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sur le développement des zones arides et semi-arides

Titre : Application of kaolin-based synthesized zeolite membrane systems in water desalination

Auteur : Aliyu, Usman Mohammed

Université de soutenance : Durban University of Technology (DUT)

Grade : Doctor of Engineering : Chemical Engineering, 2021

Résumé partiel
Accessibility to potable water worldwide is threatene, despite 71% of the earth’s surface being covered with water. However, 97% of the 71% is too saline for consumption. A usual way of treating salinity is by membrane desalination using reverse osmosis. The disadvantage of this approach is its high cost and short life span of the polymeric membrane used. Creating a new robust high-quality water treatment system using a ceramic membrane will address these challenges due to its robust mechanical properties. In this work, we synthesized different zeolites from South African kaolin under varying conditions such as crystallization time, ageing time and temperature and their effects on the properties of zeolites synthesized was investigated. Sample characterization confirmed the successful synthesis of ZSM-5 and zeolite A. In the synthesis procedure, metakaolin served as the alternative source of silica and alumina and was use to synthesize different types of zeolites under varying synthesis conditions. Synthesized samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller BET surface area. The properties of the synthesized ZSM-5 were influence by the synthesis parameters, typically, crystallization temperature, ageing time and crystallization time. Crystalline ZSM-5 zeolite produced at an ageing time of 24 hours, crystallization time of 48 hours and crystallization temperature of 180°C with Si/Al ratio of 43 and BET surface area of 282 m2 /g. After a 12-hour ageing period, Zeolite A produced at crystallization time of 20 hours, the crystallization temperature of 100°C, Si/Al ratio of 1.3 and BET surface area of 143.88 m2 /g. The findings indicate that aging influences the synthesis of zeolite A, as a relatively crystalline material formed at an ageing time of 12 hours, which continued to decrease as the ageing time was increased. We do not exclude the possibility of Ostwald ripening playing a role in this relationship.

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