Chitosan/sodium alginate hybrid membranes modified by zeolitic imidazolate framework-90 for pervaporative dehydration of butanol

Abstract

Biobutanol is one of the promising biofuels, which is produced by fermentation. The concentration of butanol in the fermentation broth does not usually reach 2% (by wt). To use biobutanol as fuel, it is necessary to purify this mixture. In this study, chitosan and sodium alginate hybrid membranes filled with zeolitic imidazolate framework-90 (ZIF-90) were synthesized and utilized for butanol dehydration by the pervaporation process. The synthesized pristine and hybrid membranes were characterized by SEM, FTIR, TGA and contact angle. The swelling resistance of the membrane was determined by sorption tests. Hybrid membranes display higher thermal and mechanical stability and swelling resistance compared to pristine membranes. The separation performance of membranes was determined through pervaporation process. The effects of ZIF loading ratio, process temperature and feed concentration on separation performance were investigated. Compared to pristine membranes, hybrid membranes were found to be more effective for dehydration of butanol by pervaporation. Among hybrid membranes, sodium alginate hybrid membranes filled with ZIF-90 displayed the best separation performance. While the highest flux and separation factor values of 0.987 kg/m2h and 1978 were obtained using sodium alginate hybrid membrane, the flux value of 0.325 kg/m2h and the separation factor value of 1124 were achieved in chitosan hybrid membrane.