Cr(VI) removal from synthetic wastewater by amine functionalized SiO2: pH, Isotherm and kinetic studies

Abstract

Abstract The purpose of this study was to investigate the possibility of the utilization of amine functionalized SiO2 as an adsorbent for removing Cr(VI). The structure property of adsorbent was characterized by N2 adsorption-desorption isotherm, XPS, SEM and CO2-TPD. The maximum adsorption capacity of amine functionalized SiO2 was 27.78 mg/g at initial pH=2, which calculated by Langmuir isotherm model. But SiO2 does not have the ability to adsorb Cr(VI) before functionalized. Additionally, the adsorption can be described by the pseudo-second-order kinetic model, which illustrated that the “surface reaction” was the controlling step in adsorption process. From the result of CO2-TPD and adsorption energy, the electrostatic attraction between Cr(VI) species and protonated amine or hydroxyl group were regards as mainly adsorption mechanism.