Degradation of bisphenol S by peroxymonosulfate activation through monodispersed CoFe2O4 nanoparticles anchored on natural palygorskite

Abstract

• Monodispersed CoFe 2 O 4 nanoparticles anchored on palygorskite to activate PMS. • 16%-CFO@PAL/PMS oxidation system can effectively degrade BPS in water. • 16%-CFO@PAL composite exhibits high activity and low metal leaching property. • SO 4 · - and 1 O 2 mainly contributed degradation of BPS in 16%-CFO@PAL/PMS system. • Fe-O-Al bond between CoFe 2 O 4 and PAL improved the stability of 16%-CFO@PAL. Bisphenol S (BPS) has been detected frequently in water bodies, which poses a serious threat to human health and the environment. The sulfate radical-based advanced oxidation process is considered as a promising water purification technology by activating peroxymonosulfate (PMS). However, a catalyst with low metal leaching rate and high effective catalytic ability is needed to activate PMS. In this study, natural clay of palygorskite (PAL) was used to mediate monodispersed CoFe 2 O 4 nanoparticles to degrade BPS by PMS activation. The monodispersed CoFe 2 O 4 nanoparticles were distributed and anchored on the surface of PAL, which caused the 16%-CoFe 2 O 4 @PAL (16%-CFO@PAL) composite expose more reaction sites, thus exhibiting excellent catalytic performance. A satisfactory BPS removal rate (> 99%) was obtained by introducing 50 mg L -1 16%-CFO@PAL and 0.16 mM PMS. The interaction mechanism between CoFe 2 O 4 nanoparticles and PAL was discussed. The Al-O-Fe bond between CoFe 2 O 4 nanoparticles and PAL endowed the 16%-CFO@PAL composite with low metal leaching property, high stability and reusability. SO 4 ·- and 1 O 2 played a dominant role in the degradation of BPS. The generation mechanism of reactive species was proposed. The influences of various degradation parameters (e.g., catalyst dosage, PMS concentration, initial solution pH, and BPS concentration) and water constituents (e.g., inorganic anions and NOM) on the degradation of BPS were investigated. Based on the identified intermediates and density functional theory (DFT) calculations, the possible degradation pathways of BPS were discussed. This study provides a new idea for the preparation of high-efficiency natural clay-based PMS catalysts for water purification.