Multifunctional porous ag/biocomposite: synthesis, catalytic reduction of p-nitrophenol and antibacterial applications

Environmental pollution, particularly water contamination, continues to be a critical global challenge, thereby necessitating the development of sustainable and high-efficiency catalytic systems for wastewater treatment. In this study, silver nanoparticles (AgNPs) were synthesized via a green chemistry approach and embedded on a biocomposite, cellulose-chitosan aerogel integrated with hydroxyapatite (HCCA) derived from Basa (Pangasius bocourti) fish bones. Notably, the synthesis route is straightforward, eco-friendly, and minimizes the use of hazardous chemicals. Durian shell (DS) extract was utilized as a natural reducing and stabilizing agent, while residual biomass was treated to obtain high-purity cellulose, highlighting the effective valorization of agricultural waste. The resulting HCCA aerogel biocomposite, fabricated through crosslinking and freeze-drying, exhibits high porosity (>97%) and ultralow density (about 0.03 g cm^-3), facilitating uniform dispersion and stabilization of AgNPs. The optimized 1.25Ag@HCCA sample achieved nearly complete conversion (about 99%) of p-nitrophenol (PNP) to p-aminophenol (PAP) within 15 minutes and retained approximately 98% efficiency after seven reuse cycles. Additionally, strong antibacterial activity against Escherichia coli and Salmonella paratyphi was observed. Overall, the Ag@HCCA sample demonstrates high potential as a multifunctional, sustainable material for wastewater treatment and waste valorization in circular economy applications.