High performance pervaporative desalination of saline waters using Na-X zeolite membrane

A high quality Na-X zeolite membrane was synthesized on a seeded a-alumina disc by the secondary growth method. Structural characterization was done by X-ray spectroscopy, FT-IR spectroscopy, SEM and AFM imaging. The performance evaluation of the membrane was firstly tested in separation of glucose/water solutions by pervaporation process. There was obtained a separation factor 182.7+-8.8, while the flux through the membrane was 3.6+-0.3 kg m-2 h-1. The zeolite membrane was then used for desalination of aqueous solutions consisting of Na+, Ca2+, Cs+ and Sr2+ because of the importance of these ions in water and wastewater treatments. The effects of some parameters such as temperature and solution concentration on the desalination process were studied for investigating of diffusion/adsorption mechanism in membrane separation. Finally, high water fluxes ranged from 2 up to 9 kg m-2 h-1 were obtained and the rejection factors were resulted more than 95% for Na+ and Ca2+ and near to 99% for Cs+ and Sr2+. Based on the results, fluxes were significantly improved due to convenient passage of water molecules from large pores of NaX, while the fouling was declining dramatically. Based on the results, NaX zeolite can efficiently use for the removal of different cations from wastewaters.