Promotion effect of KMnO4 on the oxidation of As(III) by air in alkaline solution

The mechanism of the oxidation of arsenic by air in the presence of KMnO4: (a) Oxidation of Mn2+ and formation of MnO2; (b) Catalytic oxidation of arsenic; (c) Oxidation of arsenic by dissolved oxygen; (d) Dissolution and precipitation of Mn2+.