亲水型ZSM-5分子筛填充PVA膜及分离乙酸乙酯/水的应用

为了实现低能耗且高效分离乙酸乙酯中的低含量水分,选用亲水型纳米ZSM-5沸石分子筛材料作为改性剂,填充到聚乙烯醇(PVA)聚合物中制备PVA/ZSM-5混合基质膜(MMMs)。采用SEM、FTIR、XRD、TGA和接触角测量仪等对膜材料的形态、物化性质进行表征分析,并考察膜材料在不同溶液中的溶胀行为以及通过单因素实验探究填料含量、进料温度、进料浓度对渗透汽化分离乙酸乙酯和水混合物的性能的影响。结果表明,ZSM-5与PVA结合紧密且分散均匀,除了ZSM-5固有的亲水性外,ZSM-5还与PVA分子之间存在氢键相互作用,但两者之间并没有发生化学作用。随着进料浓度的增加,渗透通量增大,而分离因子呈减小趋势;随着进料温度升高,渗透通量和分离因子均增大;随着ZSM-5填充量的增加,渗透通量和分离因子均先增大后减小。当ZSM-5填充量为6%(质量)时,渗透通量和分离因子达到最大值,分别为1231 g/(m²·h)和6072,相比纯PVA膜分离指数(PSI)提高了2.9倍。新设计的PVA/ZSM-5混合基质膜(MMMs)可在工业水平上用于乙酸乙酯及其他类似化合物的脱水。

Application of PVA membrane filled with hydrophilic ZSM-5 molecular sieve on separation of water from ethyl acetate

To remove trace water from ethyl acetate with low energy consumption and high efficiency, PVA/ZSM-5 mixed matrix membranes (MMMs) were prepared by adding the hydrophilic ZSM-5 zeolite material into polyvinyl alcohol (PVA) polymer. The morphology, physicochemical properties of MMMs were characterized by SEM, FTIR, XRD, TGA and contact angle. The swelling behavior of the membrane materials in various solutions and the influence of filler content, feed temperature and feed concentration on the performance of pervaporation separation of ethyl acetate and water mixture were investigated by single factor experiments. The results showed that ZSM-5 particles were evenly dispersed into PVA polymer. In addition to the inherent hydrophilicity of ZSM-5, there is also a hydrogen bond interaction between ZSM-5 and PVA, but there is no chemical interaction between them. With the increase of feed concentration, the permeate flux increased, while the separation factor decreased. With the increase of feed temperature, the permeate flux and separation factor increased. With the increase of ZSM-5 filling content, the permeate flux and separation factor increased first and then decreased. When filling content of ZSM-5 was 6%(mass), the permeation flux and separation factor reached the maximum value of 1231 g/(m²·h) and 6072, respectively, which was 2.9 times higher than the pure PVA membrane separation index (PSI). The newly designed PVA/ZSM-5 mixed matrix membranes (MMMs) can be used at the industrial level for the dehydration of ethyl acetate and other similar compounds.