Selective separation of Pu(IV) from nitric acid media using a novel silica-polymer based adsorbent NTAamide(C8)/SiO2-P

NTAamide(C8) exhibits high selectivity for the extraction of Pu(IV) across a wide range of nitric acid concentrations. To separate trace Pu(IV) from radioactive liquid stream generated during the PUREX process in spent nuclear fuel reprocessing, a novel silica-polymer-based adsorbent, NTAamide(C8)/SiO 2 -P, was synthesized via vacuum impregnation using NTAamide(C8) as the extractant and SiO 2 -P as the support. The adsorption performance of Pu(IV) were systematically evaluated. Batch experiments revealed that adsorption equilibrium was achieved within 2 h, with a maximum adsorption capacity of 143.2 mg/g for Pu(IV). The material demonstrated high selectivity for Pu(IV) and exhibited excellent radiation resistance and hydrolytic stability. The adsorption mechanisms were further elucidated using X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations, confirming the formation of 1:1 complexes between NTAamide(C8) and the metal ions. Column experiments using actual uranium product solution from the PUREX process verified the material's performance in trace Pu(IV) removal. After column treatment, the Pu content in the uranium product solution was reduced to below 10 Bq/gU, with no significant loss of uranium. These results demonstrate that NTAamide(C8)/SiO 2 -P is a promising adsorbent for the efficient and selective separation of Pu(IV) from radioactive liquid stream under a wide range of nitric acid concentrations.