Synthesis and characterization of porous 4VP-based adsorbent for Re adsorption as analogue to 99Tc

Technetium (99Tc), a major fission product in nuclear reactors, of high yield, long-half-life and high mobility in the environment must be removed in nuclear fuel reprocessing. Considering rhenium (Re) and Tc are both VIIB elements, Re is a good chemical analogue to 99Tc. Herein, we use Re as a substitution of 99Tc to study adsorption and desorption behavior. Porous 4-vinylpyridine-divinylbenzene-based (4VP-DVB) adsorbent containing tertiary amine groups is synthesized by suspension polymerization and characterized by BET, TGA, SEM and laser particle size analyzer. The adsorbent has high adsorption efficiency toward Re(VII) in 0.1 mol/L nitric acid solution, and the adsorption equilibrium can be achieved in 30 min. The adsorption kinetics of Re(VII) follows pseudo-second-order rate equation, the adsorption isotherm matches well with the Langmuir isotherm, and the adsorption capacity of Re(VII) on 4VP-DVB adsorbent is 352.1 mg/g at 298 K. Thermodynamic study reveals that the adsorption process is exothermic. This adsorbent is of separation convenience when a fixed-bed column is used, compared to the batch adsorption treatment.