UiO-66-(COOH)2的合成及其对锂同位素吸附分离性能研究

为研究金属有机骨架材料对⁷Li的吸附分离性能，本研以水作为溶剂，四氯化锆和均苯四甲酸为起始原料，采用水热法合成金属有机骨架材料UiO-66-(COOH)₂，对合成材料的形貌、孔径、热稳定性等进行表征与分析；通过静态吸附实验探讨吸附时间、反应温度、溶液浓度对UiO-66-(COOH)₂锂离子吸附性能及同位素分离因子的影响；并对Li⁺浓度、⁶Li/⁷Li同位素丰度进行测定。结果表明，UiO-66-(COOH)₂可实现对锂的吸附以及⁷Li的分离，且在293 K Li₂CO₃溶液中，每0.05 g UiO-66-(COOH)₂对10 mL 0.05 mol/L Li₂CO₃进行4 h的静态吸附，最大吸附量Q为9.53 mg/g，分离因子S（⁷Li/⁶Li）为1.019 54。研究结果为⁷Li的分离提供了新途径。

Synthesis and Study of UiO-66-(COOH)2 on Adsorption and Separation Properties of Lithium Isotopes

Metal-Organic Framework Material UiO-66-(COOH)₂ was synthesized from zirconium tetrachloride and pyromellitic acid by hydrothermal method, and first performed experimental study on the adsorption and separation of lithium isotopes. The morphology, aperture and thermal stability of UiO-66-(COOH)₂ were confirmed by X-ray diffraction analysis(XRD),scanning electron microscope (SEM), automatic specific surface area analysis (BET) and thermogravimetric analysis (TG). The effects of different conditions (time, temperature, concentration of lithium ions) on adsorption properties and separation in the static adsorption experiments were discussed. The concentration of Li and the isotope abundance of ⁶Li/⁷Li were determined separately using inductively coupled plasma optical emission spectrometer (ICP-OES) and multi-channel receiving inductively coupled plasma mass spectrometer (MC-ICP-MS). The results demonstrated that UiO-66-(COOH)₂ achieves lithium adsorption and the separation of lithium-7, performs static adsorption of 0.05 mol/L Li₂CO₃ at 10 mL, per 0.05 g of UiO-66-(COOH)₂ at 293 K, Li₂CO₃ solution for 4 hours. The maximum adsorption quantity (Q) was 9.53 mg/g, and the separation factor S(⁷Li/⁶Li) was 1.019 54. The results provide a new method for the separation of ⁷Li.