High permeation, biodegradable hydrogel based flow-through reactor for water disinfection with controlled silver release

Abstract

Innovative disinfection strategies for clean water access demand manufacturing and operational simplicity, offering benefits for technology adoption. A hydrogel reactor composed of chitosan/graphene oxide/nano-Ag (CS/GO/Ag) achieves complete disinfection of real water resources contaminated with natural and biomedical contaminants, present concomitantly at higher contamination levels (104-106 CFU mL−1). The hydrogel exhibits remarkable mechanical stability and maintains shape without permanent deformation through dynamic swelling behaviour. Its open-ended, porous network allows rapid water permeation with tuneable hydrophilicity to maximize hydrogel-water interactions for disinfection. Hydrogel is reusable while achieving complete disinfection and maintains a controlled silver release (87.4 ppb, 0.07 % rate) within safety limits through restricted oxidative-dissolution of immobilized AgNPs. A distinct species-specific disinfection potential was observed for completely eradicating four natural/biomedical pathogens within 120 min. The CS/GO/Ag hydrogel employs a multifaceted mechanism to combat bacteria and appears virtually non-toxic to humans along with desirable soil biodegradability, promising safer and sustainable use. In continuous-flow, the hydrogel disinfected over 30 L of contaminated water (initial count, 105 CFU mL−1) without regeneration. A consistent disinfection performance across various natural water resources, easy flow-through design, and the suitability of Weibull model highlights CS/GO/Ag hydrogel’s potential for large-scale disinfection, effectively addressing water purification challenges.