Synthesis and characterization of NaA zeolite membranes on inner side of tubular supports

NaA zeolite membranes were synthesized by the secondary growth method on the inner surface of porous tubular supports using a rotational synthesis vessel. The microstructure of as-synthesized membranes was characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy(FE-SEM). The influence of rotational speed on the performance of zeolite membranes was investigated. Dehydration performance of the membranes was tested by pervaporation of 95:5(mass) ethanol/water mixtures at 343 K. Separation factor of 2370 and permeation flux of 1.86 kg·h^-1·m^-2 were achieved through the NaA zeolite membrane synthesized under the rotational speed of 4 r·min^-1. The influence of operating temperature and feed concentration on pervaporation performance of the membranes were also investigated, and the glaze sealing of NaA zeolite membranes was discussed preliminarily in terms of the effect on separation performance. It was found that permeation flux through NaA zeolite membranes increased with increasing operating temperature while separation factor declined to a specific value. When decreasing feed water concentration, permeation flux decreased while separation factor increased initially and then declined.