Elimination Of Arsenic Research Articles

Phytochemicals in the Management of Arsenic Toxicity.

Arsenic toxicity is a major concern due to its deleterious consequences for human health. Rapid industrialization also has weakened the quality of the environment by introducing pollutants that may disrupt balanced ecosystems, adversely and irreversibly impacting humans, plants, and animals. Arsenic, an important toxicant among all environmental hazards, can lead to several detrimental effects on cells and organs, impacting the overall quality of life. Nevertheless, arsenic also has a rich history as a chemotherapeutic agent used in ancient days for the treatment of diseases such as malaria, cancer, plague, and syphilis when other chemotherapeutic agents were yet to be discovered. Arsenicosis-mediated disorders remain a serious problem due to the lack of effective therapeutic options. Initially, chelation therapy was used to metabolically eliminate arsenic by forming a complex, but adverse effects limited their pharmacological use. More recently, plant-based products have been found to provide significant relief from the toxic effects of arsenic poisoning. They act by different mechanisms affecting various cellular processes. Phytoconstituents such as curcumin, quercetin, diallyl trisulfide, thymoquinone, and others act via various molecular pathways, primarily by attenuating oxidative damage, membrane damage, DNA damage, and proteinopathies. Nonetheless, most of the phytochemicals reviewed here protect against the adverse effects of metal or metalloid exposure, supporting their consideration as alternatives to chelation therapy. These agents, if used prophylactically and in conjunction with other chemotherapeutic agents, may provide an effective approach for management of arsenic toxicity. In a few instances, such strategies like coadministration of phytochemicals with a known chelating agent have led to more pronounced elimination of arsenic from the body with lesser off-site adverse effects. This is possible because combination treatment ensures the use of a reduced dose of chelating agent with a phytochemical without compromising treatment. Thus, these therapies are more practical than conventional therapeutic agents in ameliorating arsenic-mediated toxicity. This review summarizes the potential of phytochemicals in alleviating arsenic toxicity on the basis of available experimental and clinical evidence.

Wet Process Phosphoric Acid Purification Using Functionalized Organic Nanofiltration Membrane

The utilization of phosphoric acid in various sectors, e.g., food industry, is controlled by the authorized concentration limit of impurities. However, industrial phosphoric acid is contaminated with undesirable impurities (such as F, Al, Fe, Mg, etc.). Herein, this study aimed to evaluate the efficiency of the membrane purification process of pretreated industrial phosphoric acid using a premodified nanofiltration membrane. We demonstrated that the prior pretreatment steps for industrial phosphoric acid allowed the elimination of sulfate, fluorine and arsenic. Further purification of the obtained pretreated phosphoric acid using membrane cells reduced the concentrations of Cd, Al, Fe and rare earth elements by 94.81, 99.30, 99.63 and 96.67%, respectively. The membrane is functionalized by a deposit of a high molecular weight polycationic polymer of polyethyleneimines in order to produce a highly charged membrane surface to enhance the separation efficiency, selectivity and stability of the membrane. We found that the purification process relies on electrostatic repulsion between the functionalized membrane and highly charged ions, and the reduction rate of metals is a cation charge-dependent parameter. The laboratory and industrial pilot scale results showed that this process allows the production of food-grade phosphoric acid.

Ultrasonication expedited As(III) adsorption onto chitosan impregnated Ni–Fe layered double hydroxide biosorbent: Optimization studies and artificial intelligence modelling

Chitosan intercalated Ni–Fe layered double hydroxide (Ni–Fe LDH/Ch), prepared by co-precipitation was examined for adsorptive elimination of arsenic (III). Energy Dispersive X-ray analysis, X-ray diffraction, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, and Dynamic Light Scattering validated the successful synthesis of the composite with enhanced adsorption sites. Maximal As(III) removal was obtained at adsorbent dose 1 gL-1, pH 7, ultrasonication time 30 min, temperature 298 K, and initial arsenic concentration 50 mgL−1. The experimentally obtained values fit the Langmuir isotherm and pseudo-second-order dynamics well (R2 > 0.98), while thermodynamic evaluation confirmed exothermic and spontaneous reaction (ΔG = −8.13 kJ mol−1). Further, adaptive neuro-fuzzy inference system and artificial neural network successfully predicted As(III) removal percentage with a high correlation coefficient (R2 > 0.94) and low statistical errors (MSE< 0.002, AARE< 0.063). The prepared material successfully brought down arsenic level by 62% in a natural water sample and showed good reusability up to 5 consecutive treatment cycles. The results recommended that Ni–Fe LDH/Ch has ample potential for arsenic remediation, and further investigations can be carried out for large-scale applications.

Scaled-up development of recyclable Pd@ZnO/CuO nanostructure for efficient removal of arsenic from wastewater

The purification of water from hazardous substances, like arsenic (As) containing media which causes chronic disorders, requires special types of technological approaches to tackle this problem. Among the technological advancements, adsorption is considered as one of the easiest techniques used for the treatment and purification of water. Herein, palladium (Pd) coated ZnO/CuO based nanocomposite was prepared successfully by a hydrothermal method and the product was characterized by XRD, HRTEM, SEM, EDS, TGA, FTIR and XPS techniques. The resultant adsorbent demonstrated remarkable adsorption capacity in the removal of harmful arsenic from water, which was 91.96 and 96.36 mg/g for both As(III) and As(V) respectively. Moreover, the effect of various parameters like —OH concentration and metal precursor on the morphology of Pd@ZnO/CuO nanocomposite has been studied. Consequently, both As(III) and As(V) were found to be well agreed with Langmuir and Freundlich isotherms, which ensures their adsorption through ion exchange and electrostatic interaction. Additionally, the whole process of arsenic removal was carried out at pH 4‒9 in the presence of various minerals. Finally, the adsorbent was reused and presented satisfactory results over five cycles, which render it as the best candidate for the elimination of arsenic from natural and industrial water samples.

Treatment of arsenite contaminated water by electrochemically activated persulfate oxidation process

Arsenic pollution in the groundwater is a serious worldwide problem, where arsenite and arsenate are the most prevalent forms in groundwater. Most of the conventional methods are able to remove arsenate effectively as compared with arsenite. Hence, for complete elimination of arsenic, prior oxidation of arsenite to arsenate is needed. The present work assessed the possibility of electrochemically activated persulfate (PS) based advanced oxidation process (EAOP) for arsenite removal from the aqueous medium. EAOP using Pt/Ti as both anode and cathode, can completely oxidize arsenite with an initial concentration of 1 mg L-1 within 60 min of electrolysis at pH 3; ferrous ion concentration 250 mg L-1, persulfate concentration 500.

Synergistic interplay between Aliquat 336 and organophosphorus extractants towards non-dispersive extraction of arsenic from petroleum produced water via hollow fiber membrane contactor

This work presents the elimination of arsenic from petroleum produced water via hollow fiber membrane contactor (HFMC). Results demonstrate that the extractability of arsenic is successfully achieved through the blended extractants of Aliquat 336 + Cyanex 921 suggesting the occurrence of synergism. Under optimum conditions, the extraction and stripping of arsenic achieved 94.42% and 78.90%, respectively. Slope analysis is applied to determine the stoichiometric coefficients of synergistic interplay. Both kinetics and mathematical modelling are employed to describe the behaviors arising in the HFMC system. It is seen that chemical reactions proved to govern the transportation of arsenic across HFMC. Besides, a novel approach as regards reaction mechanisms in a binary system is adopted.

INFLUENCE OF SUB-CHRONIC EXPOSURE TO ARSENIC, CADMIUM, LEAD ON GROWTH AND ACCUMULATION OF ITS IN Oreochromis sp.

The accumulation and elimination of arsenic (As), cadmium (Cd), lead (Pb) and its effect on Oreochromis sp. growth were studied after exposing fish to 1.0, 1.5 and 3.0 mgAs/L or 0.66, 1.0 and 2.0 mgCd/L or 0.12, 0.18 and 0.33 mgPb/L for 20 days in exposure phase and 10 days in the recovery phase. As Cd and Pb significantly affect on increases in weight of fish. In the exposure phase, the ratio of Metal fish organs / Metal H2O in tissues of fish was in the order muscle &gt;&gt; liver &gt; gill in the case As exposure; muscle &lt;&lt; gill &lt;&lt; liver for Cd exposure, and muscle &lt;&lt; liver &lt;&lt; gill in the case of Pb exposure. On day 10 of the recovery phase, the elimination of accumulated As, Cd, Pb in the fish organs was approximately from 12% to 29% for As, from 33% to 54% for Cd and from 14% to 39% for Pb

Abatement of As and hydrated silica from natural groundwater by electrocoagulation in a continuous plant having an electrolyzer and a flocculator-settler

• As and hydrated silica elimination from deep well water by electrocoagulation (EC). • Aluminum sacrificial anodes in an EC reactor coupled to a flocculator-settler. • Aluminum and hydrated silica react, forming aluminosilicates, As adsorbs on flocs. • As concentration after EC treatment met the WHO guideline, hydrated silica is abated. • EC is a cheap (0.48 USD m −3 ) and accessible technology to treat natural groundwater. This paper shows the elimination of arsenic (As) and hydrated silica from natural groundwater (48.63 µg L −1 arsenic, 77.5 mg L −1 hydrated silica, 0.33 mg L −1 phosphate, 5 mg L −1 sulfate, 240 mg L −1 alkalinity, 89.5 mg L −1 hardness, pH 8.44 and 450 µS cm −1 conductivity) by electrocoagulation (EC). The flow plant employed a parallel plates EC reactor in series with a flocculator-settler. Aluminum was used as the sacrificial electrode. Before the electrolysis in the flow plant, a systematic study of the aluminum dose was carried using the EC reactor adapted to a jar test. The influence of the mean linear flow velocity (1.2–4.8 cm s −1 ) and current density (6–9 mA cm −2 ) on the removal of As and hydrated silica was addressed. The residual concentration of As and hydrated silica in the flow plant was C As = 4.2 µg L −1 and C hs = 4.5 mg L −1 , respectively, at 9 mA cm −2 and 1.2 cm s −1 , which agree well with that obtained in the jar test array. The residual As concentration fulfills the World Health Organization (WHO) recommendation (<10 μg L −1 ). The total operating cost of EC was 0.48 USD m −3 , considering electrolytic energy consumption, aluminum price, pumping costs, and sludge confinement. Flocs analyses performed by SEM-EDS, XRF-EDS, XRD, and FTIR showed the existence of aluminosilicates formed by the reaction of aluminum and hydrated silica. At the same time, As, phosphates and sulfates were separated by adsorption on flocs.

Proposed mechanism for monomethylarsonate reductase activity of human omega-class glutathione transferase GSTO1-1

Contamination of drinking water with toxic inorganic arsenic is a major public health issue. The mechanisms of enzymes and transporters in arsenic elimination are therefore of interest. The human omega-class glutathione transferases have been previously shown to possess monomethylarsonate (V) reductase activity. To further understanding of this activity, molecular dynamics of human GSTO1-1 bound to glutathione with a monomethylarsonate isostere were simulated to reveal putative monomethylarsonate binding sites on the enzyme. The major binding site is in the active site, adjacent to the glutathione binding site. Based on this and previously reported biochemical data, a reaction mechanism for this enzyme is proposed. Further insights were gained from comparison of the human omega-class GSTs to homologs from a range of animals.

Summary of four scientific studies on Arsenicum album high dilution effect against Arsenic intoxication in mice

Background: Groundwater arsenic affects millions of people in about 20 countries. In West Bengal (India) and Bangladesh alone over 100 million people are exposed. The arsenic concentration in contaminated groundwater in Bangladesh was above the maximum permissible level of 0.05 mg/l as recommended by WHO for developing countries [1]. Drinking water is not the only source of poisoning. In arsenic contaminated areas, crops, vegetables, cereals, poultry, cattle, etc, also contain traces of arsenic. Chronic arsenic intoxication has been associated with several diseases such as melanosis, leuco-melanosis, hyperkeratosis, oedema, skin cancer… &#x0D; Cazin et al [2], have demonstrated the effect of high dilutions of arsenic compounds. They noted increased arsenic elimination from blood through urine and faeces in intoxicated rats. According to these research, the aim of Khuda Buksh studies [3-4-5] was to investigate whether high dilution Arsenicum album have any effect on arsenic accumulation in different tissues and to understand also how this high dilution could produce a protective effect on all the different organs.&#x0D; Methodology: Firstly, the effect of Arsenicum album 30 cH on the amount of arsenic accumulation was determined by spectrophotometric analysis in four tissues namely liver, kidney and testis in mice intoxicated by arsenic. The protective effect in chronic and acute arsenic intoxicated mice of Arsenicum Album 6cH, 30cH and 200cH has been evaluated using not only the activities of enzymatic and biomarker toxicity (aspartate amino transferase (AST), alanine amino transferase (ALT), acid phosphatase (AcP), alkaline phosphatase (AlkP), lipid peroxidation (LPO) and reduced glutathione (GSH)) but also the cytogenetical parameters (chromosome aberrations (CA), mitotic index (MI), sperm head anomaly (SHA) etc., ). Because, it is well demonstrated that these enzymes biomarkers reflect the degree of hepatotoxicity and oxidative stress caused by arsenic intoxication.&#x0D; Results: Compared to controls, Arsenicum album 30cH induced a significant decrease in accumulation of arsenic in 4 tissues namely liver, spleen, kidney and testis in intoxicated mice. In addition, both Arsenicum album 6cH, 30cH and 200cH reduced chromosome aberrations, sperm head abnormality frequencies and activities of acid and alkaline phosphatases, aspartate and alanine aminotransferases and lipid peroxidation, while mitotic index and activities of glutathione, catalase and succinate dehydrogenase were increased compared to controls. &#x0D; Conclusion: Altogether, theses results provide evidence of protective potentials of the Arsenicum album dilution against acute and chronic arsenic intoxication in mice. They also offer a new hypothesis that the mechanism of the homeopathic dilution could act through regulation of expression of certain genes. This explanation seems to be plausible because all biomarker tests are regulated by specific genetic regulatory mechanisms [6].&#x0D; keywords: Arsenicum album, arsenic intoxication, enzymatic and biomarker toxicity.&#x0D;

Investigation of arsenic removal from aqueous solution through selective sorption and nanofiber-based filters.

This research paper focuses on removing of arsenic from contaminated water via a nanofibrous polymeric microfiltration membrane, applied in prospective combination with an inorganic sorbent based on iron oxide hydroxide FeO(OH). Nanofibrous materials were prepared by electrospinning from polyurethane selected by an adsorption test. The chemical composition (FTIR), morphology (SEM, porometry) and hydrophilicity (contact angle) of the prepared nanostructured material were characterized. The process of eliminating arsenic from the contaminated water was monitored by atomic absorption spectroscopy (AAS). The adsorption efficiency of the nanofibrous material and the combination with FeO(OH) was determined, the level of arsenic anchorage on the adsorption filter was assessed by a rinsing test and the selectivity of adsorption in arsenic contaminated mineral water was examined. It was confirmed that the hydrophilic aromatic polyurethane of ester type PU918 is capable of capturing arsenic by complexation on nitrogen in its polymer chains. The maximum As removal efficiency was around 62 %. Arsenic was tightly anchored to the polymeric adsorbent. The adsorption process was sufficiently selective. Furthermore, it was found that the addition of even a small amount of FeO(OH) (0.5g) to the nanofiber filter would increase the efficiency of As removal by 30 %. The presented results showed that an adsorption filter based on a polyurethane nanostructured membrane added with an inorganic adsorbent FeO(OH) is a suitable way for the elimination of arsenic from water. However, it is necessary to ensure perfect contact between the surface of the nanostructure and the filtered medium.

The elimination of trace arsenic via hollow fiber supported liquid membrane: experiment and mathematical model

This work presents the elimination of arsenic ions from synthetic produced water via hollow fiber supported liquid membrane (HFSLM). Results demonstrate that arsenic ions in synthetic wastewater can be successfully treated to meet the wastewater standard as formulated by the Ministry of Industry and the Ministry of Natural Resources and Environment, Thailand. The discharged limit of arsenic from industrial wastewater must not be greater than 250 ppb. In a single-step operation, arsenic ions are extracted and stripped. Percentages of extraction and stripping proved to be 100% and 98%, respectively. Optimum conditions found proved to be 0.68 M Aliquat 336 dissolved in toluene as the liquid membrane, at pH 12 of feed solution, having a mixture of HCl and thiourea as the synergistic strippant, and flow rates of both feed and strippant solutions of 100 mL/min. A mathematical model, developed to predict the final concentration of arsenic ions in feed and strippant solutions, is seen to fit in well with the experimental results.

Calcium Alginate Beads with Entrapped Iron Oxide Magnetic Nanoparticles Functionalized with Methionine-A Versatile Adsorbent for Arsenic Removal.

A novel beads adsorbent, consisting of calcium alginate entrapped on magnetic nanoparticles functionalized with methionine (MFMNABs), was developed for effective elimination of arsenic from water. The material was characterized by FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopic), XRD (X-ray Diffraction) and TEM (Transmission Electron Microscopy). The arsenic removal capacity of the material was studied by altering variables such as pH of the solution, contact time, adsorbent dose and adsorbate concentration. The maximal removal of As(III) was 99.56% under optimal conditions with an equilibrium time of 110 min and pH 7.0–7.5. The adsorption followed a second order kinetics and data best fitted the Langmuir isotherm with a correlation coefficient of R2 = 0.9890 and adsorption capacity (qm) of 6.6533 mg/g. The thermodynamic study showed entropy change (∆S) and enthalpy change (∆H) to be 34.32 J mol−1 K and 5.25 kJ mol−1, respectively. This study proved that it was feasible to treat an As(III) solution with MFMNABs. The synthesized adsorbent was cost-effective, environmentally friendly and versatile, compared to other adsorbents. The adsorption study was carried by low cost spectrophotometric method using N- bromosuccinimide and rhodamine-B developed in our laboratory.

Sulfite-assisted oxidation/adsorption coupled with a TiO2 supported CuO composite for rapid arsenic removal: Performance and mechanistic studies

Owing to the lower toxicity and mobility of inorganic As(V), the oxidative removal of As(III) is deemed as the optimal approach for arsenic elimination from water. Herein, a synthetic TiO2-supported CuO material (Cu-TiO2) was coupled with sulfite (S(IV)) to remove As(III) at neutral pH. The combined process coupled oxidation with adsorption (i.e., As(III) removal by Cu-TiO2/S(IV)) was superior than a divided preoxidation-adsorption process (i.e., As(V) removal by Cu-TiO2) for arsenic removal. Attractively, low concentration of As(III) (50−300 μg L−1) could be completely removed by Cu-TiO2 (0.25 g L−1)/S(IV) (0.5 mM) within 60 min. Mechanism investigations revealed that the efficient As(III) removal was attributed to the continuous oxysulfur radicals (SOx•−) oxidation and Cu-TiO2 adsorption. The surface-adsorbed and free sulfate radicals (SO4•−) were further identified as the crucial oxidizing species. The Cu-TiO2 played the dual roles as a catalyst for S(IV) activation and an absorbent for arsenic immobility. The influence of operating parameters (i.e., As(III) concentration and sulfite dosage) and water chemistry (i.e., pH, inorganic anions, dissolved organic matters, and temperature) on As(III) removal were systematically investigated and optimized. Overall, the proposed process has potential application prospects in rehabilitating the As(III)-polluted water environment using industrial waste sulfite.

Removal of arsenic from liquid blister copper during remelting in an induction vacuum furnace

Using a reduced pressure during the smelting and refining of alloys removes dissolved gasses, as well as impurities with a high vapor pressure. When smelting is carried out in vacuum induction furnaces, the intensification of the discussed processes is achieved by intensive mixing of the bath, as well as an enhanced mass exchange surface (liquid metal surface) due to the formation of a meniscus. This is due to the electromagnetic field applied to the liquid metal. This study reports the removal of arsenic from blister copper via refining in an induction vacuum furnace in the temperature range of 1423? 1523 K, at operating pressures from 8 to 1333 Pa. The overall mass transfer coefficient kAs determined from the experimental data ranged from 9.99?10-7 to 1.65?10-5 ms-1. Arsenic elimination was largely controlled by mass transfer in the gas phase. The kinetic analysis indicated that the arsenic evaporation rate was controlled by the combination of both liquid and gas-phase mass transfer only at a pressure of 8 Pa.

Porous walnut-like La2O2CO3 derived from metal-organic frameworks for arsenate removal: A study of kinetics, isotherms, and mechanism

Exploration of renewable materials for efficient elimination of arsenic from water is highly imperative. Herein, one kind of novel porous walnut-like La2O2CO3 composite is reported for the first time, fabricated via direct pyrolysis of La-MOFs at 550 °C under the air atmosphere. The as-synthesized material predominantly consists of La2O2CO3, featuring micrometer-scale walnut-like morphology and an abundant mesoporous structure. Adsorption experiments demonstrated that a pseudo-second-order model with a high correlation coefficient (0.9976–0.9988) can depict this adsorption process in a good manner and indicates chemical adsorption. Analysis of the isotherms further revealed that this adsorption is a monolayer and homogeneous process, with an excellent adsorption capacity (210.1 As mg/g), as calculated from the Langmuir model. Thermodynamic parameters indicated this adsorption process to be a spontaneous and endothermic, with a positive change in entropy. By characterization results, it can be deduced that the anion-exchange interaction (i.e. carbonate is prone to being replaced by arsenate) and inner-sphere complexation were both responsible for arsenate removal. A broad working pH range (3.0–9.0) and a good cyclic performance (removal rate is above 90% for the fourth cycle) as well as an excellent adsorption capacity make this adsorbent a promising arsenic scavenger.

Strategies for arsenic pollution control from copper pyrometallurgy based on the study of arsenic sources, emission pathways and speciation characterization in copper flash smelting systems.

Arsenic in copper flash smelting (FS) systems not only affects the quality of products but also poses significant technological and environmental problems. Based on the assessment of arsenic mass partitioning in the FS system, arsenic elimination in off-gassing and tailings is 22%, and most of the arsenic output (69%) is recycled in the FS system. Circulating arsenic, especially arsenic in recycled dust and slag concentrate, is the key reason for high-arsenic-content feed. Dust-type recycled materials (RMs) contribute much more arsenic to the feed than slag-type RMs. Flash smelting furnace electrostatic precipitator (FSF ESP) dust contributes makese the largest contribution to arsenic among the dust-type RMs of mixed dust, especially trivalent arsenic, followed by FSF and flash converting furnace waste heat boiler (FCF WHB) dust, which contributes pentavalent arsenic. FCF WHB dust exhibits a relatively low arsenic content, consisting mainly of As(V)-O. Slag-type recycled materials contribute As(V)-O to the total feed, and As(III) originates from copper concentrates. Considering the arsenic contribution and environmental risk, reducing the recovery of FSF ESP dust can greatly decrease the arsenic grade of FSF feed and volatile As2O3. As one of the main arsenic sources in feed, FSF slag concentrate should be carefully disposed of if separated from feed materials because of its high arsenic-related environmental risk. In contrast, WHB dust and FCF slag are more suitable as RM due to their high copper content and low arsenic risk.

The Technologies Optimization for the Treatment of Underground Water with Iron and Arsenic Content – A Case Study

Generally, in Romania, the water treatment aimed at removing the classic compounds of iron, manganese, ammonium, nitrates / nitrites, etc. by the known classical technologies (chemical coagulation, precipitation, decantation, slow / fast filtration with free / under pressure, disinfection). When in the raw water, besides the classical compounds, heavy metals semi-metals are also found, together with the classical treatment technologies, advanced technologies are required combined, known as hybrid processes (Electro-coagulation / EC, oxidation, adsorption / exchange ions, membrane filtration -UF / NF / RO), which can lead to the desired results. Along with iron, manganese, ammonium, nitrites / nitrates, arsenic is a naturally occurring element in the Earth’s crust. Arsenic in drinking water is a global problem affecting the population worldwide because the arsenic and its components have carcinogenic properties. Regarding the elimination of arsenic (As) found in the water especially collected from the underground, the studies and researches applied were much more restricted and the applications completely isolated, at present the subject being more intensely approached. This situation is also caused by the fact that the Water Framework Directive no.98_83_CEE, transposed into national legislation, lowered the Arsenic (As) chemical indicator limit to 10 μg As / L (from 50 μg As / L). An alternative / complementary technology with low maintenance costs for underground treatment is Electro-oxidation/coagulation (EC), which has been of increasing interest in the last decade. The use of pilot stations / equipment for studying potential treatment technologies is essential for optimizing the treatment schemes and in order to avoid the implementation of costly technologies that cannot work for various reasons. In this case study, it was analysed comparatively from the efficiency point of view combining and optimizing oxidation-coagulation-filtration technologies in a pilot station for water treatment with iron, manganese and arsenic content, coming from the medium depth underground source (western Romania). In the initially provided technological flow (oxidation with ozone, multimedia filtration and disinfection with hypochlorite for the remanence), an electro-coagulation / oxidation (EC) cell was introduced upstream of the multimedia filter. This process aimed at eliminating the use of chemicals (ferric chloride) from the coagulation process that would have caused the rapid alteration of the multimedia filter and consequently increased operating costs. The results showed that compared to conventional technologies, the EC advantage includes high disposal efficiency, a compact treatment plant and the possibility of complete automation.

Energy Efficient Rapid Removal of Arsenic in an Electrocoagulation Reactor with Hybrid Fe/Al Electrodes: Process Optimization Using CCD and Kinetic Modeling

Threats due to insufficient, inadequate and costlier methods of treating contaminants such as arsenic have emphasized the significance of optimizing and managing the processes adopted. This study was aimed at the complete elimination of arsenic from an aqueous medium with minimum energy consumption using the electrocoagulation process. Arsenic removal around 95% was rapidly attained for optimized conditions having a pH of 7, 0.46 A current intensity, 10 mg/L initial concentration and only 2 min of applied time duration using the energy of 3.1 watt-hour per gram of arsenic removed. Low values of applied current for longer durations resulted in the complete removal of arsenic with low energy consumption. Various hydroxide complexes including ferrous hydroxide and ferric hydroxide assisted in the removal of arsenic by adsorption along with co-precipitation. Surface models obtained were checked and found with a reasonably good fit having high values of coefficient of determination of 0.933 and 0.980 for removal efficiency and energy consumption, respectively. Adsorption was found to follow pseudo-first-order kinetics. Multivariate optimization proved it as a low-cost effective technology having an operational cost of 0.0974 Indian rupees (equivalent to USD 0.0013) per gram removal of arsenic. Overall, the process was well optimized using CCD based on response surface methodology.

Betaine and choline status modify the effects of folic acid and creatine supplementation on arsenic methylation in a randomized controlled trial of Bangladeshi adults.

Methylation of ingested inorganic arsenic (InAs) to monomethyl- (MMAs) and dimethyl-arsenical species (DMAs) facilitates urinary arsenic elimination. Folate and creatine supplementation influenced arsenic methylation in a randomized controlled trial. Here, we examine if baseline status of one-carbon metabolism nutrients (folate, choline, betaine, and vitamin B12) modified the effects of FA and creatine supplementation on changes in homocysteine, guanidinoacetate (GAA), total blood arsenic, and urinary arsenic metabolite proportions and indices. Study participants (N = 622) received 400 or 800μg FA, 3g creatine, 400μg FA + 3g creatine, or placebo daily for 12weeks. Relative to placebo, FA supplementation was associated with greater mean increases in %DMAs among participants with betaine concentrations below the median than those with levels above the median (FDR < 0.05). 400μg FA/day was associated with a greater decrease in homocysteine among participants with plasma folate concentrations below, compared with those above, the median (FDR < 0.03). Creatine treatment was associated with a significant decrease in %MMAs among participants with choline concentrations below the median (P = 0.04), but not among participants above the median (P = 0.94); this effect did not significantly differ between strata (P = 0.10). Effects of FA and creatine supplementation on arsenic methylation capacity were greater among individuals with low betaine and choline status, respectively. The efficacy of FA and creatine interventions to facilitate arsenic methylation may be modified by choline and betaine nutritional status. Clinical Trial Registry Identifier: NCT01050556, U.S. National Library of Medicine, https://clinicaltrials.gov ; registered January 15, 2010.