National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming, 650093 Yunnan, China.
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093 Yunnan, China.
ACS Appl Mater Interfaces. 2023 Feb 1;15(4):5974-5989. doi: 10.1021/acsami.2c21546. Epub 2023 Jan 17.
The existence of lead ions seriously affects the quality of many metal products in metallurgical enterprises. Currently, the various methods of lead-ion removal tried by researchers will affect valuable metals in the removal process, thus resulting in low economic efficiency. In this study, a novel metal-organic framework adsorbent (UiO-FHD) which efficiently and selectively captures lead ions is developed by introducing multiple ligands. The maximum adsorption capacity of lead ions is 433.15 mg/g at pH 5. The adsorption process accords with the pseudo-second-order kinetic and the Langmuir isotherm models at room temperature. Thermodynamic experiments indicate that the removal of Pb(II) is facilitated by appropriate temperature reduction. The performance tests indicate that UiO-FHD maintains a high removal rate of 90.35% for Pb(II) after four consecutive adsorption-desorption cycles. The distribution coefficient of lead ions (26.7 L/g) shows that UiO-FHD has excellent selective adsorption for lead ions. It is revealed that the chelation of the sulfhydryl groups and the electrostatic interaction of the hydroxyl groups are the dominant factors to improve the removal rate of Pb(II) by density functional theory calculations. This study clarifies the value of self-designed novel organic ligands in metal-organic framework materials that selectively capture heavy-metal ions.
铅离子的存在严重影响冶金企业中许多金属产品的质量。目前，研究人员尝试的各种铅离子去除方法在去除过程中会影响有价值的金属，从而导致经济效益低下。在这项研究中，通过引入多种配体，开发了一种新型的金属有机骨架吸附剂（UiO-FHD），它可以高效、选择性地捕获铅离子。在 pH 值为 5 时，铅离子的最大吸附容量为 433.15mg/g。吸附过程符合室温下的拟二级动力学和朗缪尔等温线模型。热力学实验表明，适当降低温度有利于 Pb(II)的去除。性能测试表明，UiO-FHD 在连续 4 次吸附-解吸循环后，对 Pb(II)仍保持 90.35%的高去除率。铅离子的分配系数（26.7L/g）表明，UiO-FHD 对铅离子具有优异的选择性吸附。通过密度泛函理论计算表明，巯基的螯合作用和羟基的静电相互作用是提高 Pb(II)去除率的主要因素。本研究阐明了自行设计的新型有机配体在选择性捕获重金属离子的金属有机骨架材料中的价值。
