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 using a hydrothermal method were introduced as catalysts to generate powerful radicals from peroxymonosulfate (PMS) for endocrine disrupter bisphenol S (BPS) degradation in wastewater. The kinetic results showed that Co-doped FeS substantially enhanced the catalytic performance concerning FeS in activating the oxidative degradation of BPS by PMS, and activation efficiency increased with the proportion of Co-doping. The pH was controlled with a 50 mM phosphate buffer, and over 95% of BPS (20 mg/L) was removed within 20 min at pH 6 by 7% Co-doped FeS. Moreover, exceptional activation was obtained over a wide pH range (pH 4–11). Degradation efficiency increased with increasing catalyst loading and PMS concentration, and different background ions and temperatures minimally affected BPS degradation, implying suitability for 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 for BPS degradation. In addition, the catalysts presented favourable cyclability and stability in repeated batch experiments, providing insights into the application of Co-doped FeS as a promising heterogeneous catalyst for removing refractory organic contaminants in Fenton-like systems.