Enhanced efficiency of refractory organic pollutant degradation over a wide pH range by peroxymonosulfate activated by cobalt-doped FeS

Abstract

A series of cobalt-doped FeS (x% Co–FeS) nanoparticles, prepared via a hydrothermal method, were introduced as catalysts for generating radicals from peroxymonosulfate (PMS) to degrade the endocrine disrupter bisphenol S (BPS) in wastewater. The kinetic results revealed that only a small amount of Co doping (7% At.) could greatly improve the efficiency of PMS activation by FeS, leading to the rapid degradation of BPS (0.21min−1 vs. 0.0046 min−1), and no secondary pollution caused by Co leaching. Notably, exceptional activation was observed over a wide pH range from 4 to 11. Moreover, various background ions (NO3−, Cl−, CO32−) and temperatures (10.0–55.0 °C) minimally affected BPS degradation, suggesting excellent applicability in different sewage environments. Furthermore, quenching experiments, coupled with electron paramagnetic resonance technology, identified singlet oxygen (1O2) and sulfate radicals (SO4•-) as the primary reactive oxygen species responsible for BPS degradation. Due to the selectivity of 1O2 and the high redox potential of SO4•-, this technology had excellent anti-interference and degradation ability. In six repeated batch experiments, the catalysts showed favorable cyclability and stability due to Co(II)/Co(III) cycling mediated by structural S2−. These results provided insights into the potential applications of modifying natural FeS-type minerals as a promising heterogeneous catalyst for environmental restoration.