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

Automated summary

213Bi is a promising candidate for targeted alpha therapy, but finding suitable materials to separate it from its parent 225Ac is an ongoing challenge. This study evaluates sulfonated activated carbon (SNCAs) as alternative sorbents for use in radionuclide generators and finds that SNCAs have high and selective uptake of Bi3+. Different elution solutions can efficiently extract Bi3+ from SNCAs. This research suggests that SNCAs with sufficient oxygen-containing groups are promising sorbents for the separation of 213Bi in an inverse 225Ac/213Bi radionuclide generator.