A laboratory study was conducted to determine the influence of a 0.05M phosphate buffer on the adsorption of 2,4‐dichlorophenol (2,4‐DCP) and 2,4‐dinitrophenol (2,4‐DNP) from aqueous solution. Kinetic and equilibrium characteristics were studied. In summary, the phosphate buffer exhibited no discernible influence on the rate of adsorption and adsorptive capacity of an undissociated adsorbate. However, the adsorption of the dissociated forms of 2,4‐DCP and 2,4‐DNP at equilibrium exhibited differing characteristics in the presence and absence of a 0.05M phosphate buffer. The amount of adsorption of the dissociated compounds was increased in the presence of the phosphate buffer, in comparison to similar experiments in which the buffer was not present.