Absorption of CO 2 with supported imidazolium‐based ionic liquid membranes

BACKGROUND Ionic liquids ( ILs ) are considered to be one of the future solutions to CO 2 emission control because of their high CO 2 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 CO 2 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 CO 2 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 CO 2 , and some shifts of typical ILs vibration bands showed some probable structures related to CO 2 absorption. CONCLUSION SILMs improved the mass transfer process and resulted in excellent CO 2 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