Antibacterial hydrogel filters via in situ growth of Ag-doped ZIF-8 on cellulose nanofibers: A novel strategy for biofouling control in water treatment.

Abstract

Developing a green and highly efficient antibacterial filter for water disinfection was considered crucial to public health. Here, we first synthesized necklace-like Ag/Z@CNF nanofibers by in situ growth of ZIF-8 on T-CNF, followed by loading silver nanoparticles in the Z@CNF via ion exchange and chemical reduction. Finally, an anti-biofouling hydrogel filter was developed using an injection-driven filtration system that combining the Ag/Z@CNF and CNF hydrogel films. This unique necklace-like structure of Ag/Z@CNF enhanced interfacial bonding, reduced ZIF-8 aggregation and defects, and ensured long-term stability. The cellulose-based nanofiber substrate also provided excellent biocompatibility and sustainability, forming a three-dimensional porous hydrogel network. The antibacterial properties of the hydrogel film were evaluated using inhibition zone assays and Live/Dead fluorescence staining. The Ag/Z@CNF hydrogel film demonstrated higher antibacterial rates, with rates of 98.2 % against E. coli and 99.1 % against S. aureus, compared to the 79.95 % and 83.08 % antibacterial rates of the Z@CNF hydrogel film, respectively. Notably, the ·OH signal intensity generated by Ag/Z@CNF was 2.70-fold greater than that observed for Z@CNF. In dynamic antibiofouling experiments, the Ag/Z@CNF hydrogel film showed only a 14 % decline in flux, effectively inhibiting biofouling and leading to the formation of a loose and thin biofilm. The Ag/Z@CNF hydrogel films exhibited multiple synergistic antibacterial mechanisms, combining sustained Zn²⁺ and Ag⁺ release with visible-light-induced reactive oxygen species generation. This work has great potential for large-scale antibacterial filtration membranes, providing an efficient, sustainable, and cost-effective approach to water disinfection.