The extraction of boron by liquid-liquid extraction and by supported liquid membranes (SLM) using two ionic liquids, the trioctyl/decylmethylammonium-bis(2,4,4-trimethilpentyl) phosphinate (ALiCY IL) and the trioctyl/decylmethylammonium decanoate (ALiDEC IL) has been explored in this work.These quaternary ammonium based ionic liquids were synthesized from Aliquat 336 and Cyanex 272 or decanoic acid and conditioned with NaHCO3 washings. The ILs demonstrated to be efficient and selective for solvent extraction of boron from aqueous solutions with high chloride concentration (0.5M). Similar behaviour was observed for both ILs tested. About 60% of extraction can be achieved in a wide pH range when 0.54M of the IL in 10% decanol/querosene was used.Transport of boron across flat sheet supported liquid membranes was evaluated using different concentrations of the ALiCY and ALiDEC ILs. The permeability coefficient dependence on the concentration of these ILs was found. © 2013 The Institution of Chemical Engineers. ; Peer Reviewed ; Postprint (published version)