Insights into the degradation of carbamazepine using a continuous-flow non-thermal plasma: kinetics and comparison with UV-based systems

The widespread presence of carbamazepine (CBZ) in the environment and its potential impacts on non-target organisms and ecosystem dynamics raise concerns globally. In this study the degradation of CBZ was studied using an atmospheric dielectric barrier discharge (DBD) reactor. The influence of different operating parameters such as the initial concentration of the pollutant, applied voltage, pH, and conductivity on the DBD performance was investigated based on CBZ degradation efficiency. At optimal conditions (10 mg L⁻¹, 6 kV, and 5 μS cm⁻¹), a 92% degradation efficiency for CBZ was achieved. The process was less effective in an acidic medium but enhanced in neutral and slightly alkaline conditions. This study also investigated the active role of reactive species like O₃, H₂O₂, ·OH, and ·O₂⁻ produced during the treatment process. To evaluate the efficacy of the DBD system in real conditions, experiments were also performed in tap water and in final wastewater effluent within a 40 min treatment time. Lastly, the degradation efficiency of the DBD reactor, energy efficiency, and energy cost were compared with those of UV-only, UV/Fe²⁺, UV/H₂O₂, and UV/H₂O₂/Fe²⁺ systems. For all the parameters investigated, the DBD plasma used in this work demonstrated superior performance to that of the UV-assisted systems, while the UV-only system gave the worst performance.