Towards high-performance Cs and Sr removal via A coral-like dimethylamine-directed manganese thiostannate: Experimental and DFT calculations
Liqi Liu# , Deyun Sun# , Chi Ma, Shangqing Chen* , Yafei Guo , Tianlong Deng*
Chemical Engineering Science https://doi.org/10.1016/j.ces.2025.121833
Abstract
The efficient removal of 137Cs and 90Sr from complex aqueous solutions remains a critical challenge in environmental remediation. Herein, we present a unique coral-like dimethylamine-directed manganese thiostannate ion exchanger (MTIE) via a facile one-pot solvothermal method. Kinetic studies demonstrated ultrafast ion exchange within 10 min, and the Langmuir isotherm model revealed exceptional adsorption capacities of 248.8 mg/g for Cs+ and 144.2 mg/g for Sr2+. DFT calculations provided atomic-level insights into the adsorption mechanism, revealing lower incorporation energies for Cs+ (− 3.63 eV) and Sr2+ (− 2.79 eV) compared to competing ions, and reduced band gaps that facilitate efficient electron transfer. The adsorption mechanism was identified as a combination of ion exchange and Cs/Sr…S interactions, with characteristic bond distances of 3.03 Å and 3.10 Å. Furthermore, MTIE demonstrated excellent selectivity and recyclability after five regeneration cycles. These findings highlight the potential of MTIE as a practical and efficient solution for radioactive wastewater treatment.
从复杂的水溶液中高效去除 ¹³⁷Cs（铯-137） 和 ⁹⁰Sr（锶-90） 仍是环境修复领域面临的一项重大挑战。本文中，我们通过一种简便的一锅法溶剂热合成方法，制备出了一种独特的珊瑚状二甲胺导向的硫代锡酸锰离子交换剂（MTIE）。动力学研究表明，在 10分钟内即可实现超快离子交换，而基于 Langmuir等温吸附模型 的分析显示，该材料对 Cs⁺ 和 Sr²⁺ 的最大吸附容量分别高达 248.8 mg/g 和 144.2 mg/g。密度泛函理论（DFT）计算从原子层面揭示了其吸附机制：相比竞争离子，Cs⁺ 和 Sr²⁺ 的掺入能更低（分别为 −3.63 eV 和 −2.79 eV），且带隙减小，有利于高效的电子转移。吸附机制被确定为 离子交换作用与 Cs/Sr···S 相互作用 的结合，并具有特征键长距离（分别为 3.03 Å 和 3.10 Å）。此外，MTIE 在经历五次再生循环后仍展现出优异的选择性和可重复使用性。这些结果表明 MTIE 在放射性废水处理中具有广阔的应用前景，是一种实用且高效的解决方案。
