The Research On Photocatalytic Degradation Of Tetracycline With PbMoO₄-based Biochar

Tetracyclines had been widely used to prevent and cure disease in clinical treatment and aquaculture industry,resulting in their increasingly serious pollution in the environment,which seriously threaten the health of environment and even the human being.Photocatalytic technology had the advantages of low cost,cleanliness,and no secondary pollution.It had great potential for removing TC from water.PbMoO4 was a new material with strong catalytic ability and excellent stability,and had excellent application value.However,further research was needed to solve its shortcomings of low dispersibility,easy agglomeration and non-recyclability.Biochar was an excellent carrier which had rich pore structure and large specific surface area.It could prevent catalyst agglomeration and improve the separation of electron-hole pairs.In this paper,2D PbMoO4 and PbMoO4@BC was prepared based on PbMoO4;TC was used as the target to study the degradation by the photocatalysts in different sewage systems.The specific research in this paper was as follows:Firstly,using MoO3 and PbC12 as raw materials,2D PbMoO4 photocatalytic was synthesized by dipping and pulling method.As characterized by AFM,XRD,XPS,TEM,UV-Vis and photocurrent.The main active species in the photocatalytic degradation of TC were analyzed by quenching experiments.The optimal photocatalytic reaction conditions were determined by examining the dosage of catalyst,pH and initial TC concentration.The results showed that 2D PbMoO4 had the characteristics of 2D nanometer,the characteristic peak of XRD was consistent with the standard card,the binding energy does not change significantly before and after the photocatalytic reaction,and had a high band gap value.2D PbMoO4 prepared had strong photocurrent response.O2·-was the main active substance in the reaction process of 2D PbMoO4 photocatalytic degradation of TC,and the degradation rate of TC was 95%when the catalyst dosage was 90 mg·L-1,pH was 9,and the initial concentration of TC was 150 mg·L-1.Secondly,utilizing PbCl2 and(NH4)6Mo7O24 as precursors,PbMoO4 was prepared by deposition method.Then PbMoO4@BC was synthesized by high temperature calcination method,XRD,SEM,XPS,UV-Vis,PL,etc.,were used to characterize and analyze the PbMoO4@BC composite,and the active species involved in the photocatalytic reaction were determined by quenching experiments.The optimal photocatalytic reaction conditions were determined by catalyzing the composite ratio,the dosage of catalyst and the initial TC concentration.The results showed that the characteristic peaks of XRD were consistent with the standard card,PbMoO4 was evenly distributed on the biochar,no graphitized carbon impurities were founded in the XPS characterization,the band gap value in the composite was significantly increased.The recombination of BC improved the separation efficiency of the photogenerated carriers of the catalyst.The PbMoO4@BC prepared by this method improved the photocatalytic activity due to the recombination of BC.O2·-was the main active substance in the photocatalytic degradation of TC by PbMoO4@BC.And when PbMoO4:BC was 1:4,the dosage of catalyst was 300 mg·L-1 and the initial concentration of TC was 150 mg·L-1,the TC could be completely degraded.Finally,PbMoO4@BC was applied to degrade TC in different water,including UW,AW,FW,and MW.The results depicted the photocatalytic degradation rates of TC were above than 80%in different water qualities.The research demonstrated that PbMoO4@BC had high catalytic activity and stability.It had wide application prospect in water treatment for high-concentration pollutants.