Electrochemical oxidant generation for sustainable drinking water purification in rural SUDOE areas : a pilot implementation

Abstract

This study presents the design, evaluation and pilot-scale construction of a 3D-printed proton exchange membrane (PEM) electro-ozonizer for the material valorization of gas-phase ozone, generated from the oxidation of water. The novel PEM electro-ozonizer integrates a BDD anode, Ti cathode, and a PSFA membrane, assembled in a 3D-printed cell. The system features innovative changes such as added structural supports to enhance electrical conductivity and optimized current collectors with conductive channels of aluminum and silicon-based sealing materials to prevent passivation. CFD simulations, ozone bubble formation, and mass transfer analysis were employed to characterize the cell, revealing enhanced ozone transfer from the liquid to the gas phase. The system performance was evaluated based on the effect of operational parameters, including water inlet flowrate, temperature, and current intensity. Optimized conditions (3 A, 540 mL/min, and 5 ºC) were identified to achieve a maximum ozone gas generation rate of 0.69 mg O3/min and a faradaic efficiency of 3.53%. These conditions outperform several commercial PEM electro-ozonizers under mild conditions. These results confirmed the potential scale-up for larger ozone generation rates. Finally, a pilot-scale prototype was constructed with eight electrochemical cells and partially implemented to the water treatment train of Interreg SUDOE GestEAUr project, designed for sustainable operation: chemical-free and use of solar energy, in rural communities.