Quaternary phosphonium modified cellulose microsphere adsorbent for 99Tc decontamination with ultra-high selectivity

Abstract Decontamination of radioactive TcO4− 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 TcO4− 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 TcO4− adsorbents with an ultra-high selectivity, designated CMS-g-VBPPh3NO3. The prepared materials show adsorption capacities of 251 mg g-1 (for the surrogate Re). The selective factor against NO3− in 0.5 mol·kg-1 HNO3 is as high as 168, showing excellent anion-exchange selectivity towards TcO4−. Moreover, CMS-g-VBPPh3NO3 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 99mTc experiments showed that comparing to ReO4−, CMS-g-VBPPh3NO3 has a better adsorption selectivity for TcO4−.