Long-acting Antibacterial Material Application In Drinking Water Purification Technology Research

As we all know,harmful microorganisms that enter the drinking water system from drinking water storage facilities and secondary water supply facilities pose a direct threat to human health.Activated carbon,polypropylene and glass-fiber membrane are always used in drinking water treatment equipment.However,all of these materials cause excessive microorganisms in drinking water,because they are easy to feed on harmful microorganisms.Antibacterial modification of the above materials can effectively control microbial breeding.Therefore,the development of antibacterial materials,such as antibacterial activated carbon,antibacterial polypropylene,antibacterial composite glass fiber filter membrane,which have long-acting antibacterial effect and do harmless to human health,and these materials are applied to various key parts of urban drinking water treatment system in safety to ensure that the whole process of drinking water purification has become an important issue in the field of water supply sanitation.In this thesis,n-Ag@AC and nano silver hybrid four acicular Zinc Oxide whiskers(n-Ag@T-ZnO)were prepared by the method of precursor thermal decomposition,and n-Ag@T-ZnO was blended with polypropylene particles to produce antibacterial polypropylene by extruder.The antibacterial composite glass fiber filter membrane was prepared by grafting silane coupling agent and organosilicon quaternary ammonium salt onto the surface of the composite glass fiber filter membrane.And then,the antibacterial and dissolution properties of long-acting antibacterial materials were evaluated.Finally,the application of long-acting antibacterial materials in the purification of drinking water was studied in a self-designed water treatment cycle system.The specific work and main research results of this thesis include:1.The n-Ag@AC was prepared by the method of precursor thermal decomposition.According to characterization and analysis with FESEM and XRD,it was found that the precursor activated carbon was prepared by the silver load of 0.1 wt%,the precursor activated carbon was first kept at 300? for 60 min,and then annealed at 600? for 10 min,the number and size of the nano silver particles(n-Ag)on the surface of n-Ag@AC were moderate.According to the national standard for testing,it was found that the antibacterial rates of n-Ag@AC and after accelerated aging n-Ag@AC against E.coli,S.aureus and C.albicans were all >99.99%,and the apparent density,water content and pH value ofn-Ag@AC increased slightly,while the iodine adsorption value of n-Ag@AC decreased slightly.2.The n-Ag@T-ZnO was prepared by the method of precursor thermal decomposition.According to characterization and analysis with FESEM,it was found that the precursor T-ZnO was prepared by the silver load of 1.0 wt%,and then the precursor T-ZnO was kept at280? for 120 min and cooled to the room temperature,the particle size of n-Ag particles on the surface was moderate,a large amount and evenly distributed.The minimum inhibitory concentration of n-Ag@T-ZnO was 10-50 mg/L against E.coli and S.aureus according to the disinfection technique for testing,it had a good antibacterial effect.3.The antibacterial polypropylene was prepared by extruder with blending n-Ag@T-ZnO and polypropylene.The FESEM characterization and analysis showed that the n-Ag@T-ZnO could be dispersed uniformly in antibacterial polypropylene when the content of n-Ag@T-ZnO was ?0.25 wt%.According to the corresponding standards for testing,when content of n-Ag@T-ZnO in antibacterial polypropylene was 0.25 wt%,it was found that the antibacterial rates of antibacterial polypropylene against E.coli and S.aureus were all >99.99%,and the release of zinc and silver in antibacterial polypropylene satisfied the requirements of GB/T 17219-1998 Safety Evaluation Standards for Drinking Water Distribution Equipment and Protective Materials.4.The antibacterial composite glass fiber filter membrane was prepared by grafting organosilicon quaternary ammonium salt on the surface of the composite glass fiber filter membrane.By characterization and analysis with HRTEM,XPS and FTIR and the antibacterial properties testing with filter membrane method,it was found that the composite glass fiber filter membrane was pretreated by acid and alkali with a concentration of 4 mol/L,and then it was soaked in the antibacterial solution,which the proportion of silane coupling and organic silicone quaternary ammonium salt was 3:1,and then it was kept at 120? for120 min to prepare the antibacterial composite glass fiber filter membrane which had excellent antibacterial properties and released amount of Al and TOC satisfied the requirements of GB/T 17219-1998 Safety Evaluation Standards for Drinking Water Distribution Equipment and Protective Materials.5.The n-Ag@AC,antibacterial polypropylene and antibacterial composite glass fiber filter membrane were used as antibacterial materials in the self-designed water treatment cycle system.There were no bacteria in the circulating water after Cyclic treatment for 15 days,and the concentration of Ag,Zn and TOC in the circulating water Cyclic treatment for30 days could satisfy the requirements of the national standards.After 30 days of continuous circulating water scour,the antibacterial materials also had good antibacterial properties.