硅氮烷疏水改性介孔分子筛填充PDMS制备杂化复合膜及渗透汽化性能

Preparation and Pervaporation Performance of Silazane Hydrophobically Modified Mesoporous Molecular Sieves Filled PDMS Hybrid Composite Membrane

采用硅烷偶联剂对介孔分子筛疏水改性,并将其掺杂在聚二甲基硅氧烷(PDMS)中涂覆在聚砜基膜上制备有机无机杂化复合膜.对疏水改性介孔分子筛进行了BET测试及FT-IR等表征.BET测试结果显示,改性前后孔径分布发生明显变化;从FT-IR图中看出,改性后介孔分子筛的羟基峰明显减小甚至消失并且出现烷基等特征峰.通过扫描电镜(SEM)观察了有机无机杂化复合膜的形貌结构,并研究了分子筛添加量、料液浓度和操作温度等对杂化复合膜渗透汽化性能的影响.结果表明:采用1,1,3,3-四甲基二硅氮烷对介孔分子筛疏水改性最有效;疏水改性后介孔分子筛/PDMS杂化复合膜对醇/水溶液有较好的分离效果,当分子筛填充质量分数为20%、操作温度为40℃、进料液质量分数为3%时,杂化膜对乙醇/水体系的分离因子最高为9.8,渗透通量为1 002 g/(m2·h),对正丁醇/水体系的分离因子最高为65.4,渗透通量为1402 g/(m2·h).

In this study, mesoporous molecular sieves were first modified by silazanes, and then doped into polydimethylsiloxane （PDMS） solution. The mixture was coated on polysulfone membrane to obtain organic-inorganic hybrid composite membrane. The modified mesoporous molecular sieves were characterized by BET and FT-IR. The results of BET showed that pore size distribution of mesoporous molecular sieves significantly changed before and after modification. It could be observed from FT-IR that hydroxyl peaks of the mesoporous molecular sieve decreased and even disappeared after being modified. Simultaneously, the alkyl characteristic peaks appeared. The surface and cross-section morphologies of the hybrid composite membrane were characterized by SEM. The effects of molecular sieves content, feed concentration and operation temperature on the pervaporation performance were systematically investigated. Results indicated that the hydrophobic of mesoporous molecular sieves modified by 1,1,3, 3-Tetramethyldisilazane obviously increased. The modified mesoporous molecular sieves/PDMS hybrid composite membrane had an excellent performance in the separation of alcohol/water solution. When the doping amount of molecular sieve was 20% , the feed concentration was 3% , separation factor of the hybrid membrane for ethanol/water mixture was 9.8 with the permeation flux of 1 002 g/（m^2·h） , and separation factor of the n-butanol/water mixture could reach 65.4 with the flux of 1 402 g/（m^2· h） at 40 ℃.