[TiO2 photocatalyzed As (III) oxidation and adsorption in variable charge soil systems]

Toxicity and mobility of As(III) in environments is greater than As(V). The transformation of As(III) to As(V) is in favor of the adsorption and fixation of arsenic on adsorbents. TiO2 photocatalyzed As(III) oxidation in the suspension systems of variable charge soils and the adsorption of oxidation products by the soils were investigated with a batch method. The photocatalysis experiments were conducted in a reaction box made by authors. The experiment results show that the photocatalyzed As(III) oxidation increased with the increase in the amount of TiO2 added and the time of irradiation, and 1.0 g x L(-1) of TiO2 and 90 min of irradiation were enough for photocatalyzed As(III) oxidation in the soil suspension systems. The TiO2 photocatalyzed As(III) oxidation in the variable charge soils and the adsorption of oxidation products by the soils increased the removal of arsenic from water and the similar processes were observed in TiO2O-Fe/Al oxides' systems. The results also indicated that gamma-Al2O3 was able to induce the photocatalyzed oxidation of As(III) in suspension systems.