Sorption and desorption performance of La3+/Bi3+ by surface-modified activated carbon for potential application in medical 225Ac/213Bi generators

[Display omitted] •Efficient separation of La3+/Bi3+ by surface-modified activated carbonmaterials.•Large differences in La3+/Bi3+ sorption onto the sorbents can be achieved.•Bi3+ can be desorbed by halide ions from sulfonated activated carbon materials.•The sorbents show potential for use in inverse 225Ac/213Bi radionuclide generators. 213Bi is a promising candidate for targeted alpha therapy.However, the search for suitable materials to separate clinically relevant activities of 213Bi from its parent 225Ac remains an ongoing yet critical challenge. This study evaluates sulfonated Norit CA1 (activated carbon) materials (SNCAs) as alternative sorbents for use in 225Ac/213Bi radionuclide generators and gives an overview of their simultaneous sorption/desorption performance towards La3+ and Bi3+. The SNCAs exhibit high and selective uptake of Bi3+ in the presence of NaNO3 at low pH values. In contrast, the sorption performance for La3+ (which was certified as a non-radioactive surrogate for 225Ac3+) onto SNCAs was more sensitive to the salt concentrations and pH values. The desorption results show that an efficient elution of Bi3+ from SNCAs is achieved using HCl, NaI or NaCl solutions. The experimental sorption data are analysed by various kinetic and isotherm models. The SNCAs exhibit high radiolytic stability, fast sorption kinetics, good durability and recyclability for La3+/Bi3+. This research indicates that SNCAs with sufficient oxygen-containing groups are promising sorbents for the separation of 213Bi in an inverse 225Ac/213Bi radionuclide generator.