A Multistep, Multicomponent Extraction and Separation Microfluidic Route to Recycle Water-Miscible Ionic Liquid...

Area of Science:

• Green Chemistry
• Chemical Engineering
• Materials Science

Background:

• Ionic liquids (ILs) are expensive solvents, and their recycling is crucial for reducing lifecycle costs.
• Direct recycling of water-miscible ILs is challenging due to their miscibility with common washing agents like water.

Purpose of the Study:

• To develop an effective recycling route for water-miscible ionic liquids.
• To demonstrate a proof-of-concept for IL solvent recovery using a novel membrane-assisted liquid-liquid extraction method.

Main Methods:

• Utilized hydrophobic ionic liquids as accommodating agents to extract water-miscible ILs from aqueous streams.
• Employed a membrane to separate the biphasic slug flow of mixed ILs and water.
• Recovered the purified water-miscible IL using acidified water and vacuum drying.

Main Results:

• Successfully recycled 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM-OTf) using 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-NTf2) as an accommodating agent.
• Demonstrated the recycling of 1-butyl-1-methylpyrrolidinium triflate (BMPYRR-OTf) from a platinum nanoparticle synthesis application.
• Showcased the recyclability of both the water-miscible IL and the accommodating agent.

Conclusions:

• The developed membrane-assisted liquid-liquid extraction process offers an efficient method for recycling challenging water-miscible ionic liquids.
• This approach significantly reduces the cost and environmental impact associated with IL solvent usage.
• The method is applicable to both model systems and realistic synthetic applications, paving the way for sustainable IL utilization.