Cross-Linking with Diamine Monomers To Prepare Composite Graphene Oxide-Framework Membranes with Varying d-Spacing
Cross-Linking with Diamine Monomers To Prepare Composite Graphene Oxide-Framework Membranes with Varying d-Spacing
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DOI：
10.1021/cm5007873
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发表时间：
2014-05-13
影响因子：
8.6
通讯作者：
Lai, Juin-Yih
中科院分区：
文献类型：
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作者：
Hung, Wei-Song;Tsou, Chi-Hui;Lai, Juin-Yih
选择了三种二胺单体（乙二胺、丁二胺和对苯二胺）用于交联氧化石墨烯（GO），通过压力辅助自组装技术过滤制备复合氧化石墨烯骨架（GOF）膜。将这些膜应用于渗透蒸发分离乙醇 - 水混合物。未改性的GO仅包含氢键和π - π相互作用，但在与二胺交联后，衰减全反射傅里叶变换红外光谱和X射线光电子能谱表明，二胺与GO和膜支撑体均发生了化学键合。此外，GO的亲水性发生了显著变化；水接触角从24.4度增加到80.6度（从与具有脂肪族结构的二胺交联到与具有芳香族结构的二胺交联）。X射线衍射结果表明，GOF层的d间距从10.4埃变化到8.7埃。对于预先浸泡在90 wt%乙醇 - 水中的GOF，层与二胺之间的共价键可有效抑制d间距的拉伸。与乙二胺交联制备的复合膜表现出较短的层间d间距，并在80℃时具有优异的渗透蒸发性能：渗透通量 = 2297克/（平方米·小时）；渗透物中的水浓度 = 99.8 wt%。该膜在30℃下长期运行120小时期间表现出稳定性。
Three diamine monomers (ethylenediamine, butylenediamine, and p-phenylenediamine) were selected for cross-linking graphene oxide (GO) to prepare composite graphene oxide-framework (GOF) membranes through filtration using a pressure-assisted self-assembly technique. The membranes were applied to separate an ethanol water mixture by pervaporation. Unmodified GO comprised only hydrogen bonds and pi-pi interactions, but after cross-linking it with a diamine, attenuated total reflectance Fourier transform infrared and X-ray photoelectron spectroscopy demonstrated that the diamine was chemically bonded both to GO and the membrane support. Moreover, GO hydrophilicity was substantially altered; water contact angle increased from 24.4 degrees to 80.6 degrees (from cross-linking with an aliphatic structure of diamine to cross-linking with an aromatic structure). Results of X-ray diffraction showed that d-spacing in GOF layers varied from 10.4 to 8.7 angstrom. For GOFs presoaked in 90 wt % ethanol water, covalent bonds between the layer and diamine could effectively suppress stretching of d-spacing. Cross-linking with ethylenediamine produced a composite membrane that exhibited a short interlayer d-spacing and delivered an excellent pervaporation performance at 80 degrees C: permeation flux = 2297 g/(m(2) h); water concentration in permeate = 99.8 wt %. The membrane showed stability during a long-term operation at 30 degrees C for 120 h.