Huang Lei, Yang Zhihui, Alhassan Sikpaam Issaka, Luo Zhixuan, Song Baocheng, Jin Linfeng, Zhao Yixian, Wang Haiying
School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China.
Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, PR China.
Environ Sci Ecotechnol. 2021 Sep 11;8:100123. doi: 10.1016/j.ese.2021.100123. eCollection 2021 Oct.
In this study, metal-organic framework MIL-53(Al) was synthesized and studied to understand the different mechanisms between normal MIL-53(Al) and 2D metal-organic framework MIL-53(Al) for removing fluoride. Comparatively, the 2D MIL-53(Al) had two-dimensional linear morphology rather than block shape, indicating more expose adsorptive sites than normal MIL-53(Al). The batch adsorption experiments were applied to investigate the performance of 2D MIL-53(Al), including pH, adsorption kinetics, and thermodynamics. The 2D MIL-53(Al) (75.50 mg/g) showed better adsorption capacity than normal MIL-53(Al) (35.63 mg/g). The adsorption process of 2D MIL-53(Al) followed the pseudo-first-order model and Langmuir model. The adsorption mechanism of this material was further studied by using experimental characterization and density functional theory calculations in detail. The main adsorptive sites were Al and O in the 2D MIL-53(Al), and the relationship between fluoride binding with Al and O was HF > HF > F. The species of fluoride were HF , HF, F at different pH and concentrations. Hence, this study provides a significant way on the application of two-dimensional materials for removing fluoride.
在本研究中，合成并研究了金属有机框架MIL-53(Al)，以了解普通MIL-53(Al)和二维金属有机框架MIL-53(Al)在去除氟化物方面的不同机制。相比之下，二维MIL-53(Al)具有二维线性形态而非块状，这表明其比普通MIL-53(Al)有更多暴露的吸附位点。采用批量吸附实验来研究二维MIL-53(Al)的性能，包括pH值、吸附动力学和热力学。二维MIL-53(Al)（75.50 mg/g）显示出比普通MIL-53(Al)（35.63 mg/g）更好的吸附容量。二维MIL-53(Al)的吸附过程遵循准一级模型和朗缪尔模型。通过实验表征和密度泛函理论计算详细研究了该材料的吸附机制。二维MIL-53(Al)中的主要吸附位点是Al和O，氟化物与Al和O结合的关系为HF ＞ HF ＞ F。在不同pH值和浓度下，氟化物的形态分别为HF 、HF、F。因此，本研究为二维材料在去除氟化物方面的应用提供了一条重要途径。
