Removal of methyl tert-butyl ether from water by pervaporation using ceramic-supported polymer membranes

Pervaporation removal of methyl tert-butyl ether (MTBE) from dilute aqueous solutions was demonstrated using ceramic-supported polymer (CSP) membranes. These membranes were created by the free radical graft polymerization of vinyl acetate onto a vinyl trimethoxysilane-activated porous silica substrate having a native average pore size of 500 Å. The resulting membranes consisted of poly(vinyl acetate) chains terminally and covalently anchored to the membrane surface. These pervaporation membranes performed with separation factors ranging from about 68 to 577 at total permeate fluxes of 0.31–0.70 kg/m2 h over feed concentrations of 74–7400 ppm (0.01–1%, v/v). MTBE flux was controlled by the feed-side concentration boundary layer, while water permeation was controlled by the membrane resistance. The primary effect of the grafted PVAc in these CSP membranes was to increase separation by rejecting water, as opposed to increasing the flux of MTBE.