SORPTION OF TH FROM HCL SOLUTIONS ONTO PHOSPHATE CATION-EXCHANGERS

The sorption of Th (0.1 M) by the macroporous sulfonated polystyrene phosphate cation exchanger KFP-12 from 0.1-10 M HCl solutions is examined. The dependence of the sorption capacity of the cation exchanger for Th on the acidity is unusual. As the acidity is increased from 0.1 to 1-2 M. the sorptivity of Th decreases and then increases as the acidity is further increased. The equations and formulas for determining the composition of the Th compounds on the cation exchanger are found using the Donnan equation. In strongly acidic solutions, Th is absorbed by phosphate cation exchangers as chloride complexes and/or neutral molecules.