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Effects of water chemistry on arsenic removal from drinking water by electrocoagulation

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Title Effects of water chemistry on arsenic removal from drinking water by electrocoagulation
 
Creator WAN, W
PEPPING, TJ
BANERJI, T
CHAUDHARI, S
GIAMMAR, DE
 
Subject OXIDE-BASED SORBENT
IRON
GROUNDWATER
PHOSPHATE
SORPTION
COPRECIPITATION
ADSORPTION
CARBONATE
SILICATE
SULFATE
Arsenic
Water treatment
Electrocoagulation
Phosphate
Adsorption
Lepidocrocite
 
Description Exposure to arsenic through drinking water poses a threat to human health. Electrocoagulation is a water treatment technology that involves electrolytic oxidation of anode materials and in-situ generation of coagulant. The electrochemical generation of coagulant is an alternative to using chemical coagulants, and the process can also oxidize As(III) to As (V). Batch electrocoagulation experiments were performed in the laboratory using iron electrodes. The experiments quantified the effects of pH, initial arsenic concentration and oxidation state, and concentrations of dissolved phosphate, silica and sulfate on the rate and extent of arsenic removal. The iron generated during electrocoagulation precipitated as lepidocrocite (gamma-FeOOH), except when dissolved silica was present, and arsenic was removed by adsorption to the lepidocrocite. Arsenic removal was slower at higher pH. When solutions initially contained As(III), a portion of the As(III) was oxidized to As(V) during electrocoagulation. As(V) removal was faster than As(III) removal. The presence of 1 and 4 mg/L phosphate inhibited arsenic removal, while the presence of 5 and 20 mg/L silica or 10 and 50 mg/L sulfate had no significant effect on arsenic removal. For most conditions examined in this study, over 99.9% arsenic removal efficiency was achieved. Electrocoagulation was also highly effective at removing arsenic from drinking water in field trials conducted in a village in Eastern India. By using operation times long enough to produce sufficient iron oxide for removal of both phosphate and arsenate, the performance of the systems in field trials was not inhibited by high phosphate concentrations. (C) 2010 Elsevier Ltd. All rights reserved.
 
Publisher PERGAMON-ELSEVIER SCIENCE LTD
 
Date 2012-06-26T08:44:42Z
2012-06-26T08:44:42Z
2011
 
Type Article
 
Identifier WATER RESEARCH,45(1)384-392
0043-1354
http://dx.doi.org/10.1016/j.watres.2010.08.016
http://dspace.library.iitb.ac.in/jspui/handle/100/14214
 
Language English