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 irra diation. The crystalline-to-amorphous transition occurs at a total dose equ ivalent to an ionizing energy deposition of 3 x 10(10) Gy and a displacemen t dose of 0.05 dpa (displacements per atom). The ion exchange capacity of t he irradiated zeolite-NaY with 10 mM CsCl solution varies with the extent o f damage to the crystalline structure. After 25 hours of exchange, the Cs-c oncentration in the amorphous region is similar to0.8 wt.%, which is much l ower than in the undamaged region (similar to 20 wt.%). This result confirm s that radiation-induced amorphization can cause a significant loss of ion exchange capacity. The data also suggest that the radiation damage by proto n radiation in zeolite-NaY is caused by both ionizing and displacement proc esses. Mechanisms related to the radiation-induced change in the ion exchan ge capacity are discussed.