On the use of imidazolium and ammonium-based ionic liquids as green solvents for the selective recovery of Zn(II), Cd(II), Cu(II) and Fe(III) from hydrochloride aqueous solutions

► Imidazolium and ammonium-based ionic liquids as extraction agents for Zn2+, Cd2+, Cu2+ and Fe3+. ► Almost complete removal of Zn2+, Cd2+ and Fe3+ was achieved using [MTOA+][Cl−]. ► [omim+][BF4-] allows the selective separation of Zn2+ and Cd2+ over Fe3+ and Cu2+. ► Increasing metal ion concentration decrease the extraction percentage of the metal ions. ► Increasing HCl concentration increase the extraction percentages for Zn2+, Cd2+ and Fe3+.