纳滤膜脱盐性能及其在海水软化中应用的研究

选择了ESNA1型纳滤膜对NaCl、MgCl2、Na2SO4、MgSO4等4种无机单盐水溶液体系进行分离实验;考察操作压力和料液浓度等的变化对纳滤膜分离性能的影响及纳滤膜脱盐的稳定性,得到一些纳滤膜脱盐的规律;并对ESNA1膜在人工海水和海水软化脱盐中的应用作了初步探索.无机盐体系脱盐实验结果显示:随操作压力升高和料液浓度增大,ESNA1膜对4种盐溶液中的离子的截留率分别增大和减小,操作压力和料液浓度的变化对一价盐溶液的截留率影响较大,对二价盐溶液的截留率影响较小.人工海水和海水软化脱盐试验结果显示:ESNA1纳滤膜在实验过程中稳定性好,在较低的操作压力下膜通量也较高,且ESNA1纳滤膜对Ca2 、Mg2 、SO42-离子的截留率均＞90%,初步判断此种纳滤膜可用于海水软化预处理.

Studies on desalination performance of nanofiltration membranes and its application to seawater desalination

Desalination experiments of four inorganic salt solutions(NaCl,Na2SO4,MgCl2,MgSO4) have been carried out by using a kind of nanofiltration membranes(ESNA1).The effects of the species and the concentration of salts as well as the operation pressure on the separation performance and the stability of nanofiltration membranes desalination have been investigated.Some rules of the desalination with nanofiltration membranes are gained.Studies on desalination performance of artificial seawater and seawater are also introduced.Results from the desalination of inorganic salt solutions show that salt rejection increases with the increase of operational pressure,while decreased with the increase of salt concentration.Furthermore,operational pressure and salt concentration made more effect on salt rejection of univalent salt solutions than on that of bivalent salt solutions.Results from artificial seawater and seawater desalination show that ESNA1 membrane is stable during the experiment and the flux is high under low operational pressure.What's more,for all of the ions(Ca2 ,Mg2 ,SO42-),ESNA1 could achieved salt rejections up to 90%.The preliminary estimation considers that this nanofiltration membrane could be used to pretreat seawater.