Preparation of FAU type zeolite membranes by electrophoretic deposition and their separation properties

A novel method using electrophoretic deposition (EPD) is proposed for the preparation of dense FAU type zeolite membranes. The precursor membranes deposited through EPD were transformed into continuous bodies without interparticle pores by hydrothermal treatment in reaction mixtures with molar ratio Na₂O:Al₂O₃:SiO₂:H₂O = 8:1:12:360. It was found that the densification of the precursor membranes during the hydrothermal treatment was achieved via two reaction routes; one was crystal growth of FAU type zeolite seeds and the other was generation of FAU type zeolite particles in the interparticle pores from the reaction mixtures. The thus prepared FAU type zeolite self-supported membranes exhibited high performances with a selectivity of 20 in CO₂/N₂ gas separation.