Construction and Application of a Novel Three-Dimensional Electrocatalytic Ozonation System for Micropollutant Removal

Conventional two-dimensional (2D) electrocatalytic ozonation faces challenges such as low mass transfer efficiency, limited hydroxyl radical (•OH) yield, and insufficient pollutant degradation rates. To address these limitations, this study developed a novel three-dimensional electrocatalytic ozonation system using a 316 stainless-steel skeleton as the cathode. By systematically comparing the ozone decay kinetics, •OH yield, imidacloprid degradation efficiency, and ozone mass transfer characteristics among the 3D electrocatalytic ozonation system, 2D electrocatalytic ozonation system, and conventional ozonation system, combined with electrode interface reaction analysis and structural simulation, the core mechanism by which the 3D structure enhances the electrocatalytic ozonation reaction was revealed. The results showed that the 3D electrocatalytic ozonation technology primarily promotes ozone decay and •OH generation through a reaction pathway dominated by the reduction of ozone at the cathode, while simultaneously enhancing pollutant removal efficiency. The pseudo-first-order kinetic constant for ozone decay in the 3D system reached 1.0 min−1, which was five times that of the 2D system (0.2 min−1). The •OH yield increased to 38%, significantly higher than that of the 2D system (15%) and conventional ozonation (10%). The complete degradation of imidacloprid was achieved within 5 min, and the degradation rate (2.14 min−1) was 10 times that of the 2D system. The high specific surface area (75 cm2/g, 30–90 times that of the 2D flat electrode) and 70% porosity of the 3D framework overcame the mass transfer limitation of the 2D structure, exhibiting excellent reaction activity. The ozone mass transfer amount was approximately 1.5 times that of the 2D electrode and 2 times that of conventional ozonation. This study provides theoretical support and technical basis for the engineering application of 3D electrocatalytic ozonation technology in the field of micro-pollutant control.