||Water treatment processes using ozone disinfection are to assure quality and safety for drinking water. But ozone will react with bromide ion to form bromate. The bromate will cause carcinogen to human by drinking water. This study is to investigate the adsorption on bromate using granulated activated carbon (GAC) or ion exchange resin (IER) as sorbents in water.|
The influence of pH, solution ionic strength, time, and temperature on the adsorption was examined. Adsorption equilibrium of IER and GAC was both described by Langmuir model, and achieved in approximately 4 hours. The adsorption capacity of bromate by IER was increased as the temperature increased, pH decreased and the ionic strength of the solution decreased. The adsorption capacity of bromate by GAC was increased as the temperature decreased, pH decreased and the ionic strength of the solution decreased. Maximum bromate adsorption capacities of 197 and 183 μg/g were respectively attained by IER and GAC at 25 °C. The adsorption data were fitted with the three models: modified Freundlich, pseudo-first-order, and pseudo-second-order. The pseudo-first-order produced the best fit to describe the kinetic adsorption on bromate for IER. The pseudo-second-order produced the best fit to describe the kinetic adsorption on bromate for GAC. The thermodynamics parameters: equilibrium rate constant, standard free energy change, standard enthalpy change, and standard entropy change were also calculated. In summary, adsorption of bromate for IER shows spontaneously adsorption reaction and exothermic reaction for GAC.