海水纳滤预处理的优化研究

摘要

纳滤已被广泛研究用于反渗透和膜蒸馏海水淡化的预处理,它能有效避免反渗透膜和膜蒸馏装置的结垢污染,但纳滤膜同样存在结垢污染问题.通过配制人工海水及人工脱硬海水等海水体系研究了硬度离子对纳滤膜无机污染的影响,并通过接触角、SEM、EDX等表征方法研究了膜面污染物的主要成分及其对膜性能的影响.结果表明,钙离子是造成纳滤膜无机污染的主要硬度离子,脱硬或脱钙处理能有效避免海水淡化过程中纳滤预处理阶段的无机结垢问题.%Nanofiltration has been widely used for the pretreatment of seawater desalination by reverse osmosis and membrane distillation.It can effectively avoid scaling pollution on reverse osmosis membrane and membrane distillation devices,but the nanofiltration membrane still has scaling pollution problems.The effects of hardness ions on the inorganic pollution of nanofiltration membrane are studied by means of preparing artificial seawater,artificial de-hardened seawater,etc.The contact angle,SEM and EDX are used for studying the main components of pollutants on the membrane surfaces and their influences on membrane performance.The results show that calcium ions are the main hardness ions causing the inorganic pollution of nanofiltration membrane.De-hardening or decalcifying treatment can effectively avoid the inorganic scaling problem in the process of nanofiltration pretreatment in seawater desalination stage.