The uptake of Sr-85, Cs-134 and Co-57 on a framework sodium titanosilicate of an ideal formula Na2Ti2O3(SiO4) (.) 2H(2)O was investigated. Samples of varying crystallinity were synthesized and this effect on cation affinity was studied. The material exhibited high affinity for cesium in slightly acidic to alkaline solutions, but potassium and the presence of sodium at high pH interfered significantly with selective Cs-134 uptake. The weakly acidic exchanger took up Sr-85 and Co-57 efficiently above neutral pH in 0.1 M NaNO3. The crystallinity of the material proved to be an important factor in efficient removal of Sr-85 from calcium bearing effluents. The semi-crystalline titanosilicates had a high affinity for Sr-85 over Ca2+ at neutral pH. The affinity for cesium in the presence of potassium was improved as well in samples of lower crystallinity. (C) 2002 Elsevier Science B.V. All rights reserved.