This study involves the chemical modifications of fly ash by the impregnation method using two different metal ions of aluminum and iron for phenol removal from synthetic waste water. Sorption behavior of phenol from synthetic solution containing initial concentration of 200 mg/l on fly ash was examined by studying the effect of adsorption parameters: adsorbent dose, pH, contact time, and initial concentration. Aluminum impregnated fly ash was found to show the better removal efficiency of 85.6% than iron impregnated fly ash showing 82.1% removal. Pseudo second order kinetics was followed for the adsorption of phenol onto fly ash and impregnated fly ash. Different equilibrium isotherms were examined using non-linear regression technique and Redlich-Peterson isotherm was found to best fit the equilibrium data. Thermodynamic parameters for aluminum impregnated fly ash was also evaluated which showed process to be endothermic. The standard change in enthalpy and standard change in entropy was estimated to be 30.79 kJ/mol and 104.92 kJ/mol K, respectively. Negative value of Gibbs free energy change showed the process is spontaneous and feasible.