Investigating Treatment of Malathion Wastewater in Catalytic Ozonation Process by Activated Carbon With Ammonium Chloride for Catalyst

Background Malathion is a pesticide with the highest consumption in phosphoric pesticides. This pesticide has acute and chronic effects. Therefore, for the protection of the water and human health against the harmful effects of these compounds, they must be removed by appropriate treatment of wastewater and water resources. Among the treatment methods, the ozonation process has drawn more attention; one of the best options of ozonation process is the catalytic ozonation process (COP)with activated carbon.
Materials & Methods In this study, at first the synthetic wastewater was prepared at the mentioned concentration with pure malathion. Then, removal malathion experiments in a cylindrical pilot with a total volume of 200 mL were performed by single ozonation and catalytic ozonation process with use of NH4Cl-induced activated carbon (NAC) obtained from of agricultural waste. Study variables included pH, contact time, the concentration of ozone, and the concentration of catalyst. In all conditions, the sole catalytic ozonation adsorption and catalystic synergistic effects were evaluated.
Results The results showed that the removal efficiency of ozone in alkaline pH is higher. Also, in 200 mL samples containing 50 mg/L malathion and 0.1 g/L concentration of catalyst in carbon NAC, in the COP test for 50 minutes, the malathion removal performance was 62.9% in ozonation; 100% in catalytic ozonation, 22% in adsorbtion only, and 15.1% in the synergism effect. It showed the high removal efficiency of COP/NAC.