Chemical Engineering Research & Design, Vol.90, No.10, 1660-1670, 2012
Adsorption studies of Cr(III) ions from aqueous solutions by DEHPA impregnated onto Amberlite XAD7-Factorial design analysis
The present paper investigates the adsorption of Cr(III) ions using the SIR, prepared by impregnation of Amberlite XAD7 with di-(2-ethylhexyl)-phosphoric acid (DEHPA), which has been chosen as an extractant for the purpose of this study. The Amberlite XAD7-DEHPA resin was impregnated with DEHPA and ethylic alcohol as solvent trough dynamic column impregnation method. The influence of different physicochemical parameters (pH, resin dosage, initial concentration of Cr(III) ions, contact time and temperature) upon the adsorption capacity of XAD7-DEHPA, in the Cr(III) ions removal process from aqueous solution, has been investigated. The pH for Cr(III) ions adsorption was found as 3.0 for this material. The results showed that the adsorption equilibrium was reached after 45 min. The adsorption process is best described by the pseudo-second order kinetic model. Langmuir adsorption isotherm gave a satisfactory fit of the equilibrium data. The maximum adsorption capacity is similar to 3 mgCr(III) ions/g SIR. The thermodynamic studies allowed us to determine the thermodynamic parameters Delta G degrees, Delta H degrees and Delta S degrees. In this paper the factorial design of experiments was used to study the performance of the adsorption process. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Keywords:Amberlite XAD7;DEHPA;Solvent impregnated resin (SIR);Cr(III);Sorption kinetics;Factorial design