Zhang Yi, Guo Weidong, Liu Donghao, Ding Yigang
Key Laboratory of Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Hubei Key Laboratory for Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, Wuhan 430073, China.
ACS Appl Mater Interfaces. 2023 Apr 5;15(13):17233-17244. doi: 10.1021/acsami.3c00938. Epub 2023 Mar 24.
The recovery of rare earth elements (REEs) from discharged electronic devices or mineral waste water is highly essential but still facing challenges. In this work, two amino-functionalized carboxyl-UiO-66 (UiO-66-COOH-TETA and UiO-66-(COOH)-ED) prepared via the postmodification method were employed as the adsorbents for Yb(III) capture. The experimental results revealed their superior adsorption capacities of 161.5 and 202.6 mg/g, respectively. Meanwhile, their adsorption processes can be described by the pseudo-second-order kinetic model and Langmuir model. Effects of initial pH and temperature on adsorptions were systematically evaluated, affording an optimal operating condition (i.e., pH of 5.5-6, of 65 °C, of 10 h). Moreover, the fabricated materials exhibited great reusability after five adsorption-regeneration cycles. UiO-66-COOH-TETA demonstrated good separation selectivity for Yb(III) over light REEs (i.e., 3.98 of Yb/Ce, 3.51 of Yb/Nd). Based on the density functional theory calculations and characterization analysis (XPS, Zeta, mapping, and IR), the adsorption mechanisms were mainly attributed to significant electrostatic attraction and strong surface complexation between N and O sites and Yb(III).
从废弃电子设备或矿物废水中回收稀土元素（REEs）至关重要，但仍面临挑战。在这项工作中，通过后修饰法制备的两种氨基功能化羧基-UiO-66（UiO-66-COOH-TETA和UiO-66-(COOH)-ED）被用作吸附剂来捕获Yb(III)。实验结果表明它们的吸附容量分别高达161.5和202.6 mg/g。同时，它们的吸附过程可用准二级动力学模型和朗缪尔模型来描述。系统评估了初始pH值和温度对吸附的影响，得出了最佳操作条件（即pH值为5.5 - 6、温度为65 °C、时间为10 h）。此外，制备的材料在经过五个吸附-再生循环后表现出良好的可重复使用性。UiO-66-COOH-TETA对Yb(III)表现出优于轻稀土元素的良好分离选择性（即Yb/Ce为3.98，Yb/Nd为3.51）。基于密度泛函理论计算和表征分析（XPS、Zeta电位、元素分布图和红外光谱），吸附机制主要归因于N和O位点与Yb(III)之间显著的静电吸引和强烈的表面络合作用。
