The effect of air injection rate in circulated plasma electrolysis reactor for degradation of batik dyes waste

Batik industry in Indonesia frequently dispose liquid waste containing high level of toxic and carcinogenic dyes to the drainage without being treated. In accordance with it, plasma electrolysis has been proved as the efficient method to degrade dyes waste, yielding higher hydroxyl radicals than other methods. The experiment was conducted by generating plasma in circulated reactor using stainless steel cathode and tungsten anode with 2 cm depth immersed in 0.02 M Na2SO4 electrolyte solution added by 20 mg/L Fe2+ and 100 mg/L of Remazol Red initial concentration, with addition of varying air injection rate at maintained power. The results show that 1 L/min is the optimum air injection rate value to operate this reactor effectively at 450 W of optimum operating power so that it could lower the breakdown voltage, reduce energy consumption, produce more OH radicals and other reactive species, and elevate the degradation percentage. The experiment conducted in optimum operating condition provide result of 99.61% in degradation percentage for 60 minutes with final concentration of dye is 0.39 mg/L, 41.55 mg/L of COD, and 3177.16 kJ of energy consumption.