Adsorption-reduction of Fe(III) by different biochars and their co-activation of H2O2 for oxidation of refractory pollutants

Various biochar samples were used for exploring the Fe(III)/biochar interactions and transformation of reactive oxygen species during co-activation of H2O2. The enhanced •OH production is positively related to the biochars' capacity of reducing Fe(III) into Fe(II), which is then linked with their redox-active moieties and adsorption of Fe(III). Besides the •OH produced sustainably from Fenton reaction between H2O2 and regenerated Fe(II), a novel route involving dissolved O2 is proposed to enhance •OH production in the co-activated system. Consequently, faster and more efficient oxidation of refractory pollutants was achieved by co-activation of H2O2 with Fe(III) and biochar together.