Abstract: A continuous and uniform seed layer was obtained by modifying the surface defects of the low-cost macroporous α-Al₂O₃ tube support by the two-step hot-dip coating method. The ultra-thin NaA zeolite membranes were prepared by microwave-assisted synthesis in a short time,and they were used for pervaporative desalination. It is found that the permeation flux of water decreased slightly with the increase of salt concentration and the increase of operating temperature had a significant effect on the water flux. When the salt concentration of feed was 0.6mol/L and the operating temperature was 85℃,the water flux reached 11.03kg/(m²·h). But the ion retention rate was not affected by the operating temperature and the concentration of the feed solution,and remained at more than 99.9%. In addition,NaA zeolite membrane showed high stability in the pervaporative desalination,and the performance was stable for more than 72h in the 0.6mol/L NaCl solution at 75℃. The method can effectively improve water flux and ions rejection while reducing the cost of membrane preparation,which indicates that NaA zeolite membrane has a good application prospect in the field of membrane desalination.

Key words: macroporous α-Al₂O₃ alumina, NaA zeolite membrane, pervaporation, desalination, microwave heating

摘要： 以廉价大孔α-Al₂O₃管为载体，通过两步变温热浸渍涂晶法，修饰载体表面缺陷，得到连续而均匀的晶种层。在微波辅助作用下，短时间内有效诱导制备出超薄NaA分子筛膜。将其用于渗透汽化脱盐体系中，研究发现，微波加热法制备的超薄NaA沸石膜水通量明显高于常规加热法制备的较厚NaA沸石膜，水的渗透通量随着盐浓度的增大在小范围内有所降低，而操作温度的升高对水的渗透具有明显促进作用，当原料液浓度为0.6mol/L、操作温度85℃时，水通量达到11.03kg/（m²·h）。同时，离子截留率不受操作温度及原料液浓度的影响，始终保持>99.9%。此外，NaA沸石膜在渗透蒸发脱盐中表现出较高的稳定性，75℃条件下，在0.6mol/L的NaCl溶液中性能可稳定72h以上。该方法在降低制膜成本的同时有效提高了水的渗透通量及离子截留率，表明NaA沸石膜在膜法脱盐的工业化应用领域具有较好的应用前景。

关键词: 大孔&alpha, -Al₂O₃载体, NaA沸石膜, 渗透蒸发, 脱盐, 微波加热