Enhanced peroxymonosulfate activation by hierarchical porous Fe3O4/Co3S4 nanosheets for efficient elimination of rhodamine B: Mechanisms, degradation pathways and toxicological analysis

Fenton-like catalysts have usually superior catalytic activities, however, some drawbacks of ion leaching and difficult-to-recovery limit their applications. In this work, a hierarchical porous Fe3O4/Co3S4 catalyst was fabricated via a simple phase change reaction to overcome these shortcomings. The introduced iron cooperates with cobalt achieving high-efficiency activation of peroxymonosulfate (PMS) to eliminate Rhodamine B (RhB). The results showed that 0.05 g/L Fe3O4/Co3S4 and 1 mM PMS could quickly remove 100% of 200 mg/L RhB within 20 min, and the removal rate of RhB remained above 82% after 5 cycles. Moreover, the as-prepared Fe3O4/Co3S4 possessed a great magnetic separation capacity and good stability of low metal leaching dose. Radical quenching experiments and electron paramagnetic resonance (EPR) techniques proved that sulfate radicals (SO4 center dot-) were the dominant reactive oxygen species responding for RhB degradation. X-ray photoelectron spectroscopy (XPS) pointed out that the synergism of sulfur promoted the cycling of Co3+/Co2+ and Fe3+/Fe2+, boosting the electron transfer between Fe3O4/Co3S4 and PMS. Moreover, the degradation pathways of RhB were deduced by combining liquid chromatographymass spectrometry (LC-MS) analysis and density functional theory (DFT) calculations. The toxicities of RhB and its intermediates were evaluated as well, which provided significant assistance in the exploration of their ecological risks. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

In this study, a hierarchical porous Fe3O4/Co3S4 catalyst was fabricated to address the issues of ion leaching and difficult recovery commonly seen in Fenton-like catalysts. The catalyst showed high-efficiency activation of peroxymonosulfate (PMS) for the degradation of Rhodamine B (RhB), achieving rapid removal of RhB and maintaining good stability after multiple cycles.