Rafiei Maryam A, Campos-Martínez José, Bartolomei Massimiliano, Pirani Fernando, Maghari Ali, Hernández Marta I
Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (IFF-CSIC), Serrano 123, 28006 Madrid, Spain.
Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
Phys Chem Chem Phys. 2024 Sep 25;26(37):24553-24563. doi: 10.1039/d4cp02287d.
Efficient separation of oxygen and nitrogen from air is a process of great importance for many industrial and medical applications. Two-dimensional (2D) membranes are very promising materials for separation of gases, as they offer enhanced mass transport due to their smallest atomic thickness. In this work, we examine the capacity of graphdiyne (GDY), a new 2D carbon allotrope with regular subnanometric pores, for separating oxygen (O) from nitrogen (N). A quantum-mechanical model has been applied to the calculation of the transmission probabilities and permeances of these molecules through GDY using force fields based on accurate electronic structure computations. It is found that the O/N selectivity (ratio of permeances) is quite high (, about 10 and 10 at 100 and 300 K, respectively), indicating that GDY can be useful for separation of these species, even at room temperature. This is mainly due to the N transmission barrier (∼0.37 eV) which is considerably higher than the O one (∼0.25 eV). It is also found that molecular motions are quite confined inside the GDY pores and that, as a consequence, quantum effects (zero-point energy) are significant in the studied processes. Finally, we explore the possibility of O/O isotopologue separation due to these mass-dependent quantum effects, but it is found that the process is not practical since reasonable selectivities are concomitant with extremely small permeances.
从空气中高效分离氧气和氮气对于许多工业和医学应用来说是一个非常重要的过程。二维（2D）膜是用于气体分离的非常有前景的材料，因为它们由于最小的原子厚度而提供了增强的质量传输。在这项工作中，我们研究了具有规则亚纳米孔的新型二维碳同素异形体石墨炔（GDY）从氮气（N）中分离氧气（O）的能力。基于精确电子结构计算的力场，应用量子力学模型来计算这些分子通过GDY的传输概率和渗透率。结果发现，O/N选择性（渗透率之比）相当高（分别在100K和300K时约为10和10），这表明即使在室温下，GDY也可用于分离这些物质。这主要是由于N的传输势垒（约0.37eV）远高于O的传输势垒（约0.25eV）。还发现分子运动在GDY孔内受到相当大的限制，因此，量子效应（零点能）在研究过程中很显著。最后，我们探讨了由于这些质量相关的量子效应而实现O/O同位素分离的可能性，但发现该过程不实用，因为合理的选择性伴随着极小的渗透率。
