Predicting iodine solubility at high pressure in borosilicate nuclear waste glasses using optical basicity: an experimental study

Constraining the systematic evolution of iodine solubility in borosilicate glasses is required for formulation adequate glass matrices able to immobilize 129I representing a major troublesome radioisotopes produced by nuclear anthropic activities. We investigated experimentally change large series synthesized under high-pressure conditions (1.5 GPa) and at 1350 °C. The nature network modifying cation (Na, K, Rb, Ca, Ba Sr) concentration B2O3 (~ < 10 mol.% ~ > mol.%) have been tested. XPS measurements showed that speciation mostly represented iodide (I−) range from 0.3 3.1 as determined SEM EDS LA-ICP-MS analyses. enhanced with lower content higher cation. Regardless nature: alkali or alkaline-earth; increasing size appears induce decrease solubility. used optical basicity (ΛGlass) iono-covalent parameter (ICPGlass) express variety compositions; both relating electron donor capability glass. show positively correlated ΛGlass accordingly negatively ICPGlass. It implies more will be dissolved compositions having stronger electron-donating capability. Evidence relationship between oxygen shown positive trend equilibrium constant speciation. Future work should take these parameters into consideration modeling providing additional information are collected such boron, aluminum silicon glasses.