Liquid-Phase Adsorption and Separation of Xylene Isomers by the Flexible Porous Metal-Organic Framework MIL-53(Fe)
Liquid-Phase Adsorption and Separation of Xylene Isomers by the Flexible Porous Metal-Organic Framework MIL-53(Fe)
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DOI：
10.1021/cm301242d
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发表时间：
2012-07-24
影响因子：
8.6
通讯作者：
Millange, Franck
中科院分区：
文献类型：
--
作者：
El Osta, Racha;Carlin-Sinclair, Abel;Millange, Franck
我们报道了一项使用多孔金属有机骨架材料MIL-53(Fe), Fe- iii (OH)(0.8)F-0.2[O2C-C6H4-CO2]分离BTEX混合物（苯、甲苯、乙苯和三种二甲苯异构体）的研究。三种主客体材料MIL-53(Fe)[二甲苯]的晶体结构，其中二甲苯=二甲苯的邻位异构体、间位异构体或对位异构体，已经从粉末x射线衍射中得到了求解和精炼。每一个都展示了一个充分扩展的形式，各种主人：客人和客人：客人的互动负责稳定结构。虽然邻位异构体和间位异构体在MIL-53宿主中具有相似的排列，但对二甲苯与宿主的相互作用却截然不同。热处理后，二甲苯部分丢失，形成MIL-53(Fe)[二甲苯]（0.5）晶相，其结构也得到了解析。用时间分辨能量色散x射线衍射研究了MIL-53(Fe)[H2O]对每个二甲苯的吸附动力学，其中水被有机来宾取代，这显示了三种异构体吸附动力学的差异。在293 K的正烷色谱条件下，无水MIL-53（Fe）能够先洗脱对二甲苯，再分离其他两种异构体，在323 K时，宿主能够分离BTEX混合物的所有组分。
We report a study of the use of the porous metal organic framework material MIL-53(Fe), Fe-III(OH)(0.8)F-0.2[O2C-C6H4-CO2], for the separation of BTEX mixtures (benzene, toluene, ethylbenzene, and the three xylene isomers). Crystal structures of the three host:guest materials MIL-53(Fe)[xylene], where xylene = the ortho, meta, or para isomer of dimethylbenzene, have been solved and refined from powder X-ray diffraction. Each exhibits a fully expanded form with a variety of host:guest and guest:guest interactions responsible for stabilizing the structure. While the ortho- and meta- isomers present a similar arrangement when occluded in the MIL-53 host, the para-xylene shows a distinctly different set of interactions with the host. Upon thermal treatment, xylenes are partially lost to give crystalline phases MIL-53(Fe)[xylene](0.5), the structures of which have also been solved. The kinetics of uptake of each xylene by MIL-53(Fe)[H2O], in which the water is replaced by the organic guest, have been studied using time-resolved energy-dispersive X-ray diffraction: this shows differences in kinetics of the adsorption of the three isomers. Under chromatographic conditions in heptane at 293 K, anhydrous MIL-53(Fe) is able to separate the three xylene isomers with elution of the para-xylene before the other two isomers, and at 323 K the host is able to resolve all components of the BTEX mixture.