Madhuca longifolia plant mediated green synthesis of cupric oxide nanoparticles: A promising environmentally sustainable material for waste water treatment and efficient antibacterial agent

In current years, the development of efficient green methods for synthesis of metal oxide nanomaterials has attracted a great attention to the researchers since the plant-mediated synthesis is a cost-effective and a good alternative to chemical and physical methods. An efficient and eco-friendly route has been developed for the green synthesis of CuO nanoparticles (NPs) by Madhuca longifolia plant extract which acts as a non-toxic reducing agent. X-ray diffraction studies reveal the good crystallinity of the synthesized NPs and FTIR spectra confirm the synthesis of these NPs. UV–visible absorption spectra showed that the NPs have been reached at different nano scale level depending on their synthesis procedures. TEM images indicate that as-synthesized CuO NPs are spherical in shape with their different size ranges and they show different band gap values which is confirmed by Tauc's formula. The NPs exhibit good photoluminescence property depending on their particle size and they also show excellent photocatalytic activity towards the degradation of methylene blue (MB) in presence of visible light irradiation which will be a promising material for waste water treatment. The synthesized CuO NPs show good antibacterial activity against bacterial strains namely E. coli BL21 DE3 Gram-negative, S. aureus Gram-positive and B.subtilis Gram-positive and the results have been compared against Ampicillin and Tetracycline. [Display omitted] •Green synthesis of CuO nanoparticles (NPs) has been carried out by aqueous extract of Madhuca longifolia plant.•Different characterization methods such as, XRD, TEM, FTIR, UV and PL studies have confirmed the synthesis of the NPs.•The NPs will be useful for wastewater treatment due to their good photocatalytic activity in visible light irradiation.•The photoluminescence intensity and band gap of the CuO NPs change depending on their particle size.•The NPs are very efficient as antibacterial agents against bacterial strains.