Removal of strontium and cesium from soil using ion-based washing agents with similar hydrated radii

The environmental hazards associated with nuclear power plants, specifically the release of fission byproducts such as strontium (Sr) and cesium (Cs) are highlighted for their harmful attributes, even in non-radioactive forms owing to their physicochemical characteristics and potential health risks. Sr and Cs exhibit significant physicochemical resemblances to calcium (Ca) and potassium (K), respectively. These similarities are so pronounced that the human body often confuses Sr and Cs with Ca and K, leading to their accumulation. This accumulation can give rise to detrimental health conditions, including leukemia, thyroid cancer, bone marrow cancer, and general paralysis. In this study, a soil washing method was employed to eliminate Sr and Cs contaminants from the soil. We hypothesize that the efficiency of Sr and Cs removal is influenced by the resemblance in physicochemical properties. Physicochemical properties such as atomic radius, hydrated radius, electronegativity, and electron affinity of Sr, Cs, Na, Mg, K, Ca, Ba, and Al were carefully studied and summarized for the investigation. Subsequently, solutions with Na, Mg, K, Ca, Ba, and Al at concentrations of 0.1 and 0.01 M, with a pH of 7, were tested for their efficacy in removing Sr and Cs from the soil. The results showed that the greater similarity in hydrated radius between heavy metals and ions appears to be responsible for increased removal efficiencies. For example, both Ca and Sr share the same hydrated radius of 0.412 nm. Interestingly, Ca exhibited the highest efficiency in removing Sr compared to Na, K, Mg, Ba, and Al. Additionally, Ba, with a hydrated radius of 0.404 (the second closest to Sr), demonstrated the second-highest efficiency in Sr removal. Examining results for other heavy metals (i.e., Cd, Co, Cu, Ni, Pb, and Zn), a heightened resemblance in hydrated radii between the heavy metal and ion corresponded to increased removal efficiency, indicating a strong positive correlation. Overall, this study contributes valuable insights into effective strategies for mitigating the environmental impact of nuclear power plant activities on soil contamination.