Pervaporation of dichlorinated organic compounds through silicalite-1 zeolite membrane

Pervaporation utilized with a zeolite membrane is one of the economic separation technologies for liquid mixtures including organic/water mixtures. The silicalite-1 membrane was selected for pervaporation of dichloromethane, 1,2-dichloroethane and trans-1,2-dichloroethylene from their aqueous solutions since it shows very hydrophobic properties. Silicalite-1 crystals were hydrothermally grown and deposited on the inside of a porous sintered stainless steel tube by the secondary growth method. Fluxes of dichlorinated organic compounds were observed to be 0.2–71 g/(m2 h) while separation factors were 12–332 depending on a mole fraction of a dichlorinated organic compound in the feed solution and the operation temperature. The silicalite-1 membrane was found to be applicable to the selective removal of dichlorinated organic compounds from aqueous solutions composed of a low concentration at a relatively low temperature.