Pervaporation characteristics of trichlorinated organic compounds through Silicalite-1 zeolite membrane

Silicalite-1 membrane synthesized on the inside of a porous stainless steel tube was used for pervaporation of trichloromethane, 1,1,2-trichloroethane and trichloroethylene from their aqueous solutions. Fluxes of trichloromethane, 1,1,2-trichloroethane and trichloroethylene were observed to be 3.0~39.8 g/m2/h, 0.3~4.6 g/m2/h and 0.1~2.0 g/m2/h while their separation factors were 16.4~29.6, 4.2~10.3 and 5.7~18.1, respectively depending on the mole fraction of a trichlorinated organic compound in the feed solution and the operating temperature. The silicalite-1 membrane showed the best separation ability for trichloromethane, since trichloromethane has the smallest kinetic diameter and the highest fugacity among the trichlorinated organic compounds.

Synthesized silicalite-1 membranes showed reasonable fluxes and separation factors for the binary aqueous solution of trichloromethane/water, 1,1,2-trichloroethane/water and trichloroethylene/water. The fluxes and the separation factors through silicalite-1 zeolite membranes were strongly affected by both the feed concentration and the operating temperature which results in the fugacity changes of the components. The separation factors of trichloromethane/water mixture and trichloroethylene/water were found to be 3 times and 2 times higher than that obtained from 1,1,2trichloethane/water mixture, respectively. Silicalite-1 membrane might be one of the potential pervaporation membranes for separation of trichlorinated organic compounds from their aqueous solutions.