Construction Of FeS₂/MoS₂-based Heterostructures And Analysis Of Pollutant Degradation

The invention of antibiotics has saved innumerable lives,however,in recent years,the global abuse of antibiotics has caused high concentrations of antibiotics in natural water bodies.Bacteria will enhance their resistance exposed to high concentrations of antibiotics for a long time,and it is easy to give rise to bacteria with super resistance endangering human life and health.Therefore,it is urgent to solve the antibiotic pollution in water bodies,and not only should we regulate the whole process of antibiotic production,use and treatment,but also deal with the antibiotic pollution that has been caused as early as possible.In this paper,by constructing FeS₂/MoS₂-based heterojunction catalyst for photo-Fenton reaction to degrade antibiotics,which shortened the degradation time and improved the degradation efficiency.The specific research contents are as follows:(1)The sandwich-like Fe₃O₄@FeS₂@C@MoS₂ composites were prepared by coating MoS₂ on the surface of core/shell Fe₃O₄@C composites.During the coating process,part of Fe₃O₄ sulfide into FeS₂,and a Z-scheme heterojunction was formed through a carbon bridge between the matching energy bands of FeS₂ and MoS₂.The residual Fe₃O₄ ensured the catalyst could be rapidly magnetically separated.During the photo-Fenton reaction,the degradation rate of tetracycline reached 81.5%in 40 min,and the degradation efficiency can still be 76.3%after 5 cycles.After the generation paths of^·OH,^·O₂^-,~1O₂ and h⁺were analyzed through mechanism study,the contribution order of each active species was confirmed as:^·OH_surf>^·O₂^->~1O₂>h⁺>^·OH_free.(2)FeS₂/MoS₂@C nanoreactors were synthesized using Fe-MIL-101 as a template for photo-Fenton degradation of metronidazole.The research results showed that the constructed FeS₂/MoS₂@C nanoreactor had higher degradation efficiency of metronidazole,which could reach up to 90.5%in 25 min,the rate constant was k=9.4×10^-2 min^-1 and the degradation efficiency could still be 81.5%after 5 cycles.Mechanistic studies showed that the construction of nanoreactors improved the utilization efficiency of visible light,enhanced the photothermal effect,provided a confinement effect,increased the concentration of free radicals,and promoted the degradation of metronidazole.The analysis of reactive species showed that free radicals(^·OH and^·O₂^-)and non-radicals(~1O₂ and h⁺)were main active species during the degradation of metronidazole,and their contribution order was:^·OH>h⁺>~1O₂>^·O₂^-.