Highly Efficient Extraction Chromatography Resin Containing Hexa-n-Octyl Nitrilotriacetamide (HONTA) for Selective Recovery of Plutonium from Acidic Feeds

An extraction chromatography resin was prepared by impregnating hexa-n-octyl nitrilotriacetamide (HONTA) on chromosorb-W. This resin shows very efficient performance for selective separation of Pu⁴⁺ over other actinides like uranium and americium. The distribution coefficient for Pu⁴⁺ (at 3 M HNO₃) was on the order of 10⁴ mL/g, with separation factors of >10³ for other actinides. The extraction kinetics for Pu⁴⁺ was slow and took 20 min of shaking for reaching the equilibrium conditions and followed both the film diffusion and the intraparticle diffusion kinetic models. The Pu⁴⁺ sorption on the resin followed the Langmuir monolayer model with a sorption energy of 11.2 kJ/mol. The maximum Pu⁴⁺ loading capacity on the resin was 58.2 mg/g resin, which corresponds to 1:1 Pu/ligand complex formation. Excellent column performance was observed for selective separation of Pu⁴⁺ from a mixture of Pu, Am, and U in a 3 M HNO₃ solution.