Evaluation and Performance of Menthol–Polyethylene Glycol LTTM in Carbon Dioxide Capture

Abstract

Carbon dioxide capture technology, while established, faces operational and economic challenges with current absorbents. Ionic liquids (ILs), though promising for their selectivity and low volatility, often have drawbacks like high toxicity and viscosity. This study explores nonionic low transition temperature mixtures (LTTMs) of menthol (MET) and polyethylene glycol 200 (PEG200) at various ratios for CO₂ uptake. The 1:2 molar ratio showed maximum CO₂ loading of 0.599 mol CO₂/mol solvent at 303.15 K and 1000 kPa, with water addition boosting CO₂ uptake by 25%. This rise in uptake with water could be due to altered hydrogen bonding within the mixture constituents. Molecular dynamics simulations support these findings, indicating experimental results, showing that water disrupts hydrogen bonds, exposing hydroxyl and ether sites for CO₂ interaction. This LTTM solvent system presents a promising, low-toxicity alternative for efficient CO₂ capture. © 2025 Society of Chemical Industry and John Wiley & Sons, Ltd.