Ionic liquids (ILs) are a promising medium to assist in the advanced (chemical and biological) recycling of polymers, owing to their tunable catalytic activity, tailorable chemical functionality, low vapor pressures, and thermal stability. These unique physicochemical properties, combined with ILs’ capacity to solubilize plastics waste and biopolymers, offer routes to deconstruct polymers at reduced temperatures (and lower energy inputs) versus conventional bulk and solvent-based methods, while also minimizing unwanted side reactions. In this Viewpoint, we discuss the use of ILs as catalysts and mediators in advanced recycling, with an emphasis on chemical recycling, by examining the interplay between IL chemistry and deconstruction thermodynamics, deconstruction kinetics, IL recovery, and product recovery. We also consider several potential environmental benefits and concerns associated with employing ILs for advanced recycling over bulk- or solvent-mediated deconstruction techniques, such as reduced chemical escape by volatilization, decreased energy demands, toxicity, and environmental persistence. By analyzing IL-mediated polymer deconstruction across a breadth of macromolecular systems, we identify recent innovations, current challenges, and future opportunities in IL application toward circular polymer economies.
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Practical Online Monitoring of Ionic Liquid Fiber Welding Solvent
Ionic liquids (ILs) are becoming important solvents in commerce, but monitoring their purity and performance in industrial applications presents new challenges. Fiber welding technology utilizes ILs to mold and shape natural fibers (cotton, hemp, flax, silk, and wool) into morphologies that are typically attained only using synthetic, petroleum-based non-biodegradable plastics. The result is an atom-efficient process that up-converts fibrous substrates to value-added products and materials. A key aspect of bringing this and other IL-enabled technologies to market relies on efficient monitoring and recycling of IL-based solvents. Implementing online IL quality monitoring enhances the unit economics of these processes. Here, we characterize and report conductivity measurements, refractometry, and ATR–FTIR spectroscopy techniques for online IL monitoring during an industrial fiber welding process. The online analysis enables more efficient recycling of the IL solvent, increasing the process efficiency and product quality.
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- Award ID(s):
- 1651381
- PAR ID:
- 10318691
- Date Published:
- Journal Name:
- ACS omega
- Volume:
- 6
- Issue:
- 34
- ISSN:
- 2470-1343
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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