Lin Yihui, Li Yuhan, Yang Yating, Chang Po-Hsiang
Department of Geography, Hanshan Normal University, Chaozhou 521041, China.
College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Int J Mol Sci. 2025 May 30;26(11):5298. doi: 10.3390/ijms26115298.
This study investigated strontium (Sr) adsorption by Taiwan Zhi-Shin bentonite (cation exchange capacity (CEC): 80-86 meq 100 g) using Sr(NO)-simulated nuclear waste. Kinetic analysis revealed pseudo-second-order adsorption kinetics, achieving 95% Sr removal within 5 min at pH 9. Isothermal studies showed a maximum capacity of 0.28 mmol g (56 meq 100 g) at 15 mmol L Sr, accounting for 65-70% CEC and fitting the Freundlich model. Cation exchange was the dominant mechanism (84% contribution), driven by Sr displacing interlayer Ca. Alkaline conditions (pH > 9) enhanced adsorption through improved surface charge and electrostatic attraction. Thermodynamic studies demonstrated temperature-dependent behavior: increasing temperature reduced adsorption at 0.01 mM Sr but increased efficiency at 10 mM. Na addition suppressed adsorption, aligning with cation exchange mechanisms. Molecular dynamics simulations identified hydrated Ca-Sr water bridges interacting with bentonite via hydrogen-bonding networks. The material exhibits rapid kinetics (5 min equilibrium), alkaline pH optimization, and resistance to ion interference, making it suitable for emergency Sr treatment. It shows promise as a cost-effective and good performing adsorbent for radioactive waste solutions.
本研究使用硝酸锶模拟核废料，研究了台湾致伸膨润土（阳离子交换容量（CEC）：80 - 86 毫当量/100 克）对锶（Sr）的吸附情况。动力学分析表明吸附过程符合准二级吸附动力学，在 pH 值为 9 时，5 分钟内可去除 95%的锶。等温线研究表明，在 15 毫摩尔/升的锶浓度下，最大吸附容量为 0.28 毫摩尔/克（56 毫当量/100 克），占阳离子交换容量的 65 - 70%，且符合 Freundlich 模型。阳离子交换是主要机制（贡献 84%），由锶取代层间钙所驱动。碱性条件（pH > 9）通过改善表面电荷和静电吸引增强了吸附作用。热力学研究表明吸附行为与温度有关：在 0.01 毫摩尔的锶浓度下，温度升高会降低吸附量，但在 10 毫摩尔时，温度升高会提高吸附效率。添加钠会抑制吸附，这与阳离子交换机制相符。分子动力学模拟确定了水合钙 - 锶水桥通过氢键网络与膨润土相互作用。该材料具有快速动力学（5 分钟达到平衡）、碱性 pH 优化以及抗离子干扰的特性，适用于紧急锶处理。它有望成为一种经济高效且性能良好的放射性废液吸附剂。
