FUNDAMENTAL STUDIES ON DESIGN OF SEPARATION MEMBRANES FOR ORGANIC LIQUID MIXTURES AND IMPROVEMENT OF MEMBRANE SEPARATION

为了制备对有机液体混合物具有高渗透性和高选择性的聚合物膜，采用不同的聚合物材料对渗透汽化过程中乙醇水溶液的渗透和分离的膜的制备条件进行了详细的研究。此外，疏水聚合物膜，如聚氯乙烯和聚苯乙烯膜，选择性地渗透水。为了揭示这些现象，对膜中吸附液体的组成进行了分析。前者吸附水，后者吸附酒精。从这些结果可以看出，只有增加渗透物质在膜中的溶解度，才能获得良好的渗透和分离性能，而增加渗透物质在膜中的扩散系数是非常重要的。关系式b…并从分子水平上研究了膜在热处理和交联反应过程中的结构变化和分离特性。在本研究中，我们提出了一种新的膜分离技术--蒸散法，比较了蒸发法和渗透汽化法对乙醇水溶液在几种聚合物膜中的渗透和分离特性。总体来说，蒸发法的分离效果优于渗透蒸发法，但渗透蒸发法的渗透性要好于蒸发法，在蒸发法中，可以控制膜邻域与料液之间的温差。将这种温差控制的蒸散法应用于聚二甲基硅氧烷膜分离乙醇水溶液和壳聚糖膜分离二甲基亚砜水溶液时，前者高选择性地透过醇，后者高选择性地透过水.从膜的物理化学性质和渗透物种的角度探讨了有机水溶液透过这些膜的机理.较少

Purpose of preparing polymer membranes with high permeability and high selectivity for organic liquid mixtures, preparation conditions of the membrane for the permeation and separation of aqueous alcohol solutions in pervaporation was investigated in detail using various polymer materials.Hydrophilic polymer membranes such as poly(vinyl alcohol) and chitosan membrane predominantly permeated water from aqueous alcohol solutions. Also, hvdrophobic polymer membranes such as poly(vinyl chloride) and polystyrene membrane selectively permeated water. In order to reveal these phenomena, composition of liquid adsorbed in the membrane was analyzed. The former membranes adsorbed water and the latter one alcohol. From these results it was found that good performance for the permeation and separation could not be obtained only increase of solubility of the permeating species into the membrane and it was very important to increase diffusivity of the permeating species in the membrane.Relationship b … More etween the structural change of membrane with heat treatment and crosslink reaction and the separation characteristic was studied from the viewpoint of molecular level. It was found that slight change of the membrane structure significantly influenced the permeation and separation characteristics.In this study, we proposed a new membrane separation technique, which was named an evapomeation method, the permeation and separation characteristics for aqueous alcohol solutions through some polymer membranes by the evapomeation were compared with those by pervaporation. In general, the separation in evapomeation was superior to that in pervaporation, but the permeability in pervaporation was better than that in evapomeation.In evapomeation, it was possible to control temperature difference between the membrane neighborhood and the feed solution. When this evapomeation method with control of the temperature difference was applied to the separation of aqueous alcohol solutions through poly(dimethylsiloxane) membrane and aqueous dimethyl sulfoxide through chitosan membrane, the former merfibrane permeated alcohols and the latter one permeated water with high selectivity.Mechanisms for organic aqueous solutions through these membranes are discussed from the viewpoints of physicochemical nature of the membrane and the permeating species. Less