Effet du diluant sur l’extraction du cuivre(II), cobalt(II) et nickel(II) par l'acide di-(2-ethylhexyl) phosphorique

Abstract

In the present work, the extraction of copper(II), cobalt(II) and nickel(II) from sulfate media with di-(2-ethylhexyl) phosphoric acid (D2EHPA) in various polar and nonpolar solvents at 25 °C, has been carried out. The study of the acid-base behavior of the D2EHPA in a biphasic (chloroform, toluene, dichloromethane, carbon tetrachloride, isobutyl-methyl keton, cyclohexane, 1- octanol) – water (Na2SO4) systems showed that the value of A pK was increase in the order: 1-octanol < isobutyl-methyl keton < cyclohexane < carbon tetrachloride < toluene < dichloromethane ~ chloroform. The stoichiometry of the extracted species of copper(II) in the organic phase have been found to be CuL22HL and CuL2 in nonpolar and polar solvents respectively. According to the nature of the solvent, the extraction of copper(II) by D2EHPA decreased in the order: 1-octanol > cyclohexane > isobutyl-methyl keton > carbon tetrachloride > dichloromethane > chloroform ~ toluene. The stoichiometry of the extracted species of cobalt(II)in the organic phase have been found to be CoL22HL and CoL2 in nonpolar and polar solvents respectively. According to the nature of the solvent, the extraction of cobalt(II) by D2EHPA decreased in the order: 1-octanol > cyclohexane > dichloromethane> carbon tetrachloride ~ toluene > isobutylmethyl keton > chloroform. The stoichiometry of the extracted species of nickel(II) in the organic phase have been found to be NiL22HL and NiL2 in nonpolar and polar solvents respectively. According to the nature of the solvent, the extraction of nickel(II) by D2EHPA decreased in the order: 1-octanol > cyclohexane > isobutyl-methyl keton > carbon tetrachloride > dichloromethane > toluene ~ chloroform.