Study On Treatment Of Dye Wastewater With Visible Light Catalysis Coupled With Fenton-like Process

Visible-light-driven photocatalysis as a promising technology has attracted great attention in environmental remediation recently.However,it still has insufficient visible light response,severe photocorrosion,and excessive photocarrier coupling.Therefore,the preparation of high performance photocatalyst and the construction of high efficiency photocatalyst system are the research hotspots.In this study,the Z-scheme composite material was constructed by using the built-in electric field generated by the difference between the BiVO₄ and ZnIn₂S₄ energy bands to achieve efficient separation of photogenerated carriers and improve photocatalytic performance.A series of BiVO₄/ZnIn₂S₄ composites were prepared by XRD,SEM,XPS and other characterization methods.The experimental results of photodegradation of methyl orange showed that 5%BZ had the highest performance,the decolorization rate was as high as 98%after 4 h under the optimal conditions,the mineralization rate was49%,and the decolorization rate was still 70%after 4 cycles.The free radical inhibition experiment confirmed that the order of the active substances in the system is·O^2->·OH>h⁺.Combined with the migration path of photogenic carriers,it is determined that 5%BZ prepared belongs to the z-scheme material.According to the material properties of ZnIn₂S₄,a Photocatalytic/Fenton-Like system was constructed by coupling with peroxydisulfate?PS?.In the ZnIn₂S₄/PS system,the decolorization rate of methyl orange was 90%and the mineralization rate was up to 52%within 2 h under the optimal conditions,and the decolorization rate remained above 70%after 5 cycles.The free radical inhibition experiment confirmed that the order of the active substances in the system is·O^2-?·SO₄^->·OH>h⁺,the principle is that the e^-and·O₂^-produced by ZnIn₂S₄ can activate PS to generate·SO₄^-,and then generate·OH and h⁺directly participate in the reaction.This system enhances the catalytic activity of ZnIn₂S₄while activating PS,which can efficiently degrade methyl orange.According to the material properties of BiVO₄,a Photocatalytic/Fenton-Like system was constructed by coupling with peroxymonosulfate?PMS?.In the BiVO₄/PMS system,the decolorization rate of methylene blue was 99%within 90 min under the optimal conditions,and the decolorization rate remained above 90%after 5 cycles.The free radical inhibition experiment confirmed that the order of the active substances in the system is·SO₄^->·OH>·O^2->h⁺,the principle is that PMS captures the e^-generated by BiVO₄ and then produces·SO₄^-,h⁺and·SO₄^-further produce·OH and·O^2-.The photocatalytic coupling of PMS and BiVO₄ can improve the decolorization efficiency of methylene blue and broaden the pH range of the synergistic system.