Background: Several industries including petroleum refineries, petrochemical plants, olive oil mills, pesticide manufacturing, and oil field activities generate waste streams containing significant amounts of phenol and its derivatives. Since phenol is classified as a toxic and priority hazardous compound, it is required to be degraded prior to discharging the contaminated streams to the environment. The purpose of this research was to study the phenol removal by using modified zeolite (Clinoptilolite) by FeCl3 from aqueous solutions.Methods: The prepared zeolite was crushed and pulverized by standard ASTM sieves with a range of mesh 20 (0.85 mm). The chemical composition and the surface area were analyzed using X-ray diffraction (XRF) and N2 gas via BET isotherm and Belsorb software. In this study, different parameters included pH (3, 7, 12), the initial concentration of phenol (25- 200 mg/L), the contact time (20-240 min) and the amount of modified zeolite (0.25-3 g / 250 cc) which carried out in a batch reactor were examined. The concentration of Phenol was measured by the photometric method (500 nm).Findings: The results of this study indicated that increasing of the primary concentration of phenol, the adsorbent dose, and pH (3 to12) would lead to increasing of adsorption/removal of phenol. Equilibration of phenol adsorption was reached at lapse of 100 min and optimum pH for adsorption of phenol with zeolite found in 3. Adsorption of phenol with zeolite complying with Langmuir isotherm (R2=0.98).Conclusion: The results of the study show that modified pumice can be used effectively in removing phenol. The removal efficiency of phenol in higher pH is more than lower pH. Also, due to the low price of the pumice and its simple modification, it can be used to remove hazardous materials in water and wastewa.