An Anti-Scaling Strategy for Electrochemical Wastewater Treatment: Leveraging Tip-Enhanced Electric Fields

Abstract

Electrode scaling poses a critical barrier to the adoption of electrochemical processes in wastewater treatment, primarily due to electrode inactivation and increased internal reactor resistance. We introduce an antiscaling strategy using tip-enhanced electric fields to redirect scaleforming compounds (e.g., Mg(OH) 2 and CaCO 3 ) from the electrode−electrolyte interface to the bulk solution. Our study utilized Cu nanowires (Cu NW) with high-curvature nanostructures as the cathode, in contrast to Cu nanoparticles (Cu NP), Cu foil (CF), and Cu mesh (CM), to evaluate the electrochemical nitrate reduction reaction (NO 3 RR) performance in hard water conditions. The Cu NW/CF cathode demonstrated superior NO 3 RR efficiency, with an apparent rate constant (K app ) of 1.04 h −1 , significantly outperforming control electrodes under identical conditions (K app < 0.051 h −1 ). Through experimental and theoretical analysis, including COMSOL simulations, we show that the high-curvature design of Cu NW induced localized electric field enhancements, propelling OH − ions away from the electrode surface into the bulk solution, thus mitigating scale formation on the cathode. Testing with real nitrate-contaminated wastewater confirms that the Cu NW/CF cathode maintained excellent denitrification efficiency over a 60-day period. This study offers a promising perspective on preventing electrode scaling in electrochemical wastewater treatment, paving the way for more efficient and sustainable practices.