Valorization of waste polypropylene as a robust catalyst for rapid degradation of antibiotics in complex water matrices

Abstract

The escalating challenges of plastic waste accumulation and antibiotic contamination in aquatic environments demand innovative solutions. This study presents a sustainable strategy for upcycling waste polypropylene (PP) into an iron-functionalized catalyst (PP-SO3Fe) via a facile, liquid-assisted mechanochemical method. Under optimized conditions (PP:Fe(III) mass ratio of 5:1, 400 rpm, 6 h), the synthesized catalyst effectively activates peroxymonosulfate (PMS), achieving a rapid 98.7% degradation of tetracycline (TC) within 7 min. Systematic mechanistic investigations, including radical quenching tests and electron paramagnetic resonance analysis, verified that the degradation is governed by non-radical pathways, primarily involving singlet oxygen (1O2) and high-valent iron-oxo species (FeⅣ=O). The system exhibits favorable stability with 92.2% efficiency retention after 10 cycles and maintains superior performance across wide pH ranges and in complex water matrices containing various interfering ions. Notably, HCO3- and NH4+ ions were found to positively enhance the degradation process. This work presents a sustainable strategy for plastic waste valorization while providing an effective solution for antibiotic removal in practical water treatment applications.