Fabrication of a layered hybrid membrane using an organosilica separation layer on a porous polysulfone support, and the application to vapor permeation

Using 1,2-bis(triethoxysilyl)ethane (BTESE) as a single precursor, a uniform, defect-free and perm-selective organosilica layer was successfully deposited onto porous polysulfone ultrafiltration (PSF-UF) supports via a simple sol–gel spin-coating and thermal-treatment process. The layered hybrid membranes, where BTESE-derived SiO2 is deposited on polymer supports, were applied to the vapor permeation dehydration of isopropanol–water (90/10 wt%) solutions at 105 °C, and demonstrated a water flux of 1.6 kg/m2 h and a separation factor of 315 with no selectivity for a PSF-UF support. Long-term stability testing of vapor permeation also confirmed the excellent stability of these BTESE/PSF-UF layered hybrid membranes. Moreover, compared with porous PSF-UF supports, this layered hybrid membrane also showed improved gas separation performance and a moderate (≈10) separation factor for H2/N2.