Triple benefit: transforming acidic mine drainage into efficient iron-based polymetallic nanoparticles used for catalytic degradation of norfloxacin

Acid mine drainage (AMD) is a significant environmental threat, necessitating effective treatment and resource recovery strategies. This study explores the innovative synthesis of iron-based polymetallic nanoparticles (Fe PMNPs) from AMD using tea extracts, and their application as heterogeneous catalysts for the degradation of norfloxacin (NOR). Under optimal conditions (Fe PMNPs dosage = 0.3 g/L, reaction time = 2h, pH = 3.6, T = 298 K, H 2 O 2 concentration = 10 mM, and initial NOR concentration = 20 mg/L), the Fe PMNPs achieved 100 % NOR degradation efficiency and a reaction rate constant of 0.075 min −1 , maintaining over 90 % efficiency across a broad pH range (3.6 to 9.1). This demonstrates outstanding reaction performance compared to most materials synthesized by chemical and waste utilization methods. Comprehensive characterizations revealed the complex structure of Fe PMNPs, incorporating organic carbon, Fe 2+ , Fe 3+ , Al 3+ , and Cu from both AMD and tea extracts. These components synergistically activated H 2 O 2 , generating reactive oxygen species (ROS) such as 1 O 2 , SO − 4 and OH, which facilitated NOR degradation through both radical and non-radical pathways. Three distinct degradation pathways were identified based on computational results and transformation product analysis. This study offers novel insights into AMD treatment and waste resource utilization, demonstrating an environmentally friendly approach to catalytic NOR degradation using Fe PMNPs derived from AMD.