Safe trapping of cesium into doping-enhanced pollucite structure by geopolymer precursor technique

Safe trapping of radioactive nuclear waste such as ¹³⁷Cs has become a grim issue with the popularity of nuclear power and the growing yield of nuclear waste. To address this intractable problem, pollucite has been screened out as an ideal material for the long-term storage of ¹³⁷Cs due to its low leaching rate and good chemical and thermal stability. With an effort to further enhance its immobilization capability and practical values, we herein report a robust route to prepare pollucite from ion-doped geopolymer at low temperature (≤1000 °C), achieving high Cs content (33.37 wt.%) and the lowest leaching rate of Cs (2.51 × 10^-4 g m^-2 d^-1) to date. Meanwhile, the leaching mechanism of Cs in pollucite is revealed via leaching tests coupled with SEM-EDS analysis. Therefore, this contribution may provide an alternative route to preparing pollucite and open up new possibilities in the immobilization of ¹³⁷Cs for real-world applications.