| Photocatalytic technology is one of the effective methods for treating antibiotic pollution in the current water environment,with advantages such as simple process,high efficiency and thoroughness of treatment,and no secondary pollution.The photocatalysis membrane based on a mixed matrix membrane combines the advantages of photocatalysis technology with polymer membranes to achieve synergistic effects,enabling the membrane to simultaneously possess the ability to degrade pollutants through photocatalysis during the separation process.Bi2WO6（BWO）is a photocatalyst with superior photocatalytic performance in bismuth based materials,but its photo generated electron hole recombination is easy.In order to improve its photocatalytic effect,this paper constructed a series of photocatalysts consisting of PVPx%/BWO and PVP3%/BWO/rGOy%by modifying its morphology with surfactant PVP and composite rGO.Subsequently,PVP3%/BWO/rGO1%was successfully introduced into polyethersulfone（PES）using a blending method,and a mixed matrix membrane with efficient degradation of PVP3%/BWO/rGO1%-PES in antibiotic wastewater was prepared through immersion phase conversion method.The main research content includes the following aspects:（1）PVPx%/BWO and PVP3%/BWO/rGOy%series photocatalysts were prepared by hydrothermal method.Firstly,PVP was introduced to obtain a PVPx%/BWO series photocatalyst.Through photocatalytic degradation of oxytetracycline（OTC）experiments,the optimal addition amount of PVP was determined to be 3%.Then,rGO was compounded with PVP3%/BWO to obtain a PVP3%/BWO/rGOy%series photocatalyst.The degradation experiment results show that under a 150 W xenon lamp light source,when the dosage of PVP3%/BWO/rGO1%is 0.1 g·L-1,the photocatalyst can degrade 87%of OTC（10 mg/L）solution within 1 hour;When the dosage increased to 0.2 g·L-1,the degradation effect of PVP3%/BWO/rGO1%on 10mg/L OTC solution increased to 99.4%.Therefore,PVP3%/BWO/rGO1%is the optimal photocatalyst in the PVPx%/BWO and PVP3%/BWO/rGOy%series.（2）Through XRD,SEM,FTIR,BET,UV-Vis,and PL testing,a comparative analysis was conducted on the crystal form,morphology,chemical valence,adsorption performance,and light absorption performance of BWO,PVP3%/BWO,PVP3%/BWO/rGO1%.The reason for the improvement in OTC degradation performance of PVP3%/BWO/rGO1%compared to the other two photocatalysts was explored.The study found that PVP3%/BWO modified with PVP increased specific surface area,light capture efficiency,and surface permeability compared to pure BWO,After doping with rGO,the transmission ability of PVP3%/BWO/rGO1%is enhanced,and the separation of photo generated carriers is easier.Finally,through free radical quenching experiments and EPR testing,it was found that the active substances that acted during the degradation process of PVP3%/BWO/rGO1%were ranked as h+>·OH>·O2->1O2.（3）PVP3%/BWO/rGO1%-PES mixed matrix membrane was prepared by using a blending method to introduce PVP3%/BWO/rGO1%as an improver into the casting solution,and then by immersion phase transformation method.The prepared membrane was characterized by SEM,XRD,FTIR,and water contact angle testing.The practical performance of the membrane was determined by pure water flux,bovine serum protein BSA retention rate,repeatability,antibacterial activity,and stability testing.The photocatalytic performance of the PVP3%/BWO/rGO1%-PES mixed matrix membrane was investigated using 10 mg/L OTC aqueous solution as a simulated wastewater.The results showed that after the introduction of PVP3%/BWO/rGO1%photocatalyst,the pure water flux increased from 156 L/m2·h to208 L/m2·h,the BSA rejection rate increased from 95%to 99%,flux recovery rate increased from 65%to 85%and the water contact angle increased by 42.5%.When the content of PVP3%/BWO/rGO1%in the casting solution was 3%,the PVP3%/BWO/rGO1%-PES membrane had the highest photodegradation efficiency in pairs,and the degradation efficiency of OTC reached 98.88%.After 5 cycles of use,the degradation rate of the membrane remains above 90%,demonstrating good reusability and certain antibacterial ability. |
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