Removal of Arsenic from Water by Electrolysis

Abstract

Arsenic is a toxic element which occurs in water due to mineral dissolution. Arsenic occurs in water mainly in the form of arsenite [As(III)] and arsenate [As(V)] . Maximum allowable limit for arsenic in drinking water is 0.01 mg/L as per WHO guidelines. In Nepal the most severe outbreak of arsenic poisoning have been associated with ground water in the Terai Region, including Bangladesh and West Bengal (Eastern India) where an estimated total of 120 million people are at risk. The purpose of this study was to investigate the effects of the operating parameters, such as pH, treatment time, and inter-electrode spacing on arsenic removal from drinking water in the electrolysis process. The removal of arsenic increased with decreasing inter-electrode spacing. Better removal of arsenic was observed with increasing current passing time. With increase in pH, the removal of arsenic increases. Using the inter electrode spacing 2cm, pH 7 and current passing time 20 minutes with the DC power source of 2A/12V with iron and aluminum electrodes, the concentration of arsenic in natural water samples after electrolysis was reduced below the WHO standard for drinking water.