Hydrophilic Zeolite Membranes for Pervaporation of Water

摘要

Abstract: Water was separated from water/2,2,2-trifluoroethyl alcohol (TFEA) mixtures by pervaporation using hydrothermally synthesized NaA and NaY zeolite membranes. The effect of a TFEA feed concentration and a temperature was studied on the permeation flux and the separation factor. The separation factors obtained with the NaA zeolite membrane were found to be 10 times higher than those obtained with the NaY zeolite membrane which were always no less than 1,000 at all experimental conditions. The water flux through the NaY zeolite membrane was observed to be 1.2 times larger than that of the NaA zeolite membrane. The water flux increased significantly with increase of the temperature for both NaA and NaY zeolite membranes. The TFEA flux through NaA zeolite membrane was not much changed by the increase of the temperature when the TFEA concentration was below 0.8 mole fraction in a solution. On the other hand, the TFEA flux through the NaY zeolitemembrane rapidly increased with increase of the temperature at the feed concentration below 0.8 mole fraction of TFEA. Long-term pervaporation tests showed a good stability since the total flux through the NaA zeolite membrane was stabilized at about 1,250g/m 2 hr and the separation factor of 2.5 ×10 5 and total flux of about 1,750g/m 2 hr and the separation factor of about 7 ×10 3 for the NaY zeolite membrane.