Removal of arsenite from aqueous solutions using ultrasonic irradiation in the presence of a lead electrode

In this study, we performed electrochemical reduction of H2O2 (H2O2 + e− = OH + OH−, H2O2 + 2e− = 2OH−) that was generated by ultrasound irradiation and oxidation of As(III) using OH and H2O2. Electrochemical reduction was conducted using a Pb electrode, which was immersed in 10 ppm of As(III) solution containing 20 mM of KCl and 10 ppm of H2O2, and applied electrical potential of −0.5 V versus Ag/AgCl for 30 min in Ar atmosphere. After electrochemical reduction, the pH increased from 4.8 to 9.3. The concentration of As(V), which was oxidized from As(III) by H2O2, increased from 0 to 6.2 ppm. The precipitate of Pb, β-PbO, and Pb5O8 was obtained by ultrasound irradiation in the presence of the Pb electrode at −0.5 V, and the concentration of As deceased from 10 to 1.2 ppm. The precipitate adsorbed As(V) after oxidation of As(III) by OH and H2O2.