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

Dhananjay, P. and Abhilash, M. R. and Divakara Shetty, T. and Nataraj, K. and Gowtham, H. G. and Shiva Prasad, K. and Murali, M. (2025) 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, 26 (10). ISSN 1661-6596

Text (Full Text) Green Synthesis of Zinc Oxide Nanoparticles.pdf - Published Version Restricted to Registered users only Download (3MB) | Request a copy

Abstract

Nanoparticles (especially zinc and titanium oxide) have been found to be effective in photodegrading pollutants (organic/inorganic) from industrial wastewater. Presently, this study aimed at biosynthesizing zinc oxide nanoparticles (ZnO-NPs) from the leaf extract of Pavonia zeylanica, a plant with significant medical value, and evaluating their photocatalytic properties against methylene blue (MB), an azo dye (100 mg L-1, pH 7), using solar irradiation, along with the measurement of their reusability and mineralization efficiency. The characterization of the Pz-ZnO-NPs showed an absorbance peak at 313 nm, with a bandgap value of 3.04 eV and a size of 19.58 nm. This study's results show that the synthesized Pz-ZnO-NPs, upon treatment with MB dye after 2 h of solar irradiation, showed an 89.32% degradation, which was concentration-dependent and followed pseudo-first-order kinetics. The reusability studies indicated that the Pz-ZnO-NPs were able to degrade MB dye after five repeated cycles of its usage. The structural composition of the Pz-ZnO-NPs evaluated by XRD showed that the peak position stayed constant. Nevertheless, the peak intensity dropped, indicating that the ZnO-NPs' crystal structure was unaffected. Furthermore, advanced oxidation process studies, which included an evaluation of COD and TOC, revealed that both the contents decreased significantly during the photocatalysis process, wherein the electron-rich organic dyes were converted to nontoxic products through mineralization.

Item Type:	Article
Uncontrolled Keywords:	photocatalysis, Methylene blue, Pavonia zeylanica, Mineralization; kinetics,
Subjects:	D Physical Science > Material Science
Divisions:	Department of > Material Science
Depositing User:	Ms Varalakshmi
Date Deposited:	04 Nov 2025 10:25
Last Modified:	06 Nov 2025 05:52
URI:	http://eprints.uni-mysore.ac.in/id/eprint/17905

Actions (login required)

View Item