Reverse Osmosis Performance of Sulfonated Poly(2,6-dimethylphenylene Ether) Ion Exchange Membranes
Reverse Osmosis Performance of Sulfonated Poly(2,6-dimethylphenylene Ether) Ion Exchange Membranes
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磺化聚(2,6-二甲基苯醚)离子交换膜的反渗透性能
DOI：
10.1021/i360039a015
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发表时间：
1971
期刊：
影响因子：
--
通讯作者：
S. G. Kimura
中科院分区：
文献类型：
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作者：
S. G. Kimura
磺化聚（2, 6-二甲基苯醚）阳离子交换膜显示出作为反渗透膜的前景，在 1% NaCl 进料的相同脱盐水平下，其透水性是均质醋酸纤维素的 8 至 10 倍。膜的形态可以变化，以提供广泛的脱盐率和透水性。由于脱盐的主要机制是唐南排斥，膜的性能高度依赖于进料成分。基本上，存在两种类型的反渗透膜——带或不带耦合流的溶液扩散膜和离子交换膜。在溶液扩散膜中，溶剂和溶质首先溶解在膜聚合物中，然后扩散穿过膜。由于溶剂和溶质的溶解度和扩散系数不同，会发生脱盐。当膜缺陷的尺寸足够大以允许粘性流动并允许溶质通过拖曳力输送时，就会存在流动耦合。醋酸纤维素膜是溶液扩散膜的例子。离子交换膜是粘性流动膜，通过电力排除盐。当离子交换膜浸入电解质溶液中时，由于膜与周围溶液之间的浓度差，反离子有扩散到溶液中的趋势，而反离子则有从溶液扩散到膜中的趋势。因此，产生了电荷不平衡，并且膜呈现出唐南电势，这抑制了进一步的coion摄取。阳离子交换膜带有负电荷，因此排除阴离子。由于必须保持电中性，因此离子排斥相当于盐排斥。磺化
Sulfonatéd poly (2, 6-dimethylphenylene ether) cation exchange membranesshow promise as reverse os-mosis membranes, having from 8 to 10 times as high water permeability as homogeneous cellulose acetate at the same salt rejection levels for 1% NaClfeeds. Membrane morphologies can be varied to give a wide range of salt rejections and water permeabilities. Since the principal mechanism of salt rejection is Donnan exclusion, membrane performance is highly dependent on feed composition.There exist, basically, two types of reverse osmosis mem-branes—solution-diffusion membranes with or without cou-pled flows and ion exchange membranes. In a solution-diffusion membrane, solvent and solute pass through the membrane by first being dissolved in the mem-brane polymer and then diffusing across. Salt rejection occurs because solvent and solute solubilities and diffusion coefficients differ. Flow coupling exists when there are membrane imperfections of sufficient size to permit viscous flow and allow solute to be transported by drag forces. Cellulose acetate membranes are examples of solution-diffusion membranes. Ion exchange membranes are viscous flow membranes which exclude salt by electrical forces. When an ion exchange membrane is immersed in an electrolyte solution, there is a tendency for counterions to diffuse out into the solution and coions to diffuse from the solution into the membranebe-cause of concentration differences between the membrane and the surrounding solution. Thus a charge imbalance is created, and the membrane takes on a potential, the Donnan potential, which inhibits further coion uptake. A cation exchange membrane takes on a negative charge and, thus, excludes anions. Since electroneutrality must be maintained, coion rejection is equivalent to salt rejection. Sulfonated