Facile synthesis of superparamagnetic β-CD-MnFe_2O_4 as a peroxymonosulfate activator for efficient removal of 2,4- dichlorophenol: structure, performance, and mechanism

摘要

In this study, superparamagnetic beta-CD-MnFe2O4 with a large surface area was synthesized via a facile co-precipitation method, with beta-cyclodextrin (beta-CD) acting as a coating agent. The as-prepared beta-CD-MnFe2O4 exhibited better catalytic performance than bare MnFe2O4 in terms of activating peroxymonosulfate (PMS) to degrade 2,4-dichlorophenol (2,4-DCP) over a broad pH range of 5-11. Electron spin resonance spectroscopy (ESR) and free radical quenching experiments indicate that various active species (SO4 center dot-/(OH)-O-center dot/O2(center dot-)/O-1(2)) are generated in the beta-CD-MnFe2O4/PMS system and that pollutants trapped in the cyclodextrin cavity are quickly degraded. Various reaction parameters of the beta-CD-MnFe2O4/PMS system and the stability of beta-CD-MnFe2O4 were also investigated. The results indicate that beta-CD-MnFe2O4 is promising for use in water purification owing to its excellent magnetic separation and recovery properties and good resistance to humic acid (HA).