Preparation And Performance Study Of Carbon Fiber-based Flexible Composite Photocatalysts

With the rapid development of industrialization,environmental problems are becoming increasingly severe.Compared to traditional wastewater treatment methods,adsorption-degradation composite strategies can improve treatment efficiency through adsorption,without generating secondary pollution during the recycling process,and have received considerable attention in recent years.The value of traditional powdered photocatalysts in practical applications is limited by their difficult recovery.Loading the catalyst onto a substrate can effectively solve the recovery problem.In this thesis flexible electrospun carbon fibers（ECNF）was successfully prepared by electrospinning through pre-oxidation and carbonization processes.Using it as the substrate,a dual-function Bi₂O_2.33/Bi₂O₃/ECNF composite photocatalyst for adsorption and degradation was prepared after one-step solvothermal reaction.Its morphology,phase composition,and chemical structure are detailed characterized.A comprehensive analysis of its adsorption performance and kinetic behavior is conducted,and the mechanism of its adsorption and degradation is explained in conjunction with its optical and electrical properties.In order to improve the slow degradation kinetics of Bi₂O_2.33/Bi₂O₃/ECNF,Ag/Bi₂O_2.33/Bi₂O₃/ECNF composite photocatalyst was successfully prepared through further solvothermal and photo-reduction reactions based on it.The catalytic performance and behavior were analyzed,and the enhancement mechanism of heterojunction was explained.The main research findings are as follows:（1）Bi₂O_2.33/Bi₂O₃ and Bi₂O_2.33/Bi₂O₃/ECNF dual-functional photocatalysts for adsorption and degradation were obtained through a solvothermal method,and their adsorption and degradation behaviors and mechanisms were studied.The results showed that Bi₂O_2.33/Bi₂O₃ had fast adsorption kinetics,with a removal rate of 96.52%for 50 mg L^-1 methyl orange within 20 min and a maximum theoretical adsorption capacity of213.13 mg g^-1 for methyl orange.Through the cooperative effect of adsorption and degradation,the removal rate of 50 mg L^-1 tetracycline hydrochloride reached 85%within180 min.After being loaded on electrospun carbon fibers,the degradation rate of Bi₂O_2.33/Bi₂O₃/ECNF slowed down,and the removal rate of 50 mg L^-1 tetracycline hydrochloride reached 85%within 6 h.Bi₂O_2.33/Bi₂O₃/ECNF showed better cycling stability and convenient recyclability compared to Bi₂O_2.33/Bi₂O₃ during photocatalytic degradation.（2）Ag/Bi OCl/Bi₂O₃/ECNF composite photocatalyst was successfully prepared using a two-step solvothermal method and photo-reduction method on electrospun carbon fibers.The results showed that the composite photocatalyst achieved a removal rate of91.1%for 10 mg L^-1 Rhodamine B within 120 min and a removal rate of 84.3%for 20mg L^-1 tetracycline hydrochloride within 160 min through the combination of adsorption and degradation.The photocatalytic performance was greatly improved compared to that before the composite.The composite photocatalyst exhibited good cycling degradation stability and convenient recyclability,with great potential for practical applications.