Quaternary phosphonium modified cellulose microsphere adsorbent for Tc decontamination with ultra-high selectivity.

Decontamination of radioactive TcO from nuclear wastes is increasingly crucial for spent nuclear fuel reprocessing and environmental remediation. In the presence of a large excess of competitive anions, the selective separation of TcO is a major challenge for adsorbents. Herein, by using pre-radiation induced grafting polymerization, we have modified economical and environmentally friendly cellulose microspheres to obtain quaternary phosphonium decorated TcO adsorbents with an ultra-high selectivity, designated CMS-g-VBPPhNO. The prepared materials show adsorption capacities of 251 mg g (for the surrogate Re). The selective factor against NO in 0.5 mol kg HNO is as high as 168, showing excellent anion-exchange selectivity towards TcO. Moreover, CMS-g-VBPPhNO was packed in column for treating simulated acidic waste solutions containing Cs, Sr, Eu, Zr, Ru, U and Re, and it showed excellent Re separation performance. Tracer amount of Tc experiments showed that comparing to ReO, CMS-g-VBPPhNO has a better adsorption selectivity for TcO.