Tohru Kashiwagi

Separation of ethanol from ethanol/water mixtures by plasma-polymerized membranes from silicone compounds

Abstract The separation by pervaporation of ethanol/water mixtures was investigated. Plasma polymerization was used to produce membranes. Ethanol-permselective membranes can be prepared from various silicone and silane monomers under extremely mild polymerization conditions. These membranes have polydimethylsiloxane-like structures and selectivity factors of 1.5~5.2. Further investigations were carried out on the mechanism of permeation through plasma-treated silicone rubber membranes and silicone oil membranes. Highly permselective membranes can be prepared by surface treatment of thin polydimethylsiloxane membranes with silane compounds containing octadecyl groups. An ethanol permselectivity, αEtOH, of 18.0 and a flux of 0.015 kg/cm2-hr were obtained with these membranes. This report gives a novel method for producing ethanol-permselective membranes.