(562u) Pulsed Electric Field (PEF) Device Equipped with a Cathode Decorated with Copper-Titania Nanostructures for Enhanced Water Denitrification

Dy, T. R. N., Hong Kong University of Science and Technology
Song, J., Hong Kong University of Science and Technology
Yeung, K. L., The Hong Kong University of Science and Technology
With population growth comes the increase in demand on agricultural food produce, and consequently, nitrogen-based fertilizers. This is causing an upsurge in the nitrate content of groundwater due to runoff or seepage, ushering in some damaging environmental and health impacts such as eutrophication and methemoglobinemia. Previous electrochemical reduction reports on nitrate reduction of ground water or wastewater have posted (1) low nitrate reduction rate, (2) poor selectivity towards nitrogen (preferred product), and (3) energy intensiveness, as limiting factors of their treatment systems. This led to studies which utilize electrodes with micro/nano-sized structures to increase electroactive area and improve mass transfer.

This study investigated the inclusion of copper-titania nanostructures on a titanium plate cathode for the electrochemical reduction of nitrate to nitrogen. The cathode was incorporated in a batch-type undivided electrolytic cell, which allows simultaneous reduction and oxidation reactions—a process that may be detrimental to reduction efficiency since reduced nitrate can be re-oxidized near the anode but can be an opportunity to improve selectivity towards the favored harmless nitrogen. The system was operated under pulsed electric field which greatly decreased the needed electrical energy input to reduce a unit concentration of nitrate in the synthetic contaminated ground water. Parametric electric field simulations via COMSOL Multiphysics validated the improved electric field strengths brought by the addition of copper-titania nanostructures and directed the eventual design of a flow-through denitrification device.