Plasma-based preparation of bifacial graphene/TiO₂/Ta₂O₅/Ti electrode for photoelectrocatalytic ozonation of synthetic and real wastewaters with ANN modeling

In this work, the electrophoretic deposition/plasma technique was used to prepare a Graphene/TiO₂/Ta₂O₅/Ti electrode. The effect of Graphene:TiO₂:Ta₂O₅ mass ratio on the characterization of the electrode and its performance in the degradation of Reactive Orange 29 (RO29) as a model pollutant was investigated. According to the results of PL and photoelectrocatalysis (PEC) tests, the electrode with TiO₂(7):Graphene(10):Ta₂O₅(3) mass ratio was the best photoelectrocatalyt among them. This electrode was analyzed by XPS, SEM, FT-IR, XRD, DRS, BET, EIS, and MS. The results indicated the development of efficient binding between graphene and the metal oxides by plasma treatment and uniform coating of particles on the Ti surface. Furthermore, the conduction band edge and band gap of the composite were -1.09 V and 2.7 eV, respectively. The performance of the Graphene:TiO₂:Ta₂O₅ catalyst in the PEC and photoelectrocatalytic ozonation (PECO) processes was investigated. By optimizing the applied bias potential (1.2 V), electrolyte concentration (25 mM), catalyst amount (0.11 g), RO29 concentration (5 mg/L), and O₃ flow rate (4 L/min) under visible and UV-C light irradiation, complete degradation efficiency was obtained within 60 min. A mathematical model for the degradation of pollutants was developed using an artificial neural network. The model suggested that the treatment time and the catalyst amount were more critical factors among the variables examined in the pollutant degradation process. GC-MS analysis approved the degradation of pollutants through the processes. The catalytic performance and stability of the electrode were maintained well over 20 consecutive cycles, with only minor reductions in efficiency. Industrial zone wastewater was treated by the catalyst using PECO and PEC processes.