A newly developed selective grafted resin for radium

Radium analysis in natural waters remains a current challenge in the field of radiological monitoring, as well as for environmental concerns. A new Ra-selective grafted resin was developed in the present work; a calix[4]arene derivative functionalized with a crown-6 ether and two synergistic carboxylic groups serves as the selective chelating agent, while the support consists of SiO 2 . Its properties were investigated in the laboratory by coupling experimental data with a modelling approach. The resin was shown to be efficient for Ra within the pH range typical of natural waters (∼6–8). Its affinity for Ra was significantly higher than for other alkaline earth cations, although it remained sensitive to salt loading. This trend was confirmed by batch sorption tests conducted with both synthetic aqueous media and various natural water samples. The proposed resin appears promising for radium extraction and pre-concentration from natural waters.