Open Access

Wenxin Shi, Yibo Wang, Daniela Almeida StreitwieserORCiD, Tao Zhang, Yujie Yuan, Chengrong Li, Yiming Han, Mengda Feng

• The effectiveness of iron‑carbon micro-electrolysis (ICME) in wastewater treatment is limited by rapid passivation. To address this, a quantitative colorimetric method was developed to evaluate passivation rates, and this study proposes two synergistic systems: Aeration–Ultrasound–Rotating Magnetic Field (A-URM) and Non-Aerated–Activated Carbon–Rotating Magnetic Field (N-ACRM). A-URM employs ultrasonic cavitation to exfoliate passivation films, preserving active sites, enhancing reactive oxygen species generation, and inhibiting ion redeposition via a rotating magnetic field (RMF). N-ACRM prevents passivation by suppressing Fe(II) oxidation (above 90% retention), using activated carbon to form conductive networks for electron redistribution, and applying RMF-induced micro-currents (up to 9 mA/cm2) to lower charge transfer resistance from 3398 Ω/cm2 to 97.77 Ω/cm2. In both systems, RMF improves mass transfer by thinning the diffusion layer and accelerating reactions. Over 60 days, both maintained above 90% pollutant removal and below 10% passivation, outperforming conventional ICME. Techno-economic and sustainability analyses confirmed reduced costs and environmental impacts, demonstrating that A-URM and N-ACRM are safe, efficient, and scalable solutions for large-scale wastewater treatment.