title: Factors affecting ionic liquids based removal of anionic dyes from water.
abstract: Liquid--liquid extraction with imidazolium based ionic liquids--[C4mim][PF6], [C6miml][PF6], [C6mim[BF4], and [C8mim][PF6--is proposed for removal of anionic dyes including methyl orange, eosin yellow, and orange G from aqueous solutions. The effects of extraction time, pH of aqueous phase, structure of the ionic liquids, temperature, and KCl concentration on the extraction efficiencies have been studied. Extraction efficiencies of dyes were strongly affected by the pH of the aqueous phase. Under the optimized pH condition, 85-99% of methyl orange, almost 100% eosin yellows, and 69% of orange G in tested water samples were transferred into the ionic liquids in a single extraction. Extraction efficiency for a given dye was found to increase with increasing temperature and increasing alkyl chain length of cation of the ionic liquids. Presence of a small amount of KCl in the aqueous phase did not considerably improve the extraction efficiency of the dyes. Thermodynamic studies revealed that the extraction process was driven by hydrophobic interaction of the anionic dyes and the ionic liquids.
authors: School of Chemistry and Environmental Science, Henan Key Laboratory of Environmental Pollution Control, Henan Normal University, Xinxiang, Henan 453007, PR China.
authors: Yuan Chao
authors: YC
authors: Pei
authors: Jian Ji
authors: JJ
authors: Wang
authors: Xiao Peng
authors: XP
authors: Xuan
authors: Jing
authors: J
authors: Fan
authors: Maohong
authors: M
authors: Fan
mesh_terms: D000838:Anions / Q000302:isolation & purification*; D004396:Coloring Agents / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D000838:Anions; D004396:Coloring Agents; D014874:Water Pollutants, Chemical