Yamaguchi Mei, Tanaka Shunsuke
Department of Chemical, Energy and Environmental Engineering, Faculty of Environmental and Urban Engineering, Kansai University, 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan.
Department of Chemical, Energy and Environmental Engineering, Faculty of Environmental and Urban Engineering, Kansai University, 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan; Organization for Research and Development of Innovative Science and Technology (ORDIST), Kansai University, 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan.
J Colloid Interface Sci. 2023 May 15;638:513-523. doi: 10.1016/j.jcis.2023.01.143. Epub 2023 Feb 7.
Here we report the synthesis of a zeolitic imidazolate framework with RHO topology (RHO-Zn(eim); eim is the deprotonated anion of 2-ethylimidazole (Heim)) in the aqueous phase. Zn(eim) crystals were prepared by the reaction between Heim and zinc acetate in deionized water. The products prepared at relatively high Heim/Zn molar ratios were Zn(eim) whose structure assigned to RHO, qtz and ANA topologies. Zn(eim) obtained under static condition had porous RHO structure, while under stirred condition, nonporous dense qtz and ANA structures were formed. This study revealed that the formation of RHO porous structure requires the template effect of excess Heim. The RHO-Zn(eim) crystals possessed high surface area and micropore volume, whose morphology consisted of a rhombic dodecahedron. RHO-Zn(eim) exhibited high adsorption capacity (4 mmol/g) for hexane and cyclohexane. Due to the hydrophobic nature of RHO-Zn(eim), water vapor was hardly adsorbed. Although RHO-Zn(eim) was stable in the presence of water vapor, it became nonporous upon hydrolysis in aqueous solution. In contrast, partial carbonization of topmost surface improved the structural stability against hydrolysis by water, while maintaining the adsorption capacity and increasing the adsorption rate.
在此，我们报道了在水相中合成具有RHO拓扑结构的沸石咪唑酯骨架（RHO-Zn(eim)；eim是2-乙基咪唑（Heim）的去质子化阴离子）。通过Heim与醋酸锌在去离子水中反应制备了Zn(eim)晶体。在相对较高的Heim/Zn摩尔比下制备的产物为Zn(eim)，其结构归属于RHO、qtz和ANA拓扑结构。在静态条件下获得的Zn(eim)具有多孔的RHO结构，而在搅拌条件下，则形成了无孔的致密qtz和ANA结构。该研究表明，RHO多孔结构的形成需要过量Heim的模板效应。RHO-Zn(eim)晶体具有高比表面积和微孔体积，其形态由菱形十二面体组成。RHO-Zn(eim)对己烷和环己烷表现出高吸附容量（4 mmol/g）。由于RHO-Zn(eim)的疏水性，几乎不吸附水蒸气。尽管RHO-Zn(eim)在水蒸气存在下是稳定的，但在水溶液中水解后会变成无孔结构。相反，最表面的部分碳化提高了对水水解的结构稳定性，同时保持了吸附容量并提高了吸附速率。
