Phenolic contaminants generate persistent phenoxyl radicals to accelerate antibiotic degradation

Water pollution by coexisting multiple contaminants presents escalating challenges to environmental remediation and public health protection. In advanced oxidation processes, contaminant interactions are invariably regarded as detrimental, introducing competitive reactions and matrix interferences that diminish treatment efficiency. However, phenolic compounds—a prevalent class of recalcitrant water pollutants—possess latent oxidative capabilities that remain strategically unexploited. Whether their reactivity can be harnessed to accelerate, rather than impede, the removal of priority contaminants remains fundamentally unclear. Here we show that in the permanganate/chlorite (Mn(VII)/ClO 2 - ) system, phenolic compounds undergo a counterintuitive transformation into persistent phenoxyl radicals that enhance sulfamethoxazole degradation by 3.5- to 20-fold. Mechanistic investigations reveal that these radicals exhibit exceptional stability and selectivity, preferentially attacking target pollutants while demonstrating robust resistance to common matrix interferences—properties unattainable with conventional oxidants alone. Quantitative structure-activity relationships provide predictive frameworks for optimizing this contaminant-assisted oxidation strategy across diverse chemical scenarios. This contaminant-mediated oxidation strategy inverts the traditional paradigm of mutual interference, transforming recalcitrant phenolics from obstacles into powerful mediators. The findings open new avenues for self-adaptive remediation of multi-pollutant systems and suggest broader applications in environmental cleanup where contaminant interactions can be strategically exploited. • Coexisting contaminants typically impair advanced oxidation processes in water treatment. • Phenolic compounds form long-lived phenoxyl radicals in permanganate/chlorite systems. • Phenoxyl radicals accelerate sulfamethoxazole degradation by up to 20-fold. • These radicals exhibit high selectivity and strong resistance to matrix interferences. • Recalcitrant phenolics can serve as beneficial mediators for multi-pollutant remediation.