Degradation of Rhodamine B and Methylene Blue by Underwater Dielectric Barrier Discharge

Numerous reports have elucidated different methods for treating dyeing wastewater using UV irradiation, ozonation, and chlorination. However, the high operational costs of these methods have necessitated the use of plasma. In this study, dielectric barrier discharge (DBD) was used to purify dyeing wastewater, generating ozone as a byproduct. An underwater DBD plasma system was designed to directly interact with water, thereby producing reactive oxygen species (ROS) and functioning as a powerful oxidizer. Additionally, UV, O
₃
, and H
₂
O
₂
are generated by the developed plasma system without using any other additives to produce OH radicals for purifying organic pollutants; therefore, this system circumvents the use of complex and advanced oxidation processes. A simulation test was performed, which revealed that methylene blue and rhodamine B were completely removed within 7 and 3 min, respectively. Therefore, the developed plasma system can be successfully applied for the purification of dyeing wastewater.