsorbents are superior including treated slags, carbons developed from agricultural waste (char carbons and coconut husk carbons), biosorbents (immobilized biomass, orange juice residue), goethite and some commercial adsorbents, which include resins, gels, silica, treated silica tested for Arsenic Removal come out to be superior. Immobilized biomass adsorbents offered outstanding performances. Desorption of Arsenic followed by regeneration of sorbents has been discussed. Strong acids and bases seem to be the best desorbing agents to produce Arsenic concentrates. Arsenic concentrate treatment and disposal obtained is briefly addressed. This issue is very important but much less discussed.
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Arsenic Removal from water wastewater using adsorbents a critical review
Journal of Hazardous Materials, 2007Co-Authors: Dinesh Mohan, Charles U PittmanAbstract:Arsenic’s history in science, medicine and technology has been overshadowed by its notoriety as a poison in homicides. Arsenic is viewed as being synonymous with toxicity. Dangerous Arsenic concentrations in natural waters is now a worldwide problem and often referred to as a 20th–21st century calamity. High Arsenic concentrations have been reported recently from the USA, China, Chile, Bangladesh, Taiwan, Mexico, Argentina, Poland, Canada, Hungary, Japan and India. Among 21 countries in different parts of the world affected by groundwater Arsenic contamination, the largest population at risk is in Bangladesh followed by West Bengal in India. Existing overviews of Arsenic Removal include technologies that have traditionally been used (oxidation, precipitation/coagulation/membrane separation) with far less attention paid to adsorption. No previous review is available where readers can get an overview of the sorption capacities of both available and developed sorbents used for Arsenic remediation together with the traditional remediation methods. We have incorporated most of the valuable available literature on Arsenic remediation by adsorption (∼600 references). Existing purification methods for drinking water; wastewater; industrial effluents, and technological solutions for Arsenic have been listed. Arsenic sorption by commercially available carbons and other low-cost adsorbents are surveyed and critically reviewed and their sorption efficiencies are compared. Arsenic adsorption behavior in presence of other impurities has been discussed. Some commercially available adsorbents are also surveyed. An extensive table summarizes the sorption capacities of various adsorbents. Some low-cost adsorbents are superior including treated slags, carbons developed from agricultural waste (char carbons and coconut husk carbons), biosorbents (immobilized biomass, orange juice residue), goethite and some commercial adsorbents, which include resins, gels, silica, treated silica tested for Arsenic Removal come out to be superior. Immobilized biomass adsorbents offered outstanding performances. Desorption of Arsenic followed by regeneration of sorbents has been discussed. Strong acids and bases seem to be the best desorbing agents to produce Arsenic concentrates. Arsenic concentrate treatment and disposal obtained is briefly addressed. This issue is very important but much less discussed. © 2007 Elsevier B.V. All rights reserved.
Dinesh Mohan - One of the best experts on this subject based on the ideXlab platform.
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Arsenic Removal from water wastewater using adsorbents a critical review
Journal of Hazardous Materials, 2007Co-Authors: Dinesh Mohan, Charles U PittmanAbstract:Arsenic's history in science, medicine and technology has been overshadowed by its notoriety as a poison in homicides. Arsenic is viewed as being synonymous with toxicity. Dangerous Arsenic concentrations in natural waters is now a worldwide problem and often referred to as a 20th-21st century calamity. High Arsenic concentrations have been reported recently from the USA, China, Chile, Bangladesh, Taiwan, Mexico, Argentina, Poland, Canada, Hungary, Japan and India. Among 21 countries in different parts of the world affected by groundwater Arsenic contamination, the largest population at risk is in Bangladesh followed by West Bengal in India. Existing overviews of Arsenic Removal include technologies that have traditionally been used (oxidation, precipitation/coagulation/membrane separation) with far less attention paid to adsorption. No previous review is available where readers can get an overview of the sorption capacities of both available and developed sorbents used for Arsenic remediation together with the traditional remediation methods. We have incorporated most of the valuable available literature on Arsenic remediation by adsorption ( approximately 600 references). Existing purification methods for drinking water; wastewater; industrial effluents, and technological solutions for Arsenic have been listed. Arsenic sorption by commercially available carbons and other low-cost adsorbents are surveyed and critically reviewed and their sorption efficiencies are compared. Arsenic adsorption behavior in presence of other impurities has been discussed. Some commercially available adsorbents are also surveyed. An extensive table summarizes the sorption capacities of various adsorbents. Some low-cost adsorbents are superior including treated slags, carbons developed from agricultural waste (char carbons and coconut husk carbons), biosorbents (immobilized biomass, orange juice residue), goethite and some commercial adsorbents, which include resins, gels, silica, treated silica tested for Arsenic Removal come out to be superior. Immobilized biomass adsorbents offered outstanding performances. Desorption of Arsenic followed by regeneration of sorbents has been discussed. Strong acids and bases seem to be the best desorbing agents to produce Arsenic concentrates. Arsenic concentrate treatment and disposal obtained is briefly addressed. This issue is very important but much less discussed.
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Arsenic Removal from water wastewater using adsorbents a critical review
Journal of Hazardous Materials, 2007Co-Authors: Dinesh Mohan, Charles U PittmanAbstract:Arsenic’s history in science, medicine and technology has been overshadowed by its notoriety as a poison in homicides. Arsenic is viewed as being synonymous with toxicity. Dangerous Arsenic concentrations in natural waters is now a worldwide problem and often referred to as a 20th–21st century calamity. High Arsenic concentrations have been reported recently from the USA, China, Chile, Bangladesh, Taiwan, Mexico, Argentina, Poland, Canada, Hungary, Japan and India. Among 21 countries in different parts of the world affected by groundwater Arsenic contamination, the largest population at risk is in Bangladesh followed by West Bengal in India. Existing overviews of Arsenic Removal include technologies that have traditionally been used (oxidation, precipitation/coagulation/membrane separation) with far less attention paid to adsorption. No previous review is available where readers can get an overview of the sorption capacities of both available and developed sorbents used for Arsenic remediation together with the traditional remediation methods. We have incorporated most of the valuable available literature on Arsenic remediation by adsorption (∼600 references). Existing purification methods for drinking water; wastewater; industrial effluents, and technological solutions for Arsenic have been listed. Arsenic sorption by commercially available carbons and other low-cost adsorbents are surveyed and critically reviewed and their sorption efficiencies are compared. Arsenic adsorption behavior in presence of other impurities has been discussed. Some commercially available adsorbents are also surveyed. An extensive table summarizes the sorption capacities of various adsorbents. Some low-cost adsorbents are superior including treated slags, carbons developed from agricultural waste (char carbons and coconut husk carbons), biosorbents (immobilized biomass, orange juice residue), goethite and some commercial adsorbents, which include resins, gels, silica, treated silica tested for Arsenic Removal come out to be superior. Immobilized biomass adsorbents offered outstanding performances. Desorption of Arsenic followed by regeneration of sorbents has been discussed. Strong acids and bases seem to be the best desorbing agents to produce Arsenic concentrates. Arsenic concentrate treatment and disposal obtained is briefly addressed. This issue is very important but much less discussed. © 2007 Elsevier B.V. All rights reserved.
Ahmed Abdelwahab - One of the best experts on this subject based on the ideXlab platform.
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Arsenic Removal using advanced reduction process with dithionite uv a kinetic study
Journal of water process engineering, 2018Co-Authors: Vishakha Kaushik, Yuhang Duan, Bahngmi Jung, Bill Batchelor, Ahmed AbdelwahabAbstract:Abstract The paper describes the use of advanced reduction processes (ARPs) with dithionite/UV to remove Arsenic from water/wastewater. The highly reducing radicals generated by the ARP react with arsenite and arsenate to produce solid phases such as elemental Arsenic or Arsenic sulfides that can be readily removed. This study evaluated the effectiveness in removing Arsenic at 5 different pH values (5, 6, 7, 8, and 9) as well as the mechanism of resolubilization for solids. Moderate pH values of 6, 7, and 8 were found to be the most effective for Arsenic Removal. Resolubilization occurred at all pH values because dithionite was consumed under UV irradiation. A simple kinetic model was applied to describe the changes in concentrations of Arsenic and dithionite with time. Arsenic Removal kinetics was fast at the first 10–20 min for all pH values. The highest rate constant was observed at pH 6 for arsenate Removal (616 L/mol/min) and at pH 7 for arsenite Removal (534 L/mol/min).
Kito Ahmad - One of the best experts on this subject based on the ideXlab platform.
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electrocoagulation treatment of Arsenic in wastewaters a comprehensive review
Chemical Engineering Journal, 2017Co-Authors: Peipei Song, Zhaohui Yang, Guangming Zeng, Xia Yang, Like Wang, Weiping Xiong, Kito AhmadAbstract:Abstract Arsenic, classified as a carcinogen, is being subject to high concern due to its high toxicity especially in drinking water. Electrocoagulation (EC) has displayed a great potential as an effective and environmentally friendly method to remove Arsenic from wastewaters. This review summarizes the recent development of Arsenic Removal in EC process including the effects of primary operating parameters, optimization of the EC performance, as well as the evaluation of EC reactor configurations. Production and characterization of EC products with respect to different electrodes are systematically discussed. Besides, this review sheds light on the debate about the mechanism involved in As(III) oxidation and further explores the Arsenic adsorption behavior in EC process. Moreover, the performance of EC and other technologies are compared, and future research needs for Arsenic Removal in EC process are suggested accordingly. Overall, this review will contribute to deepening the understanding of EC process for Arsenic Removal and offer useful information to researchers in this field.