Green biosynthesis of Ag-doped hetero-metallic oxide nanocomposite for efficient sunlight-driven photo-adsorptive degradation of carcinogenic naphthalene and phenanthrene

Abstract

One of the most significant issues facing the world today is environmental contamination due to the polycyclic aromatic hydrocarbons, or PAHs release of reactive chemicals into the environment. Here, a green technology was used to synthesis the Ag doped Bi₂O₃@Co₃O₄ nanocomposite utilizing an extract from Azadirachta indica leaves. The morphological and structural examination of Ag doped Co₃O₄@Bi₂O₃ revealed an image in the form of a hollow spherical or flake adsorbed on a Ag surface with an increase surface area. New peaks in the FT-IR spectra of Ag–O and Co–O–Bi at 678 cm⁻¹ and 1130 cm⁻¹, respectively, show the coupling of Ag. Following this, under various reaction conditions (pollutant: 10–30 mg/L; catalyst: 10–30 mg; pH: 3–11, dark sunlight) the doped nanocomposite was assessed for the efficient removal of NAP and PHE. Ag doped Co₃O₄@Bi₂O₃ displayed maximum degradation of NAP (96 %) and PHE (94 %) at 10 mg/L conc. of each PAH with a 25 mg catalytic dose at neutral pH in the presence of direct sunlight. First-order kinetics followed by initial Langmuir adsorption constituted the degradation process. Predominant reactive species and safer metabolite formation in the photocatalysis process of PAHs were studied by scavenger and GC–MS analysis. The green nano photocatalyst that was created demonstrated excellent stability, sensitivity, and reusability (up to 8th cycles) during the degrading process, which likely qualified it for use in industrial uses.