Bromate Adsorption on Three Variable Charge Soils: Kinetics and Thermodynamics

Abstract

A series of batch experiments about adsorption of bromate onto three variable charge soils from Southern China was carried out. The adsorption behavior of bromate was estimated as a function of reaction time (0–240 min), and the concentration of bromate at a fixed value (100 μg/L) at 25, 35, and 45°C. Bromate adsorption increased with the rise of temperature, indicating that bromate adsorption onto the variable charge soils was an endothermic process. The pseudo‐second‐order kinetic equation was used to describe the kinetic data. The adsorption equilibrium time of BrO3– onto three soils was about 120 min and independent of the reaction temperature. The data of isotherm experiments fit well with the Langmuir model, which implied that monolayer adsorption was feasible during the sorption process. The data of the adsorption experiments at different reaction temperatures were used to calculate thermodynamic parameters. The thermodynamic parameters calculated suggest that bromate adsorption onto the variable charge soils from Southern China was a spontaneous, endothermic, and entropy‐driven reaction as well as a physical adsorption process.