Simultaneous oxidation and removal of arsenite by Fe(III)/CaO₂ Fenton-like technology

Arsenite contaminated water is one of severe global environmental problems. It is challenging to treat As(III) pollution by a one-step technology. In this study, we developed a Fe(III)/CaO₂ Fenton-like technology for the treatment of As(III). The simultaneous oxidation of arsenite and removal of arsenic were achieved with efficiencies of nearly 100% and 95.8% respectively, which outperforms conventional technologies. It worked well in pH 3 to 9, and in the presence of cationic heavy metals, anions and humic acid. Moreover, the PO₄^3- inhibited the removal of As(III). •OH and ¹O₂ played the important roles in the oxidation of As(III). The Ca(II) derived from CaO₂ made a significant contribution to the oxidation and removal of As(III). The SEM and XPS studies confirmed that the formation of Ca-Fe nascent colloid caused the effective removal of arsenic. Our study demonstrates that the one-step Fe(III)/CaO₂ technology has a great potential for purification of the As(III)-contaminated water.