Photocatalytic degradation of organic pollutants and antibacterial properties of CuO nanoparticles: a study on methylene blue, congo red, tetracycline, ampicillin, ciprofloxacin, and azithromycin

Abstract

This study focuses on the synthesis of pure metal oxide nanoparticle -CuO through the sol-gel method. CuO nanomaterial with optical, structural and morphological properties are thoroughly examined using diverse instrumental techniques to determine their suitability for specific applications. The X-ray diffraction (XRD) patterns confirmed the high crystallinity of CuO, and crystallite size was determined to be 19 nm using the Scherrer formula and the lattice strain was determined to be approximately ∼2.17 × 10⁻³ through the Williamson−Hall plot. Morphological studies of CuO nanoparticles were observed the nanoparticle shapes. Due to the substantial quantum size confinement effect, CuO nanoparticles exhibited an optical energy band gap of approximately ∼1.7 eV. This measurement, determined through Tauc’s plots of the ultraviolet−visible (UV) spectrum, contributes to the notable photocatalytic efficiency of the material. The photocatalytic activity of Methylene Blue (MB) and Congo Red (CR) dyes under both UV and Visible lamps. The MB (79%) and CR (81%) dye degradation with 120 min duration. Furthermore, the degradation potential of Sol gel synthesised nanoparticles was tested against Tetracycline (TC), Ampicillin (AMP), Ciprofloxacin (CIP), and Azithromycin (AZM) antibiotics. The findings indicated the optimal degradation efficiency over 81.3%, 70.1%, 76.3% and 71.1% of 30 mg dose of CuO NPs and 3 ppm concentration of antibiotics solution in about 120 min. Subsequently, the obtained data were employed to the reaction rate law of kinetic fitting allowing for the determination of the correlation coefficient (R²) to assess the particle’s performance and exhibiting remarkable recycling capabilities in the degradation dyes, proved to be highly favourable and efficient catalysts. Antibacterial activity was assessed using the agar well diffusion method -Bacteroides fragilis and Bacillus cereus. Among the tested pathogens, B. cereus exhibited higher susceptibility, with a zone of inhibition measuring 10 mm, in response to the synthesized CuO NPs.

Graphical Abstract