Stabilization of [BMIM][PF6] ionic liquid membrane in structurally optimized multilayer ceramic support through aqueous DEA solution for CO2/CH4 separation.

[Display omitted] • Stability of multilayer ceramic supported liquid membranes was experimentally studied. • Effect of substrate structure on multilayer ceramic support was investigated. • Effects of feed gas pressure and temperature on performance of supported ionic liquid membranes were investigated. • The support containing substrate made at higher pressing pressure showed longer stability. • Supported liquid membranes using the ionic liquid as solvent provided higher stability. The stability of the ceramic supported liquid membranes (SLMs) is one of the most interesting research subjects. In this work, the SLMs' stability for CO 2 /CH 4 separation was investigated. Following pressing α-Al 2 O 3 substrates at 400, 600, and 800 bar, colloidal and polymeric TiO 2 intermediate and top layers were coated. Aqueous diethanolamine (DEA) solution was used as solvent in the SLM to optimize support structure based on CO 2 /CH 4 separation performance. The pressed support at 800 bar and coated with TiO 2 demonstrated best performance and selected for further study. Subsequently, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]) ionic liquid (IL) was immobilized inside the selected support and used as the supported ionic liquid membrane (SILM) for CO 2 /CH 4 separation. The SILM separation performance was evaluated under different pressures and temperatures. Temperature was found to has greater effect than pressure due to a decrease in IL's viscosity and an increase in penetrant diffusivity. At 25 °C and 1 bar, SILM exhibited consistent and reliable performance as CO 2 and CH 4 permeabilities of 244.0 and 7.4 Barrer, respectively, and CO 2 /CH 4 selectivity of 33.0 over 6 h. The findings contribute to understanding the implementation of multilayer ceramic SILMs for CO 2 /CH 4 separation and highlight its potential along with opening up new avenues. [ABSTRACT FROM AUTHOR]