Phytosynthesized copper oxide nanoparticles and their application in Pb2+ detection from surface water.

In the current work, phytosynthesized Copper oxide nanoparticles (CuO-NPs) were obtained in facile and sustainable way utilizing leaves of Ocimum sanctum, to detect heavy metals from surface water. The presence of phytochemicals in the green extract helps in stabilizing the nanoparticle by reducing metallic Cu2+ to CuO-NPs. Further standard physical techniques like XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), UV-Vis spectroscopy and FESEM (Field-Emission Scanning Electron Microscope) confirmed the formation of CuO-NPs. The phytosynthesized CuO-NPs revealed spherical conformation with 40 nm average crystallite size, calculated by Scherrer's formula. A linear colorimetric behaviour of CuO-NPs was observed in the range of (10–400 nM) Pb2+ ions and the R2 value of 0.992 with limit of detection of 60 nM was observed. The UV-Vis spectroscopy results confirmed pronounced sensitivity and selectivity for Pb2+ ions among all the metals tested (Ba2+, Ca2+, Hg2+, K+, Mg2+, Na+, Ni2+ and Zn2+). Interference tests indicated no interference on adsorption of Pb2+ ions from aqueous solutions from other metal ions tested. Kinetic studies on Pb2+ adsorption by CuO-NPs revealed best fit to the equilibrium data of Freundlich isotherm. Besides, Pseudo 2nd order kinetics was observed to be much appropriate with R2 (linear regression coefficient) equal to 0.999 for the adsorption process. Thus, in this study phytosynthesized CuO-NPs could be a promising candidate for effective detection and elimination of Pb2+ ions from surface water making it potable. [ABSTRACT FROM AUTHOR]