Iodine Capture Using Zr-Based Metal-Organic Frameworks (Zr-MOFs): Adsorption Performance and Mechanism
Iodine Capture Using Zr-Based Metal-Organic Frameworks (Zr-MOFs): Adsorption Performance and Mechanism
复制标题
使用 Zr 基金属有机框架 (Zr-MOF) 捕获碘：吸附性能和机制
DOI：
10.1021/acsami.0c02129
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发表时间：
2020-05-06
影响因子：
9.5
通讯作者：
Zhang, Wen
中科院分区：
文献类型：
--
作者：
Chen, Peng;He, Xihong;Zhang, Wen
有效捕获核相关活动产生或释放的放射性碘对核能的可持续发展至关重要。本文研究了一系列具有Zr-6（mu（3）-O）（4）（mu（3）-OH）（4）簇和各种羧酸酯连接体的锆基金属有机骨架（Zr-MOFs）对挥发性碘的捕获。研究了它们在干燥和潮湿环境中的吸附动力学和可回收性。利用X射线粉末衍射和孔结构测量研究了Zr-MOFs在碘捕获过程中的结构变化。实验光谱（拉曼和X-射线光电子能谱）和密度泛函理论（DFT）计算的链接器和锆簇进行理解的捕获机制的框架。当与碘分子相互作用时，具有高度连接和/或刚性接头的M0 F-808、NU-1000和Ui 0 -66具有比具有较少连接性的柔性接头的Ui 0 -67和M0 F-867更好的结构稳定性。特别地，具有刚性和三位苯三羧酸酯连接基的M0 F-808具有最高的碘吸附容量（2.18g/g，80 ° C），以及碘洗脱后的最大孔体积。相比之下，具有长线性双位连接基的UiO-67由于其最严重的孔结构崩溃而表现出最弱的稳定性和最低的吸附容量（0.53 g/g，80 ℃）。加入强给电子的咪唑/吡啶配体后，MOF-808/NU-1000的稳定性和吸附容量均有所下降。密度泛函理论计算证实了氮杂环基团通过强电荷转移增强了对碘的亲和力。DFT计算还表明，MOF-808中的末端-OH对碘（-54 kJ/mol（-1））和水（-63 kJ/mol H2O）具有强亲和力，对NO2（-27 kJ/mol NO2）具有弱亲和力。MOF-808具有较高的吸附容量和良好的稳定性，在可持续去除放射性碘方面显示出巨大的潜力。
The effective capture of radioiodine, produced or released from nuclear-related activities, is of paramount importance for the sustainable development of nuclear energy. Here, a series of zirconium-based metal-organic frameworks (Zr-MOFs), with a Zr-6(mu(3)-O)(4)(mu(3)-OH)(4) duster and various carboxylate linkers, were investigated for the capture of volatile iodine. Their adsorption kinetics and recyclability were investigated in dry and humid environments. The structural change of Zr-MOFs during iodine trapping was studied using powder X-ray diffraction and pore structure measurements. Experimental spectra (Raman and X-ray photoelectron spectroscopy) and density functional theory (DFT) calculations for the linkers and Zr clusters were performed to understand the trapping mechanism of the framework. When interacting with iodine molecules, MOF-808, NU-1000, and UiO-66, with highly connected and/or rigid linkers, have better structural stability than UiO-67 and MOF-867, which have flexible linkers with less connectivity. Particularly, MOF-808, with a rigid and tritopic benzenetricarboxylate linker, has the highest iodine adsorption capacity (2.18 g/g, 80 degrees C), as well as the largest pore volume after iodine elution. In contrast, UiO-67, with long linear ditopic linkers, exhibits the weakest stability and lowest adsorption capacity (0.53 g/g, 80 degrees C) because of its most serious collapse of pore structures. After incorporating with strong electron-donating imidazole/pyridine ligands, both the stability and adsorption capacity of MOF-808/NU-1000 decrease. DFT calculations verify that the N-heterocycle groups could enhance the affinity toward iodine by strong charge transfer. DFT calculations also suggest that the terminal -OH in MOF-808 has a strong affinity toward iodine (-54 kJ/mol(-1)) and water (-63 kJ/mol H2O) and a weak affinity toward NO2 (-27 kJ/mol NO2). With high adsorption capacity and excellent stability, MOF-808 shows great potential for the sustainable removal of radioiodine.