Adsorption behavior of Cr(VI) on activated carbon: isotherm, kinetic, and thermodynamic studies

Abstract

In this study, the removal of Cr(VI) with activated carbon obtained by activation of chestnut inner shells with H3PO4 agricultural waste, was examined. The effect of different parameters such as initial pH to adsorption (1.0-8.0), initial Cr(VI) concentration (25-250 mg L-1), amount of adsorbent (0.05-1.0 g 100 mL(-1)), temperature (293-313 K), and contact time (5-120 min), were examined. As a result of experimental studies, the highest Cr(VI) removal was identified as 60 min. The highest yield of Cr(VI) was obtained at pH 2.0. The adsorption capacity of activated carbon is 227.27 mg g(-1). According to the obtained experimental data, it was observed that the equilibrium adsorption was consistent with the Langmuir isotherm. Kinetic studies have determined that Cr(VI) adsorption is the pseudo-second-order. The thermodynamic parameters calculated to estimate the nature of adsorption indicated a spontaneous and endothermic adsorption. All experimental results showed that the environmentally friendly, low-cost, and easily available adsorbent for the removal of Cr(VI) ion from aqueous solution by activated carbon obtained with activation of chestnut inner shells with H3PO4.