Huang Zhen, Xiong Chao, Ying Lingri, Wang Welong, Wang Shixing, Ding Jing, Lu Jianfeng
School of Materials Science and Engineering, Sun Yat-Sen University, Guangzhou 510006, PR China.
Fine Chemical Industry Research Institute, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, PR China.
J Hazard Mater. 2022 Jun 15;432:128700. doi: 10.1016/j.jhazmat.2022.128700. Epub 2022 Mar 15.
Lead ions in water have notorious effects on humans and environment. It is important to design an adsorbent with high adsorption capacity and reproducibility for efficiently removing Pb (II)ions from polluted water. Here, a novel Ti-based MOFs material (BDB-MIL-125(Ti)@FeO) was prepared by modifying NH-MIL-125(Ti) with sulfhydryl and amino groups. Due to the large number of active sites, the maximum Pb (II) adsorption capacity of BDB-MIL-125(Ti)@FeO was 710.79 mg/g at 25 °C and pH = 6 within 120 min corresponding to a maximum removal rate of 95.68%. The adsorbent also has extremely high selectivity and good cycling adsorption performance. The adsorption isotherms and kinetics agree with the Langmuir and the pseudo-second-order models, indicating that the process was chemisorption. Thermodynamic studies prove that spontaneous processes enhance Pb (II) adsorption at higher temperatures. DFT and FMOs calculations were used to discuss the adsorption mechanism. The sulfhydryl groups on the surface of organic ligands have a stronger affinity for Pb (II).
水中的铅离子对人类和环境有着不良影响。设计一种具有高吸附容量和可重复性的吸附剂，以有效去除污染水中的Pb (II)离子非常重要。在此，通过用巯基和氨基修饰NH-MIL-125(Ti)制备了一种新型的钛基金属有机框架材料（BDB-MIL-125(Ti)@FeO）。由于大量的活性位点，BDB-MIL-125(Ti)@FeO在25°C、pH = 6时，120分钟内对Pb (II)的最大吸附容量为710.79 mg/g，对应最大去除率为95.68%。该吸附剂还具有极高的选择性和良好的循环吸附性能。吸附等温线和动力学符合朗缪尔模型和准二级模型，表明该过程为化学吸附。热力学研究证明，自发过程在较高温度下增强了Pb (II)的吸附。采用密度泛函理论（DFT）和前线分子轨道（FMOs）计算来探讨吸附机理。有机配体表面的巯基对Pb (II)具有更强的亲和力。
