MOF-templated synthesis of CoFe2O4 nanocrystals and its coupling with peroxymonosulfate for degradation of bisphenol A

Abstract

Porous magnetic cobalt ferrite nanocrystals (CoFe2O4 NC) are synthesized via a one-step process by using bimetal-organic frameworks (Co/Fe bi-MOFs) as a template for the catalytic degradation of bisphenol A (BPA). The properties of the prepared catalyst are evidenced by a series of characterization techniques. Overall, the unique ferromagnetic nature (34.73 emu/g) make its efficient separation from the liquid phase possible. CoFe2O4 NC activates peroxymonosulfate (PMS) to degrade BPA more efficiently than hydrothermally fabricated CoFe2O4 nanoparticles. The difference in catalytic capacity is attributable to the larger specific surface area (60.4 m2 g−1) and well developed mesoporous structure (0.64 cm3 g−1) of the CoFe2O4 NC. EPR analysis demonstrate the production of HO and SO4− radicals in the CoFe2O4 NC/PMS system. The degradation process positively correlates with the increase of initial solution pH, catalysts dosage, and PMS dosage. The degradation rate of 0.112 min−1 is achieved at [PMS]/[BPA] of 10, catalyst dosage of 0.1 g L−1, temperature of 25 °C, and initial pH of 10.2 in deionized water. The existence of Cl- and HCO3−/CO32− show significant positive synergistic effects on the catalytic process. Moreover, simple thermal treatment at 400 °C for 15 min in open air fully regenerates the catalytic capacity of CoFe2O4 NC for reuse. Findings from this work shed light on the rational design of bimetallic oxide catalysts and provide new insight into the development of high-performance magnetic separable catalysts.