Preparation Of Polypyrrole Zinc Oxide Composites And Study On Degradation Of Antibiotics

Objective In this thesis,a new photocatalyst with high photocatalytic activity,good chemical stability and improved reaction range in the visible region was successfully prepared by modifying Zn O nanomaterials in order to solve ecological problems and remove antibiotic wastewater.This research result better meets the practical needs of people.Methods Zn O nanoparticles were synthesized by precipitation method.Binary and ternary composite samples were prepared by compounding polypyrrole and carbon nanotubes with Zn O nanosamples of different contents.Each prepared sample was studied around morphological particle size,crystalline structure,elemental species and their functional groups.Rhodamine and tetracycline hydrochloride were selected for degradation experiments,and the performance of composite samples was analyzed and evaluated,combined with the kinetic equation of degradation reaction,cycle stability experiment,free radical capture and identification of intermediate products.Escherichia coli was selected as the strain to study the antibacterial properties of the composite samples.Results The photocatalytic effect of the prepared samples was evaluated using Rh B as the degradation species.Controlling the factors such as light and p H,Zn O was found to have the best photocatalytic effect on DRh B=46.3%,Zn O/PPy sample DRh B=91.2%,Zn O/CNTs sample DRh B=89.3%,and Zn O/PPy/CNTs sample DRh B=92.4%,which indicates that the ternary Zn O/PPy/CNTs composite sample has the best photocatalytic effect.The degradation of Rh B for each sample corresponds to the kinetic equation of the primary reaction.The cyclic stability test showed that the composite samples were stable.Based on the radical capture experiments,it was concluded that h+and-O^2-were the main active species of Zn O/PPy,Zn O/CNTs and Zn O/PPy/CNTs samples,with-O^2-being the main active species of Zn O/PPy/CNTs samples.The Zn O/PPy/CNTs samples also showed good photocatalytic degradation of TC-HCl with D_TC=91.5%using tetracycline hydrochloride as the degradant,and the degradation of TC-HCl was in accordance with the primary reaction kinetic equation,and the identification of the intermediates indicated that the intermediates played a role in the degradation process.The antibacterial performance of the composite samples was also studied by selecting Escherichia coli as the strain.The antibacterial experiments on E.coli showed that the inhibition rate of Zn O/PPy was73.06%,Zn O/CNTs was 99.44%and ZPC was 99.99%.Conclusions The doping of polypyrrole and carbon nanotubes increased the reaction rate of Rh B degradation by Zn O nanoparticles.The prepared Zn O nanoparticles possess a large specific surface area,which can improve the adsorption performance,while the introduction of polypyrrole and carbon nanotubes can promote electron transfer and reduce the composite of photogenerated electron-hole pairs in the composites,and the photocatalytic performance of the composite samples was improved.In addition,the new visible photocatalyst has a strong degradation effect on TC-HCl and has good antibacterial effect.This research will lay a certain theoretical foundation for improving the water environment and effectively removing and mineralizing antibiotics for human development.