Arsenic and hydrated silica remotion from drinking water by electrocoagulation using iron as sacrificial electrodes

Author(s): Jonathan Valentin Reyes
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Institution or organization of origin: Universidad de Guanajuato
Country: Mexico


Many regions in the world consider groundwater a safe source of drinking water; however, various metallic and non-metallic ions are found in groundwater1. In Bajio region, central Mexico, the groundwater is mainly polluted with arsenic and hydrated silica, among other ions such as fluoride, sulfates, and phosphates 2–4. The present work reports arsenic and hydrated silica remotion from groundwater by electrocoagulation (EC) using an up-flow reactor with sacrificial iron anodes. A sample was taken in the northern area of Guanajuato in Mexico containing arsenic 25.70 µg L-1, hydrated silica 237.75 mg L-1, fluoride 1.43 mg L-1, sulfate 45.0 mg L-1, phosphate 0.61 mg L-1, pH 8.62, and conductivity 577 µS cm-1. The EC process efficiency on pollutants removal was evaluated by varying current densities (4 ≤ j ≤ 8 mA cm-2) and mean linear flow velocities (1.1 ≤u ≤4.5 cm s-1). The best EC trial was obtained at 8 mA cm-2 and 2.3 cm s-1. The residual concentrations of arsenic and hydrated silica were 2.8 µg L-1 and 139.5 mg L-1, respectively, giving an electrolysis energy consumption and overall cost of 0.647 kWh m-3 and 0.118 USD m-3, respectively.

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