A Novel Method for Dye Removal: Ionic Liquid-Based Dispersive Liquid-Liquid Extraction (IL-DLLE)

A novel, simple, fast, and efficient ionic liquid-based dispersive liquidliquid extraction (IL-DLLE) has been applied to extract and remove Congo Red (CR; a carcinogenic textile dye) from aqueous solutions. In this methodology a binary solution, containing the extraction solvent (1-hexyl-3-methylimmidazolium bis(trifluormethylsulfonyl) imid) and a suitable disperser solvent, was rapidly injected into the water sample containing CR dye. Therewith, a cloudy solution was formed, and most of the dye molecules were extracted into fine IL droplets and removed from aqueous phase. The effects of pH, type, and amount of IL, initial concentration of the dye, type and volume of the dispersant, and concentrations of salt on the extraction of the dye were studied. Experimental surveys were also accomplished for recovery of the IL by applying a reverse dispersive liquidliquid extraction using acidic stripping solutions.