Dehydration of ethylene glycol by pervaporation using gamma alumina/NaA zeolite composite membrane

High-quality zeolite NaA membranes were synthesized on modified α-alumina supports. The surface of macroporous α-alumina supports was modified by deposition of an ultrafiltration layer of γ-alumina. The zeolitic top layers were synthesized via the secondary growth method. The required seeds for the membrane synthesis were prepared via the hydrothermal synthesis using organic template of tetra methyl ammonium hydroxide (TMAOH) to obtain nano-sized seeds. The synthesized seeds and membranes were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The separation performance of membranes was evaluated in pervaporation (PV) dehydration of ethylene glycol (EG). Effect of operational parameters including feed composition, feed flow rate, and feed temperature on separation performance of the synthesized NaA zeolite membranes were investigated. The membranes showed separation factor of 10,996 and high total flux of 7.16 kg m⁻² h⁻¹ for feed temperature of 80 °C, feed flow rate of 1.5 L/min, and feed concentration of 90 wt.% EG.