Trace FeS-Modified mZVI for Enhanced H₂O₂ Activation in Industrial Wastewater Treatment: from Lab to Field

Fenton-based advanced oxidation processes (AOPs) are widely applied for the degradation of recalcitrant organic pollutants in chemical industrial wastewaters. However, traditional systems often generate excessive iron sludge and face challenges in sustaining Fe2+ production, which reduces hydroxyl radical (·OH) utilization efficiency and increases treatment costs. Here, we present a FeS-modified micron-sized zerovalent iron (FeS-mZVI) catalyst that enhances continuous Fe2+ release and prevents FeOOH passivation. The FeS-mZVI/H2O2 system achieved nearly 90% COD removal of phenol within 2 h and maintained high efficiency in pilot-scale testing, achieving over 50% COD reduction in real industrial wastewater with a 47% reduction in operational costs compared to traditional Fenton processes. Mechanistic studies confirmed that ·OH, generated through a Fe2+-dominated homogeneous Fenton reaction, are the primary reactive species. These findings indicate that the FeS-mZVI/H2O2 system is a promising and practical approach for large-scale chemical industrial wastewater treatment, offering both economic and environmental advantages.