Abstract
Zinc oxide nanoparticles (ZnO.NPs) were synthesized by green method from Eichhornia crassipes leaves extract. Then it characterized by Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), and field emission scanning electron microscopy (FESEM). XRD spectrum reveals that crystallite size obtained is about (17.36) nm for (ZnO.NPs) which agreed fairly well with FESEM data (22.89) nm.The excellent purity of ZnO-NPs has been confirmed by EDX data. In this study, the ability of prepared zinc oxide nanoparticles to adsorb Ni(II) and Co(II) ions from their aqueous solutions in single and multicomponent systems were investigated. It also includes the effect of some adsorption factors such as the time required to remove Co(II) and Ni(II) ions and showed that contact time were (60 and 45) min in single and multicomponent system respectively. The removal of Ni (II) and Co(II) ions was found to be slightly reduce by increasing the concentration of adsorbate and increase by increase the weight of the surface, whereas the effect of temperature on metals removal showed that the percentage removal is reduced by increasing the temperature, which means that the process is exothermic. It is found also that the adsorption of cobalt (II) and nickel (II) ions on (ZnO.NPs) surfaceat could be described by the Freundlich and Halsey isotherm models owing to the high correlation coefficient values compared to the rest of the isotherms. Three kinetic equations, which are the pseudo-first order, the pseudo second order equation and the internal particles diffusion equation were tested. It was found through the obtained results that the adsorption follow pseudo second order model at all temperatures.
The values of the thermodynamic functions of the adsorption process (ΔH, ΔG,ΔS˚) indicate that the adsorption process is exothermic, spontaneous, and less random when metal ions overlap with the prepared ZnO oxide.
The antibacterial activity of ZnO.NPs was assessed against a few dangerous pathogens. Zinc oxide nanoparticles were shown to have an interesting antibacterial action against both gram positive and gram negative bacteria at micromolar concentrations because they exhibit the maximum diameter of inhibition zone at concentrations 100 mg/ml of of S. aureus ,E. coli, K. pneumonia, Acintobacret spp, S. fecalis reaching (27,19,18,17,and 14) mm, respectively while S.pneumonia were resistance . While the ZnO.NPs recorded at concentration 12.5 mg/ml lowest areas of inhibition zone against the same isolates reaching (16, 11, 11, 12 and 10) mm while S.pneumonia were resistance respectively, as well.
