Solution diffusion modeling of a composite PVA/fumed silica ceramic supported membrane

The permeation behavior of thin films of fumed silica loaded polyvinyl alcohol (PVA) coated over tubular porous ceramic supports were investigated. Mullite based support enhances mechanical strength of PVA membranes. Effects of temperature, fumed silica loading and active layer thickness on the permeation behavior of the prepared membranes were studied in terms of permeation flux and water selectivity. Experimental data were obtained by dehydration of 90 wt.% ethanol using pervaporation (PV). The privileges of the synthesized membrane to its rivals, superior permeation flux (0.05-2.92 kg/m(2)h), water selectivity (3-180) and pervaporation separation index (PSI) (5.84-82.81) along with its low manufacturing costs, let it have a potential to be used for dehydrated ethanol production in industrial scale. A solution diffusion based mathematical model, including surface exchange and bulk diffusion resistances, was developed to predict permeation flux of both components as functions of temperature, fumed silica loading, active layer thickness and feed composition. Results showed that permeation flux enhances with temperature, fumed silica loading and diminishes with membrane thickness. Besides, increasing temperature and fumed silica loading reduces selectivity while increasing membrane thickness increases selectivity. (C) 2016 Elsevier B.V. All rights reserved.