A comparative study of experimental optimization and response surface optimization of Cr removal by emulsion ionic liquid membrane

► A comparative study on the optimization of process parameters of an emulsion ionic liquid membrane (EILM) by experimental work and response surface methodology (RSM) has been carried out. ► The comparison showed that all the values were in good agreement except for the internal phase concentration and the treat ratio. ► Various interactions of the parameters affecting the final removal of Cr have been discussed to improve the efficiency of EILM. ► Under optimum conditions, 97% of Cr could be recovered.