Pervaporation Separation of Isopropanol/Benzene Mixtures Using Inorganic-Organic Hybrid Membranes

A series of pervaporation hybrid membranes were prepared from polyethylene glycol (PEG) and phenylaminomethyl trimethoxysilane (PAMTMS) based on the sol-gel process, in which PEG was used as an organic moiety to improve the affinity for organic alcohols and silicone of PAMTMS was used as inorganic moiety to increase the permeation flux of organic species. Their application to separate isopropanol/benzene mixtures was investigated. FTIR spectra confirmed the reaction products. DSC measurement revealed that the influence of PEG content on the T(g) and thermal behavior of membranes A, B, and C. FE-SEM images exhibited that phase-separated structure has occurred when the PEG content elevated to some extent. Pervaporation experiments showed that the permeation flux increased and the separation factor decreased with an increase in isopropanol (IPA) content in feed at 30 degrees C. Meanwhile, the separation factor increased with an increase in feed temperature at 60 vol % IPA content. Moreover, it was found that the permeation flux was independent of the feed temperature, suggesting that feed temperature has little impact on the thermal motion of polymer chains. The increasing cross-linking degree in hybrid matrix might be responsible for such trend. Based on these findings, it can be concluded that these pervaporation hybrid membranes have potential applications in the separation of isopropanol/benzene binary mixtures. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2464-2471, 2010