Pervaporation Separation from low Concentration of Alcohol Aquoeus Solution using Capillary Model

本计画的目的是制备适用于乙醇-水混合物渗透汽化分离的乙醇选择性分离膜。为此，本论文开展了四个研究项目，研究结果如下：1.乙醇选择性分离膜的基本设计本文讨论了渗透汽化分离膜的优先吸附-毛细流动模型。用于乙醇选择性分离的膜需要具有使乙醇分子穿过膜的孔，并且具有小于30 mJ/m^2.2的疏水表面。疏水表面的制备为了获得小于30 mJ/^2M的疏水表面，在聚合物上引入CF、CF_2和CF_3残基是有效的。这些残基的疏水效率为CF_3>CF_2>CF.3。聚合物表面的耐久性接枝聚合物的表面改性导致即使在高温下暴露于亲水性或疏水性气氛中，表面性质也没有改变。分离膜的表面接枝聚合等离子体接枝聚合与氟化丙烯酸酯单体的多孔聚乙烯和聚丙烯膜在乙醇-水混合物的渗透蒸发中显示出高的乙醇分离因子。用等离子体接枝聚合的多孔膜渗透蒸发浓缩含5wt%乙醇的乙醇-水混合物中的24wt%乙醇。

The objective of the project is to prepare ethanol-selective separation membranes for pervaporation of ethanol-water mixtures. Four research programs for the aim were carried out and results of the researches were summarized as follows.1. Basic Design of Ethanol-Selective Separation MembranesA model of preferential-sorption-capillary flow was discussed for application of separation membranes in the pervaporation process. The membranes used for ethanol-selective separation are required to have pores to travel ethanol molecules across membrane and to have hydrophobic surface with less than 30 mJ/m^2.2. Preparation of Hydrophobic SurfaceTo obtain hydrophobic surface with less than 30 mJ/^2M, the introduction of CF, CF_2, and CF_3 residues onto polymers was effective. The efficiency of these residues in hydrophobicity was CF_3>CF_2>CF.3. Durable Surface of PolymersSurface modification by graft-polymers led to unchanged surface properties even when the surface was exposed to hydrophilic or hydrophobic atmosphere at elevated temperature.4. Separation Membranes Surface-modified by Graft PolymerizationPorous polyethylene and polypropylene membranes that were plasma-graft-polymerized with fluorinated acrylate monomers showed high ethanol separation factors in pervaporation of ethanol-water mixtures. An ethanol-water mixture with 5 wt% ethanol was concentrated 24 wt% ethanol in pervaporation using the porous membranes plasma-graft-polymerized.