纳滤在水处理与回用中的应用现状与展望

Application of nanofiltration in water treatment and water reclamation:Current status and future aspects

纳滤(nanofiltration,NF)作为一种分离效果介于超滤和反渗透之间的膜过滤技术,在过滤过程中同时兼具物理孔隙产生的筛分效应和膜面电荷产生的道南效应作用.纳滤对水中的大多数有机物和多价盐离子具有很高的截留率,而对单价离子截留率较低,因而对单价多价盐具有良好的选择分离特性,近年来在饮用水软化、污水深度处理与回用、工业过程浓缩分离等方面得到了较为广泛的应用.据估计,到2019年纳滤膜的全球市场份额将达到4.451亿美元,同时在2015—2019年间将保持高达15.6%的年复合增长率(compound annual growth rate,CAGR).本文总结了目前市场上的纳滤膜品种、产品性能以及纳滤膜在水处理与回用中应用情况,并针对纳滤膜在应用中存在的问题提出了可行的方法和建议,最后对纳滤膜未来的发展方向提出了展望.

As a membrane technology with the separation capability between ultrafiltration and reverse osmosis,the separation of solutes by nanofiltration（NF） membranes results from a complex mechanism including steric hindrance,as well as Donnan and dielectric effects（in the case of charged solutes）.NF membrane shows high retention for the most organic matters and multivalent ions in water,while relatively low retention for the monovalent ions,demonstrating a perfect capability in the selective separation of ions with different valence states.NF membrane has been applied in many fields,including drinking water treatment,advanced wastewater treatment,water reuse,concentration and separation in industrial processes.According to the statistical analysis,the global market for NF membrane is estimated to $ 445.1 million in 2019,a compound annual growth rate（CAGR） of 15.6% during 2015 to2019.The varieties,characteristics and application of commercial NF membranes were summarized in this study.Practical methods and advices were proposed for solving the existing major problems in the applications of NF,and finally the future development of NF is put forward.