CO_2 Capture Performance of Supported Phosphonium Dual Amine-Functionalized Ionic Liquids@MCM-41

摘要

To screen the efficient media for CO_(2) capture of flue gas from power plants, a strategy for improving the CO_(2) capture capacity by dual functionalized ionic liquids (ILs) with multiple active sites is proposed. Three phosphonium dual functionalized ILs ([aP_(4443)][2-Np], [aP_(4443)][2-Op], and [aP_(4443)][Triz]) have been prepared. The sorption capacities of the synthesized ILs under pure CO_(2) atmosphere and the supported ILs under different loading amounts from 10 to 50%, temperatures of 30–80 °C, and CO_(2) partial pressure varied from 10 to 15% were determined. Fourier transform infrared (FTIR) spectroscopy was applied to reveal the interaction between CO_(2) and ILs, and the pseudo-second-order model and the intraparticle diffusion model were used for a better understanding of the CO_(2) adsorption behavior. The results showed that a high capacity up to 1.88 mol of CO_(2)/mol of IL for [aP_(4443)][2-Np] is achieved, and 30% IL–MCM-41 can reach 3.19 mmol/g with excellent reversibility under the atmosphere of CO_(2):N_(2) (15%:85%) at 30 °C and 0.1 MPa. Raising the temperature or decreasing the CO_(2) concentration is not conducive to improving the CO_(2) capacity. FTIR spectroscopy demonstrated that the amino and hydroxyl react with CO_(2) to form NHCOO~(–) or CO_(3)~(–). Combined with the activation energy calculation, the kinetic analysis revealed that the CO_(2) capture of supported ILs is an internal diffusion controlled physical adsorption.