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

Nidia Rivera-Reyna, Laura Hinojosa-Reyes, Jorge Luis Guzmán-Mar, Yong Cai, Kevin O'Shea, Aracely Hernández-Ramírez

Index: Photochem. Photobiol. Sci. 12(4) , 653-9, (2013)

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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.