MOR zeolite membranes were treated by using a high temperature CVD method.Pervaporation (PV) separation of isopropyl alcohol (IPA)/water through a MOR zeolite membrane was investigated before and after the Propyltrimethoxysilane (PrTMOS) CVD treatment.Water selectivity improved from 4.4 to 31 by the treatment.On the other hand, water selectivity did not increased by the CVD treatment for the membrane having 25 of the initial water selectivity.In this case, water selectivity improved up to 106 by the N2 post treatment at 500 ℃ after the CVD treatment.