Pervaporation of ethanol/water mixtures using bacterial cellulose-poly(vinyl alcohol) membrane

Abstract

Modifying bacterial cellulose (BC) membranes by immersing BC in 5-12 (% w/v) poly(vinyl alcohol)(PVA) solution and cross-linking with glutaraldehyde solution were studied for the dehydration of ethanol-water azeotropic mixture. The results were compared with the unmodified BC membrane and cross-linked PVA membrane. To be able to understand the effects of membrane properties on the pervaporation separation performance, the membranes were characterized for the morphology by scanning electron microscopy, intermolecular interactions by Fourier transform infrared spectroscopy, the crystalline of membrane by X-ray diffraction, mechanical properties by Instron testing machine, contact angle measurements and adsorption capacity. According to the pervaporation experiments under the conditions at the feed solution of 95 (% v/v) ethanol, temperature of 30 °C and permeate pressure of 10 mmHg, it was found that the modified BC membranes by immersion in 10% PVA solution gave the highest selectivity toward water (αH2O/EtOH ≈ 125) when compared with the BC and BC- PVA modified by 5, 7 and 12 % PVA solution. In the study of the influences of feed temperature, the result showed that with the increase in the feed temperature, the permeate flux increased, but selectivity decreased.