On the solubility and dissolution mechanism of CO2 in{[Bmim][BF4]+alkali metal salt}metal complex ionic liquid
WANG Lanyun
ZHOU Huajian
ZHANG Yajuan
Abstract：In order to capture carbon dioxide more economically and effectively,reduce environmental pollu-tion,and strengthen the rational use of resources,various concentrations of metal complex ionic liquids[Bmim][BF4]+MBF4(M=Li+,Na+and K+)were prepared in this paper.Under the pressure range of 100～4 000 kPa,the gas absorption experiment was carried out at 30,40 and 50℃by using a high-pressure reactor,and the solubility of CO2 in metal complex ionic liquids(MILs)was measured.Density functional simulation was used to calculate the charge distribution,Fukui index,and binding energy parameters of the stable con-figuration of the mixed system of MILs and CO2,and to analyze the CO2 absorption mechanism of MILs from a microscopic perspective.The experimental results show that the solubility of CO2 in MILs decreases with increasing temperature and decreasing pressure.Adding alkali metal salt can promote the absorption of CO2 by ILs,but when the concentration of alkali metal salt in ILs is≥1 mol/L,it will inhibit CO2 absorption.Be-sides,0.010 mol/L[Bmim][BF4]+KBF4 absorbs the highest amount of CO2.The density functional calcula-tion results demonstrate that[Bmim][BF4]+KBF4 has a large K+volume and strong hydrogen bond force,and the solubility of K+in the ionic liquid is small,resulting in less steric hindrance,so[Bmim][BF4]+KBF4 has more free volume to accommodate CO2.Overall,MILs have higher CO2 absorption than pure ILs,and have a better application prospects in greenhouse gases management.
Keywords：CO2 absorptionalkali metal salts[Bmim][BF4]ionic liquidmetal complex ionic liquiddensity functional
Publication Date：2023-12-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 86-95 )