Enhanced degradation of carbamazepine in water over SC-modified NiFe2S4 nanocomposites by peroxymonosulfate activation

In this study, novel Semi-coke-modified NiFe2S4 nanocomposites with different mass ratios are successfully prepared by hydrothermal method to activate peroxymonosulfate (PMS) for the degradation of carbamazepine (CBZ) in water. The factors affecting the degradation of CBZ, such as initial solution pH, PMS and catalyst dosage, inorganic anions, and humic acid (HA) are investigated. The possible PMS activation mechanism and CBZ possible degradation pathways are also explored. The results show that the performance of SCNF-0.5/PMS (mass ratio of SC:NiFe2S4 = 1:2) is better than that of monomeric NiFe2S4 and semi-coke (SC). X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectrometer, and free radical quenching experiments show that both non-radical (O-1(2) and O-v) and free radical pathways (SO4 center dot- and radical (OH)-O-center dot) may be responsible for the degradation of CBZ, but O-1(2) is dominant active species. S2- promotes the Ni2+/Ni3+, Fe2+/Fe3+ cycle to ensure the stable performance of the catalyst, and the oxygen vacancies (O-v) in the SC act synergistically with the catalyst to promote the degradation of CBZ. This study may provide new insights into the degradation of antibiotics in water by modifying stable bimetallic sulfide to activate PMS.