In situ growth of FeOOH nanoflakes on iron foam for efficient activation of peroxymonosulfate in organic pollutant degradation

Sulfadiazine (SDZ), a widely used antibiotic, poses significant environmental risks due to its persistence and potential to induce bacterial resistance. This study presents a novel FeOOH-modified iron foam (FeOOH/IF) catalyst for efficient peroxymonosulfate (PMS) activation to degrade SDZ. The catalyst was synthesized via a simple NaBH₄-induced surface modification, forming FeOOH nanoflakes with abundant oxygen vacancies. Comprehensive characterization (SEM, TEM, XRD, XPS, EPR) confirmed the successful formation of FeOOH/IF with enhanced catalytic properties. The FeOOH/IF/PMS system achieved nearly complete SDZ removal (100 %) within 20 min, exhibiting 4.7 times higher k obs value (0.18 min −1 ) than unmodified IF (0.038 min −1 ). Mechanistic studies revealed a dual radicals ( • OH and SO 4 • − ) and non-radicals ( 1 O 2 , Fe IV O, electron transfer) oxidation pathway, with non-radical processes dominating (53.12 % contribution). DFT calculations and LC-MS identified four primary degradation pathways, demonstrating effective detoxification of SDZ. Moreover, the as-synthesized exhibited excellent recyclability (over 90 % removal in the four repeated cycles) and versatility, efficiently degrading various organic pollutants (tetracycline, carbamazepine, etc.). This work provides a highly efficient, stable, and eco-friendly PMS-activating catalyst for antibiotic wastewater treatment, with insights into reaction mechanisms and practical applicability.