水厂超滤系统中非均质PTFE和PVDF中空纤维复合膜运行阻力和膜污染对比研究  

Study on the operational resistance and pollution of PTFE and PVDF hollow fiber composite membranes in submerged filtration systems of drinking water plants

作　　者：张祚群 苏功建 高扬[1] 郑祥[3] 薛立新 ZHANG Zuoqun;SU Gongjian;GAO Yang;ZHENG Xiang;XUE Lixin(Center for Membrane Separation and Water Science&.Technology,College of Chemical Engineering,Zhejiang University of Technology,Hangzhou 310014,China;Ningbo Water and Environmental Service Groups,LLC,Ningbo Waterworks Construction Co.,Ltd,Ningbo 315048,China;College of Environmental Sciences,People's University of China,Beijing 100872,China)

机构地区：[1]浙江工业大学化工学院,膜分离与水科学技术中心,杭州310014 [2]宁波市水务环境集团宁波市自来水工程建设有限公司,宁波315048 [3]中国人民大学环境学院,北京100872

出　　处：《膜科学与技术》2023年第4期99-109,共11页Membrane Science and Technology

基　　金：国家自然科学基金联合基金重点项目(U1809213);国家自然科学基金面上项目(NSFC-21975222)。

摘　　要：各种材质的超滤膜已广泛应用于各大净水厂中,不同材质超滤膜的运行阻力、跨膜压差、膜通量会随着膜污染和清洗方式的不同而出现显著差异.以非均质聚四氟乙烯(PTFE)和聚偏氟乙烯(PVDF)中空纤维超滤膜为研究对象,系统对比了两种膜在自来水厂长期应用过程中的运行阻力和膜污染情况,分析了不同化学清洗剂对两种膜的清洗效果,旨在为该水厂超滤系统长期稳定运行提供一定的借鉴意义.研究结果表明,相比于PVDF膜,PTFE膜不仅拥有较低的固有阻力和膜污染阻力,而且在近5年同等压力参数运行过程中,平均膜通量达到54.07 L/(m^(2)·h),是PVDF膜的1.4~1.5倍.Fe、Al等高价阳离子的无机污染物以及金属有机络合物在膜表面的沉积是PTFE膜阻力增加的主要因素;无机胶体和有机大分子在膜表面的堆积以及有机小分子污染物在膜孔内部的吸附是PVDF膜阻力增加的主要原因.柠檬酸(CA)和盐酸(HCl)溶液作为单一清洗剂,对PTFE膜通过配合络合协同作用,在清洗金属沉积物的同时,可以将有机金属络合物协同剥离膜表面,产生很好的清洗效果;单一清洗剂包括CA、HCl和氢氧化钠(NaOH)溶液,均很难同时去除PVDF膜表面的污垢和堵塞在膜孔内部的污染物,清洗效果有限.Ultrafiltration membranes of various materials have been widely used in major water purification plants.Operating parameters such as trans-membrane pressure difference and membrane flux vary significantly with different membrane pollution and clean methods.The water permeating resistance and fouling performance of polyvinylidene fluoride(PVDF)and polytetrafluoroethylene(PTFE)composite hollow fiber composite membranes in the submerged filtration systems of water purification plants were compared.The purpose is to provide some reference for the long-term stable operation of the ultrafiltration system in the water plant.The results show that PTFE composite membrane showed not only better durance in chemical cleaning,but also lower resistance during operation.PTFE composite membrane showed average water flux of 54.07 L/(m^(2)·h),1.4~1.5 times higher than those of PVDF composite membrane and with greatly reduced water permeating resistance components.It was found that the major performance deterioration of PTFE composite membrane came from the deposition of inorganic pollutants with high valence cations of Fe and Al,and metal-organic complexes on the membrane surface,while the deterioration of PVDF membrane was mainly caused by the inorganic colloids and organic macro-molecules accumulated on the membrane surfaces and adsorbed in the pores.For PTFE membranes,hydro-chloric acid and citric acid solution showed good cleaning effect for the pollutants on the membrane surface.Through coordination and complexation,the organic-metal complexes could be simultaneously stripped off the membrane surface while cleaning metal deposits.Used PVDF membranes could not be effectively cleaned by single cleaning agent from citric acid,hydro-chloric acid,or sodium hydroxide solution.

关 键 词：超滤 聚四氟乙烯 聚偏氟乙烯 膜阻力 膜污染 

分 类 号：TQ028[化学工程] TU991.2[建筑科学—市政工程] X522[环境科学与工程—环境工程]