Background: The presence of nitrate in drinking water causes various health and environmental problems. The aim of this study was to evaluate the efficacy of nitrate reduction by Fe/H2O2 process and adsorption on activated carbon. Materials and Methods: This experimental study investigated nitrate oxidation by advanced oxidation process of Fe°/FeІІ/FeШ/H2O2 at pH 2-10, nitrate concentrations of 50-300 mg/L. After adjusting the pH, 0.5, 1, 2, 5, and 10 g/L values of GAC, PAC, H2O2/GAC, and Fe/H2O2/GAC together with H2O2 at retention times of 15, 30, 45, 60, and 90 minutes, respectively, were added and mixed. Results: At retention time of 10 minutes and 0.5 mL H2O2 and 1 g/L from Fe°, FeІІ, and FeІІІ, the removal efficacy was 88.5, 84 and 78%, respectively. At 50 mg/L nitrate and 0.5, 1, and 10 mg/L GAC concentrations, the removal efficacy was 56.5, 93.6, and 82.6%, respectively. The nitrate removal efficiency at pH=4 was approximately 50%, whereas at pH=3 with 30% efficacy, it increased to 80%. Conclusion: Modified Fe/H2O2 process with iron nano-particles and activated carbon adsorption can effectively reduce nitrate under optimal conditions. The use of activated carbon at a concentration of 1 g/L increased the removal efficiency of nitrate to 90%.

Keywords: Advanced oxidation process, aqueous system, iron compound, nitrate absorption

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