Removal of Cr (III) in Batch and Pilot Scale Dynamic Systems Using zeolite NaA Prepared from Egyptian Kaolin

Zeolite NaA was prepared from Egyptian kaolin on pilot scale through metakaolinization and zeolitization. Sorption experiments of chromium (III) ions using the prepared zeolite were carried out in batch and pilot scale dynamic systems at 30 C. Models including Langmuir, Freundlich and Dubinin–Radushkviech isotherms were investigated for the nominated systems. Sorption results were best interpreted by Langmuir isotherm. The relevant batch Langmuir isotherm parameters; namely the maximum adsorption capacity (qm) and the dissociation constant for the ion-adsorbent interaction (Kd) were estimated as 25.32 ± 2.05 mg/g and 1.51 ± 0.15 mg/l, respectively. The estimated dynamic Langmuir isotherm parameters were compared to their batch counterparts. The dynamics of column sorption were represented by a lumped kinetic model. The model takes into account the axial dispersion to simulate the breakthrough curves. Both the values of the time corresponding to half the initial feed concentration (t1/2) and the equilibrium position (outlet concentration ”C”/ feed concentration ”Cf”) for the investigated concentration range (36-148 mg/l) were successfully predicted through the adopted model. The results in general elucidate the promising features of NaA zeolite developed from local low cost Egyptian kaolin for chromium (III) removal from specific industrial effluents.