Absorption of CO₂with supported imidazolium-based ionic liquid membranes

Abstract

BACKGROUND Ionic liquids (ILs) are considered to be one of the future solutions to CO2 emission control because of their high CO2 solubility. Infiltrating ionic liquids into porous materials to prepare a supported ionic liquid membrane (SILM), could increase the absorption efficiency. RESULTS Four SILMs were prepared from imidazolium‐based ILs and PVDF microporous membranes. The CO2 absorption capacities of the SILMs were in the range of 0.88–3.64 mol mol−1, which were much higher than the solubility in ILs. After 20 min desorption at 60 °C or 0.08 MPa negative pressure, desorption rate reached 90%. And under the combined condition of 60 °C and 0.08 MPa, the desorption period was shortened and full desorption was obtained. The renewed SILMs maintained excellent CO2 absorption performance during several absorption–desorption cycles. A new peak at 1274–1284 cm−1 on the surface enhanced Raman scattering (SERS) spectra indicated the absorbed CO2, and some shifts of typical ILs vibration bands showed some probable structures related to CO2 absorption. CONCLUSION SILMs improved the mass transfer process and resulted in excellent CO2 absorption capacity. SILMs performed well in multiple absorption–desorption cycles, and showed great potential for industrial application. SERS is a feasible method for the characterization of SILMs. © 2014 Society of Chemical Industry

Key Applications and Potential Limitations of Ionic Liquid Membranes in the Gas Separation Process of CO2, CH4, N2, H2 or Mixtures of These Gases from Various Gas Streams

“…The investigation of the difference in the interaction of CO 2 with the monocationic ILs and dicationic ILs was governed by the quantum chemical calculations [ 79 ]. Cao, et al [ 80 ] synthesized four SILMs from imidazolium-based ILs and PVDF microporous membranes. The results of their study have shown that the synthesized SILMs have maintained an excellent CO 2 absorption level during several cycles of absorption–desorption.…”

Enhanced NH3 capture by imidazolium‐based protic ionic liquids with different anions and cation substituents

“…During recent decades, ionic liquids (ILs) have emerged as new solvents in the field of gas separations owing to their outstanding properties, such as high thermal stability, negligible vapor pressures and tunable structures. [14][15][16][17][18][19][20][21][22] Therefore, the NH 3 absorption by ionic liquids has aroused interest around the world, and researchers have paid a lot of attention to the screening and designing of ILs to increase NH 3 solubility along with good desorption performance. Yokozeki 2 ] as an example and explained that hydrogen atoms of the cation played an important role in NH 3 absorption.…”

Effect of ionic liquid confinement on CO2 solubility and permeability characteristics

“…In contrast to the organic amine scrubbing CO 2 from flue gas process, ionic liquids (ILs) can be an alternative for CO 2 absorption and natural gas purification for their non‐volatility and lower regeneration energy consumption . The supported ionic liquid membranes (SILMs), where IL is immobilized in a porous support by capillary forces, possess ILs’ chemical stability and huge membrane contact surface to make them attractive for CO 2 capture and offer a high potential for industrial applications …”