Recovery of the N,N-Dibutylimidazolium Chloride Ionic Liquid from Aqueous Solutions by Electrodialysis Method

Abstract

Ionic liquids (ILs), named also as liquid salts, are compounds that have unique properties and molecular architecture. ILs are used in various industries; however, due to their toxicity, the ILs’ recovery from the postreaction solutions is also a very important issue. In this paper, the possibility of 1,3-dialkylimidazolium IL, especially the N,N-dibutylimidazolium chloride ([C4C4IM]Cl) recovery by using the electrodialysis (ED) method was investigated. The influence of [C4C4IM]Cl concentration in diluate solution on the ED efficiency was determined. Moreover, the influence of IL on the ion-exchange membranes’ morphology was examined. The recovery of [C4C4IM]Cl, the [C4C4IM]Cl flux across membranes, the [C4C4IM]Cl concentration degree, the energy consumption, and the current efficiency were determined. The results showed that the ED allows for the [C4C4IM]Cl recovery and concentration from dilute solutions. It was found that the [C4C4IM]Cl content in the concentrates after ED was above three times higher than in the initial diluate solutions. It was noted that the ED of solutions containing 5–20 g/L [C4C4IM]Cl allows for ILs recovery in the range of 73.77–92.45% with current efficiency from 68.66% to 92.99%. The [C4C4IM]Cl recovery depended upon the initial [C4C4IM]Cl concentration in the working solution. The highest [C4C4IM]Cl recovery (92.45%) and ED efficiency (92.99%) were obtained when the [C4C4IM]Cl content in the diluate solution was equal 20 g/L. Presented results proved that ED can be an interesting and effective method for the [C4C4IM]Cl recovery from the dilute aqueous solutions.

Enabling Sustainable Chemistry with Ionic Liquids and Deep Eutectic Solvents: A Fad or the Future?

“…One research area focuses on recycling, which can mitigate environmental pollution and probably ameliorate economic competitiveness. Because of the low vapor pressure of ILs and DESs, the distillation of volatile or thermally stable compounds seems the simplest method to recover and recycle ILs from a mixture [76–80] . A caveat is that distillation consumes energy, making the process costly and unsustainable, and could trigger the formation of unwanted products and thermal decomposition.…”

Enabling Sustainable Chemistry with Ionic Liquids and Deep Eutectic Solvents: A Fad or the Future?

“…Because of the low vapor pressure of ILs and DESs, the distillation of volatile or thermally stable compounds seems the simplest method to recover and recycle ILs from a mixture. [76][77][78][79][80] A caveat is that distillation consumes energy, making the process costly and unsustainable, and could trigger the formation of unwanted products and thermal decomposition. When an IL or DES is mixed with non-volatile or thermally sensitive compounds, adsorption, crystallization, electrodialysis, membrane separation, two-phase aqueous extraction, or extraction with organic solvents or supercritical carbon dioxide proves effective in recovery or recycling, depending on the properties of the IL and DES.…”

Recent Advances in Synthesis, Characterization and Applications of Innovative Materials in Removal of Water Contaminants

“…This Special Issue also includes the study of Babilas et al [21] on the recovery of the N,N-Dibutylimidazolium chloride ionic liquid from aqueous solutions by an electrodialysis method. The fact that the recovery ratio, the [C 4 C 4 IM]Cl molar flux, and the electric current efficiency increase with a rising concentration of [C 4 C 4 IM]Cl in the feed solution was reported [21]. The energy consumption also highly depends on the initial [C 4 C 4 IM]Cl content and increases linearly with the increase in the [C 4 C 4 IM]Cl concentration in the initial solution.…”

“…The energy consumption also highly depends on the initial [C 4 C 4 IM]Cl content and increases linearly with the increase in the [C 4 C 4 IM]Cl concentration in the initial solution. The ionic liquids concentration in the feed solution influences the solution conductivity, electrical resistance, and concentration polarization, as well as the electrodialysis efficiency [21] by a reduction in electrical resistance of the initial dilute with the increasing ionic liquids concentration and the acceleration of ions transport across membranes [21].…”