High-performance sulfonated polyimide/polyimide/polyhedral oligosilsesquioxane hybrid membranes for ethanol dehydration applications
High-performance sulfonated polyimide/polyimide/polyhedral oligosilsesquioxane hybrid membranes for ethanol dehydration applications
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DOI：
10.1016/j.memsci.2013.11.053
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发表时间：
2014-03
影响因子：
9.5
通讯作者：
N. Le;T. Chung
中科院分区：
文献类型：
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作者：
N. Le;T. Chung
研究了一种新型的共聚(1，5-萘/3，5-苯甲酸-2，2‘-二(3，4-二羧基苯基))六氟丙二胺6FDA-NDA/DABA及其磺化聚酰亚胺共混物作为选择性水层，制备了用于乙醇渗透汽化脱水的双层中空纤维膜。合成的纤维表现出良好的通量>；3.0 mg/m2.h。这可能归因于磺酸基团在聚合物基质中的均匀分布，以及磺酸基团引起的亲水性增强和空间增大，并通过偏光显微镜(PLM)、接触角测量、吸附测试和X射线衍射仪进行了验证。采用了三种不同的后处理方法，即热处理、PDMS包覆和多面体倍半硅氧烷(POSS)改性，以提高膜的选择性。借助于先进的PALS技术，研究了它们对聚合物链堆积、致密皮肤厚度和乙醇脱水性能的影响。热处理可以使选择层结构致密，而PDMS涂层提供了一层薄的屏蔽层，以保护选择层免受饲料诱导的膨胀。更重要的是，由于POSS无机纳米粒子的抗溶胀性能、聚合物链的迁移率限制以及聚合物结构中空间的狭窄，POSS修饰是提高膜选择性的最有效方法。与文献中的各种膜相比，本研究中新开发的中空纤维对乙醇脱水具有优良的通量>；2.0 kg/m2h和良好的分离系数>；200。这项研究可能会为探索新材料和生物燃料分离的后处理提供有益的见解。
A novel miscible polymer blend of copoly(1,5-naphthalene/3,5-benzoic acid-2,2′-bis(3,4-dicarboxyphenyl)) hexafluoropropanedimide 6FDA-NDA/DABA and its sulfonated polyimide has been investigated as a water-selective layer to develop dual-layer hollow fiber membranes for ethanol dehydration via pervaporation. The resultant fibers display an excellent flux of >3.0 kg/m2h. This is possibly ascribed to a good distribution of sulfonic groups in the polymer matrix, the increased hydrophilicity and enlargedd-space induced by sulfonic groups, which are verified by polarized light microscopy (PLM), contact angle measurement, sorption tests and XRD. Three different post-treatment approaches, namely, thermal treatment, PDMS coating and modification with polyhedral oligosilsesquioxane (POSS) were employed to improve the membrane selectivity. Their effects on polymer chain packing, dense skin layer thickness and ethanol dehydration performance have been investigated with the aid of the advanced PALS technique. Thermal treatment can densify the selective layer structure while PDMS coating provides a thin shielding layer to protect the selective layer from feed-induced swelling. More importantly, POSS modification displays as the most effective way to enhance the membrane selectivity due to the anti-swelling property of POSS inorganic nanoparticles, mobility restriction of polymer chains and narrowedd-space in polymer structure. Compared to various membranes in the literature, the newly developed hollow fibers in the present study have superior fluxes of >2.0 kg/m2h and good separation factor of >200 for ethanol dehydration. This study may provide useful insights for the exploration of new materials and post-modifications for biofuel separations.