WS as highly active co-catalyst for the regeneration of Fe(II) in the advanced oxidation processes.

The greatest constraint in the advanced oxidation processes involved Fe(II)/PMS was the low utilization of Fe(II) and PMS. In the present study, the co-catalytic effect of WS on the Fe(II)/PMS system for the degradation of organics was investigated. In the presence of WS, Fe(III) was reduced to Fe(II) during the reaction and resulted in improved decomposition of PMS as well as the degradation of 4-chloriphenol (4-CP). The decomposition rate of PMS and degradation efficiency of 4-CP were 10% and 25% in the Fe(II)/PMS process, while the efficiencies respectively increased to 99% and 100% in the WS assisted Fe(II)/PMS system. The degradation of 4-CP was completed via the free radical pathway and SO• played a more important role than other active species. Low concentration of inorganic ions such as Cl and HCO exhibited irrelevant effect while humic acid showed significant suppression on the WS/Fe(II)/PMS system. Additionally, characterization and recycle results implied that WS maintained a good stability during the co-catalytic processes.