Résumé
•F/P system outperformed F/H in virus inactivation and pH adaptability.•Capsid sulfur-containing amino acids were primary inactivation targets.•Non-radical Fe(IV) and 1O2 dominated the inactivation mechanism.•Viruses and their degradation products enhanced the F/P catalytic cycle.•Fe(III)-π intermediates boosted Fe(II)/Fe(III) redox cycling.
The conventional Fenton system suffers from critical limitations, including significant pH dependence and inefficient iron cycling. This study innovatively developed a Fe(II)/peracetic acid (PAA) hybrid disinfection system, systematically investigating its viral inactivation performance and molecular mechanisms under near-neutral conditions. The results demonstrated that this system achieved above 5 logs viral inactivation (under 50 μM Fe(II)/50 μM PAA, pH 3–7) through a unique three-stage mechanism. This mechanism included radical burst, self-catalytic iron cycling and coordination environment reconstruction, inducing deformation and conformational changes in capsid protein. Notably, non-radical species (Fe(IV) and 1O2) consistently accounted for over 50% of total inactivation efficiency. Steady-state concentration calculations, cumulative reactive species quantification, and 30% Fe(II) regeneration observed within 30 min all jointly confirmed the virus enhanced Fe(II)/Fe(III) cycling. Study on the mechanism revealed that the components of virus capsid performed dual roles: sulfur-containing amino acids (e.g., cysteine) acted as oxidation targets, while aromatic residues (e.g., phenylalanine) served as catalytic sites. Through strong coordination interactions via Fe(III)-π intermediates, an efficient Fe(II)/Fe(III) coupling cycle was achieved. This system reveals a novel mechanism whereby the virus itself catalyzes and enhances iron cycling. In practical applications, it is expected to reduce chemical reagent usage and decrease iron sludge production, offering a new pathway for developing cost-effective green disinfection technologies.
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