Highly efficient Cesium ion adsorption using KNbSnS: A DFT-guided approach for wastewater treatment

Abstract

Cesium (Cs) contamination, particularly from nuclear waste, poses significant environmental and health risks due to its high solubility and mobility in water. The development of effective adsorbent materials to remove Cs⁺ contamination from wastewater is crucial. In this study, we designed and investigated a series of open-framework metal-sulfur ion-exchange materials (KMSnS, where M = Co, Mg, Nb, Zn) using density functional theory (DFT). The goal was to identify materials with high affinity for cesium ions. DFT calculations revealed that among the studied materials, KNbSnS exhibits superior affinity for Cs⁺, and its adsorption mechanism was thoroughly examined from a microscopic perspective, including adsorption spontaneity. KNbSnS was successfully synthesized through a hydrothermal method and applied to simulated wastewater treatment to evaluate its practical performance. The synthesized material demonstrated outstanding adsorption capacity, with a maximum value of 457.58 mg·g⁻¹. More importantly, KNbSnS maintained its high performance over 10 adsorption–desorption cycles, making it a promising candidate for sustainable cesium ion removal in real-world applications. This research not only provides a theoretical and experimental basis for the development of KNbSnS as a cesium ion adsorbent but also highlights its potential for large-scale applications in wastewater treatment, particularly in mitigating radioactive contamination. The results have significant implications for environmental protection, particularly in the context of nuclear waste management and the remediation of contaminated water bodies.