Calcium alginate gels-functionalized polyurethane foam decorated with silver nanoparticles as an antibacterial agent for point-of-use water disinfection

This paper reports the preparation of calcium alginate gels-functionalized PUF decorated with AgNPs (CA/[email protected]) by in situ reduction of Ag+ ions to form AgNPs with weakly reducing glycerol in CA/PUF composite. The water-adsorbing capacity, chemical structure, crystalline nature, elemental composition and morphologies of the composite were characterized. The Ag release behavior of CA/[email protected] was investigated. The inhibition zone test, time-dependent co-culture assay, test tube test, and antibacterial filtration experiment with Escherichia coli as an indicator of bacterial contamination were conducted to explore the antimicrobial efficacy. Results indicated that the CA/[email protected] prepared at 0.25 % w/v of SA could absorb more water with a higher swelling ratio of 8.0 g/g than that of [email protected] (6.0 g/g), which was subsequently squeezed by minimal pressure stimuli. The CA/[email protected] had a larger initial AgNPs loading amount (8.48 mg/g), lower Ag release concentration (44.35 μg/L) and lower Ag release rate (0.27 %) after 14 days tests than those of [email protected] (7.93 mg/g, 80.87 μg/L and 0.60 % respectively). The CA/[email protected] was highly reusable because bacterial cells in the squeezed water recovered from the composite were completely inactivated over five cycles of operation, and exhibited good antibacterial efficacy as an antibacterial filter in a flow test.