MOFs-derived magnetic hierarchically porous CoFe2O4-Co3O4 nanocomposite for interfacial radicals-induced catalysis to degrade chloramphenicol: Structure, performance and degradation pathway

Abstract

Bimetallic organic frameworks derived bimetallic oxides as novel heterogeneous catalysts have been admitted to enhance catalytic capacity to great extent for peroxymonosulfate (PMS) activation. Herein, a magnetic hierarchically porous CoFe2O4-Co3O4 nanocomposite derived from heterometallic MIL-100 was one-step synthesized via manipulation of Fe/Co ratio and used to degrade chloramphenicol (CAP) in water. The structure of CoFe2O4-Co3O4 nanocomposite was evaluated by various characterization modes. The catalytic activity of CoFe2O4-Co3O4 nanocomposite was evaluated according to removal efficiency of CAP. Furthermore, the interfacial activation mechanism was deduced by a series of analysis. The results revealed CoFe2O4-Co3O4 nanocomposite was sphere-like nanoparticles with hierarchically micro/mesoporous structure. The nanocomposites had well-performed degradation efficiency toward 200 mL CAP of initial concentration of 10 mg/L (100% within 60 min). All of degradation followed the pseudo-first order kinetic reaction equation (kobs = 0.091 min−1). The whole degradation relied on interfacial radical generation via synergistic catalysis and sulfate radical (SO4•−) as well as hydroxyl radical (HO•) were ascertained as main reactive oxygen species (ROS). The possible degradation pathways involving dehydration, hydroxylation, substitution, oxidation, ring opening were proposed accordingly. This paper paid much attention to synergistic catalytic activity of Fe/Co and interfacial electron-transfer mechanism between CoFe2O4-Co3O4 nanocomposite and PMS, shedding a light on in-depth exploration of MOFs-derivates induced heterogeneous catalysis.