ORGANICS WATER SEPARATION BY PERVAPORATION WITH A ZEOLITE MEMBRANE/

Organic/water mixtures are separated at ambient temperature and pressu re by pervaporation through a silicalite zeolite membrane supported on the inner surface of a porous stainless-steel cylindrical tube. Metha nol, ethanol and acetone were preferentially separated from aqueous so lutions. For methanol/water separations, a relatively constant separat ion factor between 11 and 14 was obtained over a wide range of methano l feed concentrations. Total mass fluxes of 1 to 2.7 kg/(m(2) h) were obtained. Water and methanol permeances were independent of methanol f eed concentration, except at low concentrations. Pervaporation has a h igher separation factor than expected for vapor-liquid equilibrium sep aration. The highest separation factor obtained for acetone/water was 255 at an acetone feed concentration of 0.8 wt% with an acetone flux o f 0.20 kg/(m(2) h). The highest acetone flux of 0.95 kg/(m(2) h) was o btained at an acetone concentration of 43 wt%, when the separation fac tor was 37. Separation factors decreased. with increasing acetone conc entration. The production indices for the silicalite membrane were muc h higher then other membranes at similar feed concentrations. The sili calite membrane was unable to selectively remove acetic acid from aque ous solutions at low acid concentrations.