Pulsed Electrochemical Degradation of Micropollutants via In Situ Generated Sulfate Radical: Rapid Reaction Kinetics and Low Energy Requirement

The electrochemical oxidation technology shows considerable promise for decentralized water purification. However, conventional direct current (DC)-based electrochemical approaches encountered significant challenges in micropollutant degradation and energy efficiency due to inherent mass transfer limitation and high energy requirements. Herein, we introduced a pulse-induced strategy to strengthen the electrochemical oxidation process and enhance the decontamination of micropollutants. The proposed pulsed current (PC)-based electrochemical system leveraged the ubiquitous SO42– in water to achieve the sequential electro-generation of S2O82– and SO4•–, thereby improving efficiency and sustainability. Periodic fluctuations in anode potential induced by square-wave currents dynamically reconfigure the composition of the electric double layer (EDL) on the anode surface, resulting in an increase in the local concentration of reactants and facilitating the release of nonreactive ions. This mechanism established favorable alternating conditions for efficient purification of micropollutants. Under optimal conditions, the PC mode (kobs = 0.028 min–1) exhibited a superior degradation rate constant for bisphenol A (BPA) compared to the DC mode (kobs = 0.016 min–1) while simultaneously reducing energy consumption by 65.9%. Finite element simulations based on Fick’s second law revealed the release of S2O82– and the replenishment of BPA at the anode surface under PC conditions. This study presents an efficient and economically viable strategy for environmental remediation that not only demonstrates exceptional treatment efficiency but also exhibits immense potential for widespread implementation across various environmental scenarios.