title: Dehydration of an ethanol/water azeotrope through alginate-DNA membranes cross-linked with metal ions by pervaporation.
abstract: To obtain high dehydration membranes for an ethanol/water azeotrope, dried blend membranes prepared from mixtures of sodium alginate (Alg-Na) and sodium deoxyribonucleate (DNA-Na) were cross-linked by immersing in a methanol solution of CaCl2 or MaCl2. In the dehydration of an ethanol/water azeotropic mixture by pervaporation, the effects of immersion time in methanol solution of CaCl2 or MaCl2 on the permeation rate and water/ethanol selectivity through Alg-DNA/Ca(2+) and Alg-DNA/Mg(2+) cross-linked membranes were investigated. Alg-DNA/Mg(2+) cross-linked membrane immersed for 12h in methanol solution of MaCl2 exhibited the highest water/ethanol selectivity. This results from depressed swelling of the membranes by formation of a cross-linked structure. However, excess immersion in solution containing cross-linker led to an increase in the hydrophobicity of cross-linked membrane. Therefore, the water/ethanol selectivity of Alg-DNA/Mg(2+) cross-linked membranes with an excess immersion in cross-linking solution was lowered. The relationship between the structure of Alg-DNA/Ca(2+) and Alg-DNA/Mg(2+) cross-linked membranes and their permeation and separation characteristics during pervaporation of an ethanol/water azeotropic mixture is discussed in detail.
authors.affiliation: Department of Chemistry and Materials Engineering, Japan; Organization for Research and Development of Innovative Science and Technology, Kansai University, Suita, Osaka 564-8680, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Uragami
authors.affiliation: Department of Chemistry and Materials Engineering, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Banno
authors.affiliation: Department of Chemistry and Materials Engineering, Japan; Organization for Research and Development of Innovative Science and Technology, Kansai University, Suita, Osaka 564-8680, Japan. Electronic address: v701489@kansai-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyata
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D002413:Cations, Divalent / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D003890:Desiccation; D004058:Diffusion; D000431:Ethanol / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry; D008567:Membranes, Artificial; D010539:Permeability; D014867:Water / Q000737:chemistry*
chemical_list: D000464:Alginates; D002413:Cations, Divalent; D003432:Cross-Linking Reagents; D006603:Hexuronic Acids; D008567:Membranes, Artificial; D014867:Water; D000431:Ethanol; D020723:Glucuronic Acid; D004247:DNA; D008274:Magnesium; D002118:Calcium
keywords: DNA; Dehydration of azeotrope; Ionic cross-linking; Membrane; Pervaporation; Sodium alginate; Soution-duffusion model