Assessing the toxicity and biodegradability of deep eutectic solvents

Area of Science:

• Green chemistry
• Ecotoxicology
• Ionic solvents

Background:

• Deep eutectic solvents (DESs) are emerging ionic solvents with diverse applications.
• DESs are often considered "green" due to their components: ammonium salts and hydrogen bond donors (HBDs).
• The ecotoxicological profile and biodegradability of DESs remain incompletely understood.

Purpose of the Study:

• To evaluate the toxic effects of cholinium-based DESs on various organisms.
• To assess the biodegradability of these DESs using standard tests.
• To contribute to understanding the structure-based ecotoxicological behavior of DESs.

Main Methods:

• Cholinium-based DESs were synthesized using choline chloride (ChCl) or choline acetate (ChAc) as the salt and urea (U), acetamide (A), glycerol (G), or ethylene glycol (EG) as the HBD.
• Toxicity was tested against Escherichia coli (bacterium), Allium sativum (garlic plant), and Hydra (invertebrate).
• Biodegradability was assessed using closed bottle tests.

Main Results:

• The evaluated DESs demonstrated antibacterial properties and inhibitory effects on the tested organisms.
• Toxicity and inhibitory effects were dependent on DES composition and concentration.
• Not all tested DESs were found to be readily biodegradable.
• Potential mechanisms involve interactions between DESs and cellular membranes.

Conclusions:

• Cholinium-based DESs exhibit varying ecotoxicological impacts and biodegradability.
• The study highlights the need for comprehensive ecotoxicological data for DESs.
• Findings provide insights into the structure-activity relationships governing DES ecotoxicity.