Volatile organic compounds are a major source of air pollutants. Absorption is an effective solution to treat polluted air loaded with volatile organic compounds, but most actual absorbents are often toxic and non-biodegradable. Here, we tested eutectic solvent mixtures for the absorption of volatile organic compounds for the first time. The affinity of solvent mixtures for toluene, acetaldehyde and dichloromethane was determined by measuring vapour–liquid partition coefficients and liquid phase absorption capacities. Results show that the vapour–liquid partition coefficients vary, at 30 °C, from close to zero for acetaldehyde in the mixtures choline chloride:urea, choline chloride:glycerol and tetrabutylphosphonium bromide:glycerol to 0.124 for dichloromethane in the choline chloride:urea eutectic mixture. These values are similar or even superior to those published for ionic liquids and organic solvents. Solvents based on choline chloride, a food additive, and urea, can solubilize up to 500 times more volatile organic compounds compare to water. Moreover, deep eutectic solvents are easier to prepare and more biodegradable than ionic liquids, which are also toxic. Deep eutectic solvents are more biodegradable than silicone oils, which are also expensive. Furthermore, in terms of recycling, the absorption capacities of the tested solvents remained unchanged during five absorption–desorption cycles. These findings are patented.
Air pollution Absorption Deep eutectic solvent Green chemistry Remediation
Darracq G, Couvert A, Couriol C et al (2010) Silicone oil: an effective absorbent for the removal of hydrophobic volatile organic compounds. J Chem Technol Biotechnol 85:309–313. doi:10.1002/jctb.2331CrossRefGoogle Scholar
Fourmentin S, Outirite M, Blach P et al (2007) Solubilisation of chlorinated solvents by cyclodextrin derivatives. A study by static headspace gas chromatography and molecular modelling. J Hazard Mater 141:92–97. doi:10.1016/j.jhazmat.2006.06.090CrossRefGoogle Scholar
Jérôme F, Ferreira M, Bricout H et al (2014) Low melting mixtures based on β-cyclodextrin derivatives and N, N′-dimethylurea as solvents for sustainable catalytic processes. Green Chem 16:3876–3880. doi:10.1039/C4GC00591KCrossRefGoogle Scholar