Mechanism investigation of arsenic remediation in contaminated soil by Fe anode using the electrochemical method

Abstract

Heavy metal polluted soil remediation is a global concern. Therefore, it is urgently needed to develop new ways for soil remediation. Although the electrochemical method is a simple, efficient, and promising process, the reaction mechanism of arsenic (As) in contaminated soil treated by the electrochemical method is rarely noticed. Herein, electrochemical techniques were developed for As removal from contaminated soil, which can be effectively achieved by using a Fe sacrificial anode to form Fe3+ species and by combining manganese oxide in soils for remediation. The results showed that the As was changed from an unstable to a stable state, and As pollutions were effectively removed by this electrochemical method. Further, the dissolution kinetics of Fe and Mn oxides, arsenic reaction kinetics and the phase transformation process during the remediation process were investigated by cyclic voltammetry (CV) methods. From the simulation experiments, it was found that As(III) should be oxidized by Mn4+ and Fe3+ to form As(V), and As(V) was the main reactant with Fe and Mn oxides for As removal. Consequently, the current work may provide a new insight into solve As contamination in soil, and provide some new insights into the interaction mechanism between multiple components.