Electrochemical activation of persulfate by particle electrodes in three-dimensional systems: Mechanisms, applications, and future perspectives

The electro-activation of persulfate (PS) using particle electrodes in three-dimensional electrochemical systems (3DPE-PS) has emerged as a promising advanced oxidation process (AOP) for the efficient degradation of emerging contaminants (ECs). This technology combines the strong oxidizing capability of PS with the enhanced mass transfer and abundant active sites provided by particle electrodes. This comprehensive review analyzes current developments in 3DPE-PS, focusing on four key aspects: (1) characterization and performance of particle electrode materials, (2) optimization of critical operational parameters (electrode composition, applied current/voltage, persulfate dosage, and pH) to maximize degradation efficiency, (3) mechanistic understanding of electrochemical persulfate activation pathways, and (4) its applications for EC removal in various water matrices. The synergistic effects between electrochemical processes and PS activation are highlighted, emphasizing enhanced mass transfer and electron utilization in 3D systems. Despite significant progress, challenges such as long-term stability, scalability, and byproduct formation are faced. Future research directions include the design of cost-effective particle electrodes, mechanistic elucidation under complex water matrices, pilot-scale validation, and byproduct toxicity. This work provides valuable guidance for both fundamental research and practical implementation of 3DPE-PS technology, ultimately contributing to more sustainable water treatment solutions.