An Efficient Catalytic Composite Material of Mesoporous Carbon Loaded Nano Zero-Valent Iron as an Activator for the Degradation of Sulfadiazine

Sulfadiazine (SDZ) was effectively removed by the heterogeneous catalytic sulfate radical (SO4 center dot-) oxidation using a novel composite material of mesoporous carbon (MC) loaded nano zero-valent iron (nZVI). Possessing larger specific area (433.3 m(2) g(-1)) and high mesopores volume (2.537 cm(3) g(-1)), the composite material (nZVI/MC) was used as the activator to activate persulfate for the degradation of SDZ. The results of degradation experiments indicated that the removal efficiency of SDZ in nZVI/MC+ persulfate (PS) process reached the highest, due to good dispersing property of MC for nZVI. The removal of SDZ was further enhanced by the increase of nZVI loading as well as the nZVI/MC composite content. Quenching experiments showed that SO4 center dot- acted a crucial role in the degradation process of SDZ. Both the FT-IR and XPS analyses showed that the FeO contents decreased after degradation reaction, which indicated the occurrence of active oxidation reaction between SO4 center dot- and Fe2+ from the breakage of the Fe-O bond. The LC-MS analysis indicated that the cleavages of C-N bond in the heterocyclic ring and N-S bond were the major degradation pathway of SDZ, attributing to the attack of SO4 center dot- and center dot OH. These results demonstrated that the novel nZVI/MC composite with excellent stability could be used for the effective degradation of SDZ through activating PS to produce SO4 center dot-. Graphical Abstract