The Removal of Chromium(VI) from Aqueous Solution by Amine-Functionalized Zeolite: Kinetics, Thermodynamics, and Equilibrium Study

摘要

In this study, the removal of Cr(VI) from aqueous solution by modified zeolite with 3-aminopropyltriethoxysilane was investigated. The effect of various parameters such as pH, contact time, temperature, initial concentration of Cr(VI) ion, common cations, and anions on the adsorption of Cr(VI) was studied. The modified zeolite was characterized by following instrumental analysis of XRD, SEM/EDS, BET, and FT-IR. Based on calculated thermodynamic parameters values (ΔG ~(0) < 0, ΔH ~(0) > 0, and ΔS ~(0) > 0) and kinetic properties of the adsorption of Cr(VI) by modified zeolite, it was concluded that the rate-limiting step of the process is a second-order chemical reaction. The results of the adsorption isotherm study confirmed that the adsorption follows the Langmuir isotherm model. The maximum adsorption capacity was 13.5 mg/g.