Highly Selective Transport of Organic Compounds by Using Supported Liquid Membranes Based on Ionic Liquids

Abstract

Trennen, stetig und effektiv: Durch selektiven Transport durch eine in einer Trägermembran immobilisierten Flüssigkeit lassen sich in einem kontinuierlichen Verfahren organische Verbindungen trennen. Die Membran besteht aus der bei Raumtemperatur in den Poren einer hydrophilen Polyvinylidenfluorid‐Membran immobilisierten ionischen Flüssigkeit 1‐n‐Butyl‐3‐methylimidazoliumhexafluorophosphat. Ohne erkennbaren Selektivitätsverlust wurde 14 Tage lang kontinuierlich eine Mischung der isomeren Amine Diisopropylamin (S1) und Triethylamin (S2) im molaren Verhältnis 1:1 fraktioniert (siehe Schema).

Recent progress and perspectives in microbial fuel cells for bioenergy generation and wastewater treatment

“…can be adapted to specific purposes by varying their composition [16]. In fact, ILs have already been applied in lab-scale processes to replace conventional organic solvents in purification or separation processes [15,51,52,92,124,125], in reaction media in biochemistry [123,126,131] and as chemical catalysts [32,137,140]. In membranes, they have been found to be of great interest due to their high ion conductivity and solvent power.…”

Ionic liquids in supported liquid membrane technology

“…Ionic liquids (ILs), also called room temperature ionic liquids (RTILs) and ambient temperature molten salts, which are liquids at ambient temperature have virtually no vapor pressure loss by evaporation can be effectively suppressed [77,78]. The high viscosity and high surface tension of ionic liquids provide mechanically stable membranes more tolerant of mechanical forces, pressure and temperature changes.…”

“…alcohols, ketones and amines [83], by allowing selective transport of the compounds through the SLM. Branco and his co-workers clearly suggest that the nature of the supporting membrane and the selected room temperature ionic liquids strongly affects the transport phenomena in a particular separation process [78]. The use of 1-butyl-3-methyl-imidazolium hexafluorophosphate in a polyvinylidene fluoride membrane was found to exhibit an extremely highly selective transport of secondary amines over tertiary amines, because of stronger hydrogen bonding of the secondary amine to the slightly acidic C-2 positioned hydrogen in the ionic liquid imidazolium cation [78].…”

“…Branco and his co-workers clearly suggest that the nature of the supporting membrane and the selected room temperature ionic liquids strongly affects the transport phenomena in a particular separation process [78]. The use of 1-butyl-3-methyl-imidazolium hexafluorophosphate in a polyvinylidene fluoride membrane was found to exhibit an extremely highly selective transport of secondary amines over tertiary amines, because of stronger hydrogen bonding of the secondary amine to the slightly acidic C-2 positioned hydrogen in the ionic liquid imidazolium cation [78]. Selective transport of the aromatic hydrocarbons benzene, toluene and pxylene in polyvinylidene fluoride membranes containing different ionic liquids have also been examined [77] and the permeation rates observed followed the order of the increasing hydrophobicity of the ionic liquids and are smaller than water-based SLMs because of the high viscosities of the ionic liquids.…”

“…Some researchers have recently reported that the SILMs [78,83,94] achieved selective transport of organic compounds such as alcohol, ketones and amines [77,93]. There is a rapid development in the field of separation of hydrocarbons focused on the isolation of aromatics from aliphatic hydrocarbons.…”