1,3-Propanediol-Based Supported Deep Eutectic Liquid Membranes as an Efficient Material for Carbon Dioxide Separation

Abstract

In this study, new polypropylene-based supported liquid membranes (SLMs) with a liquid phase composed of deep eutectic solvents (DESs) containing choline chloride, acetylcholine chloride, or tetrabutylammonium chloride and 1,3-propanediol were introduced. Fourier transform infrared spectroscopy was employed to verify DES formation, and the thermal stability was assessed using thermogravimetric analysis. The physicochemical properties, namely, density, refractive index, and viscosity, of DESs and their carbon dioxide capacities were measured across a temperature range of 293.15–313.15 K. The study examined how the structure of the hydrogen bond acceptor and the molar ratio of acceptor to donor influenced the properties and potential for CO₂ separation. The permeability of CO₂ and N₂ through DES-based SLMs was measured, and the ideal selectivity for CO₂ over N₂ was evaluated. Results indicated that the permeability of CO₂ through SLMs containing 1,3-propanediol-based DES ranged from 89 to 123 barrer at 293.15 K, with an ideal CO₂/N₂ selectivity between 22 and 32. The performance of the studied DES-SLMs demonstrates that they are a viable alternative to commercially used CO₂ separation methods due to their environmentally friendly nature and comparable gas separation capabilities.