Study of the Microwave Assisted One Pot Green Synthesis of Inorganic Metal Oxide Nanoparticles and their Potential Biological and Photocatalytic Applications

Abstract

This study focuses on the microwave-assisted green synthesis of Nickel Oxide (NiO) and Magnesium Oxide (MgO) nanoparticles using the leaf extract of Pedilanthus tithymaloides (Devil s Backbone). The plant extract, rich in phenolic compounds, serves as a reducing and stabilizing agent, enabling an eco-friendly and efficient method of nanoparticle synthesis. The use of microwave irradiation enhances the reaction speed and improves the morphology of the nanoparticles. newlineThe synthesized nanoparticles were characterized using X-ray Diffraction (XRD), which confirmed their crystalline nature. Scanning Electron Microscopy (SEM) revealed that NiO particles had a needle-like, agglomerated structure, while MgO appeared in spherical clusters. Energy Dispersive X-ray Spectroscopy (EDS) confirmed the presence of nickel and magnesium, validating the successful formation of NiO and MgO. Fourier Transform Infrared Spectroscopy (FTIR) identified functional groups involved in synthesis. newlineThe nanoparticles showed promising biological activities. Antibacterial tests showed that NiO produced a maximum inhibition zone of 37 mm against gram-positive Streptococcus, while MgO showed 30 mm against gram-negative bacteria such as Klebsiella pneumoniae and E. coli. In antifungal tests, MgO exhibited superior activity with a 28.9 mm zone of inhibition compared to NiO s 21.5 mm. Antioxidant activity was higher in MgO (86.72%) than in NiO (70.12%) at 100 µL concentration. newlinePhotocatalytic degradation studies demonstrated that MgO nanoparticles effectively degraded dyes such as malachite green and indigo carmine under sunlight, turning malachite green colorless. This indicates their high catalytic potential in wastewater treatment. Overall, MgO nanoparticles show excellent multifunctional properties and could be used in biological and environmental applications. newline newline