Tin antimonates of different structure were studied for their uptake of cobalt and nickel in the decontamination of floor drain water and neutral bond water simulates. Selectivity was observed to vary with the structures and degree of crystallinity of the tin antimonates (pyrochlore, rutile, and mixed metal oxides). High selectivity for cobalt of exchangers with pyrochlore structure is attributed to ion exchange of cobalt inside the tunnel structure; nickel uptake evidently took place mostly at the outer surfaces of the materials. Electrostatic forces governed the ion exchange of rutile tin antimonates owing to their particle hydrate structure. With some limitation, the prediction of nickel uptake on tin antimonates from the more abundant cobalt uptake data is considered possible.