Surface-Treated Activated Carbon for Removal of Ammonia from Water

Abstract

As-received commercial activated carbons do not adsorb noticeable amounts of ammonia from aqueous solution. Following oxidation, pH values of aqueous carbon suspensions decrease appreciably with a concomitant increase in their ammonia adsorption capacities. Oxidative treatment with nitric acid is most effective for enhancing ammonia adsorption capacity of a carbon. Irrespective of the oxidative treatment, the relative concentration of carboxylic, lactonic, and phenolic groups on different oxidized carbons is more or less constant. Breakthrough curves have been measured at different flow rates for two oxidized carbons. Bed capacities are essentially constant after the first cycle and could be regenerated with 0.1 N HCl.