Tannic acid/Fe3+ functionalized magnetic graphene oxide nanocomposite with high loading of silver nanoparticles as ultra-efficient catalyst and disinfectant for wastewater treatment

Silver nanoparticle (Ag NPs) and their nanocomposite materials have been widely applied as catalysts and disinfectants for wastewater treatment. However, most reported Ag NP-based nanocomposites possess a low loading of Ag NPs, which require a high dosage to achieve satisfactory catalytic decontamination performance to organic pollutants and good disinfection to the bacteria. Herein, we synthesize a novel Ag NPs nanocomposite with an extremely-high loading of Ag NPs (up to 30 wt%) via tannic acid (TA)/Fe3+ complexation by using magnetic graphene oxide (MGO). The [email protected]/Fe3+ catalyst shows excellent stability in aqueous environment and can achieve an ultrahigh catalytic reduction rate of 0.054 s−1 for methylene blue (MB) at an extremely low dosage (i.e., 0.05 mg/mL), which is about ten times higher than that of most NPs-based catalysts reported previously under similar condition. Moreover, the magnetic nanocomposites can be easily regenerated and are highly recyclable without any obvious performance loss. In addition, the novel [email protected]/Fe3+ nanocomposites exhibit disinfection performance against Escherichia coli (E. coli) with ~100% killing efficacy at a very low dosage (i.e., 20 μg/mL). This work provides new insights into the rational design of advanced recyclable NP-based nanomaterials with ultrahigh catalytic rate and outstanding antimicrobial performance for water treatment and various environmental engineering applications.