Insights into enhanced peroxydisulfate activation with S doped Fe@C catalyst for the rapid degradation of organic pollutants

[Display omitted] •A novel S doped Fe@C catalyst were prepared for the PS activation.•Performance on the degradation of various organic pollutants was estimated.•Effects of anions and dissolved organic matters on PS activation were studied.•Main species during the PS activation were confirmed.•Role of S in promoting PS activation was also explored. In this study, the S modified iron-based catalyst (S-Fe@C) for activating peroxydisulfate (PDS) was fabricated by heating the S-MIL-101 (Fe) precursor at 800 °C. The resulted S-Fe@C composite mainly consisted of carbon, Fe0, FeS, FeS2, and Fe3O4, and showed strong magnetism. Compared with Fe@C obtained from MIL-101 (Fe), the S-Fe@C exhibited much higher performance (1.5 times larger) on PDS activation and the S-Fe@C/PDS could rapidly degrade various organic pollutants in 5 min under the attack of the species of SO4-·, 1O2, electro-transfer and Fe(IV). The S element in enhancing the PDS activation mainly involved two mechanisms. Firstly, the doped S could speed up the electron transfer efficiency, resulting in a promotion on PDS decomposition; secondly, the S2- S22- or S0 could achieve the circulation of Fe2+ and Fe3+, leading to the formation of non-radicals Fe(IV) and 1O2.