Fig. 4. (a) 29Si-NMR spectra of glasses, (b) 29Si-NMR spectra of dried gels G and G–Zr (c) 31P-NMR spectra of glasses. Dotted lines: least-square fitings.Figure optionsDownload full-size imageDownload as PowerPoint slide
The comparison of the ANA 12 of Qn species and the average number of bridging oxygens per tetrahedron between glasses G and G–Zr indicates a decrease in the average connectivity of the Si–O–Si network in the glass containing ZrO2. This result indicates proximal tubule Zr4+ ions are at least partially entering the glass network.
Because we observed a clear difference in the intensity of Si–NBO in the FTIR spectra of the dried gels G and G–Zr (Fig. 3a), we decided to perform a 29Si-NMR analysis of the dried gels as well. The 29Si-NMR spectra of the dried gels G and G–Zr are presented in Fig. 4b. The relative intensity of the Qn species, average numbers of Si–O–Si bridging oxygens and average chemical shifts are presented in Table 3.