Visible light-driven photocatalytic self-fenton systems with β-ketoenamine covalent organic frameworks for rapid aquaculture pathogen inactivation

Aquaculture operations generate substantial volumes of wastewater containing pathogenic bacteria that threaten cultured species and surrounding ecosystems. Conventional treatment methods face limitations in efficiency, cost, and environmental protection, necessitating sustainable and innovative disinfection technologies for on-site treatment. This study constructed photocatalytic self-Fenton systems (PSFs) using β-ketoenamine covalent organic frameworks (COFs) for aquaculture wastewater disinfection. Two β-ketoenamine-linked COFs, TpBpy and TaTp, with the irreversible keto-enamine transformation providing chemical stability in aquatic environments. Photocatalytic H 2 O 2 production under visible light revealed that TpBpy achieved a yield of 3852.6 μmol/g over 90 min, outperforming TaTp of 1349.6 μmol/g. This higher efficiency of TpBpy may be attributed to its stronger O 2 adsorption and greater electron transfer capacity. Kinetic analysis demonstrated minimal H 2 O 2 decomposition, suggesting system stability for continuous oxidant supply. Coupling β-ketoenamine COFs with Fe(II) created PSFs that effectively eliminated key aquaculture pathogens, achieving 7-log removal of V. parahaemolyticus and A. hydrophila within 10 min, while P. aeruginosa and E. coli required 30–50 min. Mechanical study confirmed sustained hydroxyl radical (•OH) production, with TpBpy-PSF exhibiting higher efficiency due to enhanced Fe 2 + binding. Field validation in fish tanks and river water demonstrated 99% disinfection within 30 min against native microorganisms, confirming real-world viability. To the best of our knowledge, this is the first report of β-ketoenamine COF-based PSFs designed for aquaculture wastewater treatment, systematically evaluated against key aquaculture pathogens and the native microbial community. These findings highlight PSFs as an innovative and sustainable approach to aquaculture wastewater disinfection with potential for broader water treatment applications.