Sol-Gel Synthesis of High-Density Zeolitic Imidazolate Framework Monoliths via Ligand Assisted Methods: Exceptional Porosity, Hydrophobicity, and Applications in Vapor Adsorption
Sol-Gel Synthesis of High-Density Zeolitic Imidazolate Framework Monoliths via Ligand Assisted Methods: Exceptional Porosity, Hydrophobicity, and Applications in Vapor Adsorption
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DOI：
10.1002/adfm.202102716
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发表时间：
2020-10-29
影响因子：
19
通讯作者：
Williams, Daryl R.
中科院分区：
文献类型：
--
作者：
Hunter-Sellars, Elwin;Saenz-Cavazos, Paola A.;Williams, Daryl R.
采用新型配体辅助方法在室温下合成整体 ZIF-8 和 ZIF-67 吸附剂。尽管某些样品的结晶度降低，但由于密度增加，整体式沸石咪唑酯骨架（ZIF）相对于其颗粒对应物具有优异的体积相对微孔率、总孔隙率和表面积。使用单一调节剂正丁胺合成的样品具有分级孔隙率，从而提高了中高吸附压力区域的吸附能力。通过混合调节剂合成、正丁胺和 1-甲基咪唑生产的 ZIF-67 整体材料几乎完全是微孔的。蒸气吸附等温线发现，虽然其无定形含量导致吸水量增加，但整体 ZIF 比传统非极性吸附剂具有更高的表面和吸附疏水性。在潮湿条件下对常见 VOC 甲苯进行的共吸附测量发现，这些整体式 ZIF 样品的性能优于粉末同类产品，与所研究的粉末 ZIF 相比，混合调制器 ZIF-67 整体式样品由于其卓越的体积效率，多捕获 28% 的 VOC。这项研究提供了对整体 ZIF 内基于调制器的孔隙率调节的好处的见解，结合其疏水性，可以促进其在工业有机蒸汽回收或室内空气净化中的应用，在这些领域中，可以在潮湿环境中运行的高效疏水吸附剂至关重要。
Monolithic ZIF-8 and ZIF-67 adsorbents are synthesized at room temperature using a novel, ligand-assisted method. Despite reductions in crystallinity within some of the samples, monolithic zeolitic imidazolate frameworks (ZIFs) have superior volume-relative microporosity, total porosity, and surface areas relative to their particulate counterparts due to increased density. Samples synthesized using a single modulator, n-butylamine, have a hierarchical porosity resulting in improved adsorption capacities in mid- to high- sorbate pressure regions. ZIF-67 monoliths produced through mixed-modulator synthesis, n-butylamine and 1-methylimidazole, are almost entirely microporous. Vapor adsorption isotherms find that, whilst their amorphous content results in increased water uptake, monolithic ZIFs are found to possess higher surface and adsorption hydrophobicity than traditional non-polar adsorbents. Cosorption measurements with a common VOC toluene, under humid conditions, find that these monolithic ZIF samples outperform powder equivalents, with the mixed-modulator ZIF-67 monolith capturing 28% more VOC compared to the powder ZIFs studied due to its superior volumetric efficiency. This study provides insights into the benefits of modulator-based tuning of porosity within monolithic ZIFs which, combined with their hydrophobicity, may facilitate their application for industrial organic vapor recovery or indoor air cleaning, where efficient hydrophobic adsorbents which can operate in humid environments are essential.