Copper oxide nanoparticles (CuONPs) were phytosynthesized by Laurus nobilis leaf extract, which was used as a reducing and capping agent. UV‐vis spectroscopy was applied, and the spectrum of CuONPs gave a peak around 300 and 325 nm. An intense Fourier transform infrared spectroscopy between 4000 and 500 cm−1 wavelengths exhibited exterior functional groups of CuONPs. The results of scanning electron microscopy and transmission electron microscopy revealed that the green synthesized CuONPs were spherical in shape with sizes between 90 and 250 nm. Antibacterial activity of CuONPs was evaluated against both Gram‐positive and Gram‐negative bacteria. Brilliant Blue R‐250 was employed in the dye decolorization studies, and CuONPs achieved 69% decolorization in 60 Min. The antioxidant activity of CuONPs was calculated by analyzing total phenolic compounds and flavonoid content. Furthermore, the reducing power of extract and nanoparticles was determined. Total phenolic compounds of CuONPs were determined as 6.7 µg of pyrocatechol equivalent/mg, while total flavonoids were measured as 236.62 µg catechin/mg sample. Results indicated that the method of CuONP formation is simple and low cost and the phytosynthesized CuONPs had antibacterial, antioxidant, and dye decolorization activity.

No abstract

S ince dyes are colored compounds, they are one of the most easily recognizable contaminants in the environment. These compounds are found in many areas of the industry like: textile, color photography, cosmetics, paper, printing, plastic, food, etc. for product coloring (1-4). The fact that dye is poisonous reveals how important it is to remove dye from wastewater in terms of ecology (5, 6).The discharge of dyes is carried out using a variety of methods such as biological degradation, membrane technologies, coagulation-flocculation, electrochemical techniques, advanced oxidation, chemical flocculation and precipitation, electrochemical, membrane filtration, ion exchange, aerobic, anaerobic and biosorption methods(7-9). Apart from these methods, the biosorption technique has been very popular in recent years in terms of chromatographic processes (10, 11).For the first time, the adsorption method was introduced by Scheele in 1773 and Abbe Fontana in 1777 (12). Adsorption can be defined as the increase of surface concentration by attaching atoms, ions, and molecules to a solid surface (13). Several different natural and waste adsorbents have been investigated to remove