Removing the Acid Orange 12 Azo Dye from Aqueous Solution Using Sodium Hypochlorite, A Kinetic and Thermodynamic Study

Abstract

This study investigated the feasibility of using sodium hypochlorite as an advanced oxidation process to remove Acid Orange 12 azo dye from wastewater. For this purpose, batch reactor experiments were done. Several variables to address the efficiency of using this process were considered. These variables are initial pH (5, 7, and 9), the concentration of hypochlorite (50 - 250 mg/l), temperature (20-50) degrees Celsius, and time of electrolysis (1-75) min. also investigate the effects of UV on the process was done. Experimental results showed that the color removal efficiency using NaOCl with UV is more effective than NaOCl alone. The highest removal efficiency was obtained by increasing the concentration of NaOCl from (50-250mg/l) at PH=5. When the solution temperature was increased from (20-50) °C, the removal efficiency increased, and at the same time, the time required was reduced from (20-5) minutes to obtain the highest removal efficiency. The kinetic study also showed that the oxidation process follows a second-order reaction. The thermodynamic functions indicate that the response is spontaneous, endothermic, and increases randomness.