Pervaporative dehydration of organic mixtures using a commercial silica membrane - Determination of kinetic parameters

In this work, the performance of a pervaporation commercial silica membrane referenced as PVP (supplied by Pervatech BV, The Netherlands), has been studied. The solvent mixtures used in the experiments were: (i) a synthetic water-isopropanol mixture with 15-20 wt.% inital water content and (ii) an industrial mixture containing about 25 wt.% water-75 wt.% acetone, coming from a reaction process devoted to the manufacture of rubber antioxidants. In both systems the flux of water through the membrane was obtained at different water concentrations in the feed, as dehydration proceeded. The effect of temperature was studied in the range 40-90 degrees C. It was found that for the range of conditions investigated, water fluxes through the PVP membrane were larger than those previously reported through the Pervap SMS commercial membrane (supplied by Sulzer Cherntech). Water flux data were fitted to a semi-empirical correlation that expresses water flux as an exponential function of the water activity in the feed mixture, Ln(J(w,mass)) = (Ln J(00,w) - E-act/RT) + zeta a(w)(r). The values of the characteristic mass transfer parameters corresponding to the Pervatech PVP membrane zeta, E-act and LnJ(00,w), were obtained, as required for design purposes. (C) 2004 Elsevier B.V. All rights reserved.