A green, efficient and recyclable magnetic BiFeO 3 /Cl-g-C 3 N 4 photocatalyst was prepared for the simultaneous removal of Cr(Ⅵ) and tetracycline (TC) from water by wet chemical and thermal synthesis methods. Experimental results revealed that BiFeO 3 /Cl-g-C 3 N 4 achieved a removal efficiency of 96.1 % for Cr(Ⅵ) and 98.2 % for TC under visible light irradiation for 50 min at pH 6. The results of the work function, charge density difference, UV–vis DRS, PL, PC and EIS tests indicate the formation of S-scheme heterojunctions between BiFeO 3 and Cl-g-C 3 N 4 , which exhibits superior carrier separation and migration efficiency. The evidence for interfacial charge transfer from BiFeO 3 to Cl-g-C 3 N 4 within BiFeO 3 /Cl-g-C 3 N 4 was further corroborated by means of ISIXPS, EPR and KPFM. Moreover, calculations of the density of states demonstrate that the introduction of Cl enhances the reduction capability of BiFeO 3 /Cl-g-C 3 N 4 . Results from ESR tests and trapping experiments has demonstrated that the singlet oxygen ( 1 O 2 ) and electrons are the primary active species. Furthermore, the high removal rates of TC and Cr(VI) from industrial wastewater and groundwater, coupled with the lower ecotoxicity of TC degradation intermediates, indicate that BiFeO 3 /Cl-g-C 3 N 4 has the potential for practical applications. After five cycles, the BiFeO 3 /Cl-g-C 3 N 4 still removed 90.5 % of TC and 96 % of Cr(Ⅵ).
Tianrui Xu,Guanghui Wang,Xuewen Zhang,Nansheng Deng
Within the domain of animal husbandry, the misuse of antibiotics in conjunction with elevated levels of heavy metals in feed has led to the contamination of agricultural soils with these metals and antibiotics. In this study, S-scheme heterojunction photocatalyst, BiFeO 3 /Cl-g-C 3 N 4 , was synthesized for the photochemical remediation of tetracycline (TC) and Cr(Ⅵ) in co-contaminated soil, utilizing pyrolysis methods. Following an 8-h photocatalytic reaction, 89.6 % of TC and 75.7 % of Cr(Ⅵ) were effectively removed in soil with the application of BiFeO 3 /Cl-g-C 3 N 4 at a mass ratio of 5 %. The diversity of microbial communities in the remediated soil increased, with a shift in dominant genera from redox bacteria to nutrient bacteria associated with carbon and nitrogen cycling. Moreover, the incorporation of BiFeO 3 /Cl-g-C 3 N 4 in the remediation of soil contamination at depths ranging from 0 to 20 cm resulted in reductions of 40.2 % and 50 % in TC and Cr(Ⅵ) concentrations in subsoil layers, respectively, after 21-days of sunlight irradiation. In comparison to the contaminated group soil, soil from the remediation treatment demonstrated increased growth potential for cabbage and spinach. This work definitely demonstrates that this soil photochemical remediation method based on BiFeO 3 /Cl-g-C 3 N 4 is technologically feasible and has immense potential in the application of remediation of organic pollutants and heavy metals co-contaminated soils.
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