Preparation of zeolite ZSM-5 membrane by electrophoretic deposition method

In the present work, electrophoretic deposition (EPD) has been applied as the seeding method to formation of zeolite ZSM-5 layers with thicknesses about a few micrometers on the porous alumina substrates. Alumina discs were fully covered with ZSM-5 crystal seeds via this method. The resulting seeded supports were submitted to hydrothermal treatment yielding uniform dense zeolite membranes. The membranes were characterized by using scanning electron microscopy (SEM), and X-ray diffractometry (XRD). It was concluded that thickness and density of the membranes could be modified by varying the Si/Al ratio of zeolite ZSM-5 particles, concentration of seeding suspension and seeding time. The selectivity of the produced ZSM-5 membrane for i-propanol permeation over water was observed on every membrane and at some optimum conditions separation factors higher than 40 was obtained. At the same time, a total flux of about 1.75 kg/m2h was achieved which is well comparable with the published data on similar membranes.