Three tire pyrolysis chars were activated in a CO2 atm. at 1100 degrees C and used as adsorbents for removal 2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid and 2-methyl-4-chlorophenoxypropionic acid from their aq. solns. The amt. of adsorbed acids was correlated with the activation time and the degree of adsorbent surface development. The best adsorbent had a sp. surface area of 255 m(2)/g and a total pore volume of 0.447 cm(3)/g after 135 min long activation. The best adsorption efficiency was achieved at pH 2-3. The best compatibility of exptl. and model data was obtained for the Sips model.