Biosynthesis of NiO nanoparticles from different sources; characterization and determination of photocatalytic activity

Recently, the synthesis of nanoparticles using extracts of waste biomass has attracted the attention of many researchers worldwide due to their reduced chemical toxicity. In this study, NiO nanoparticles were synthesized using the hydrothermal extract obtained from lemon, orange and tangerine peels by green synthesis method. The characterization of the synthesized NiO nanoparticles was performed with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-ray pattern diffraction (XRD) and transmission electron microscopy (TEM). The synthesized NiO nanoparticles were used as a catalyst in the photocatalytic reduction of methylene blue. NaBH4 was used as the reducing agent in the photocatalytic reduction of methylene blue. The effects of the initial solution pH, NaBH4 concentration, methylene blue concentration and catalyst amount parameters on the photocatalytic reduction of methylene blue were investigated. Photocatalytic reduction of methylene blue with NaBH4 is pseudo-first order and the rate constant is NiO nanoparticles (L-NiO NPs) from lemon peel extract, NiO nanoparticles from orange peel extract (P-NiO NPs), and NiO nanoparticles from tangerine peel extract (M). -NiO NPs) were determined to be 1,56 min⁻¹, 0,66 min⁻¹ and 1,12 min⁻¹, respectively. It has been determined that NiO nanoparticles synthesized from lemon, orange and tangerine peel extracts by the environmentally friendly green synthesis method are active and usable in the photocatalytic reduction of methylene blue.