Preparation, Diagnosis, Theoretical Study, Biological Evaluation and Antioxidant Assay of ZrO<sub>2</sub> Oxide Nanoparticles Using Environmentally Friendly Method

This research included using an environmentally friendly method to synthesize nano particles of zirconium oxide using chamomile plant extract as a reducing agent in basic medium at pH 12, and then preparing the metal oxide using various techniques such as FTIR spectroscopy, scanning and transmission electron microscopy (SEM and TEM), energy-dispersive X-ray spectroscopy (EDX) to calculate the percentages of elements. The infrared spectrum showed the appearance of spectral bands at 559 and 441 cm–1 due to the formation of the bond between the oxygen and zirconium. Depending on AFM analysis, the average mean size of ZrO2 Nano partials was 45.11 nm, the measurement of crystal size in nanoparticles was conducted using Debye Scherer’s equation in x-ray diffraction, resulting in a value of 7.59 nm. XRD showed that the ZrO2 nanoparticles had a tetragonal crystal structure. The zirconium oxide was also studied theoretically using the Hyper Chem-8.0.7 program, where Vibration frequencies of t-zirconium dioxide were calculated at 567 cm–1, which matches the practical value, draws the tetragonal geometry optimization. Antimicrobial activities of ZrO2 nanoparticles have been studied against Bacillus, Klebsiella and Candida fungus in different concentrations of (25%, 50%, and 100%) in DMSO solvent medium, ZrO2 nanoparticles showed different efficacy towards these antimicrobial. The DPPH radical scavenging activity in different concentrations (12.5, 25, 50, 100, and 200 ppm) were used to analyze the antioxidant scavenging activity of ZrO2 nanoparticles, the potential antioxidant activity of ZrO2 NPs could be useful as anticancer agents and other deleterious diseases in future.