Photocatalytical removal of inorganic and organic arsenic species from aqueous solution using zinc oxide semiconductor

Abstract

The photocatalytic removal of arsenite [As(iii)] and monomethylarsonic acid [MMA(v)] was investigated in the presence of UV light (350 nm) and aqueous suspensions of ZnO synthesized by the sol-gel technique. Photocatalytic removal of these potent arsenic compounds results in the effective and rapid mineralization to less toxic inorganic arsenate [As(v)]. The effect of ZnO loading and solution pH on the treatment efficiency of the UV/ZnO photocatalytic process was evaluated. The optimal conditions for the removal of 5 mg L -1 [As(iii)] and [MMA(v)] aqueous solutions were observed at catalyst loadings of 0.25 and 0.50 g L-1 with solution pH values of 7 and 8, respectively. Under these conditions, the activity of photocatalyst sol-gel ZnO was compared with TiO2 Degussa P25 and commercial ZnO catalyst. The results demonstrate that the high adsorption capacity of ZnO synthesized by sol-gel gives enhanced removal of arsenic species from water samples, indicating that this catalyst is a promising material for treatment of arsenic contaminated groundwater. © The Royal Society of Chemistry and Owner Societies 2013.