Experimental and predictive analysis of deep eutectic solvent gel membranes for efficient CO₂ separation

The capture of Carbon Dioxide (CO₂) is very relevant nowadays as global warming hits its peak. The separation of CO₂ using membranes has received wide recognition by researchers because of its energy efficiency. Various Ionic Liquid supported membranes have been proven effective in this regard; however, their higher cost and toxicity are limitations, which opens possibilities for Deep Eutectic Solvents (DES). This work explains how DES gel membrane fabrication separates CO₂ from CO₂/CH₄ mixtures. DES, composed of choline chloride and glycerol, is mixed with Pebax1657 polymer, and Polyvinylidene fluoride sheets are used as supports for casting. Fourier transform infrared spectroscopy has been used to confirm the synthesis of DES. X-ray Diffraction and Scanning Electron Microscopy analysis were used to analyse the membrane structure and cross-section. The physicochemical properties of DES are measured at a temperature range from 293.15 to 343.15 K. Pure and mixed gas permeabilities of CO₂ and CH₄ with increased pressure have been calculated. The highest permeability values obtained for pure and mixed gas CO₂ were 138.98 Barrer and 93.17 Barrer, respectively. Density Functional Theory (DFT) is also applied to predict the interaction energy between DES and gas molecules. The efficacy of the DES-gel membrane was evaluated against other DES-supported liquid Membranes, revealing that DES may serve as a viable substitute for hazardous and costly ionic liquids.