Synthesis of Zeolites and their Application to the Desalination of Seawater

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
In this study, zeolite X and Y were synthesized hydrothermally in the laboratory at 90˚C and 100˚C respectively. The synthesized zeolites were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infra-red spectroscopy (FTIR), EDX and thermogravimetric analysis. Exchange of Ca, Mg and K for Na ions in seawater were evaluated in Linde type X and Y. The desalination capacity of both zeolite X and Y were evaluated by adding 0.5 g and 1.0 g of each zeolite to 100 ml of seawater on a rotary shaker. The kinetics of desalination was carried by taking analyte samples at 10, 15, 30, 60, 90 and 120 minutes. The results obtained showed that zeolite mass to seawater ratio of 0.5:100 yielded higher removal efficiencies. Ion exchange was carried out at room temperature. Replacement of Na cations by Ca, K and Mg in the zeolite framework was noted. The overall ion exchange selectivity of both X and Y showed preference in the order of Ca > Mg> K > Na. Removal efficiencies obtained when zeolite X was used was Ca 81.5%, Mg 75%, K 59.9% and Na 11.5%. Efficiencies obtained in the case of zeolite Y was Ca 53.9%, Mg 38.5%, K 35.5% and Na 34.5%. Silver nitrate was used to reduce chloride ions and reduce electrical conductivity. It was concluded that zeolites are efficient in the desalination of seawater. The quality of water produced was not suitable for drinking. However, it can be used for irrigation and other industrial purposes. It is suggested that, to effectively desalinate seawater, zeolites without sodium will be appropriate. Also alternate methods like the Column method could be utilized.
A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the award of the Degree of Master of Science in Materials Science