Understanding Pulsed Electrolysis Effects in Flow Cell Architecture for Low-Concentration Pollutants

Abstract

Electrochemical pollutant removal from low-concentration wastewater matrices poses challenges due to the high electrical effort required to overcome inherently low mass transfer rates. Pulsed electrolysis offers a potential solution by adjusting the on and off periods of redox reactions to engineer the rates required for sustained, low-voltage, and consistent removal. Flow cells, industrially relevant configurations, are affected by a multiphysics interaction between fluid and electrolysis mechanisms, unlike batch designs. However, the mass transfer optimization under both electrochemical and flow parameters remains ambiguous. It is essential to understand and optimize pulse parameters such as waveform, duration, and magnitude in relation to flow rates. While cathodic duration and magnitude dictate depletion rate, the corresponding anodic parameters affect the recovery time. Waveform design can smooth the depletion-recovery transition, helping with variable depletion and recovery rates and allowing more engineered pulse responses. While square-wave pulses produce more intense depletion and recovery, sinusoidal waveforms provide a continuously varying current profile that enables more flexible control of surface depletion and recovery In this work, we reveal mechanisms underlying mass transfer behaviors under various flow and pulsing conditions. To support industrial-scale pollutant removal systems, we explore optimization practices and machine learning methods for fit-for-purpose electrolyzer sizing under a pulse pattern optimized for the rapid, energy-efficient pollutant removal.