Efficient abatement of organic pollutants by Fe(III)/Fe(II) cycle activating H2O2 with the assistance of sulfurized manganese-supported graphene

This study develops a novel sulfurized manganese-supported graphene material (S-Mn@GO) designed for promoting Fe(III)/Fe(II) cycling in Fenton treatment. The excellent combination of manganese oxides (MnOx) and graphene oxide (GO), along with subsequent, impart S-Mn@GO with excellent electron transfer capabilities. Selecting Bisphenol A (BPA) as the model compound to evaluate the efficacy of the novel material, the findings indicate that the addition of 0.1 g/L of S-Mn@GO in the Fe(II)/H2O2 system enhanced the removal of BPA from 49.7 % to 98.3 % within 30 min. Results show that the abatement of pollutants in the S-Mn@GO/Fe(II)/H2O2 system was significantly influenced by pH, with the maximum removal efficiency (98.3 %) attained at pH 3.5. And the common coexist substances at environmental concentration levels on pollutant abatement was examined and this system showed excellent tolerance to anions. Quenching experiments and EPR analyses demonstrate that the hydroxyl radicals (HO•) dominates the abatement of BPA and the other reactive species (e.g., FeIVO2+) show negligible contribution. Density Functional Theory (DFT) calculations and other evidences indicate that the rapid cycling of iron species was due to the coupling of GO and manganese/sulfur (Mn/S) species. Moreover, the degradation pathway of BPA was analyzed through DFT calculations and LC-MS detection. Further, cycling experiments and long-term experiments confirm the stability of the material. Herein, using GO-based composite as an accelerator of Fe(III)/Fe(II) cycling provides a new strategy to promote the pollutant degradation in the Fenton process.