Design And Research Of Multi-metal Oxide Materials For Deep Treatment Of Wastewater Containing Antibiotics And Cr⁶⁺

With the progress of science and technology and the development of society,there are increasingly serious shortage of resources and environmental pollution,among which the most prominent problem is the lack of water resources and water pollution.In order to achieve effective treatment of pollutants in water environment,photocatalysis technology has the advantages of high efficiency and stability,energy saving and environmental protection,low cost and no risk of secondary pollution,and has been widely studied.In this paper,bas ed on the synthesis and preparation of Bi₂Sn₂O₇,NaBiO₃,Bi₂WO₆ the photocatalytic activity of the above polymetallic oxides in the degradation of antibiotics or Cr⁶⁺was enhanced by the construction of heterojunction to broaden the photoresponse range,improve the efficiency of carrier separation and migration,and improve the chemical stability.The main research contents are as follows:（1）CuBi₂O₄/Bi₂Sn₂O₇/Sn₃O₄ Z-scheme heterojunction photocatalytic materials were synthesized by hydrothermal method.During the visible light degradation of Tetracycline hydrochloride,the degradation efficiency of Bi₂Sn₂O₇ reached 56.2%and that of CBS-2 was reached 89%.The enhanced photocatalytic activity was mainly attributed to heterojunction effect.Direct Z-scheme heterojunction can promote the separation of electrons and holes,inhibit the recombination of photogenerated carriers,retain strong reduction and oxidation ability and improve photocatalytic performance while keeping the optical response range unchanged.（2）BiOCl_xBr₁-_x/NaBiO₃ bismuth-based multielement metal oxide photocatalytic materials were prepared by in situ generation method.In the process of degradation of Sulfadiazine under visible light,the degradation efficiency of NaBiO₃ was 44%,and that of CBN-3 was 72%.The improvement of the activity is mainly attributed to the heterojunction effect,which promotes the separation of carrier and the absorption of visible light,enhancing the their own reduction and oxidation efficiency.（3）CuWO₄/Bi₂WO₆ heterojunction photocatalytic materials were prepared by hydrothermal method.The photocatalytic efficiency of 4-Acetamidophenol and Cr（VI）were investigated separately and cooperatively under visible light.The photocatalytic efficiency of Bi₂WO₆ was 14.2%and that of CWO/BWO-2 was 44.1%when the 4-Acetamidophenol was degraded alone.When Cr⁶⁺was reduced alone,the photocatalytic efficiency of Bi₂WO₆ was65.4%and that of CWO/BWO-2 was 76.3%.After co-treatment,the photocatalytic activity of Bi₂WO₆ was almost unchanged,the photocatalytic degradation efficiency of 4-Acetamidophenol by CWO/BWO-2 was increased by 32.3%,and the photocatalytic reduction efficiency of Cr⁶⁺was increased by 10.2%.In the collaborative treatment,CWO/BWO-2respectively uses holes and electrons to achieve oxidation and reduction,which improves both reduction and oxidation efficiency.In addition,cyclic experiments show that CWO/BWO-2exhibits excellent photochemical stability after four photocatalytic processes.