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Bauxite wastes of alumina manufacture, z'.e., red muds, have been tested for radiocesium and strontium removal from water. The red muds were water-washed, acid-, and heat-treated before usage to produce hydrous oxide like sorbents. Surface treatment of the sorbent was benefical for 13'Cs uptake, while heat-treatment was detrimental to the -SOH surface sites responsible for high affinity. Fractionation of the sorbent with respect to apparent grain size did not produce significant differences in the sorption efficiency. The distribution coefficients US. equilibrium activity in solution showed a maximum with Cs, and a gradual decrease trend with Sr. The solution activity us. adsorption data were fitted to B.E.T. (essentially types IV-V) isotherms for Cs and B. E. T.-Langmuir isotherms for Sr. Desorption, temperature-, pH-, and ionic strength-dependence tests revealed that the primary mode of sorption for both cations is specific adsorption while the secondary mode is ion exchange. A rise in pH favours the ionexchange sorption of Sr while the specific adsorption of Cs is negatively affected. Competitive adsorption of an inert electrolyte, i.e., NaCI, severely hinders Cs sorption, while S r sorption on water-washed red mud is not significantly affected.

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