Esfandiarpoor Somaye, Fazli Mostafa, Ganji Masoud Darvish
Department of Applied Chemistry, Semnan University, Semnan, Iran.
Department of Nanochemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran, Iran.
Sci Rep. 2017 Nov 29;7(1):16561. doi: 10.1038/s41598-017-14297-w.
The separation of gases molecules with similar diameter and shape is an important area of research. For example, the major challenge to set up sweeping carbon dioxide capture and storage (CCS) in power plants is the energy requisite to separate the CO from flue gas. Porous graphene has been proposed as superior material for highly selective membranes for gas separation. Here we design some models of porous graphene with different sizes and shape as well as employ double layers porous graphene for efficient CO/H separation. The selectivity and permeability of gas molecules through various nanopores were investigated by using the reactive molecular dynamics simulation which considers the bond forming/breaking mechanism for all atoms. Furthermore, it uses a geometry-dependent charge calculation scheme that accounts appropriately for polarization effect which can play an important role in interacting systems. It was found that H-modified porous graphene membrane with pore diameter (short side) of about 3.75 Å has excellent selectivity for CO/H separation. The mechanism of gas penetration through the sub-nanometer pore was presented for the first time. The accuracy of MD simulation results validated by valuable DFT method. The present findings show that reactive MD simulation can propose an economical means of separating gases mixture.
分离直径和形状相似的气体分子是一个重要的研究领域。例如，在发电厂建立全面的二氧化碳捕集与封存（CCS）面临的主要挑战是从烟道气中分离出CO所需的能量。多孔石墨烯已被提议作为用于气体分离的高选择性膜的优质材料。在此，我们设计了一些不同尺寸和形状的多孔石墨烯模型，并采用双层多孔石墨烯实现高效的CO/H分离。通过使用考虑所有原子键形成/断裂机制的反应分子动力学模拟，研究了气体分子通过各种纳米孔的选择性和渗透性。此外，它使用了一种与几何形状相关的电荷计算方案，该方案适当地考虑了极化效应，而极化效应在相互作用系统中可能起着重要作用。结果发现，孔径（短边）约为3.75 Å的H修饰多孔石墨烯膜对CO/H分离具有优异的选择性。首次提出了气体通过亚纳米孔的渗透机制。MD模拟结果的准确性通过有价值的DFT方法得到验证。目前的研究结果表明，反应性MD模拟可以提出一种经济的分离气体混合物的方法。
