Membrane-based technologies have shown potential for successful application in CO₂ removal from flue gas and upgrading of biogas, and have gained intensive research interest. In this context, two alkyl methylimidazolium tricyanomethanide ionic liquids were immobilized into the pores of tubular ceramic membranes, the separation layer of which had a pore size of 3, 70, or 100 nm. CO₂, N₂, and CH₄ mixed-gas permeances and gas separation efficiency of the developed hybrid membranes, for CO₂/N₂ and CO₂/CH₄ mixtures, were evaluated with respect to the feed composition, operation temperature, pore size and nature of the embedded ionic liquid phase. For the supplied CO₂/N₂ and CO₂/CH₄ mixtures, the maximum separation selectivity reached 72.7 and 11.3 respectively. Additional investigation was conducted on the effect of low concentrations of H2S contained in simulated biogas streams, on the separation performance of two of the developed membranes. It was found that the addition of H₂S led to a clear increase of CO2 and CH4 mixed-gas permeances, at the expense of CO₂/CH₄ separation selectivity, whereas the H₂S/CH₄ and H₂S/CO₂ selectivity values were quite significant reaching 59 and 28 respectively.