Behavior of hydrophobic ionic liquids as liquid membranes on phenol removal: Experimental study and optimization

►Ionic liquids behave as new stable liquid membranes for phenol transport. ►Ionic liquids' hydrogen bond basicity strength highly affects phenol extraction. ►Ionic liquids can be regenerated in a high percentage with good reusability. ►[Bmim][NTf2] has similar behavior with organic membrane solvents. ►Ionic liquids showed comparable efficiencies with organic membrane solvents.