Extraction of Cu(II) ions from aqueous solutions by free fatty acid-rich oils as green extractants

Three types of free fatty acid (FFA)-rich oil, i.e. Jatropha oil (JO), palm fatty acid distillate (PFAD) and palm kernel fatty acid distillate (PKFAD), were investigated into their potentiality as green extractants for Cu(II) ion extraction from aqueous solutions. The physicochemical properties of FFA-rich oils and their progressive phase separations with Cu(II)-containing aqueous solutions were studied. The effect of initial Cu(II) ion concentration on the extraction efficiency by different FFA-rich oils along with their pH-extraction isotherms and back-extraction (stripping) were also explored. The results revealed that PKFAD showed the most favorable physicochemical properties and phase separation behavior while achieving a high extraction efficiency (> 95%) among all the FFA-rich oils studied. Therefore, PKFAD is a prospective green exractant for Cu(II) ions from aqueous solutions.