A coal-based activated carbon was treated chemically with nitric acid, sodium hydroxide and ammonia for its surface modification, and its adsorption capacity was investigated with bromate. Several techniques were used to characterize the physicochemical properties of these materials including BET, XPS, pHpzc and Boehm titration. The results indicated that the specific surface area of the activated carbon decreased after oxidation with nitric acid. But the amount of surface acidic oxygencontaining functional groups of the oxidized sample increased compared to the raw carbon and the points of zero charge (pHpzc) decreased. The specific surface area of the activated carbon also decreased after sodium hydroxide treatment and the points of zero charge increased. The changes of surface chemical properties after the ammonia treatment was opposite to the oxidized sample. As a result, the pHpzc of the carbon was increased to near pH9.3, the amount of surface basic groups was increased. Furthermore, the data of bromate adsorption on all the samples were fitted to the Langmuir isotherm model well which indicates monolayer adsorption. In addition, the adsorption capacity of ammonia treatment sample was the highest and its saturated adsorption capacity reached 1.55mg/g. A strong correlation was found between basic groups and adsorption capacity of bromate. Enhancement of basic groups was favorable for bromate removal.

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, pHpzc, and Boehm titration. Results indicated that surface physical and chemical properties can influence the adsorption uptake of bromate on ACs simultaneously. Surface basicity and pHpzc 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.

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