Atmospheric air plasma corona discharge for dye degradation of indonesian batik wastewater

Plasma technology is promising method in wastewater management. In the present work, plasma corona discharge was used to degrade batik wastewater that contained synthetic dyes such as naphthol and procion. The plasma corona discharge was generated by a high voltage alternating current of 3.07–11.5 kV through a pair of stainless-steel electrodes with a tip radius of 2 ± 0.5 mm. The electrodes were separated by 2 ± 0.05 cm and placed 3 ± 0.05 cm above the wastewater. UV–Vis spectra of the wastewater, monitored at different intervals of plasma treatment, were used to quantify the degradation of wastewater. We found that the degradation efficiency of wastewater reached 55% after 40 min of plasma treatment. Species generated during the discharge (e.g., O3, OH+, N2O+, and NO) were observed using an optical emission spectrometer. These species continued to dissolve in the liquid phase and reacted to molecules of wastewater. FTIR spectra revealed that the main functional group in the wastewater was O–H. This band showed a reduced intensity with plasma treatment time due to oxidative damage caused by the attack of reactive oxygen on the outer hydrogen bonds of wastewater. Other properties, such as color, pH, temperature, conductivity, total dissolved solids, and dissolved oxygen, changed due to the production of active species during plasma treatment. The findings of this study present plasma treatment as a prospective method for wastewater treatment.