Removal of bromate from water using modified activated carbon

Coal-based activated carbon (AC) was treated chemically with nitric acid, sodium hydroxide and ammonia, and its ability to adsorb bromate was investigated. Several techniques were used to characterize the physicochemical properties of these materials, including surface area, pH_pzc, and Boehm titration. Results indicated that surface physical and chemical properties can influence the adsorption uptake of bromate on ACs simultaneously. Surface basicity and pH_pzc were both found to influence the electrostatic interactions between the bromate ions and the surface of the carbon. A correlation was found between basic groups and the adsorption capacity for bromate. The adsorption capacity of the carbon was found to be linearly proportional to the amount of basic groups on the surface. The bromate adsorption data collected from all the samples were found to fit the Toth isotherm model, indicating that the bromate adsorption process could occur on heterogeneous surfaces.