Three birds with one stone: Fe(Ⅲ)-coordinated cross-linked antibiofouling cellulose composite membrane for synergistic photodynamic and Fenton-like water disinfection

[Display omitted] •A “three birds with one stone” strategy was used to develop an Fe(Ⅲ)-coordinated cross-linked cellulose composite membrane with multiple benefits.•Fe(Ⅲ)-coordinated cross-linking enhances membrane stability, preserves photodynamic efficiency, and accelerates Fenton-like reactions.•The composite membrane demonstrates synergistic antibacterial activity, eliminating gram-positive and gram-negative bacteria through photodynamic and Fenton-like mechanisms..•The membrane exhibits high bacterial repellency , exceptional anti-biofouling properties, and potential for practical applications in advanced water purification . The development of green and highly efficient antimicrobial filter membranes for water disinfection is crucial to public health. Photodynamic therapy (PDT), an emerging bactericidal strategy, has shown significant potential for the preparation of antimicrobial filter membranes. Unfortunately, its antibacterial efficacy is often compromised by self-quenching caused by the aggregation of photosensitizers, as well as the short diffusion length and lifespan of the reactive oxygen species (ROS) generated. Herein, a Fe(Ⅲ)-coordinated cross-linked antibiofouling cellulose composite membrane (Fe/TOCNF-TPZnPc-1.5) with significantly enhanced synergistic photodynamic and Fenton-like bactericidal performance was fabricated via a facile flow-based sequential filtration method for water disinfection. The formation of a Fe(Ⅲ)-coordinated cross-link increases the structural stability of the membrane, prevents the migration and aggregation of tetra(4-carboxyphenoxy)-phthalocyaninatozinc (ii) (TPZnPc), and also provides the Fe(Ⅲ) complexes for the accelerated Fenton-like reaction. Through synergistic photodynamic and Fenton-like reactions, the Fe/TOCNF-TPZnPc-1.5 membrane achieves rapid and effective inactivation for E. coli and B. subtilis with a lethality rate of 100 % under NIR irradiation and H2O2 treatment. The primary active species responsible for bacterial inactivation are singlet oxygen species (1O2) and hydroxyl radicals (OH). The disinfection performance of the Fe/TOCNF-TPZnPc-1.5 membrane in river water samples demonstrated 100 % disinfection efficiency for waterborne pathogenic bacteria. In addition, the Fe/TOCNF-TPZnPc-1.5 membrane exhibits moderate water permeance (26.6 L m−2 h−1), high bacteria rejection (＞96 %), excellent antifouling ability, and 100 % biodegradation within 90 days. These attributes indicate significant potent