Green Preparation of Waste-Derived Nanocellulose/Chitosan/Ag Aerogels for Multifunctional Water Treatment

Waste-derived nanocellulose aerogels offer a sustainable route for converting lignocellulosic residues into functional porous materials, but balancing antibacterial activity, catalytic performance, adsorption capacity, and Ag-release control remains challenging. Here, sugarcane bagasse was converted into waste-derived nanocellulose through alkaline treatment, hydrogen peroxide bleaching, high-pressure homogenization, and sonication, then combined with chitosan and in situ green-loaded Ag nanoparticles using standardized green tea extract. The optimized Ag-WNC/CS-A-3 aerogel retained high porosity, improved mechanical stability, and a BET surface area of 66.4 +/- 5.2 m2/g. It showed CFU-based antibacterial reductions of 93.7 +/- 3.1% against Escherichia coli and 96.2 +/- 2.4% against Staphylococcus aureus, efficient 4-nitrophenol reduction with an apparent rate constant of 0.184 +/- 0.017 min-1, and enhanced adsorption toward methylene blue and Pb(II), with equilibrium capacities of 118.7 +/- 7.1 mg/g and 72.4 +/- 6.3 mg/g, respectively. Although Ag-WNC/CS-A-5 showed slightly higher short-term antibacterial and catalytic activity, it reduced adsorption balance and increased Ag release. Overall, Ag-WNC/CS-A-3 provided the most balanced combination of structural integrity, multifunctional activity, reuse stability, and Ag-release control. This work supports a sustainable design strategy for recoverable bio-based aerogels in antibacterial, catalytic, and water-treatment applications.