COMPARISON OF CR(VI) ADSORPTION ONTO POLYMER-BASED MAGNETIC HYBRID ADSORBENTS BY NONLINEAR ISOTHERM AND KINETIC MODELS

Abstract

In the present study, polyglycidyl methacrylate graft copolymer (PG) and ethylene glycol dimethacrylate based polymers (EG) were synthesized and modified by iron oxides in order to have magnetic form (PG-M and EG-M). Batch hexavalent chromium (Cr(VI)) adsorption experiments were carried out as a function of pH. Adsorption data were applied to Langmuir, Freundlich, Dubinin-Raduskevich, Sips, Toth and Redlich-Peterson isotherm models by utilizing non-linear techniques. The Dubinin-Radushkevich isotherm model was found to be the most suitable one for PG-M sample, while Langmuir model fitted best to the experimental data of EG-M sample. The contact time needed for both adsorbents was relatively short, ranging from 1 to 30 min. Approximately 73% of Cr(VI) was rapidly removed by PG-M within ten minutes; and for EG-M sample, 88% of Cr(VI) was removed at the end of five minutes. The rate of the adsorption is governed by a pseudo-second order rate equation.