Magnetic recyclable MIL-88A(Fe)@WS2/CuFe2O4 ternary composite promotes peroxymonosulfate activation for efficient phenol removal: Performance, mechanism and toxicity evaluations

The development of efficient, recyclable catalysts for peroxymonosulfate (PMS) activation remains challenging due to limitations including low electron transfer efficiency, metal leaching, and poor stability in conventional Fenton-like systems. To overcome these, we synthesized a novel magnetic recyclable ternary composite, Materials Institute Lavoisier-88A(Fe) (MIL-88A(Fe)) modified with tungsten disulfide (WS2) and copper ferrite (CuFe2O4), denoted as MIL-88A(Fe)@WS2/CuFe2O4 (MWC), through a multistep solvothermal method. This composite material features a stable nanosheet-wrapped rod structure that can directly activate PMS and efficiently degrade organic pollutants including phenol, Rhodamine B (RhB) and ofloxacin (OFX). The degradation performance of the catalysts for phenol was thoroughly assessed, and PMS activation by MWC was systematically analyzed. At a catalyst dosage of 0.3 g/L and a PMS dosage of 1 mM, the phenol removal efficiency reached 95.3 % within 20 min, which is surpassing most reported heterogeneous PMS Fenton-like catalysts. The system demonstrated significant degradation efficiency, superior anti-interference capabilities, and excellent cycle stability in various situations. After five cycles, the phenol removal rate remained at 91.3 %. Mechanistic studies showed that pollutant oxidation occurs by both free radical and nonradical pathways, among which sulfate radicals (SO4 center dot-) and singlet oxygen (1O2) play leading roles, and the main driving factors are the Fe2+/Fe3+, W2+/ W4+, and Cu+/Cu2+ redox cycles and sulfur vacancy (Sv) mediated PMS activation. The phenol degradation process was examined, and nine intermediates were qualitatively analyzed. Furthermore, the toxicity of the intermediates was simulated and assessed. This work provides new insights into designing magnetic recyclable Fenton-like catalysts for organic contaminant remediation.