An Eco-Friendly Synthesis Approach for Enhanced Photocatalytic and Antibacterial Properties of Copper Oxide Nanoparticles Using Coelastrella terrestris Algal Extract

Manisha Khandelwal,1 Sunita Choudhary,2 Harish,2 Ashok Kumawat,3 Kamakhya Prakash Misra,3 Yogeshwari Vyas,1 Bhavya Singh,4 Devendra Singh Rathore,4 Kanchan Soni,3 Ashima Bagaria,3 Rama Kanwar Khangarot1 1Department of Chemistry, University College of Science, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, India; 2Department of Botany, University College of Science, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, India; 3Department of Physics, School of Basic Sciences, Manipal University Jaipur, Jaipur, Rajasthan, 303007, India; 4Department of Environmental Sciences, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, IndiaCorrespondence: Rama Kanwar Khangarot, Department of Chemistry, University College of Science, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, India, Email ramakanwar@mlsu.ac.inBackground: In the current scenario, the synthesis of nanoparticles (NPs) using environmentally benign methods has gained significant attention due to their facile processes, cost-effectiveness, and eco-friendly nature.Methods: In the present study, copper oxide nanoparticles (CuO NPs) were synthesized using aqueous extract of Coelastrella terrestris algae as a reducing, stabilizing, and capping agent. The synthesized CuO NPs were characterized by X-ray diffraction (XRD), UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and field emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray spectroscopy (EDS).Results: XRD investigation revealed that the biosynthesized CuO NPs were nanocrystalline with high-phase purity and size in the range of 4.26 nm to 28.51 nm. FTIR spectra confirmed the existence of secondary metabolites on the surface of the synthesized CuO NPs, with characteristic Cu–O vibrations being identified around 600 cm− 1, 496 cm− 1, and 440 cm− 1. The FE-SEM images predicted that the enhancement of the algal extract amount converted the flattened rice-like structures of CuO NPs into flower petal-like structures. Furthermore, the degradation ability of biosynthesized CuO NPs was investigated against Amido black 10B (AB10B) dye. The results displayed that the optimal degradation efficacy of AB10B dye was 94.19%, obtained at 6 pH, 50 ppm concentration of dye, and 0.05 g dosage of CuO NPs in 90 min with a pseudo-first-order rate constant of 0.0296 min− 1. The CuO-1 NPs synthesized through algae exhibited notable antibacterial efficacy against S. aureus with a zone of inhibition (ZOI) of 22 mm and against P. aeruginosa with a ZOI of 17 mm.Conclusion: Based on the findings of this study, it can be concluded that utilizing Coelastrella terrestris algae for the synthesis of CuO NPs presents a promising solution for addressing environmental contamination. Keywords: green synthesis, CuO NPs, photocatalysis, antibacterial activity, wastewater treatment