Removal of phenolic compounds from aqueous solutions by emulsion liquid membrane containing Ionic Liquid [BMIM]+[PF6]− in Tributyl phosphate

An experimental study on removal of phenolic compounds from aqueous solutions using Ionic Liquid Mixed Carrier (ILMC) containing 1-Butyl 3 Methylimidazolium Hexafluorophosphate [BMIM]+[PF6]− dissolved in Tributyl phosphate (TBP) in an Emulsion Liquid Membrane (ELM) was carried out. The effects of various operating parameters such as TBP Concentration, stripping reagent concentration, surfactant concentration, emulsification time, phase volume ratio, treat ratio, stirring speed, external phase pH and [BMIM]+[PF6]− concentration in TBP on removal of phenol has been experimentally investigated. It was found that addition of 0.02% (v/v) of [BMIM]+[PF6]− in membrane phase has enhanced the emulsion stability by 5 times and this was carried out using Rose Bengal dye to visualise the emulsion separation. An FTIR spectrum for TBP, ILMC and membrane phase before and after loading of phenol was generated to indicate their interactions and bonding. By selecting appropriate operating conditions, it was found to remove 99.5% of phenol and more than 90% of chlorophenols from aqueous solutions at the treat ratio of 3.

► BMIM]+[PF6]− with TBP as Ionic Liquid Mixed Carrier (ILMC) for phenol removal.
► Minimum usage of Ionic Liquid in ILMC for stable emulsion with maximum percentage removal of phenolic compounds.
► ILMC characterized by FTIR.
► ILMC reduces the extraction time and maximizes the removal efficiency for higher treat ratio.
► Emulsion stability was tested under a static conditions using Rose Bengal Dye.