Abstract: An activated carbon is modified to have bactericidal properties and/or an additional ability to remove heavy metals and other toxic substances. Said modified activated carbon is especially suitable for purifying drinking water and can be readily modified to be suitable for various regions with specific tap water impurities. Pursuant to the invention, activated carbon fiber is treated to adsorb a member of the group consisting of cations, anions, organic complex forming agents, surfactants, polyelectrolytes and organic bactericidal compounds.

Abstract: Activated carbon fiber is made by pre-treating a carbonized fibrous material, preferably a carbonized cellulose fiber, with a solution of nitrogen-containing compound, comprising at least one of the following substances: urea, ammonium carbonate, ammonium bicarbonate, ammonium acetate, and other organic salts of ammonia such as formate, carbamate, citrate and oxylate, and activating the pre-treated carbonized material at 800.degree. to 1200.degree. C. in an atmosphere comprising steam and/or carbon dioxide until a high degree of activation is produced. The activated carbon fiber material is amphoteric, wherein both acidic and basic functional groups are present on its surface. The resulting material is suitable for removing organic impurities, cations and anions from water and other fluids.