The effect of H+ irradiation on the Cs-ion exchange capacity of zeolite-NaY

Radiation effects on zeolite-NaY have been investigated by irradiation with a 500 keV Hz beam. Zeolite-NaY suffers structural damage under proton irradiation. The crystalline-to-amorphous transition occurs at a total dose equivalent to an ionizing energy deposition of 3 x 10(10) Gy and a displacement dose of 0.05 dpa (displacements per atom). The ion exchange capacity of the irradiated zeolite-NaY with 10 mM CsCl solution varies with the extent of damage to the crystalline structure. After 25 hours of exchange, the Cs-concentration in the amorphous region is similar to0.8 wt.%, which is much lower than in the undamaged region (similar to 20 wt.%). This result confirms that radiation-induced amorphization can cause a significant loss of ion exchange capacity. The data also suggest that the radiation damage by proton radiation in zeolite-NaY is caused by both ionizing and displacement processes. Mechanisms related to the radiation-induced change in the ion exchange capacity are discussed.