Structure and ion exchange properties of tin antimonates with various Sn and Sb contents

Extensive series of tin antimonates were synthesized with a degree of Sn/Sb substitution from 0% to 100%. Metal chlorides were used as starting reagents, and the product materials were precipitated from the liquid phase by raising the pH of the solution using ammonia. The materials were characterized by means of powder X-ray diffractometry and thermogravimetry. The structures of rutile (P4(2)/mnm) for tin dioxide and pyrochlore (Fd3m) for antimony pentoxide were identified. The synthesized materials were categorized into rutile, pyrochlore and a mixture of these metal oxides, which helped the interpretation of earlier metal uptake results from the literature. The ion exchange properties of the synthesized materials were studied by measuring the distribution coefficients (K-d) for cobalt, and values as high as 652 000 and 602 000 ml/g from 0.1 M Ca(NO3)(2) and 0.1 M HNO3 solutions were obtained, respectively. (C) 2002 Elsevier Science Inc. All rights reserved.