石墨填充聚乙烯醇膜渗透蒸发分离苯和环己烷

采用液相共混法制备了石墨填充聚乙烯醇膜，采用FTIR，SEM，XRD等对石墨填充聚乙烯醇膜的物理和化学结构进行了分析表征，结果表明石墨与聚乙烯醇存在较强的氢键作用，石墨在聚乙烯醇中分散均匀，且具有一定的取向性.考察了石墨填充聚乙烯醇膜在苯和环己烷溶液中的溶胀和吸附行为.采用正电子湮没寿命谱仪表征了石墨聚乙烯醇膜的自由体积特性，计算得到石墨聚乙烯醇膜的表观自由体积分数，并且与渗透通量进行关联性对比.最后，研究了石墨含量和粒径对渗透蒸发分离性能的影响，结果表明，石墨的引入有利于苯的优先透过，石墨填充聚乙烯醇膜对苯和环己烷混合物具有良好的分离效果，苯的渗透通量和分离因子分别可达90.7 g•m^-2•h^-1和100.1.

Pervaporative separation of benzene/cyclohexane mixture using graphite-filled PVA membranes

Graphite-filled poly-vinyl alcohol(CG-PVA) membranes were prepared by the solution blending method and characterized with FTIR, SEM and XRD methods. The results showed that graphite was uniformly distributed in the membrane matrix, there was stronger interaction between PVA and graphite particle, the crystallinity of the membranes decreased after the incorporation of graphite. The swelling and sorption properties of CG-PVA membranes in benzene/cyclohexane mixtures were investigated. The free volume properties of CG-PVA membrane were analyzed by positron annihilation lifetime spectroscopy, and apparent fractional free volume was calculated, which showed the same tendency of charge as permeation flux. Finally, the effect of graphite content and particle size on pervaporation properties were investigated. The pervaporation results indicated that the CG-PVA membranes exhibited good separation properties for benzene/cyclohexane mixtures, and the benzene flux and separation factor could reach 90.7 g•m^-2•h^-1 and 100.1, respectively, for benzene/cyclohexane［50/50,%(mass)］mixtures.