Amino-Functionalized Silica Membrane for Pervaporation of Ethanol/Water Mixtures
Amino-functionalized silica membranes applied to the separation of ethanol / water mixtures by pervaporation. The increase of surface interaction for the silica membrane with permeate materials is important in order to enhance separation. In this study, the improvement of ability for the permeance of water and selectivity was examined by the surface of silica membrane functionalized amino group. Silica membranes were prepared by the sol-gel method of the hydrolysis and condensation process of tetraethoxysilane (TEOS) as silica source and 3-aminopropyl-triethoxysilane (APTES) to introduce amino group. The membrane prepared by various molar ratios of TEOS / APTES, and the performance of silica membrane evaluated by pervaparation of water / ethanol. The silica membrane prepared by TEOS as silica source showed 0.11kg/m2 h for the flux of water and 2.8 for separation factor. On the other hand, the water flux for the amino-functionalized membrane of TEOS/APTES=1/3 was 0.085kg/m2 h. However the separation factor showed 280, and increased compared with the membrane of only TEOS. The membranes characterized by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and single gas permeation of He, H2, CO2, N2, CH4. The difference of performance is probably due to the amino group of pore surface in the silica, and pore size decreased by amino group. Therefore, it is suggested that the adsorption of water is promoted, and blocks the transport of ethanol.