School of Water Resources & Environmental Engineering, East China University of Technology, Nanchang, 330013, China.
State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, 330013, China; School of Water Resources & Environmental Engineering, East China University of Technology, Nanchang, 330013, China.
J Environ Radioact. 2023 Dec;270:107305. doi: 10.1016/j.jenvrad.2023.107305. Epub 2023 Oct 17.
Human activities such as mining uranium resources, hydrometallurgy, and nuclear fuel preparation inevitably produce wastewater sludge containing radionuclides, posing a severe threat to the environment around the production site. Natural clay minerals have been widely used in groundwater pollution remediation because of their high cation exchange capacity. Through static batch experiments, the optimal pH range of vermiculite for U(VI) adsorption was 6-8,the maximum adsorption capacity was 1.62 × 10 mol g. The kinetic adsorption results indicated that the adsorption mode was mainly multilayer non-homogeneous chemisorption. In addition, the adsorption of vermiculite on U(VI) was found to be a heat absorption process according to the thermodynamic model fitting, and the spontaneous reactivity of U(VI) adsorption on vermiculite surface was positively correlated with temperature and negatively correlated with the initial concentration of U(VI). Combined with SEM-EDS and FT-IR results, the adsorption process of vermiculite on U(VI) is mainly an ion exchange and complexation reaction, and U(VI) is removed in the form of ≡ SUOU2 or ≡ SOUOOH, etc., by XPS means. The results of this study not only investigated the adsorption behavior and mechanism of natural vermiculite in groundwater contaminated with simulated uranium but also provided theoretical support for its feasibility in remediating uranium-polluted groundwater.
人类活动，如铀资源开采、湿法冶金和核燃料制备，不可避免地会产生含有放射性核素的废水污泥，对生产现场周围的环境构成严重威胁。由于天然粘土矿物具有高阳离子交换能力，因此已被广泛应用于地下水污染修复。通过静态批量实验，发现蛭石吸附 U(VI) 的最佳 pH 范围为 6-8，最大吸附容量为 1.62×10-3mol/g。动力学吸附结果表明，吸附模式主要为多层非均相化学吸附。此外，根据热力学模型拟合，发现蛭石对 U(VI) 的吸附是一个吸热过程，并且 U(VI)在蛭石表面的吸附自发性与温度呈正相关，与 U(VI)的初始浓度呈负相关。结合 SEM-EDS 和 FT-IR 结果，蛭石对 U(VI)的吸附过程主要是离子交换和络合反应，通过 XPS 手段以≡SUOU2 或≡SOUOOH 等形式去除 U(VI)。本研究的结果不仅考察了天然蛭石在模拟铀污染地下水中的吸附行为和机制，而且为其修复铀污染地下水的可行性提供了理论支持。
