Evaluation of nitrate removal from water by Fe/H2O2 and adsorption on activated carbon

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. 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. 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%. 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%.