How do operating conditions affect As(III) removal by iron electrocoagulation?

WATER RESEARCH

卷:112

Article

Delaire, Caroline¹  Amrose, Susan¹  Zhang, Minghui¹  Hake, James²  Gadgil, Ashok^1,3 

[1] Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA

[2] Univ Calif Berkeley, Dept Chem & Biomol Engn, Berkeley, CA 94720 USA

[3] Lawrence Berkeley Natl Lab, Energy Technol Area, Berkeley, CA 94720 USA

关键词: Arsenic;    Iron electrocoagulation;    Operating conditions;    pH;    Computational model;    Synthetic Bengal groundwater;   

DOI  :  10.1016/j.watres.2017.01.030

来源: Elsevier

【 摘 要 】

Iron electrocoagulation (Fe-EC) has been shown to effectively remove arsenic from contaminated groundwater at low cost and has the potential to improve access to safe drinking water for millions of people. Understanding how operating conditions, such as the Fe dosage rate and the O-2 recharge rate, affect arsenic removal at different pH values is crucial to maximize the performance of Fe-EC under economic constraints. In this work, we improved upon an existing computational model to investigate the combined effects of pH, Fe dosage rate, and O-2 recharge rate on arsenic removal in Fe-EC. We showed that the impact of the Fe dosage rate strongly depends on pH and on the O-2 recharge rate, which has important practical implications. We identified the process limiting arsenic removal (As(III) oxidation versus As(V) adsorption) at different pH values, which allowed us to interpret the effect of operating conditions on Fe-EC performance. Finally, we assessed the robustness of the trends predicted by the model, which assumes a constant pH, against lab experiments reproducing more realistic conditions where pH is allowed to drift during treatment as a result of equilibration with atmospheric CO2. Our results provide a nuanced understanding of how operating conditions impact arsenic removal by Fe-EC and can inform decisions regarding the operation of this technology in a range of groundwaters. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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