STUDY OF THE SORPTION OF Cr(III) WITH XAD-2 RESIN IMPREGNATED WITH DI-(2,4,4 TRIMETHYLPENTYL)PHOSPHINICACID (CYANEX 272)

Abstract

ABSTRACT Solvent impregnated resin containing Cyanex 272 (di-(2,4,4-trimethylpentyl)phosphinic acid, denoted HL) was prepared by adsorption of the organophosphorus extractant into the polymeric macroporous support Amberlite XAD-2. The extraction of Cr(III) from nitrate solution at 0.1 ionic strength by the impregnated resin has been studied at 25°C The sorption of the metal ion was studied as a function of both pH and extractant concentration in the resin phase. The impregnated resin shows good affinity towards the extraction of Cr(III). The best sorption efficiency (98%) was obtained at pH≈5. A thermodynamic model is proposed for modeling the distribution data. This model shows that Cr(III) is extracted as Cr(OH)(HL)2(N03) 2 and Cr(OH)L2. The elution of the metal from the resin was accomplished (95%) with 6.0 M HCI. The elution treatment allows the impregnated resin to be reused.