Facile synthesis of superparamagnetic β-CD-MnFe2O4 as a peroxymonosulfate activator for efficient removal of 2,4- dichlorophenol: structure, performance, and mechanism

In this study, superparamagnetic β-CD-MnFe 2 O 4 with a large surface area was synthesized via a facile co-precipitation method, with β-cyclodextrin (β-CD) acting as a coating agent. The as-prepared β-CD-MnFe 2 O 4 exhibited better catalytic performance than bare MnFe 2 O 4 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 (SO 4 − / OH/O 2 − / 1 O 2 ) are generated in the β-CD-MnFe 2 O 4 /PMS system and that pollutants trapped in the cyclodextrin cavity are quickly degraded. Various reaction parameters of the β-CD-MnFe 2 O 4 /PMS system and the stability of β-CD-MnFe 2 O 4 were also investigated. The results indicate that β-CD-MnFe 2 O 4 is promising for use in water purification owing to its excellent magnetic separation and recovery properties and good resistance to humic acid (HA).