Textural and structural effects of heat treatment and γ-irradiation on Cs-exchanged NaX zeolite, bentonite and their mixtures

• Published in: Microporous and mesoporous materials Vol. 161; pp. 115 - 122
• Main Authors: Belkhiri, S., Guerza, M., Chouikh, S., Boucheffa, Y., Mekhalif, Z., Delhalle, J., Colella, C.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-10-2012; Elsevier
• Subjects: Bentonite; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Heat treatment; Ion-exchange; NaX zeolite; Porosity; Porous materials; Surface physical chemistry; Zeolites: preparations and properties; γ-Irradiation; Bentonite; NaX zeolite; Heat treatment; Porosity; γ-Irradiation; Scanning electron microscopy; Crystalline phase; Zeolite; Analyzer; Nitrogen; X ray diffraction; Porous material; Molecular sieve; Powder; Resistance; Adsorption
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2012.05.027

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► NaX zeolite, Algerian bentonite, and their mixtures as getters of cesium. ► Heat treatment of both NaX and CsX zeolites up to 1000°C reveals new phases. ► Bentonite enables the partial amorphisation of the heat treated mixture zeolite–bentonite. ► Cs exchanged NaX zeolite improves resistance to γ-irradiation.
NaX zeolite, Algerian bentonite, their mixtures, and their Cs-exchanged forms are subjected to heat treatment at different temperatures (800, 1000, and 1100°C) and γ-irradiation doses varying from 100 to 1000kGy. The effects of these treatments on structural and textural properties of the above materials as getters of radionuclides are studied using powder X-ray diffraction (XRD), nitrogen adsorption surface analyzer, and scanning electron microscopy (SEM). A thermal treatment of NaX and CsNaX zeolites up to 1000°C results in the formation of new crystalline phases (nepheline and carnegieite). In contrast, bentonite becomes totally amorphous when it is heat treated up to 800°C. Heat treating of zeolite–bentonite mixtures gives rise to partial amorphisation. γ-Irradiation of the studied materials reveals a good resistance of the Cs exchanged NaX zeolite. This is due to its higher basic character resulting from the Cs2O formed by the reaction between Cs+ present in the zeolite and the O2− anion liberated after γ-irradiation.