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采用HF酸对3种MFI型沸石(ZSM-5,silicalite-1)进行刻蚀,通过SEM和TEM对刻蚀前后沸石的表面和本体形貌进行了表征,发现酸刻蚀造成沸石表面出现微米级孔洞,但本体仍保留了规则的孔道结构。将刻蚀后的ZSM-5填充至聚二甲基硅氧烷(PDMS)中制备了复合膜,用于乙醇/水混合物的分离,研究了沸石硅铝比、HF酸浓度、操作温度和料液浓度对复合膜渗透汽化分离性能的影响。研究发现HF酸处理,可以有效地提高ZSM-5/PDMS膜的分离因子,由12.3最高上升至16.8([EtOH]=5wt%,50℃),渗透通量稍有下降;随着操作温度的升高,复合膜渗透通量增大,分离因子在50℃达到极大值;料液中乙醇浓度提高,复合膜渗透通量增大,分离因子减小。
Three types of MFI zeolites (ZSM-5, silicalite-1) were etched by HF acid. The surface and bulk morphology of the zeolites before and after etching were characterized by SEM and TEM. It was found that acid etching resulted in the appearance of micron Level holes, but the body still retains the regular pore structure. The etched ZSM-5 was filled into polydimethylsiloxane (PDMS) to prepare a composite membrane for the separation of ethanol / water mixtures. The effects of Si / Al ratio, HF acid concentration, operating temperature, Effect of Liquid Concentration on Pervaporation and Separation Performance of Composite Membrane. The results showed that the HF acid treatment could effectively increase the separation factor of ZSM-5 / PDMS membrane from 12.3 up to 16.8 ([EtOH] = 5wt%, 50 ℃). The permeation flux decreased slightly with the increase of operating temperature And the permeation flux of the composite membrane increased. The separation factor reached the maximum at 50 ℃. The ethanol concentration in the feed solution increased, the permeate flux of the composite membrane increased, and the separation factor decreased.