How do operating conditions affect As(III) removal by iron electrocoagulation?
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 O2recharge 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 O2recharge rate on arsenic removal in Fe-EC. We showed that the impact of the Fe dosage rate strongly depends on pH and on the O2recharge 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.
Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720-1710, United States. Electronic address: caroline.delaire@orange.fr.
Caroline
C
Delaire
Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720-1710, United States.
Susan
S
Amrose
Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720-1710, United States.
Minghui
M
Zhang
Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720-1710, United States.
James
J
Hake
Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720-1710, United States; Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States.
Ashok
A
Gadgil
D001151:Arsenic; D004564:Electrocoagulation; D007501:Iron; D014874:Water Pollutants, Chemical; D018508:Water Purification
D014874:Water Pollutants, Chemical; D007501:Iron; D001151:Arsenic
Arsenic; Computational model; Iron electrocoagulation; Operating conditions; Synthetic Bengal groundwater; pH