Synthesis and characterization of Araucaria columnaris leaf-mediated NiO nanoparticles for removal of pharmaceutical pollutants in municipal water bodies

Nickel oxide nanoparticles (NiO NPs) were effectively prepared from nickel nitrate salt using sonication-assisted chemical (S-NiO NPs) and green (G-NiO NPs) approaches with the effect of reagents sodium hydroxide and Araucaria columnaris leaf extract. To study the role of reducing and stabilizing agents employed, the physiochemical properties of prepared S-NiO and G-NiO NPs were evaluated using XRD, PSA, FTIR, FE-SEM, TEM, BET, UV–Vis, and TG–DTA analysis. The highly reactive phytochemical constituent of leaf extract had significant control over the size and morphology, which produced spherical-shaped NiO NPs with a mean particle size of 23 nm and a high specific surface of 88.191 m 2 g −1 . The above result was tuned to the active UV–Visible absorption band gap of 3.39 eV and 3.15 eV, respectively, for S-NiO NPs and G-NiO NPs. The prepared NiO NPs were promoted to real-time application in treating severe pharmaceutical residuals of Naproxen and Carbamazepine through visible light photocatalytic degradation. The highest degradation efficiency was achieved with green synthesis NiO NPs against Carbamazepine at 98.82% and Naproxen at 98.22%. The proposed lower concentration of 0.5 g/L NPs with specific physicochemical and optical properties may address pharmaceutical pollution, especially in municipal water bodies and protect the aquatic environment.