The invention relates to processes and compositions for at least partially removing cations of one or more metals selected from the group consisting of caesium, strontium, lead, silver, transition metals, lanthanides and actinides from a liquid containing the cations. The process comprises contacting the liquid with a sorbent material in an amount and for a time sufficient to at least reduce the concentration of the cations, wherein the sorbent material is a metal oxide composition having the empirical formula A.sub.x/n[B.sub.yM.sub.1-yO.sub.3+.delta.].sup.x.ZH.sub.2O where M is one or more metals of Group Vb or VIb of the Periodic Table; A is a cation selected from the group consisting of alkali metals, alkaline earth metals, silver, ammonium, hydrogen and mixtures thereof; n is the charge on the cation A; B is one or more elements selected from the group consisting of W, Zr, Mo, V, Ti, Fe, Ce, Sb, Nb, Mn, Co, Cr, Fe, Ta, Sn and Cu, provided that M and B are different; x represents the quantity of framework charge; y is a number in the range of O to about 0.5; Z is a number in the range O to 3; and 3+.delta. indicates the oxygen stoichiometry. Preferably, y is greater than zero.