ABSTRACT
Exploring the role of structural defects of iron oxides on the generation of ROS near the rhizosphere zone is essential for understanding As geochemical process and its regulation in paddy soils. Herein, the adsorption and oxidation of As(III) on the surface of goethite with different defects (i.e. oxygen vacancy) in the presence of Fe(II) under oxic conditions have been examined. Results indicate that Fe(II) rapidly triggers the As(III) oxidation, and the oxidation is enhanced with increasing of OVs. Both pH and Fe(II) content play an important role in As(III) oxidation, while the overall adsorption of As is barely affected. Importantly, superoxide radical and H2O2 are found responsible for As(III) oxidation. The finding of this work provides an insight into understanding the As(III) reaction process on iron oxides in paddy soils.
