Dehydration of deep eutectic solvent by pervaporation with time-gated Raman spectroscopy

An article titled Role of Membrane Technology in Biorefineries - Dehydration of Deep Eutectic Solvent by Pervaporation has been published in the Journal of Membrane Science & Research Volume 8, Issue 2.

In this research, dehydration of a class of solvents called deep eutectic solvents (DESs) is investigated. They are relatively new and green media that can be used in biomass processing, for instance. In the study, the researchers used Timegated® Raman spectroscopy to analyze the samples and the paper proves that time-gated Raman spectroscopy is an excellent tool in the analysis of the DESs ChCl-urea samples.

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Abstract

In this paper, the dehydration and purification of a deep eutectic solvent choline chloride-urea (ChCl-urea) by pervaporation is presented. The stability of polymeric pervaporation membranes was first studied by exposing the membranes to ChCl-urea for 5 days at 40 °C and 60 °C. The results showed that the membranes were stable when in contact with ChCl-urea and no membrane material was dissolved. In the dehydration experiments, the permeate fluxes were highest with the polydimethylsiloxane (PDMS) membrane: 267.65 g m^-2 h^-1 at 50 °C and 413.39 g m^-2 h^-1 at 60 °C. Raman spectroscopy was employed in the analysis of the samples. The results also showed the decomposition of ChCl-urea, and the presence of the decomposition products, i.e., ammonia and carbamate, in the PDMS and PDMS-PVA-TiO₂ permeates. With the highest permeate fluxes and simultaneous removal of water and decomposition products, PDMS appeared to be the most promising membrane for the purification and dehydration of ChCl-urea.

The open access article can be found here: Role of Membrane Technology in Biorefineries - Dehydration of Deep Eutectic Solvent by Pervaporation.