Green preparation of versatile silver-based nanocomposites using whole biomass-based Tannin-Furfural as raw materials

Phenolic resin (PR) nanomaterials, which serve as excellent carriers for precious metals, are typically synthesized via the cross-linked reaction of phenol and formaldehyde, and both are toxic. Therefore, replacing them with whole biomass-based materials is an attractive alternative; however, it has proven to be a significant challenge. In this study, we successfully prepared versatile Ag-based resin nanocomposites (referred to as TFR@Ag) by utilizing whole biomass-based tannin and furfural as raw feedstock. The resulting TFR nanospheres exhibited high stability and uniformity, with tunable sizes ranging from 280 to 1430 nm by adjusting the amount of ammonia used in the synthesis process. Importantly, compared to traditional PR nanospheres, the novel and environmentally friendly TFR nanospheres possess abundant phenolic-OH groups that significantly enhance their adsorption, reduction and chelation capacity for Ag+. The highest loading amount of silver nanoparticles (Ag NPs) achieved was up to 60.3 wt% with a size of only 10.6 nm. The as-obtained TFR@Ag nanocomposites demonstrated excellent catalytic activity in treating typical hazardous dye-containing wastewater. As catalyst, the 0.4 mg TFR@Ag were capable of achieving full reduction of 2 mL 40 mg·mL−1 methylene blue (MB) and methyl orange (MO) in just one minute, exhibiting reaction rate constants of 1.71 min−1 and 2.40 min−1, respectively. Moreover, as antibacterial agents, the TFR@Ag nanocomposite effectively inhibited the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with a bacterial inhibition rate close to 100 %. This work presents a new strategy for green synthesis of multi-functional Ag-based nanocomposites that hold great potential in various fields such as catalysis, nanomaterials science and biomedicine.