Borosilicate glasses with barium oxide modifier BBS [(Na₂O)_0.143(B₂O₃)_0.268(SiO₂)_0.473(BaO)_0.116] and without modifier SBS [(Na₂O)_0.162(B₂O₃)_0.303(SiO₂)_0.535] were used for the uptake of uranyl ion. The amount of metal ion taken up is expressed in terms of Kd which is a ratio of concentraiton of metal ion in solid to that left behing in solution. variation of Kd value with metal ion concentration for both SBS and BBS glass samples shows that the presence of BaO modifier (in BBS sample) improves the efficiency of metal ion uptake to a great extent. The variation of equilibration time at a fixed uranyl ion concentration showed that the Kd values increased to a maximum value after 24 h Therefore, all equilibrations were carried out for 24 h. It is seen that for uranyl ion, the Kd value increases a maximum at a concentration of 0.01 M (2380 ppm) and then decreases, This could be due to the fact that with increase in the sorbate concentration in solution, there is an increase in the amount left behind in solution after equilibration and this factor affects the value of Kd. The difference in ion exchange behaviour between the two glass samples could be due to the difference in the number of non-bridging oxygen atoms present as revealed by ¹¹B and  ²⁹ Si MAS NMR studies. ²⁹ Si MAS NMR patterns revealed the addition of BaO as modifier (BBS) results in the increase in the concentration of the Q³ structural units containing more non-bridging oxygen atoms. ¹¹B MAS NMR patterns revealed that BBS contain only one sharp peak around –22 ppm, characteristic of the tetrahedrally coordinated boron (BO₄)^- structural units whereas for SBS, in addition to the sharp peak at –22ppm, a broad peak characteristic of trigonally coordinated boron (BO₃) structural units is observed. The (BO₄)^– structure is charge neutralized by Na+ ion. From ¹¹B and ²⁹Si MAS NMR studies, it is established that increase in the Si-O--Na⁺ and B-O- Na⁺ results in the higher exchange capacity of BBS.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/10793 must be provided.

1. Effect of composition on ion exchange property of glasses