Jin Xiaoheng, Foller Tobias, Wen Xinyue, Ghasemian Mohammad B, Wang Fei, Zhang Mingwei, Bustamante Heriberto, Sahajwalla Veena, Kumar Priyank, Kim Hangyel, Lee Gwan-Hyoung, Kalantar-Zadeh Kourosh, Joshi Rakesh
Sustainable Material Research and Technology Centre, School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia.
Centre for Advanced Solid and Liquid based Electronics and Optics (CASLEO), School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia.
Adv Mater. 2020 Apr;32(17):e1907580. doi: 10.1002/adma.201907580. Epub 2020 Mar 17.
Graphene-based materials, primarily graphene oxide (GO), have shown excellent separation and purification characteristics. Precise molecular sieving is potentially possible using graphene oxide-based membranes, if the porosity can be matched with the kinetic diameters of the gas molecules, which is possible via the tuning of graphene oxide interlayer spacing to take advantage of gas species interactions with graphene oxide channels. Here, highly effective separation of gases from their mixtures by using uniquely tailored porosity in mildly reduced graphene oxide (rGO) based membranes is reported. The gas permeation experiments, adsorption measurement, and density functional theory calculations show that this membrane preparation method allows tuning the selectivity for targeted molecules via the intercalation of specific transition metal ions. In particular, rGO membranes intercalated with Fe ions that offer ordered porosity, show excellent reproducible N /CO selectivity of ≈97 at 110 mbar, which is an unprecedented value for graphene-based membranes. By exploring the impact of Fe intercalated rGO membranes, it is revealed that the increasing transmembrane pressure leads to a transition of N diffusion mode from Maxwell-Stefan type to Knudsen type. This study will lead to new avenues for the applications of graphene for efficiently separating CO from N and other gases.
基于石墨烯的材料，主要是氧化石墨烯（GO），已显示出优异的分离和纯化特性。如果孔隙率能够与气体分子的动力学直径相匹配，那么使用基于氧化石墨烯的膜进行精确的分子筛分是有可能实现的，这可以通过调节氧化石墨烯的层间距来利用气体物种与氧化石墨烯通道之间的相互作用来达成。在此，报道了通过在轻度还原的氧化石墨烯（rGO）基膜中采用独特定制的孔隙率来从气体混合物中高效分离气体。气体渗透实验、吸附测量以及密度泛函理论计算表明，这种膜制备方法能够通过特定过渡金属离子的插层来调节对目标分子的选择性。特别是，插层有铁离子且具有有序孔隙率的rGO膜，在110毫巴下展现出约97的出色可重现的N₂/CO₂选择性，这对于基于石墨烯的膜来说是一个前所未有的值。通过探究插层有铁的rGO膜的影响，发现跨膜压力的增加会导致N₂扩散模式从麦克斯韦 - 斯蒂芬型转变为克努森型。这项研究将为石墨烯在从N₂和其他气体中高效分离CO₂的应用开辟新途径。
