Green Nanoremediation of Phytogenic Copper Oxide Nanoparticles for Concurrent Organic Pollutant Degradation in Industrial Wastewaters and Antibacterial Activity

In the present investigation, culture A. niger was used for the biosynthesis of CuO-NPs using mango (Mangifera indica) leaves aqueous extract. This method of green synthesis is simple, more environment friendly and easy to scaled up. The obtained CuO-NPs were characterized using FT-IR, XRD, TEM, EDX and DLS to evaluate their structure, morphology, elemental composition, and particle size distribution. These findings verify the generation of spherical, crystalline CuO-NPs with an average size of 35.1 nm. The biosynthesized plant-based CuO-NPs showed potential antimicrobial and catalytic, with the higher concentration (till 6.0 mg/mL) having effect better the effect. When used for wastewater treatment, under solar light, the NPs exhibited superior decolorization with a performance of 80.1 ± 1.5% at 6.0 mg/mL after 250 min, which is better than the 61.3 ± 1.3% observed in the dark. Moreover, the physicochemical parameters, viz., (TSS), (TDS), (COD) and (BOD) were also decreased significantly by 90.93%, 82.59%, 91.2% and 82.65%, respectively in the best process condition. Also the concentrations of heavy metals (cobalt, Co; lead, Pb; nickel, Ni; cadmium, Cd; and hexavalent chromium, Cr (VI)) were significantly reduced up to 69.9%, 79.7%, 75.0%, 77.0%, and 91.2%, respectively. Antimicrobial analysis demonstrated the CuO-NPs at the minimum inhibitory concentrations (MICs) of 100, 25, 100, 100, 25, and 50 μg/mL against Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, correspondingly. To sum up, mango leaf mediated synthesis of CuO-NPs acts as potent antibacterial agent as well as a catalyst for the wastewater treatment so as to their application in sustainable treatment of industrial effluent.