Adsorption of hexavalent chromium on Arundo donax Linn activated carbon amine-crosslinked copolymer

A composite sorbent (AC-EDT) was prepared by grafting amine-group onto activated carbon (AC). Both raw AC and AC-EDT were characterized by scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Batch experiments with variable pH, time, and concentrations of Cr(VI) were conducted to evaluate the sorption performance of Cr(VI) by both adsorbents from aqueous solutions. The total chromium in the aqueous solution was also recorded to study the mechanism of adsorption/transformation of Cr(VI). The ratio of the amount of Cr(VI) to Cr(III) on the sorbent was confirmed by the XPS analysis results. Langmuir, Freundlich and Temkin adsorption isotherms were used to fit the experimental equilibrium data and values of the parameters of the isotherms were reported. When compared with the untreated activated carbon, the modified activated carbon provided more faster kinetics and the sorbent exhibits greater adsorption capacity for chromium(VI) by comparing the maximum adsorption capacity calculated by Langmuir model. Overall, AC-EDT can effectively remove Cr(VI) from aqueous solutions under a wide range of experimental conditions. (C) 2012 Elsevier B.V. All rights reserved.