Molecular simulation for separation of ethylene and ethane by functionalised graphene membrane

Abstract

ABSTRACTGraphene is an excellent adsorbent and a membrane material for separation which has attracted wide attention in recent years. Moreover, compared with typical polymer materials, porous graphene has exhibited superior performance. In this paper, molecular dynamics and quantum mechanics were used to explore the appropriate pore size and separation mechanism of graphene. The 2N-Pore-13 (modified by N and H atom) membrane can prevent the penetration of ethane while maintaining high ethylene flux. The permeation rate of ethylene reached 3.7×106 GPU in 5N-Pore-13 membrane, while the one of ethane was only 227 GPU. The mechanism is based on the fact that molecular structure of ethylene is two-dimensional, so that ethylene can get closer to membrane surface when it is adsorbed. When passing through the pores, ethylene has lower enthalpy and entropy barrier.