Pervaporation performance of hollow-fiber chitosan-polyacrylonitrile composite membrane in dehydration of ethanol.

Abstract

Performance of a pervaporation membrane consisting of polyacrylonitrile hollow fiber with a thin ionized cross-linking chitosan layer, developed for dehydration from aqueous organic mixture, was evaluated at the scale of a 6 m2 module under various conditions of feed composition (95–99.8 wt%), temperature (40–75°C) and pressure (0.1–1.8 kPa). The data indicate high performance of the module in both permeation rate and separation factor, 0.6 kg/(m2·h) and 5000 respectively at an ethanol concentration of 95 wt%.It was also shown that the permeation rates vary in proportion to the mole fraction of water in the feed to the power of 1.3, while the separation factor was almost constant in the range of ethanol concentration from 95 to 99.5 wt%. Under an operating pressure lower than the partial vapor pressure of water in the feed, the temperature dependence of the permeation rate follows the Arrhenius equation with an activation energy of 54 kJ/mol independently of the operating pressure.