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

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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.