Application of response surface methodology with central composite design to evaluate the extraction of U(VI) into ionic liquids

•Extraction of Uranium (VI) from acidic aqueous solution by tri-n-butyl phosphate (TBP) into Ionic liquids ([EMIM][TF2N], [BMIM][TF2N] & [Trihexyl Tetradecyl Phosphonium] [TF2N]) compared to conventional solvents such as dodecane and TBP.•Distribution ratio of uranium into ionic liquids EMIM][TF2N] at lower aqueous acidity(0.01 M HNO3) showed the excellent results compared to [BMIM][TF2N], [Trihexyl tetradecyl phosphonium][TF2N]. At higher aqueous acidity (8 M HNO3) [Trihexyl tetradecyl phosphonium][TF2N] takes over.•The percent extraction of uranium into [EMIM][TF2N] is found to be highest 93% at lower aqueous acidity.•RSM with CCD was employed to predict the optimum extraction parameters.