Abstract

CO₂ Capture and Utilization (CCU) is a promising technique for reducing global warming. Conventional methods include absorption and adsorption, chemical looping combustion and cryogenic distillation, hydrate-based separation and membrane separation have been used for CO₂ separation, but they have certain limitations like high energy intensive, solvent degradation, solvent loss, corrosive nature of the solvents and toxicity of solvents. Novel materials and techniques are always being developed in order to achieve greater optimization. Ionic Liquids (ILs) have demonstrated great potential for cost-effective CO₂ separation. Similarly, Supported Ionic Liquid Membranes (SILMs) have also shown effective CO₂ separation performance. This review offers the detailed mechanism, advantages and disadvantages and comparison of various conventional methods used for CO₂ capture. In addition, different ionic liquids used for CO₂ separation have also been discussed in detail. Lastly, Various challenges, and future recommendations in SILMs are identified and explained.

Keywords:Conventional technologies for CO₂ capture; Ionic liquids; SILM; CO₂/N₂ permeability and selectivity

Abbreviations:CO₂: Carbon Dioxide; N₂: Nitrogen; H2O: Water; CH₄: Methane; H₂: Hydrogen; GPU: Gas Permeation Unit; IL: Ionic Liquid; TSIL: Task-Specific Ionic Liquid; RTIL: Room-Temperature Ionic Liquid; SLM: Supported Liquid Membrane; SILM: Supported Ionic Liquid Membrane; PF₆: Hexafluorophosphate; Tf₂N: Bis(trifluoromethylsulfonyl)-amide; BF₄: Tetrafluoroborate; C₂mim: 1-ethyl-3-methyl-imidazolium; C4mim: 1-butyl-3-methyl-imidazolium; C8mim: 1-octyl-3-methyl-imidazolium; DCA: Dicyanamide; Gly: Alanate; P66614: Trihexyl(tetradecyl)phosphonium; PI: Polyimide; PVDF: Polyvinylidene Fluoride; PS: Polysulfone; PES: Polyether Sulfone; PTFE: Poly (Tetrafluoroethylene); MMM: Mixed Matrix Membrane; GHG: Greenhouse Gases; CCU: Carbon Capture and Utilization; C5H6NCl: Pyridinium Chloride; H₄P⁺: Phosphonium; NH4+: Ammonium; Gt: Gigatonnes; IGCC: Integrated Gasification Combined Cycle; ASU: Air Separation Unit; MEA: Mono-Ethanolamine; HSO₄−: Hydrogen Sulfate; CILs: Conventional Ionic Liquids; [bmim][PF6]: 1-Butyl-3-methylimidazolium hexafluorophosphate; [bmim][Tf2N]: 1-Butyl-3-methylimidazolium bis[trifluoromethyl)sulfonyl]- imide; [bmim][BF4]: 1-butyl-3-methylimidazolium tetrafluoroborate; [bmim][Ac]: 1-butyl-3-methylimidazolium acetate; [bmim][DCA]: 1-butyl-3-methylimidazolium dicyanamide; [bmim][TCM]: 1-butyl-3-methylimidazolium tricyanomethanide; [bmim][NO₃]: 1-Butyl-3-methylimidazolium nitrate; [Bmim][Gly]: 1-butyl-3-methylimidazolium glycinate; [Bmim][Ala]: 1-butyl-3-methylimidazolium L-alaninate