Study On Perylene Diimide Visible Photocatalyst Activated Persulfate To Degrade Carbamazepine

Pharmaceuticals and Personal Care Products（PPCPs）are a category of emerging contaminants with wide sources,hidden effects and risk lag.The impact on human health and ecological environment has aroused wide concern in the society.Carbamazepine（CBZ）is a typical representative of PPCPs,which is difficult to be completely degraded by conventional water treatment process。It is necessary to explore new and efficient advanced oxidation combined process.In this study,photocatalytic advanced oxidation technology and persulfate advanced oxidation technology were coupled to degrade carbamazepine in water environment.Bis-PDI-T@TiO₂ composite catalyst was prepared by bisolvent phase transfer method,which was used to activate persulfate（PS）to enhance photodegradation of pollutants under visible light.The catalytic degradation performance of the composite catalyst to the target pollutant probe molecule（CBZ）was investigated.The experiment explored the reaction mechanism of the Vis/PS/Bis-PDI-T@TiO₂ system,and constructed a mechanism model for degradation of carbamazepine in the coupled system,which provided new thinking and theoretical guidance for photoactivated PS.The research content and results are as follows:（1）In this paper,Bis-PDI-T,a PDI derivative,was designed and synthesized.Bis-PDI-T@TiO₂ composite photocatalyst was successfully prepared by double solvent exchange method and physicochemical characterization was performed.The degradation capability of visible photocatalytic system was tested with the target pollutant probe molecule（phenol）.The experimental results showed that Bis-PDI-T had the best photocatalytic activity when the doping amount was 0.1wt%,and its performance rate constant value was 0.088 h^-1,which was about 11 times higher than TiO₂ and 4.2 times higher than Bis-PDI-T.At the same time,the composite material was used to degrade methyl orange and methyl blue,and the degradation efficiency proved that the catalyst had great potential in the actual wastewater treatment process.（2）The catalytic degradation performance of Vis/PS/Bis-PDI-T@TiO₂ system was evaluated by using CBZ as the degradation substrate in water environment.The results showed that when the doping amount of Bis-PDI-T was 0.1 wt%,the CBZ in the wastewater could be completely degraded within 30 min in the system,and the corresponding first-order kinetic constant was 0.11878 min^-1,which was 14.5 and 28.2 times that of Vis/PS/TiO₂ and Vis/Bis-PDI-T@TiO₂,respectively.The results showed that Bis-PDI-T@TiO₂ composite material in Vis/PS/Bis-PDI-T@TiO₂ system,driven by visible light,greatly improved the efficiency of PS activation and enhanced the ability of carbamazepine degradation.The degradation performance of CBZ was correlated with Bis-PDI-T doping amount,initial p H,initial CBZ concentration,catalyst and PS dosage.After five cycles,the removal rate of CBZ was still close to 90%.（3）Through radical quenching experiment and ESR detection,it was found that there were4 types of reactive oxidizing substances in the Vis/PS/Bis-PDI-T@TiO₂ reaction system,namely sulfate radical,hydroxyl radical,superoxide radical and hole,among which hydroxyl radical played a major role.HPLC/MS was used to analyze the intermediate products in the process of CBZ degradation,and the way of deep degradation and improvement of salinity was proposed.Finally,based on the analysis results,a Vis/PS/Bis-PDI-T@TiO₂ reaction system degradation mechanism model was constructed.