Construction Of Zinc Oxide Based Piezoelectric Catalysts And Their Degradation Performance Of Tetracycline Antibiotics

Tetracycline antibiotics（TCs）are semi-synthetic broad-spectrum antibiotics.In the process of medical treatment or livestock breeding,TCs cannot be completely absorbed and will enter the external environment with excreta.Therefore,they are often detected in the aquatic environment,especially in drinking water,which poses a serious threat to the natural environment and human health.As an emerging technology,piezoelectric catalysis is widely used in the degradation of organic pollutants.ZnO has excellent optical,electrical,and mechanical properties,and is considered a promising piezoelectric catalytic material.This study focuses on the structural regulation and catalytic performance optimization of ZnO based piezoelectric catalytic materials,and prepares ZnO@YFC,Zn Co O@PVDF and ZnO/CQDs/PVDF piezoelectric catalysts for the degradation of Tetracycline antibiotics in water.The main research content and conclusions of this paper are as follows:（1）A novel Biochar based piezoelectric catalyst was synthesized by in-situ growth and hydrothermal growth of flower shaped zinc oxide on the surface of Yang flocculent carbon（YFC）.After 20 min of ultrasound ZnO@YFC-4 The degradation rate of tetracycline（TC）reached 89.07%,and the first-order kinetic constant was0.682 min^-1.The characterization results prove that,ZnO@YFC The high catalytic activity of ZnO is due to the large surface area,porous structure and excellent conductivity of carbon microtubules formed after carbonization of yang flocculent,which increase the migration rate of ZnO Surface charge and ZnO@YFC piezoelectric catalytic activity.The results of free radical quenching and electron paramagnetic resonance indicate that·O₂^-and·OH are the main free radicals involved in TC degradation,with contribution rates of 58.78%and 37.39%,respectively.（2）In order to make the powdered catalyst recyclable,high voltage electrical properties were prepared by co precipitation and phase conversion methods Zn Co O@PVDF The characterization analysis of the flexible piezoelectric film shows that Co entering the lattice of ZnO changes the electrical properties of ZnO and forms oxygen vacancy defects in ZnO.Co doping increases the piezoelectric coefficient of ZnO by 6.5 times;The doping of Zn_0.8Co_0.2O causes a change in the crystal structure of PVDF,which has piezoelectric propertiesβ.The piezoelectric coefficient increased by 31.96%from 27.3 p C·N^-1 of PVDF to 44.7 p C·N^-1;Zn_0.8Co_0.2O@PVDF The removal rate of Chlortetracycline（CTC）by the membrane under ultrasound treatment reached 92.72%within 60 min,3.68 times that of PVDF.The degradation process was in line with the second-order kinetic model;The toxicity assessment software tool（T.E.S.T）was used to calculate the toxicity of CTC and its by-products,further confirming the reduction of environmental risk after piezoelectric catalytic degradation.（3）ZnO/CQDs/PVDF was prepared by hydrothermal and co-precipitation method,and the film was formed in polyethylene pipe by phase inversion.Characterization analysis revealed that CQDs enhanced the transfer rate of ZnO surface charges,and PVDF withβ-rich phase was more sensitive to low-frequency pressure response.Under the action of hydrodynamic force,the ZnO/CQDs/PVDF pipeline system achieved a TC removal rate of 95.17%within 70 min,and the second-order kinetic constant was 0.28 L·（mg·min）^-1.Maintain a degradation efficiency of67.98%.Based on liquid chromatography-mass spectrometry results and density functional theory（DFT）calculations,the degradation mechanism of tetracycline molecules was predicted,including hydroxylation,C–C and C–N bond cleavage processes.And ZnO/CQDs/PVDF showed antibacterial properties,the survival rate of Escherichia coli was only 0.001‰,which obviously inhibited the growth of bacteria.