Drinking water arsenic removal

EC is a simple, efficient, and promising method to remove arsenic form water. Arsenic removal efficiencies with different electrode materials follow the sequence iron > titanium > aluminum. The process was able to remove more than 99% of arsenic from an As-contaminated water and met the drinking water standard of 10p,gL 1 with iron electrode. Compared with the iron electrodes, aluminum electrodes obtained lower removal efficiency. The plausible reason for less arsenic removal by aluminum in comparison to iron could be that the adsorption capacity of hydrous aluminum oxide for As(III) is much lower in comparison to hydrous ferric oxides. Comparative evaluation of As(III) and As(V) removal by chemical coagulation (with ferric chloride) and electrocoagulation has been done. The comparison revealed that EC has better removal efficiency for As(ni), whereas As(V) removal by both processes was nearly same (Kumar et al. 2004). 

Whereas studies have been carried out on the factors (surface coverage, residence time, pH) which influence the desorption of arsenate previously sorbed onto oxides, phyllosilicates and soils (O Reilly et al. 2001 Liu et al. 2001 Arai and Sparks 2002 Violante and Pigna 2002 Pigna et al. 2006), scant information are available on the possible desorption of arsenate coprecipitated with iron or aluminum. In natural environments arsenic may form precipitates or coprecipitates with Al, Fe, Mn and Ca. Coprecipitation of arsenic with iron and aluminum are practical and effective treatment processes for removing arsenic from drinking waters and might be as important as sorption to preformed solids. 

Thirunavukkarasu OS, Viraraghavan T, Subramanian KS (2003) Arsenic removal from drinking water using iron oxide-coated sand. Water Air Soil Poll 142 95-111... 

Hering, J.G., P.Y. Chen, and J.A. Wilkie. 1997. Arsenic removal from drinking-water by coagulation the role of adsorption and effects of source water composition. Pages 369-381 in C.O. Abernathy, R.L. Calderon, and W.R. Chappell (eds.). Arsenic. Exposure and Health Effects. Chapman Hall, London. 

One way to remove arsenic from drinking water in Bangladesh is by coprecipitation with Fe(OH)3.6 Fe(ll) or Fe(s) is added to the water and allowed to oxidize in air for several hours to precipitate Fe(OH)3. After filtration through sand to remove solids, the wdter is drinkable. 

Hlavay, J. and Polyak, K. (2005) Determination of surface properties of iron hydroxide-coated alumina adsorbent prepared for removal of arsenic from drinking water. Journal of Colloid and Interface Science, 284(1), 71-77. 

Maldonado-Reyes, A., Montero-Ocampo, C. and Solorza-Feria, O. (2007) Remediation of drinking water contaminated with arsenic by the electro-removal process using different metal electrodes. Journal of Environmental Monitoring, 9(11), 1241-47. 

Thirunavukkarasu, O.S., Viraraghavan, T., Subramanian, K.S. et al. (2005) Arsenic removal in drinking water — impacts and novel removal technologies. Energy Sources, 27(1-2), 209-19. 

Yuan, T., Luo, Q.-F., Hu, J.-Y. et al. (2003) A study on arsenic removal from household drinking water. Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering, 38(9), 1731-44. 

With the lowering of the US arsenic drinking water standard (MCL) from 50 to 10 pg L-1 (Appendix E), water treatment facilities may have had to modify their procedures to comply with the new standard. Boccelli, Small and Dzombak (2005) identifies some of the factors associated with Fe(III) chloride coprecipitation that might require modification while still maintaining reasonable costs. Besides the influent arsenic concentration and Fe(III) chloride dose, other critical factors in improving arsenic removal may include pH, the calcium and major anion concentrations of the influent, the volume of sludge, equilibrium sorption constants, and filter efficiency. 

Gillman, G.P. (2006) A simple technology for arsenic removal from drinking water using hydrotalcite. Science of the Total Environment, 366(2-3), 926-31. 

Gu, Z. and Deng, B. (2007) Use of iron-containing mesoporous carbon (IMC) for arsenic removal from drinking water. Environmental Engineering Science, 24(1), 113-21. 

Hering, J.G., Chen, P.-Y., Wilkie, J.A. and Elimelech, M. (1997) Arsenic removal from drinking water during coagulation. Journal of Environmental Engineering, 123(8), 800-7. 

Jekel, M.R. (1994) Removal of arsenic in drinking water treatment, in Arsenic in the Environment Part I Cycling and Characterization (ed. J.O. Nriagu), John Wiley Sons, Inc., New York, pp. 119-32. 

Korngold, E., Belayev, N. and Aronov, L. (2001) Removal of arsenic from drinking water by anion exchangers. 

Kosutic, K., Furac, L., Sipos, L. and Kunst, B. (2005) Removal of arsenic and pesticides from drinking water by nanofiltration membranes. Separation and Purification Technology, 42(2), 137-44. 

Krauskopf, K.B. and Bird, D.K. (1995) Introduction to Geochemistry, 3rd edn, McGraw-Hill, Boston, p. 647. Krishna, M.V.B., Chandrasekaran, K., Karunasagar, D. and Arunachalam, J. (2001) A combined treatment approach using Fenton s reagent and zero valent iron for the removal of arsenic from drinking water. Journal of Hazardous Materials, 84(2-3), 229-40. 

Sagitova, F Bejan, D Bunce, N.J. and Miziolek, R. (2005) Development of an electrochemical device for removal of arsenic from drinking water. Canadian Journal of Chemical Engineering, 83(5), 889-95. 

Uddin, M.T., Mozumder, M.S.I., Islam, M.A. et al. (2007a) Nanofiltration membrane process for the removal of arsenic from drinking water. Chemical Engineering and Technology, 30(9), 1248-54. 

Vatutsina, O.M., Soldatov, V.S., Sokolova, V.I. et al. (2007) A new hybrid (polymer/inorganic) fibrous sorbent for arsenic removal from drinking water. Reactive and Functional Polymers, 67(3), 184-201. 

Zhang, Q.L., Lin, Y.C., Chen, X. and Gao, N.Y. (2007b) A method for preparing ferric activated carbon composites adsorbents to remove arsenic from drinking water. Journal of Hazardous Materials, 148(3), 671-78. 

Chwirka, J.D., Colvin, C., Gomez, J.D. and Mueller, P.A. (2004) Arsenic removal from drinking water using the coagulation/microfiltration process. Journal of American Water Works Association, 96(3), 106-14. 

Anonymous, Arsenic in Drinking Water Treatment Technology Removal, 1993, http // www.dainchi-consul.co.jp/ENGLISH/arsenic/treat1.html (Accessed March 2001). 

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