Beschreibung:
The oxidization of As(III) to As(V) is necessary for both the detoxification of arsenic and the removal of arsenic by solidification. In order to achieve high efficiency and low cost As(III) oxidation, a novel process of catalytic aerial oxidation of As(III) is proposed, using air as oxidant and supported manganese-based diatomite as a catalyst. As(III) oxidation efficiency and the catalysis process were characterized in order to establish the reaction law and mechanism of catalytic aerial oxidation of As(III) by supported manganese-based diatomite. Results show that supported manganese-based diatomite achieved a good catalytic effect for aerial oxidation of As(III) and maintained high performance over multiple cycles of reuse, which was directly related to the structure of diatomite and the behavior of the active component manganese. Under the conditions of a catalyst dosage of 20 g/L, an air flow rate of 0.3 m 3 /h, a reaction temperature of 50 °C and an initial pH of 12.6, 96.04% As(III) oxidation was achieved after 3 h. Furthermore, the As(III) oxidation efficiency did not change significantly after four cycles of reuse. XPS analysis of the reaction products confirmed that the surface of the catalyst was rich in Mn(III), Mn(IV) and adsorbed oxygen(O-H), which was the fundamental reason for the excellent catalytic oxidation of As(III) by supported manganese-based diatomite