Mechanism Of Bimetal Oxide/nitrogen Doped Carbon Composites For Peroxymonosulfate Activation In Removal Of Antibiotics

Water environment pollution caused by the abuse of antibiotics has seriously threatened the survival and development of human beings.It is a great urgency to develop effective treatment technologies to deal with antibiotic pollution in water bodies.Sulfate radical(SO4·–)based AOPs(SR-AOPs)possess broad practical application prospect due to their excellent oxidation activity and strong environmental adaptability.Reactive oxygen specie(ROS)which produced by peroxymonosulfate(PMS)activation have been proved to exhibit good antibiotic degradability.Currently,radical and non-radical dominated PMS activation have been extensively researched,but the driving force of this activation process is still indistinct.On this basis,Cu Fe2O4/NC composite catalysts were prepared by anchoring Cu Fe2O4 nanoparticle on nitrogen-doped carbon nanosheets(NC)in this study.The physical and chemical properties of the material,such as morphology,specific surface area,surface chemical element,were analyzed by various characterization methods,and the catalytic performance of Cu Fe2O4/NC/PMS catalytic system under different conditions was explored with levofloxacin(LVFX)as the target antibiotic.Most importantly,the electronic interaction between Cu Fe2O4 and NC in the composite catalyst and its role in the catalytic reaction were explored by combining experiments,characterizations and Density Functional Theory(DFT)theoretical calculations.The experimental results and DFT calculations indicate that a built-in electric field(BIEF)is formed between Cu Fe2O4 and NC,which is proposed as the driving force to adjust the electron transfer for triggering radical and non-radical pathways.Specifically,Cu+/Cu2+ and Fe2+/Fe3+ redox cycles are regarded to be the dominant catalytic sites for radical generation.Whereas graphitic N,sp2 hybridized structure,as well as C=O functional group are main active sites for non-radical production.Under the radical and non-radical processes dominated by BIEF,LVFX can be degraded and mineralizated by piperazine ring oxidation,carboxylation and de-methylation processes in Cu Fe2O4/NC/PMS catalytic system,and the best degradation efficiency reaches 84.87% within 90 min.This work offers a feasible strategy for designing metallic oxides-carbon catalyst with strong electric field effect to satisfy the charge transfer in PMS catalytic reaction.