Cyclodextrin-based supramolecular low melting mixtures: efficient absorbents for volatile organic compounds abatement

Area of Science:

• Environmental Chemistry
• Materials Science
• Separation Science

Background:

• Cyclodextrins (CDs) and deep eutectic solvents (DESs) are advanced absorbent materials.
• These materials show promise for the removal of volatile organic compounds (VOCs).

Purpose of the Study:

• To investigate the absorption characteristics of four supramolecular low-melting mixtures (LMMs) derived from modified CDs and levulinic acid.
• To evaluate the LMMs' efficacy in removing five specific volatile organic compounds (VOCs): acetaldehyde, butanone, dichloromethane, thiophene, and toluene.

Main Methods:

• Formation of four DES analogs (supramolecular LMMs) using modified cyclodextrins and levulinic acid.
• Measurement of vapor-liquid partition coefficients for five VOCs using the developed LMMs.
• Assessment of absorption capacity, synergy, and reusability over multiple absorption/desorption cycles.

Main Results:

• Supramolecular LMMs demonstrated up to a 250-fold reduction in vapor-liquid partition coefficients compared to water.
• Absorption capacity was synergistic and correlated with the hydrophobicity of the VOCs.
• High absorption rates (99% for toluene, 95% for dichloromethane) were achieved, with linear concentration dependence and maintained capacity over five cycles.

Conclusions:

• The developed supramolecular LMMs are highly effective absorbents for volatile organic compounds (VOCs).
• These LMMs exhibit excellent absorption capacity, selectivity influenced by hydrophobicity, and robust reusability.
• The findings highlight the potential of CD-DES based LMMs for efficient VOC removal applications.