Air injection effect on energy consumption and production of hydroxyl radicals at plasma anode

Background and Objective: Plasma anode has been known as a very productive method of producing hydroxyl radicals that oxidize effectively in almost all organic and non-organic liquids. This research was conducted to investigate the effect of air injection and anode depth variation on required energy for plasma generation and production of hydroxyl radicals. Materials and Methods: A batch reactor (diameter 130 mm, height 190 mm) with tungsten electrodes (cathode diameter 6 mm and anode diameter 0.5 mm) was used by applying a continuous cooling system. The experimental parameters were composed of different rate of air injection (0, 2, 4 and 6 L min ^-1 ) and various depth of anode (5, 25, 45 and 65 mm). The current was observed at various voltage (20-700 V) in 30 sec for each voltage. Result: The energy consumption of plasma formation was getting smaller at a higher rate of air injection, while at deeper anode position, the energy consumption found higher. Although the ^• OH production became lower at a higher rate of air injection, the process efficiency observed higher. Conclusion: This research clarified that air injection on plasma anode and the anode depth position affected the energy consumption and production of hydroxyl radicals where the addition of air injection and variation of the anode depth could reduce energy consumption and also improved process efficiency.