Study of the parameter affecting the adsorption of substiuted phenols by … 45 indicated that, the increase of initial concentration increases the efficiency of adsorbed phenols. The highest adsorption efficiency is observed in the neutral medium of the studied compound. Increasing the temperature decreases the amount of adsorbed phenols suggesting the physical nature of adsorption system under consideration. Depending on the effect of temperature, the thermodynamic functions of adsorption were estimated. The obtained values showed that, the adsorption process is spontaneous, exothermic and controlled by entropy effect. The application of Freundlich isotherm is good Fitted the experimental data of the adsorption system. The overall results showed that, the adsorption of the investigated compounds are affected by the resonance and inductive effect of the concerned subsistent.