Selective Removal of Cr (VI) Ion from Aqueous Solution using Gum Arabic-polyaniline Cross - linked Citric Acid Imprinted Polymer

Abstract

The aim of this study is to prepare ion-imprinted polymers, which can be used for the selective removal of Cr(VI) anions from aqueous media. Aniline was used as functional monomer, Gum Arabic as co-polymer to stabilize the polymer, ammonium per sulfate as initiator and hydrochloric acid as porogen. The Cr(VI)-imprinted polyaniline-gum particles were prepared by bulk polymerization. The Cr(VI)-imprinted polymer particles were grinded and the template ions (i.e., Cr(VI)) was removed using 0.1M NaOH. The control polymer (non-imprinted polymer) was prepared in the same manner in the absence of Cr(VI) ion. The polymers were characterized by FTIR and SEM. The specific surface area of the IIP and NIP particles were found to be 554.58m2/g and 511.43m2/g respectively. The swelling ratio was obtained for IIP and NIP with three solvent (D.W , 0.1M HCl and 0.1M NaOH). The contact time, pH of the medium and the effect of initial concentration of Cr(VI) anions on adsorption capacity of Cr(VI)-imprinting polymer and non-imprinted polymer were studied. The results showed that the maximum experimental adsorption capacity was obtained at optimum pH2, 120 min and 100 mg/L initial concentration at 25 ◦C. The first- and second order kinetics models were estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. The adsorption systems was followed pseudo-second order kinetic. The Langmuir adsorption isotherm model was well described the Cr(VI)-imprinted system. The selectivity study that the adsorption capacity of Cr(VI)-imprinted particles for Cr(VI) folds greater than that of the competitive ions Cu(II) and Fe(III)ions.