COMPETITIVE ADSORPTION OF 2,4-DICHLOROPHENOL AND 2,4,6-TRICHLOROPHENOL IN THE NANOMOLAR TO MICROMOLAR CONCENTRATION RANGE

This study shows how effectively trace amounts of chlo-rophenols are adsorbed by activated carbon under the competitive conditions encountered in natural waters. Chloro-phenols are odor-producing contaminants which form in water supplies via the reaction between chlorine and phenol during disinfection, and activated carbon is one of the best-available methods for removing chlorophenols from water. Strong competition was observed between anionic and neutral species of dichlorophenol and trichlorophenol even at the 1 µg/L level. Of the competitive adsorption models studied, the Langmuir model best fit the observed data. Evaluation of the competitive adsorption between chlorophenols and humic substances, which are present in nearly all municipal water supplies, indicated that the presence of these materials decreased the capacity of carbon for chlorophenols. The extent of competition was dependent on the source of the humic substances and pH was found to have a significant effect on the adsorption of both chlorophenol and the humic substances. © 1979, American Chemical Society. All rights reserved.