Adsorption of Cr(VI) from aqueous solutions onto activated pomegranate peel waste
E. A. Abdel-Galil, L. M. S. Hussin, Wafaa Mohamed El-Kenany
Abstract
ABSTRACT The present study deals with the employ of the chemically activated pomegranate peel (PGP-1N H 2 SO 4 ) as a low-cost adsorbent for the retention of Cr(VI) ions from aqueous solutions. The physicochemical characteristics of the chemically activated pomegranate peel were studied using Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. The influences of several factors such as contact time, pH of the solution, initial concentration of the adsorbate ion, and adsorbent mass on the removal of Cr(VI) ions were studied using the batch sorption technique. The equilibrium data fitted reasonably well to the Langmuir model, while pseudo-second-order best designated the kinetics of the adsorption process. The maximum adsorption capacity for Cr(VI) ions onto pomegranate peel as calculated by the Langmuir model was found to be 28.28 mg/g at 25°C ± 1°C. The values of thermodynamic parameters (ΔG°, ΔH°, and ΔS°) were computed from the Van’t Hoff plot which revealed that the adsorption of Cr(VI) was feasible, endothermic, and spontaneous. Based on good uptake capacity, PGP-1N H 2 SO 4 was successfully used for the removal and recovery of Cr(VI) from double-distilled water (DDW), tap water, synthetic seawater, natural seawater, and wastewater. The adsorbed metals were easily recovered by desorption in 0.5 N NaOH.