Treatment of surface water contaminated arsenite using continuous flow air-cathode electrocoagulation

Abstract

Air-cathode Electrocoagulation (ACEC) is a new emerging technology that combines the concepts of electrocoagulation and fuel cell technology for treating water contaminated by pollutants without the addition of external energy. In this study, the ACEC reactor was used for the removal of Arsenite (As3+) contained in river water. The effects of the different anode materials and hydraulic retention time (HRT) to the performance of the reactor were investigated. The water containing 3,5 ppm of arsenite was used as a representation of river water contaminated by heavy metal. Three types of metal plates (magnesium, iron, and aluminum) were used as anode materials, while a wet-proof (30%) carbon cloth used as a cathode electrode. The reactor performance was evaluated by measuring the removal efficiency of arsenite, metal hydroxide concentration, current density, and maximum power density of the reactor. The result showed that the ACEC reactor with iron, aluminium, and magnesium anode were able to remove 99%, 17%, and 73% of arsenite respectively. In further experiments, the reactor was conducted in continuous mode with 4, 8, and 12 hours of HRT. The ACEC reactor with 12 hours HRT was able to remove arsenite up to 99% for 24 hours. This result indicated that ACEC process is a promising technology for the effective removal of arsenite from aqueous solution without additional energy.