Hydrothermal stability of LTA zeolite membranes in pervaporation

Aiming at the application in pervaporation dehydration process, the hydrothermal stability of LTA zeolite membranes in pervaporation was investigated. Although our LTA zeolite membranes possessed excellent long-term stability in vapor permeation, they failed in pervaporation at high water concentration. The changes of morphology and asymmetric stretching vibrations of TO4 (T = Si or Al) of the LTA zeolite membranes after stability test were detected by SEM and FrIR/ATR, respectively. XRD characterization was performed to detect the changes of diffraction intensity of the LTA zeolite membranes. It was found that the damage of LTA zeolite membrane by water mainly occurred in the grain boundary regions. The amorphous-like structure of the grain boundary is probably the principal cause of the low hydrothermal stability of LTA zeolite membrane at high water concentration. (c) 2007 Elsevier B.V. All rights reserved.