Electro-oxidation of ammonia using a continuous system equipped with RuO2@Ti mesh anode: Optimization of the design parameters with a focus on energy consumption and removal efficiency

Abstract

In this study, the influence of the main parameters, such as electrode distance, flow rate, electrode numbers, electrode arrangements, initial pH, and alkalinity on ammonia removal and energy consumption was investigated in a continuous electrochemical system. The optimal distance, the number of the anode, and electrode pairs were 2 cm, 1 anode, and 2, respectively. The comparison between electrode arrangements showed that the lowest energy consumption was achieved using the monopolar parallel arrangement (160–254 kWh/kg TN). The pH is neutral and slightly alkaline between the electrodes, which increases the rate of ammonia reaction. The highest removal and anode efficiency were observed at the initial pH of 6.5 to 9.0, and the optimal alkalinity was 50–200 mg/L as HCO3–. The results showed that the optimization of design parameters has a significant impact on energy consumption and ammonia removal in the continuous reactor, bringing the technology closer to real-world application in wastewater treatment.