Cyclodextrins (CDs) and deep eutectic solvents (DESs) are emerging absorbent materials for the removal of volatile organic compounds (VOCs). DESs are easily prepared by the combination of a hydrogen bond acceptor (HBA) with one or more hydrogen bond donors (HBD) leading to a liquid having a much lower melting temperature than the initial component.
In this study, modified CDs (HBA) and levulinic acid (HBD) were combined to form four DESs analogs, referred to as supramolecular low-melting mixtures (LMMs), to study their absorption characteristics towards five VOCs, namely acetaldehyde, butanone, dichloromethane, thiophene, and toluene. The supramolecular LMMs showed up to 250-fold reduction in the vapor-liquid partition coefficients compared to water. The overall absorption capacity found to be synergistic and seemed to be dictated by the hydrophobicity of the VOCs. Toluene and dichloromethane were absorbed at 99 and 95% by the supramolecular LMMs (see featured diagram above), respectively, even at higher concentrations, with a linear relationship between the concentration and absorption capacity. The LMMs also retained their absorption capacities even after five absorption/desorption cycles.
Panda, ., Fourmentin, S. Cyclodextrin-based supramolecular low melting mixtures: efficient absorbents for volatile organic compounds abatement. Environ Sci Pollut Res (2021).