Extraction of cation mixture with Di(2-ethylhexyl) phosphoric acid immobilized on amberlite resins

Author(s): Omar Abderrahim, Mohamed Amine Didi, Didier Villemin

Extraction of Zn(II) fromacetate media aswell as froma cationmixture of Zn(II), Cd(II), Co(II), Cu(II), Fe(III), Ni(II) and Pb(II) derived froma solid waste dissolved in nitric acid (65%), by resin-supported di(2-ethylhexyl) phosphoric acid (D2EHPA) was investigated. The treatment by selective extraction of this recovered solid waste is of great economic and ecological importance. The resins XAD-1180, XAD-7 and XAD-4 were impregnated byD2EHPA. The effects of pH, the concentrations, the nature and amount of impregnated resins were also examined. The extraction yield of each metal ionwas determined as a function of pH. The affinity series for cations is Fe(III) >Cu(II)>Ni(II)>Zn(II)>Pb(II)>Cd(II)>Co(II). The interaction between D2EHPA and the polymeric support was examined through 13CMagic Angle Spinning Nuclear Magnetic Resonance (13C-MAS-NMR), 31P-MAS-NMR and Fourier Transform Infra-Red(FTIR) analyses. It was found that the adsorption of D2EHPA on the resin surface involves an alkyl-aryl interaction. The results obtained herein allow concluding that the process occurs mainly via an ion-exchange pathway, but increasing pH enhances an additional chelating process. FTIR measurements gave clear evidence of interaction between D2EHPA and the different resins, and indicate formation of metal complex in the resin phase.

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