J. Chem. Chem. Eng. 7 (2013) 6-12 On the Production of OH Radical through Plasma Electrolysis Mechanism for the Processing of Ammonia Waste Water Setijo Bismo * , Krisna Irawan, Eva Fathul Karamah and Nelson Saksono Chemical Engineering, Engineering Faculty, Universitas Indonesia, Depok 16424, Indonesia Received: November 19, 2012 / Accepted: December 08, 2012 / Published: January 25, 2013 Abstract: Plasma produced many active species such as OH radical and H radical. As well known, OH radical plays an important role in degrading complex pollutants. This study aims to measure the production of OH radicals and evaluate important parameters that have influent in degradation process of waste water contains ammonia in circulated system and analyze the level of energy consumptions are resulted by this research. The production of OH radical was detected by formation of hydrogen peroxide which was resulted by recombination reaction between OH radicals during plasma electrolysis process. From the measured concentration of hydrogen peroxide, obtained concentration of OH radical is 2,020 ppm. The depth of anode, applied voltage and ammonia initial concentration have affected ammonia degradation percentage and energy consumption level. The highest result for ammonia degradation percentage is 63.2% which gets from applied voltage 700 V, with depth of anode 1 cm, initial concentration of ammonia 100 ppm, and lowest energy consumption of 110 KJ/mmol. Key word: Plasma electrolysis, OH radical, ammonia. 1. Introduction Ammonia is a pollutant in water and has many resources that is hard to be detected. Ammonia comes from industrial waste such as paper, rubber, plastic and paint. In addition, waste ammonia also produced in huge capacity from urine, which is a result of kidney secretion in human or animals. The presences of ammonia (NH 3 ) in the water are extremely harmful to human and animal, if concentrations exceed the threshold limits. Moreover, it can cause body of water (lakes, ponds, and rivers) acquires a high concentration of nitrogen compounds eutrophication, strong odor and reduces the process of disinfection in drinking water [1]. Currently many researches have developed for processing of waste ammonia, such as photolysis using a UV lamp, electrolysis and advanced oxidation * Corresponding author: Setijo Bismo, Processor, research fields: ozone and plasma technology. E-mail: bismo@che.ui.ac.id; sbismo@gmail.com. processes, however these processes have not reached optimum results. Electrolysis plasma is a novel of electrochemical process in which plasma is sustained by DC glow discharges between electrodes and the surface of the electrolyte [4]. Plasma that form on solution shows electrons excitation at high-energy around electrodes that trigger OH radical production. OH radical is one of active species that include as powerful oxidizing agents having potential oxidation 2.8 mV, with this ability, it can degrade complex pollutants [5]. It was proven by research that had succeeded in degrading complex organic compounds such as dye, nitrophenol and eosin [6]. In this research, authors will review more deeply about OH radicals production which is generated by plasma electrolysis and evaluates the performance of plasma electrolysis reactor by using several important parameters such as applied voltage, anode deepness and initial concentration of ammonia. DAVID PUBLISHING D