Formation of Highly Dispersed Faujasites in Natural Aluminosilicate Gels

• Published in: Protection of metals and physical chemistry of surfaces 2021-03, Vol.57 (2), p.329-334
• Main Authors: Tsitsishvili, V. G., Dolaberidze, N. M., Mirdzveli, N. A., Nijaradze, M. O., Amiridze, Z. S.
• Format: Article
• Language: English
• Subjects: Aging (natural); Aluminosilicates; Aluminum; Aluminum silicates; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Crystallization; Gels; Hydrochloric acid; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Ion exchange; Materials Science; Metallic Materials; Nanoscale and Nanostructured Materials and Coatings; Reagents; Room temperature; Silicon; Sodium hydroxide; Specific surface; Surface area; Transition metals; Tribology; Zeolites
• ISSN: 2070-2051; 2070-206X
• DOI: 10.1134/S2070205121010202

The article considers the hydrothermal formation of micrometric crystals of zeolite type FAU in aluminosilicate gels obtained from water suspension of natural phillipsite, treated with hydrochloric acid, mixed with sodium hydroxide, and followed by aging during several days at room temperature. At a high concentration of sodium in the reaction mixture, zeolite X with a high aluminum content (Si/Al = 1.4) is formed, having a high specific surface area (590 m 2 /g) and micropore volume (0.3 cm 3 /g), as well as a system of cylindrical pore channels (0.28 cm 3 /g) with an average diameter of 55 nm. Crystallization of a diluted gel with an average sodium content leads to the formation of zeolite X with a higher silicon content (Si/Al = 2.5), having a lower specific surface area (440 m 2 /g) and micropore volume (0.23 cm 3 /g), and irregular system of mesopores (0.15 cm 3 /g) with a diameter of 20–30 nm. The secondary porous network ensures the delivery of reagents to active sites on the surface and determines the possibilities of using the obtained materials as catalysts, especially since they have a fairly high ion exchange capacity and can be easily modified by the introduction of transition metals.