Pervaporation of methanol/dimethyl carbonate using SiO sigma ub 2membranes with nano-tuned pore sizes and surface chemistry

Porous silica membranes with different pore sizes (average pore size: 0.3-1.2 nm) and surface chemistry were prepared from SiO..., steam-treated SiO..., SiO... ZrO..., and SiO... TiO... by sol-gel processing, and were applied to the pervaporation (PV) separation of methanol (MeOH) /dimethyl carbonate (DMC) mixtures at 50 degree C. Although SiO... ZrO... membranes demonstrated a separation factor of 10, the SiO... porous membranes had an increased separation factor from 10-160. Silica membranes with an average pore size of 0.3 nm showed the highest permselectivity of methanol with a separation factor of 140 and a methanol flux of 180 mol/(m...h) for MeOH 50 mol% at 50 degree C. To characterize the surface property of SiO... membranes, SiO... powdered samples were used for an adsorption experiment of vapor (MeOH, DMC) in single and mixed systems, revealing increased MeOH selective adsorption for SiO... powders with hydrophilic and small pores, which was consistent with PV performance. (ProQuest: ... denotes formulae/symbols omitted.)