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

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 1000 kGy. 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.

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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.