Ceramic-supported thin PVA pervaporation membranes combining high flux and high selectivity; contradicting the flux-selectivity paradigm
Ceramic-supported thin PVA pervaporation membranes combining high flux and high selectivity; contradicting the flux-selectivity paradigm
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DOI：
10.1016/j.memsci.2005.06.066
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发表时间：
2006-05-01
影响因子：
9.5
通讯作者：
Keurentjes, JTF
中科院分区：
文献类型：
--
作者：
Peters, TA;Poeth, CHS;Keurentjes, JTF
在中空纤维陶瓷支撑体上制备了薄的、高通量且高选择性的交联聚乙烯醇水选择层。支撑体由α - Al₂O₃中空纤维基底和中间的γ - Al₂O₃层组成，中间层为超薄聚乙烯醇层的沉积提供了足够光滑的表面。通过扫描电子显微镜（SEM）和渗透蒸发实验对膜进行了表征。在γ - Al₂O₃中间层上形成的聚乙烯醇层厚度约为0.3 - 0.8μm。未观察到聚乙烯醇明显渗入中间的γ - Al₂O₃层。在1 - 丁醇脱水（80℃，5 wt.%水）过程中，膜表现出高水通量（0.8 - 2.6 kg·m⁻²·h⁻¹）以及高分离因子（500 - 10000）。通量和分离因子的值超过了在聚合物支撑体上的交联聚乙烯醇膜所获得的典型值。在2 - 丙醇和1 - 丁醇脱水过程中，随着温度或水浓度的升高，观察到水通量和分离因子同时增加。这种显著的行为与聚合物膜通常观察到的权衡现象相反，即通量增加通常伴随着分离因子降低。这种行为的一种可能解释是由于结构稳定性增强，在γ - Al₂O₃ - 聚乙烯醇界面附近三维溶胀程度较低。在乙醇和1 - 丙醇脱水过程中，观察到了通量和选择性之间的传统权衡关系。（c）2005 Elsevier B.V.保留所有权利。
Thin, high flux and highly selective cross-linked poly(vinyl)alcohol waterselective layers have been prepared on top of hollow fibre ceramic supports. The supports consist of an alpha-Al2O3 hollow fibre Substrate and an intermediate y-Al2O3 layer, which provides a sufficiently smooth surface for the deposition of ultra-thin PVA layers. Membranes have been characterised by SEM and pervaporation experiments. The thickness of the PVA layer formed on top of the gamma-Al2O3 intermediate layer is in the order of 0.3-0.8 mu m. No significant infiltration of PVA into the intermediate gamma-Al2O3 layer can be observed. In the dehydration of 1-butanol (80 degrees C, 5 wt.% water) the membranes exhibit a high water flux (0.8-2.6 kg m(-2) h(-1)), combined with a high separation factor (500-10,000). The values for the flux and separation factor exceed typical values obtained for cross-linked PVA membranes on polymeric supports. In the dehydration of 2-propanol and 1-butanol, a simultaneous increase in both water flux and separation factor is observed with increasing temperature or water concentration. This remarkable behaviour is in contrast to the trade-off generally observed for polymer membranes, i.e., an increase in flux is typically combined with a decrease in separation factor. A possible explanation for this behaviour is a low degree of three-dimensional swelling in the vicinity of the gamma-Al2O3-PVA interface due to an enhanced structural stability. In the dehydration of ethanol and 1-propanol the traditional trade-off between flux and selectivity was observed. (c) 2005 Elsevier B.V. All rights reserved.