Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
J Phys Chem B. 2010 Sep 16;114(36):11827-37. doi: 10.1021/jp103862v.
The ionic liquid-CO(2) system is of interest because ionic liquids have potential to be used for CO(2) capture. Using classical molecular dynamics simulations, the vacuum-liquid and CO(2) gas-liquid interfaces of the ionic liquid 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf(2)N]) have been studied at a range of temperatures and pressures. Interfacial ordering and orientational tendencies of the ionic liquid at the vacuum interface generally agree with previous experimental and simulation studies. The interfacial structure of the IL remains relatively unperturbed when the liquid is in contact with CO(2). CO(2) adsorbs rapidly onto the liquid interface, forming a dense layer. Diffusion into the bulk occurs on a much slower time scale. Interfacial fluxes and diffusivities were determined. The potential of mean force for interfacial crossing and corresponding residence time distributions of interfacial crossing events of CO(2) were also calculated. CO(2) desorption from the liquid was also simulated. A high density CO(2) layer forms for desorption with CO(2) present but not for desorption into a vacuum. The interfacial behavior and transport dynamics have been characterized by studying these properties.
离子液体-CO2 体系引起了人们的兴趣，因为离子液体具有用于 CO2 捕获的潜力。本文使用经典分子动力学模拟，研究了离子液体 1-丁基-3-甲基咪唑双（三氟甲基磺酰基）亚胺([bmim][Tf2N])在不同温度和压力下的真空-液相和 CO2 气-液相界面。真空界面处离子液体的界面有序性和取向趋势通常与先前的实验和模拟研究一致。当液体与 CO2 接触时，IL 的界面结构仍然相对未受干扰。CO2 迅速吸附到液相界面上，形成一个密集的层。扩散到体相的过程要慢得多。测定了界面通量和扩散系数。还计算了界面穿越的平均势能和界面穿越事件的停留时间分布。也模拟了 CO2 从液体中的解吸。对于存在 CO2 的解吸，会形成一个高浓度的 CO2 层，但对于真空解吸则不会。通过研究这些特性，对界面行为和输运动力学进行了表征。
