Accelerate the Electrolyte Perturbed-Chain Statistical Associating Fluid Theory-Density Functional Theory Calculation With the Chebyshev Pseudo-Spectral Collocation Method. Part II. Spherical Geometry and Anderson Mixing.

Yunhao Sun,Xiaoyan Ji,Xiang Ling,Xiaohua Lu,Zhengxing Dai,Gulou Shen

doi:10.3389/fchem.2021.801551

Abstract

To improve the efficiency of electrolyte perturbed-chain statistical associating fluid theory–density functional theory (ePC-SAFT-DFT) calculation of the confined system, in this work, first, the Chebyshev pseudo-spectral collocation method was extended to the spherical pores. Second, it was combined with the Anderson mixing algorithm to accelerate the iterative process. The results show that the Anderson mixing algorithm can reduce the computation time significantly. Finally, based on the accelerated ePC-SAFT-DFT program, a systematic study of the effects of the temperature, pressure, pore size, and pore shape on the CO2 solubilities in the ionic liquids (ILs) confined inside the silica nanopores was conducted. Based on the simulation results, to obtain high CO2 solubilities in the ILs confined in silica, a better option is to use the silica material with a narrow spherical pore, and the IL-anion should be selected specifically considering that it has a more significant impact on the absorption enhancement effect.

Highlights

Mitigating CO2 emission from fossil-fueled power plants as well as from transports has become an urgent and worldwide research topic, in which CO2 separation is often needed (MacDowell et al, 2010; Boot-Handford et al, 2014)
Calculating the density profile of [C6mim] [Tf2N]-CO2 confined in electronic neutral silica pore with different structures at 333 K and 16.1 bar was selected as an example here to demonstrate the performance of the general scheme combined with the Anderson mixing, and the calculation efficiency was compared with the general scheme only using the Picard iterations
We used 120 collocation points to represent the density profile inside the slit-shaped pore, while 60 collocation points were used for the cylindrical pore and spherical cavity

Summary

Introduction

Mitigating CO2 emission from fossil-fueled power plants as well as from transports has become an urgent and worldwide research topic, in which CO2 separation is often needed (MacDowell et al, 2010; Boot-Handford et al, 2014). Research has been conducted to address the confinement effect on the gas solubility in ILs via experiments and molecular simulations (Baltus et al, 2005; Ilconich et al, 2007; Ilconich et al, 2007; Zhang et al, 2010; Iarikov et al, 2011; Ren et al, 2012; Banu et al, 2013; Shi and Luebke, 2013; Romanos et al, 2014; Santos et al, 2014; Budhathoki et al, 2017; Shen and Hung, 2017). It is desirable to develop a theoretical model to predict the properties of confined IL–CO2 systems

Methods

Results

Conclusion