Novel Citrus aurantifolia leaves based biosynthesis of copper oxide nanoparticles for environmental and wastewater purification as an efficient photocatalyst and antibacterial agent

Water contamination by organic dyes and micro-organisms is an immense threat towards human and aquatic life. Nanotechnology is the promising technology for resolution of these problems by introducing novel and efficient photocatalytic nanomaterials. In this study, Copper Oxide (CuO) nanoparticles are synthesized through biological synthesis method using leaves extract of citrus aurantifolia (key-lime) which is a cost effective, eco-friendly and non-toxic method. The physical and optical features of biosynthesized CuO nanoparticles were characterized which confirmed the crystalline nanoparticles with an average crystallite size of similar to 22 nm and 3.48 - 3.51 eV band gap. Further, the purity of the biosynthesized CuO nanoparticles was verified for usage as a photocatalyst. The bio-synthesized CuO nanoparticles were applied as photocatalyst and antibacterial agent for purification of the wastewater from the industries and living places. The photocatalytic activity of bio-synthesized CuO nanoparticles is tested for an industrial dye Rhodamine B (RhB) and 91 % dye removal was observed. Furthermore, the antibacterial activity of the synthesized nanoparticles is also tested against a gram-positive bacteria Staphylococcus aureus (S. aureus) as well as gram-negative bacteria Escherichia coll. (E. coli) which disclosed efficient efficiency. Therefore, biosynthesized CuO nanoparticles can be the potential photocatalyst for dye removal and antibacterial agent for contaminated water.