Preparation and Application of Multifunctional Chitosan–Polyvinyl Alcohol–Nanosilver–Chrysanthemum Extract Composite Gel

In this study, we designed the preparation method and application study of chitosan–polyvinyl alcohol–chrysanthemum extract–nanosilver composite gel (CTS/PVA/Ag/CHR), constructed a composite gel system with chitosan/polyvinyl alcohol as the carrier, and utilized chrysanthemum extract within the gel to convert silver nitrate into nanosilver via green reduction. In the bacterial inhibition experiments, the CTS/PVA/Ag/CHR gel showed excellent antibacterial properties, and the diameter of the inhibition circle for Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa by the agar diffusion method was 32.5 mm, 30.5 mm, and 34.0 mm, respectively. In the aqueous bacterial inhibition experiments, the gel’s inhibition rate against the three kinds of bacteria was 100% after 5 h. The abundant hydroxyl groups contained in the polyvinyl alcohol (PVA) formed hydrogen bonds with the amino groups present in chitosan (CTS), which maintained the stability of the gel structure and enhanced the moisturizing and water storage properties of the gel. The adsorption curves of the CTS/PVA/Ag/CHR gel were fitted using a proposed pseudo-second-order kinetic model. Methylene blue, methyl orange, Congo red, and malachite green were discovered to have strong adsorption capacities, with the most significant adsorption effect for methyl orange at 205.65 mg/g. Moreover, the CTS/PVA/Ag/CHR gel showed good freshness preservation in milk simulation experiments. Due to its superior adsorption capability and antibacterial qualities, the CTS/PVA/Ag/CHR gels have great potential for applications in wastewater purification and food preservation.