Effect of dilution on the performance of ionic liquids in milliflow solvent extraction applications: Towards integration of extraction, scrubbing and stripping operations with in-line membrane-based phase separation

•Loss of secondary slug flow recirculations can be avoided by ionic liquid dilution.•Balancing of mass-transfer and reaction-limitations by IL concentration modulation.•Improved extraction selectivity, reagent use and slug flow stability upon dilution.•In-line membrane-based phase separation up to 65 vol% [A336][HSO4] in p-cymene.•Integration of millifluidic Ge(IV) solvent extraction, scrubbing and stripping.