Peroxymonosulfate activation by immobilized CoFe2O4 network for the degradation of sulfamethoxazole

Heterogeneous activation of peroxymonosulfate (PMS) has been frequently proposed for the degradation of organic pollutants via the generation of reactive oxygen species (ROS). Spinel ferrite such as CoFe 2 O 4 shows great advantage for PMS activation but suffers from aggregation problem and lack of microstructure. Herein, network-like CoFe 2 O 4 immobilized on volcanic rock was synthesized for PMS activation for degrading sulfamethoxazole (SMX). The immobilized CoFe 2 O 4 network exhibited good catalytic performance for SMX removal. Systematic investigations, including in situ ATR-FTIR and Raman spectroscopy analysis, chemical quenching experiments and electron paramagnetic resonance (EPR) tests, revealed that a redox cycle of Co 2+ /Co 3+ induced the generation of ROS (SO 4 •− , OH • and 1 O 2 ) that participated in the degradation of SMX. Background constituents (e.g., inorganic ions and natural organic matters) exhibited limited influence on SMX removal. A continuous flow-through reaction in a fixed-bed column revealed the immobilized CoFe 2 O 4 network could efficient degrade SMX with long-term durability, which therefore can be a promising catalyst for PMS activation for the degradation of SMX. Network-like CoFe 2 O 4 with high exposure of active sites was successfully immobilized on the surface of volcanic rock. The immobilized CoFe 2 O 4 network exhibited good catalytic performance of PMS activation for sulfamethoxazole removal via both radical (SO 4 •− , OH • ) and nonradical ( 1 O 2 ) oxidation process. • Network-like CoFe 2 O 4 was immobilized on volcanic rock by annealing coated MPNs. • Immobilized CoFe 2 O 4 network was highly active toward PMS activation for SMX removal. • Both radical and nonradical oxidation were involved in the degradation of SMX.