Modification of tetraethylorthosilicate crosslinked poly(vinyl alcohol) membrane using chitosan and its application to the pervaporation separation of water–isopropanol mixtures

✍ Scribed by Srikant S. Kulkarni; Subhashchandra M. Tambe; Arjumand A. Kittur; Mahadevappa Y. Kariduraganavar

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 143 KB
• Volume: 99
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.22514

✦ Synopsis

Abstract

Tetraethylorthosilicate crosslinked poly(vinyl alcohol) membrane was modified by varying the amounts of chitosan. The resulting membranes were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The effects of chitosan content and feed composition on the pervaporation performance of the membranes were analyzed. The modified membranes exhibit simultaneous increase of both flux and selectivity. The membrane containing 15 mass % of chitosan shows the highest separation selectivity of 2991, with a flux of 2.39 × 10^−2^ kg/(m^2^ h) at 30°C for 10 mass % of water in the feed. The total flux and flux of water are almost overlapping each other, manifesting that the membranes could be used effectively to break the azeotropic point of water–isopropanol mixture, so as to remove water from the isopropanol. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The activation energy values obtained for water permeation (E~pw~) are significantly lower than those of isopropanol permeation (E~pIPA~), suggesting that the membranes developed here have higher separation ability for water–isopropanol system. In addition, difference was negligibly small between the activation energy values of total permeation (E~p~) and water permeation (E~pw~), indicating that coupled transport is minimal because of a higher selective nature of membranes. The E~p~ and E~D~ values ranged between 40.92 and 52.60, and 39.58 and 52.47 kJ/mol, respectively. The positive heat of sorption (Δ__H__~s~) values observed in all the membranes suggests that Henry's mode of sorption is predominant. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1380–1389, 2006