Composite polymeric beads containing N,N,N′,N′-tetraoctyldiglycolamide for actinide ion uptake from nitric acid feeds: Batch uptake, kinetic modelling and column studies

Polyethersulphone (PES) based composite polymeric beads (CPB) containing TODGA (N,N,N′,N′-tetraoctyldiglycolamide) as the extractant were prepared by conventional phase inversion technique and were tested for the uptake of actinide ions such as Am3+, UO22+, Pu4+, Np4+ and fission product ions such as Eu3+ and Sr2+. The CPBs containing 2.5-10 wt.% TODGA were characterized by various physical methods and their porosity, size, surface morphology, surface area and the degradation profile by thermogravimetry were analyzed. The batch uptake studies involved kinetics of metal ion sorption, uptake as a function of nitric acid concentration, kinetic modelling and adsorption isotherms and most of the studies involved the Am3+ ions. The batch saturation sorption capacities for Eu3+ loading at 3 M HNO3 were determined to be 6.6 ± 0.02, 9.1 ± 0.02 and 22.3 ± 0.04 mg g−1 of CRBs with 2.5 wt.%, 5 wt.% and 10 wt.% TODGA, respectively. The sorption isotherm analysis with Langmuir, D-R and Freundlisch isotherms indicated chemisorption monolayer mechanism. Chromatographic studies indicated breakthrough of Eu3+ (using a solution containing Eu carrier) after about 0.75 bed volume (3.5-4 mL). Elution of the loaded Eu was carried out using 0.01 M EDTA as the eluent.