An activated carbon based adsorbent carrying an acid is provided for eliminating mercury or mercury compounds contained in hydrocarbons. Preferably the activated carbon base is provided with more than 80 ml/g micropore volume having radii less than 8 angstroms. Preferably the acid carried on the activated carbon is hydrochloric acid, sulfuric acid, or phosphoric acid. Hydrochloric acid is most preferred. The active carbon base is preferably manufactured by activating a carbonaceous material in an atmosphere comprising less than 30 vol. % water vapor. The adsorbent can be used to eliminate mercury or mercury compounds contained in hydrocarbons by contacting the adsorbent with the hydrocarbons in liquid phase. Particular hydrocarbons include naphtha and intermediates of oil products or petrochemical products. Minimal amounts of carried acid are desorbed from the adsorbent to the hydrocarbons. The adsorbent is useful to treat hydrocarbons in the oil industry to prevent possible harmful amalgamation due to mercury.