The use of zeolites as amendments in radiocaesium- and radiostrontium-contaminated soils: A soil-chemical approach. Part I: Cs-K exchange in clinoptilolite and mordenite

Zeolites of the clinoptilolite and mordenite type have been frequently proposed as countermeasure amendments to reduce radiocaesium soil-to-plant transfer in contaminated soils. The radiocaesium ion exchange behavior has been studied on a natural clinoptilolite and on a natural and a synthetic mordenite, in order to obtain quantitative data on the radiocaesium sorption competition of these zeolites relative to soils. The relative effect of K, NH 4 , and Ca—the most important competitive cations under soil conditions—was assessed, and a multisite ion exchange model has been applied to describe the change of the Cs-K selectivity coefficient as a function of the Cs loading. The relevance of the results in regard to the potential use of these zeolites as countermeasure amendments in radiocaesium-contaminated soils is discussed.