The surface interaction between WO42 ions and the alumina support in the 188W → 188Re/Al2O3 biomedical generator system was examined by the dynamic adsorption method employing the 187W tracer and by FT-IR, Raman, 27Al MAS NMR, and XPS spectroscopic methods. These studies demonstrated the complex physical and chemical nature of WO42- ion adsorption on alumina. The dynamic adsorption studies indicated that the adsorption process includes several stages from initial monolayer formation to almost complete saturation of the alumina surface. FTIR, Raman, and 27Al MAS NMR data showed that adsorption of WO42- on the Al2O3 surface in slightly acidic solutions proceeds via formation of thermodynamically stable complexes of tetrahedrally coordinated aluminum atoms and WO42- tetrahedrons. Previously, these complexes were shown to form, and were identified, only under calcination conditions. Our conclusion on the nature of WO42--Al2O3 complex in aqueous solutions was further supported by the results from XPS studies where it was shown that W-containing species are strongly attached to the surface of alumina via W-O bonds.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of physical chemistry|
|State||Published - Jul 6 1995|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry