Self-assembled nano-structured polyelectrolyte composite membranes for pervaporation
Self-assembled nano-structured polyelectrolyte composite membranes for pervaporation
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DOI：
10.1016/j.msec.2005.03.008
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Zhaoqi Zhu;Xian-she Feng;A. Penlidis
中科院分区：
文献类型：
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作者：
Zhaoqi Zhu;Xian-she Feng;A. Penlidis
这项工作是关于纳米结构聚电解质复合膜的溶剂渗透汽化脱水。通过在微孔聚丙烯腈基膜上逐层静电沉积聚乙烯亚胺和聚丙烯酸，制备了聚丙烯腈基膜。每一轮交替沉积的阳离子和阴离子聚合物形成一个双层聚电解质，并使用多次沉积循环来实现膜的渗透选择性。为了改善聚电解质的初始沉积，对聚丙烯腈基膜进行了部分水解。建议在沉积的前几个循环中使用相对稀释的聚电解质浓度，然后使用浓度更高的聚电解质溶液进行沉积(但仍远低于临界重叠浓度，以确保聚电解质分子的构象得到很好的扩展)。结果表明，使用该技术可以在不到10个循环的情况下获得良好的渗透选择性，这比文献中使用的循环次数(例如60-90次)要少得多。该膜对水和异丙醇具有良好的分离性能，当进水浓度为8~10wt.%时，水的渗透浓度可达99wt.%以上，渗透通量约为0.6 kg/m~2·h。
This work is concerned with nano-structured polyelectrolyte composite membranes for solvent dehydration by pervaporation. The membranes were prepared by the electrostatic layer-by-layer deposition of polyethylenimine and poly(acrylic acid) onto a microporous polyacrylonitrile substrate membrane. Each cycle of alternating deposition of the cationic and anionic polymers formed a bilayer of polyelectrolyte, and multiple deposition cycles were used to achieve the permselectivity of the membrane. The polyacrylonitrile substrate membrane was partially hydrolyzed to improve the initial deposition of polyelectrolytes. It was proposed to use a relatively dilute concentration of the polyelectrolytes in the first few cycles of deposition, followed by depositions with more concentrated polyelectrolyte solutions (but still far below the critical overlapping concentration to ensure well extended conformation of the polyelectrolyte molecules). It was demonstrated that using this technique a good permselectivity could be achieved with less than 10 cycles of deposition, which was much less than the number of cycles used in the literature (e.g. 60–90). The membrane showed good separation performance for separation of water from isopropanol; at a feed water concentration of 8–10 wt.%, a permeate concentration of over 99 wt.% water was achieved with a permeation flux of about 0.6 kg/m2h.