Evaluation models of inorganic solids as separation and containment media

摘要

Several evaluation models of inorganic solids have been reviewed for their extent of validity. They include use of the corrected selectivity coefficients (CSC), Langmuir's equation, power-exchange function, Vanselow's equation, and others. Use of the CSC plot allows calculation of the isotherm and the distribution coefficient as functions of the total charge concentration of solution phase and ratio of solid weight to solution volume. Langmuir equation is a modification of the CSC. Other models are simplified forms of the CSC plot. Activity coefficients are crucial to calculate the CSC values. Unfortunately, they are not available for actinides and hence the ion-exchange process cannot be predicted as a function of the charge fraction in solid and solution phases. Low distribution coefficients often observed on clay minerals may include electrolyte absorption or invasion into solids. Their chemical bond states of ionic species could be clearly distinguished from each other by using the MASNMR.