Efficient radon removal using fluorine-functionalized natural zeolite

Radon (Rn) can easily leak into the environment through groundwater owing to its high water solubility. Therefore, studying the chemical factors influencing the content and removal of Rn from groundwater is crucial for the evaluation and mitigation of its radiological risks to public health. In this study, we conducted a redundancy analysis (RDA) of Rn in groundwater and performed batch sorption experiments for efficient Rn removal from the groundwater collected from Daejeon using natural zeolite (NZ) and fluorine-functionalized natural zeolite (FFNZ) sorbents. The redundancy analysis revealed a positive correlation between the concentrations of Rn and fluorine (F) in groundwater, indicating that F can support the long-term retention of Rn in groundwater. NZ and FFNZ achieved ~40% and ~70% removal of Rn, respectively, following 24 h of treatment, indicating a significant impact of F (in FFNZ) toward Rn removal from groundwater. Based on the results, Rn is considered to interact with F through the van der Waals force, which limits the volatilization of Rn from the solution. Similarly, the fluorine-functionalized sorbent would interact preferentially with Rn, thereby enhancing its sorption and removal from groundwater.