Recycling of 1,2-Dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide Ionic Liquid by Stacked Cation and Anion Exchange Adsorption-Desorption

Techniques for recovery and recycling of ionic liquids: A review

Due to beneficial properties like non-flammability, thermal stability, low melting point and low vapor pressure, ionic liquids (ILs) have gained great interest from engineers and researchers in the past decades to replace conventional solvents. The superior characteristics of ILs make them promising for applications in fields as wide-ranging as pharmaceuticals, foods, nanoparticles synthesis, catalysis, electrochemistry and so on. To alleviate the high cost and environmental impact of ILs, various technologies have been reported to recover and purify the used ILs, as well as recycling the ILs. The aim of this article is to overview the state-of-the-art research on the recovery and recycling technologies for ILs including membrane technology, distillation, extraction, aqueous two-phase system (ATPS) and adsorption. In addition, challenges and future perspectives on ILs recovery are discussed. This review is expected to provide valuable insights for developing effective and environmentally friendly recovery methods for ILs.

Microwave Encounters Ionic Liquid: Synergistic Mechanism, Synthesis and Emerging Applications

Progress in microwave (MW) energy application technology has stimulated remarkable advances in manufacturing and high-quality applications of ionic liquids (ILs) that are generally used as novel media in chemical engineering. This Review focuses on an emerging technology via the combination of MW energy and the usage of ILs, termed microwave-assisted ionic liquid (MAIL) technology. In comparison to conventional routes that rely on heat transfer through media, the contactless and unique MW heating exploits the electromagnetic wave-ions interactions to deliver energy to IL molecules, accelerating the process of material synthesis, catalytic reactions, and so on. In addition to the inherent advantages of ILs, including outstanding solubility, and well-tuned thermophysical properties, MAIL technology has exhibited great potential in process intensification to meet the requirement of efficient, economic chemical production. Here we start with an introduction to principles of MW heating, highlighting fundamental mechanisms of MW induced process intensification based on ILs. Next, the synergies of MW energy and ILs employed in materials synthesis, as well as their merits, are documented. The emerging applications of MAIL technologies are summarized in the next sections, involving tumor therapy, organic catalysis, separations, and bioconversions. Finally, the current challenges and future opportunities of this emerging technology are discussed.

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

Recycling ionic liquid (IL) solvents can reduce the lifecycle cost of these expensive solvents. Liquid-liquid extraction is the most straightforward approach to purify IL solvents and is typically performed with an immiscible washing agent (e.g., water). Herein, we describe a recycling route for water-miscible ILs in which direct recycling is usually challenging. We use hydrophobic ILs as accommodating agents to draw the water-miscible IL from the aqueous washing stream. A biphasic slug flow of the mixed ILs and water is then separated by using a membrane. The water-miscible IL can then be drawn out from the mixed IL phase with acidified water and dried under vacuum. Both the water-miscible IL and the accommodating agent are then recycled. Here, we demonstrated a proof-of-concept of this process by recycling 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM-OTf) in the presence of the accommodating agent 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-NTf2) and acidified water. We then demonstrated the capacity to recycle 1-butyl-1-methylpyrrolidinium triflate (BMPYRR-OTf) from a realistic synthetic application: Pt nanoparticle synthesis in the water-miscible IL.

Detoxification of ionic liquids using glutathione, cysteine, and NADH: Toxicity evaluation by Tetrahymena pyriformis

Ionic liquids (ILs), also known as green solvents, are widely acknowledged in several fields, such as chemical separation, synthesis, and electrochemistry, owing to their excellent physiochemical properties. However, their poor biodegradability may lead to environmental and health risks, posing a severe threat to humans, thus requiring further research. In this study, the biotoxicities of the imidazolium-based ILs were evaluated in Tetrahymena pyriformis. Moreover, IL detoxification was investigated by addition of glutathione (GSH), cysteine, and nicotinamide adenine dinucleotide (NADH). Reactive oxygen species (ROS) initiated by different IL types caused damage to Tetrahymena, while glutathione, cysteine, and NADH eliminated ROS, achieving the detoxification purposes. Detoxification results showed that NADH exhibited the best detoxification ability, followed by glutathione and cysteine. Finally, RT-PCR results suggested that metallothionein might have participated in IL detoxification.