Green Synthesis of Zinc Oxide Nanoparticles for Environmental Remediation

Researchers from the University of Mysore have successfully biosynthesized zinc oxide nanoparticles (ZnO-NPs) using the leaf extract of a plant with significant medical value, Pavonia zeylanica. This innovative approach has been shown to be effective in photodegrading pollutants, specifically methylene blue, an azo dye, with a degradation rate of 89.32% after 2 hours of solar irradiation. The study highlights the potential of this green synthesis method for environmental remediation, as it reduces the need for chemical solvents and produces nontoxic products.

Key Takeaways:

• The study demonstrated the photocatalytic properties of ZnO-NPs synthesized from Pavonia zeylanica leaf extract, achieving a degradation rate of 89.32% of methylene blue after 2 hours of solar irradiation.
• The ZnO-NPs showed reusability and mineralization efficiency, with the ability to degrade MB dye after five repeated cycles of its usage.
• The study's findings suggested that the advanced oxidation process, including an evaluation of COD and TOC, resulted in significant decreases in these contents during the photocatalysis process.
• The research concluded that the electrochemical property of ZnO-NPs enables the conversion of electron-rich organic dyes to nontoxic products through mineralization.
• The study employed a green synthesis method, using an aqueous extract of Pavonia zeylanica, which reduces the need for chemical solvents and produces nontoxic products.
• The characterization of Pz-ZnO-NPs showed an absorbance peak at 313 nm, a bandgap value of 3.04 eV, and a size of 19.58 nm.
• The structural composition of the Pz-ZnO-NPs was evaluated by XRD, which showed that the peak position stayed constant, but the peak intensity dropped, indicating that the ZnO-NPs' crystal structure was unaffected.
• The research was conducted by Abhilash Mavinakere Ramesh, Dhananjay Purushotham, Divakara Shetty Thimmappa, Nataraj Kalegowda, Gowtham Hittanahallikoppal Gajendramurthy, Shiva Prasad Kollur, and Murali Mahadevamurthy from the University of Mysore.

Statistics:

• The degradation rate of methylene blue after 2 hours of solar irradiation was 89.32%.
• The ZnO-NPs showed reusability and mineralization efficiency after five repeated cycles of its usage.
• The advanced oxidation process, including an evaluation of COD and TOC, resulted in significant decreases in these contents during the photocatalysis process.
• The electrochemical property of ZnO-NPs enables the conversion of electron-rich organic dyes to nontoxic products through mineralization.
• The characterization of Pz-ZnO-NPs showed an absorbance peak at 313 nm, a bandgap value of 3.04 eV, and a size of 19.58 nm.

Sources:

• Green Synthesis of Zinc Oxide Nanoparticles Using Aqueous Extract of Pavonia zeylanica to Mediate Photocatalytic Degradation of Methylene Blue: Studies on Reaction Kinetics, Reusability and Mineralization. International Journal of Molecular Sciences, 2025;26(10):4739.
• Mdpi, St Alban-Anlage 66, Ch-4052 Basel, Switzerland.
• Abhilash Mavinakere Ramesh, Dept. of Studies in Environmental Science, University of Mysore, Manasagangotri, Mysuru 570006, Karnataka, India.