High n-Hexane Adsorption Capacity of Composite Adsorbents Based on MOFs and Graphene with Various Morphologies

Abstract

Adsorption is an important technique for the separation and purification of various gases. In this study, two types of graphene materials with various morphologies are employed to modify metal–organic frameworks (MOFs) and improve their adsorption capacities. SEM, XRD, as well as Raman and IR spectroscopies are adopted to analyze the microstructures of these as-prepared samples. After the combination process, the adsorption abilities of UiO-66 and ZIF-8 are enhanced significantly (an increase of more than 48% for the n-hexane adsorption), and the adsorption amounts of CO2, methanol, and n-hexane reach 9.32, 17.48, and 4.26 mmol g–1, respectively. The remarkably improved performances are induced by the more favorable orbit interaction between the graphene basal plane and the adsorbed gases. Moreover, the natural three-dimensional (3D) continuous and porous structure of the 3D graphene network is not only beneficial to the adsorption ability but also improves the stability of MOFs at a high temperature.

Synthesis of graphene foams and their sorption properties of n-hexane

“…While the best ZIF-8/3DGN sample adsorbed 4.26 mmol g −1 (367 mg g −1 ) of n-hexane at 40 bars, the n-hexane adsorption capacity was lower than about 40 mg g −1 at 1 bar as follows from Fig. 1e in [32]. A comparison of separate results showing N2 uptake at − 196 °C on ZIF-8/3DGN (Fig.…”

“…On the other hand, another recent article on similar hybrid materials reports quite different adsorption capacities of n-hexane. Namely, rGO and three-dimensional graphene network (3DGN) were combined with ZIF-8 (ZIFs-zeolitic imidazolate frameworks) and UiO-66 (zirconium-based metal-organic frameworks) to increase their adsorption capacities [32]. Although these hybrid materials performed much better than pure ZIF-8 and UiO-66, they still had poorer n-hexane adsorption capacities than our Acrylic/GF 24 h 950C sample.…”

Research Progress in Metal-Organic Framework and Its Composites for Separation of C2Based on Sieving Multiple Effects

“…表 6 列出了部分 ZIF 材料的组成和 结构参数 [77] . Bux 等 [78] [82] Figure 15 Synergistic sorbent separation technology (SSST) [82] 除 MOF/膜、MOF＋MOF 外, MOF/MOF 是一种利 用一个 MOF 为核, 另一个 MOF 为壳, 外延生长的多层 核壳 MOF 结构 [83] , MOF/共价有机骨架(COF) [84] 合成过 程与其相似; MOF/(石墨烯/还原氧化石墨烯/氧化石墨 烯)(GR/RGO/GO)则是以二维蜂巢平面 GR/RGO/GO 为 生长基底, 原位生成多层结构的 MOF 复合材料 [85][86][87][88] , MOF/ 三 维 石 墨 烯 网 (3DGN) [86] 和 MOF/ 碳 纳 米 管 (CNT) [89]…”