A new nanocomposite as adsorbent and catalyst for enhanced removal of methylene blue

In this study, we present, for the first time, the preparation and characterization of a few-layer graphene (FLG)/ Fe3O4/Ag nanocomposite functionalized with polyacrylic acid (PAA) polymer for the removal of methylene blue (MB). X-ray Powder Diffraction (XRD) analysis confirmed the coexistence of Fe3O4 and Ag nanoparticles. The results demonstrate a high adsorption ability (qmax 141.60 mg/g) of the nanocomposites, achieving 98% removal of MB dye within 40 min at a concentration of 50 mg/L, with a nanoadsorbent amount of 100 mg. Furthermore, the findings indicate that the FLG/Fe3O4/Ag@PAA adsorbent maintains high dye removal efficiency over four consecutive cycles. The FLG/Fe3O4/Ag@PAA nanocomposites exhibit significantly enhanced catalytic reduction activity on organic pollutants. The reduction of MB can be completed in 300 s in the presence of NaBH4 as a reducing agent, using 5 mg of nanocatalyst and a concentration of MB dye of 50 mg/L. These results suggest that the nanocomposite can serve not only as an adsorbent but also as a promising catalyst for the reduction of organic dyes.