Highly porous, water stable metal–organic frameworks, MIL-100(Fe,Al), were investigated for the adsorptive removal of arsenates. Superb adsorption properties were exhibited with maximum adsorption capacities of as high as 116 mg g⁻¹ and 128 mg g⁻¹ for MIL-100(Fe) and MIL-100(Al), respectively. The arsenate adsorption capacities of MIL-100(Fe,Al) were much higher than those of previously reported Fe-based and Al-based nanomaterials or porous materials. Owing to the unsaturated metal sites and organic ligand species, three types of organic contaminants could be removed with fast adsorption kinetics. The organic dye molecules (10 mg L⁻¹ initial concentrations) could be rapidly removed by the MIL-100(Fe,Al) adsorbents with a removal efficiency of more than 80% in five minutes. The structural investigation of the adsorption behavior revealed that the guest molecules (arsenate or dye molecules) enter into the ordered mesopores of MIL-100(Fe,Al), and disrupt the long-range order of these uniform mesoporous channels. Electronic structure changes of the coordinative metal ions were investigated using X-ray photoelectron spectroscopy and Mössbauer spectroscopy to understand the interaction mechanism. The pore structure-occurring adsorption process of the Fe/Al-based MOFs is much more efficient than the traditional surface-occurring adsorption process, therefore the frameworks show good prospects for a variety of adsorptive separation applications.

中文翻译：

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介孔金属-有机骨架对水溶液中砷和有机污染物的吸附行为和结构转变†

研究了高度多孔，水稳定的金属有机框架MIL-100（Fe，Al）对砷的吸附去除。表现出极好的吸附性能，对于MIL-100（Fe）和MIL-100（Al）的最大吸附容量分别高达116 mg g ^-1和128 mg g ^-1。MIL-100（Fe，Al）对砷的吸附能力远高于以前报道的铁基和铝基纳米材料或多孔材料。由于不饱和金属位点和有机配体种类，可以快速吸附动力学去除三种类型的有机污染物。有机染料分子（10 mg L ^-1初始浓度）可以通过MIL-100（Fe，Al）吸附剂在五分钟内快速去除，去除效率超过80％。吸附行为的结构研究表明，客体分子（砷酸盐或染料分子）进入MIL-100（Fe，Al）的有序介孔中，并破坏了这些均匀介孔通道的长距离有序。使用X射线光电子能谱和Mössbauer光谱研究了配位金属离子的电子结构变化，以了解其相互作用机理。Fe / Al基MOF的孔结构吸附过程比传统的表面吸附过程有效得多，因此该框架在各种吸附分离应用中显示出良好的前景。