Preparation Of Novel Bismuth-based Photocatalyst And Application For Efficient Removal Of Tetracycline

Tetracyclines are one of the most common types of spectrum antibiotics.Due to the durability of TC,a large number of antibiotics discharged in water which caused great harm to the environment and human health.The vigorous development of photocatalytic oxidation technology has ushered the down of removal of tetracycline.Thus,Exploiting efficient photocatalysts for degradation of tetracycline is an ideal strategy for address environmental pollution.Bismuth-based photocatalysts have been broadly utilized within the photocatalytic oxidation prepare.Bi₂WO₆ as outstanding photocatalyst has intrigued scientists.Meanwhile,as a novel photocatalyst,BiO_2-x has become a research focus due to its excellent oxidative capacity,full-spectrum responses in recent years.In the present thesis,Bi₂WO₆ and BiO_2-x were selected as the research objects,to find the improved strategy for the photocatalytic degradation of tetracycline by formed a binary complex.The study contents were predominately following sections:1.In this study,Bi₂WO₆（BWO）with three different morphologies（a disordered one dimension dot-like BWO-D,two dimension flake-like BWO-P,three dimension flower-like BWO-F）have been prepared by hydrothermal and solvothermal methods.The structure and crystallinity were explored by XRD and FT-IR.SEM was carried out to characterize the morphology of BWO.The tests of the photocatalytic degradation of TC had showed that a disordered 1-D dot-like BWO-D exhibits optimal photocatalytic degradation performance(94.2%for 20 mg·L^-1 initial TC under 120 min simulated solar light irradiation).The predominant execution of BWO-D is credited to the huge particular surface region and tall obvious light reaction.This ponder found that the morphology of the catalysts is greatly influenced by the different solvents used in preparation process and subsequently the different morphology will affect the properties of degradation TC.2.The novel photocatalyst of BiO_2-x/Bi₂WO₆ composites were first synthesized by a simple hydrothermal process to removal residual TC in waterbodies.The XRD,SEM and TEM analyses revealed that the novel series of BiO_2-x/Bi₂WO₆ photocatalysts were successfully synthesized.Among these different ratios of complexes,BiO_2-x/Bi₂WO₆composites displayed an excellent visible-light photocatalytic performance of 96.4%degradation rate of TC,compared to pure Bi₂WO₆（47.9%）and BiO_2-x（73.3%）.XPS analysis demonstrated that the redox couple(Bi⁵⁺/Bi³⁺)which was contained in composite facilitates the photo-generated electrons transfer and thus further promotes the great enhancement of photocatalytic activity of BiO_2-x/Bi₂WO₆.This study proposed a novel photocatalytic material and revealed that the redox couple(Bi⁵⁺/Bi³⁺)plays an significant role for the transfer of photo-generated electrons to improve the degradation of TC.A novel facile and easy-to-extend synthesis method for the preparation of the photocatalyst in this thesis can be further expanded to the applications of dealing with environmental pollution.3.Three bismuth-based oxides(BiO_2-x、Bi₂O₄、Bi₄O₇),which demonstrated the strong response over full spectrum have been synthesized under hydrothermal conditions.Among these three bismuth oxides,BiO_2-x presented better photodegradation performance.Subsequent BiO_2-x was loaded into covalent triazine frameworks（CTF）which has high surface area.CTF/BiO_2-x complex exhibited a high TC degradation capacity and TC was degraded entirely within 60 min under the illumination of 300 W xenon lamp.This composite takes advantage of the cooperative interactions between the adsorption performance of CTF and excellent visible light photocatalytic performance of BiO_2-x.Also,CTF with outstanding electronic conductivity is in favour of the separation of electron-hole pairs.Besides,the radical-capture tests affirmed that·O₂^-and h⁺were the most dynamic species for the TC corruption.Thus,CTF/BiO_2-x have potential applications in degradation of organic pollutants.