Effect of operation conditions in the pervaporation of ethanol-water mixtures with poly(1-trimethylsilyl-1-propyne) membranes

Poly(l-trimethylsilyl-l-propyne) (PTMSP) is known to show preferential permeation of ethanol in the pervaporation of ethanol-water mixture. Although this polymer presents good characteristics for the separation of organic-water solutions, operation conditions and membrane characteristics, such as thickness, affect its pervaporation performance. The effect of temperature and feed concentration on pervaporation was studied. During pervaporation of 10 wt % ethanol-water solution, the separation factor (alpha(H20)(EtOH)) remains almost constant, whereas the permeation flux (F) increases exponentially with operation temperature. On the other hand, the separation factor decreases, whereas the permeation flux increases with ethanol content in the feed mixture. The membrane thickness also affects the performance of PTMSP polymer films: selectivity increases sharply with membrane thickness up to 50 mum, whereas it remains constant for thicker membranes. The permeation flux decreases with membrane thickness in the whole range studied. (C) 2004 Wiley Periodicals, Inc.