Sorption Modelling of Th(IV), Np(IV), and Np(V) on Illite and Montmorillonite

Abstract

Sorption of Np(IV) and Np(V) on illite and montmorillonite were studied using PHREEQC by reproducing the 2SPNE SC/CE model with Th(IV) sorption edges, and using experimental sorption measurements to optimize the SCCs and test LFERs. The model was not effective for all ranges of I and pH, and needs improvement with the addition of CE and electrostatic interactions. The LFERs do not account for all illite and montmorillonite soils, and relies too heavily on the availability and accuracy of HCs. Further research is required to develop accurate sorption models for all soils at a wide range of pH and I.