It is a great challenge for conventional NaA zeolite membrane to maintain stable water flux in pervaporation (PV) dehydration of polar aprotic solvents because the aggressive adsorption of these solvents on membrane surface restrain water adsorption and thereby reduce water flux gradually. To address this issue, a facile surface modification method was adopted to decorate the surface of NaA zeolite membrane with sol-gel derived TiO₂ nanoparticles for PV dehydration of N, N-Dimethylacetamide (DMAc). Effect of TiO₂ precursor composition on properties and separation performance of TiO₂/NaA zeolite composite membranes was investigated extensively in terms of SEM, XRD, XPS, solvent adsorption and water contact angle. The results showed that the porous TiO₂ layer on top of zeolite membrane not only hindered the electrostatic interaction between DMAc molecules and sodium cations from zeolite membrane but also allowed water permeation without large loss in flux. The minimum loss in water flux of TiO₂/NaA zeolite membrane was about 17% after continuous PV dehydration of 10 wt% water/DMAc mixture for 24 h at 363 K while that of bare NaA zeolite membrane was over 95% within 15 h, indicating the effective improvement on separation stability of NaA zeolite membrane for PV dehydration of DMAc.

对于常规的NaA沸石膜而言，在极性非质子溶剂的全蒸发（PV）脱水中保持稳定的水通量是一个巨大的挑战，因为这些溶剂在膜表面上的强力吸附会抑制水的吸附，从而逐渐降低水的通量。为了解决这个问题，采用了一种简便的表面改性方法，用溶胶-凝胶衍生的TiO ₂纳米颗粒装饰NaA沸石膜的表面，以对N，N-二甲基乙酰胺（DMAc）进行PV脱水。从SEM，XRD，XPS，溶剂吸附和水接触角等方面广泛研究了TiO ₂前驱体组成对TiO ₂ / NaA沸石复合膜性能和分离性能的影响。结果表明，多孔TiO沸石膜顶部的₂层不仅阻碍了DMAc分子与沸石膜中的钠阳离子之间的静电相互作用，而且使水得以渗透而通量没有大的损失。在363 K下将10 wt％的水/ DMAc混合物连续PV脱水24 h后，TiO ₂ / NaA沸石膜的水通量的最小损失约为17％，而在15 h内裸NaA沸石膜的水通量的最小损失超过95％，这表明NaA沸石膜对DMAc进行PV脱水的分离稳定性得到了有效的改善。