Combined electrosorption and chemisorption of As(III) in aqueous solutions with manganese dioxide as the electrode

Abstract The combined electrosorption and chemisorption (CEC) behavior of As(III) with diluted concentration by manganese dioxide (MnO2) as the electrode was studied in this work. The CEC adsorption was better conformed to the pseudo-first-order kinetics and Langmuir model with the maximum adsorption capacity of 10.45 mg/g. Moreover, the conversion rate of As(III) to As(III) can reach 98% at pH 4 and 1 V with an initial As(III) concentration of 3.5 mg/L, which was almost 2.2 times of that with only chemisorption. The conversion of As(III) to As(V) can be attributed to the oxidation by MnO2 on the electrode and further enhanced by the electrostatic force provided by applied voltage.