Design and utilization of a novel trickle-bed electrochemical reactor for advanced treatment of synthetic wastewater

In the present thesis, the design and utilization of an innovative and novel trickle bed electrochemical reactor for the advanced treatment of synthetic wastewater was aimed. In this reactor, firstly, the reduction of dissolved oxygen on the surface of a cathode composed of carbon and polytetrafluoroethylene (CPTFE) was carried out, followed by electrochemical production of hydrogen peroxide (H2O2). Subsequently, catalytic decomposition-based generation of hydroxyl radicals was carried out. These hydroxyl radicals were used to oxidize the methyl orange (MO) as an organic pollutant. The cathode design in the TBER was obtained from a double-layer bed consisting of a C-PTFE mixture tightly attached to a stainless-steel mesh. Thus, both a highly efficient electrode and a continuously operating treatment process were aimed. The effectiveness of different operating parameters such as voltage, initial MO concentration, oxygen flow rate, electrolyte flow rate, KOH concentration and temperature were investigated to increase the removal efficiency. The optimum operating conditions were determined as 1 V, 20 ppm, 7 L/min oxygen flow rate, 200 mL/min electrolyte flow rate, 0.2 M KOH concentration and 30 oC. Maximum MO removal of 98% was achieved under these conditions. Kinetic studies showed that the MO degradation process fitted well with pseudo-first order kinetics. The reaction rate constant was calculated as 0.0179 1/min at 30°C and 0.0111 1/min at 5°C. Based on these calculations, the activation energy of the TBER-based MO removal process was obtained as 14.062 kJ/mol. Thermodynamic studies showed that the TBER was endothermic and spontaneously. As a result, the experimental findings were found to be in great accordance with the related literature and TBER was considered to be a promising process. KEYWORDS: Methyl orange, Trickle bed reactor, Wastewater treatment, Kinetic, Thermodynamic.