Exploring Mongolian natural zeolites as effective adsorbents for radioactive Cs and Sr.

The types and contents of minerals contained in natural zeolites vary depending on the production conditions. As a result, the adsorption properties of natural zeolites also vary depending on the production area. To utilize natural zeolites as adsorbents in various fields, it is crucial to identify the adsorption properties based on the type and content of minerals they contain. Therefore, this study aimed to analyze the adsorption characteristics of Cs and Sr using six types of natural zeolites from Mongolia (M-1, M-2, M-3, M-4, M-5, and M-6) to determine their potential as radioactive waste treatment agents. The experiments conducted showed that the adsorption equilibrium for Cs and Sr was reached within 4 and 8 h., respectively. Among the six samples, M-2 and M-6 exhibited relatively high adsorption rates, with Cs adsorption rates of 80% and 84%, and Sr adsorption rates of approximately 18% and 21%. Furthermore, the single-component isothermal adsorption experiments demonstrated that all six samples followed the Langmuir model. The maximum adsorptions of Cs was highest in M-2 (154.7 mg/g), M-4 (148.8 mg/g), and M-6 (150.2 mg/g) respectively. Additionally, the maximum adsorptions of Sr for M-2 and M-6 were 29.66 and 33.67 mg/g, respectively. It was observed that the natural zeolite with a higher content of 8-ring in the framework and higher CEC exhibited greater selectivity for Cs compared to the other six natural zeolites. Therefore, the maximum adsorption of Cs was attributed to the high total content of 8-rings in the natural zeolite framework, as well as the cation exchange capacity (CEC). [ABSTRACT FROM AUTHOR]