Green Synthesis of Zinc Oxide Nanoparticles Using Aqueous Leaf Extract of Citrus sinensis and Their Photocatalytic Activity

International Journal of Chemistry | Vol. 3, No. 2, February 2012 | pp. 10–17

DOI: 10.46882/2012/IJC/000041

Article Type: Original Research Paper

Title: Green Synthesis of Zinc Oxide Nanoparticles Using Aqueous Leaf Extract of Citrus sinensis and Their Photocatalytic Activity

Names of Authors: S. I. Musa¹, O. R. Popoola²*

Authors’ Affiliations:
¹Department of Chemistry, University of Jos, Jos, Nigeria.
²Department of Chemistry, Ekiti State University, Ado-Ekiti, Nigeria.

Abstract: The biological synthesis of metal oxide nanoparticles using plant extracts represents an eco-friendly and sustainable alternative to traditional chemical preparation methods. This study describes the green synthesis of zinc oxide nanoparticles (ZnO-NPs) using the aqueous leaf extract of Citrus sinensis (Sweet orange) as a reducing and capping agent. The formation of the nanoparticles was monitored via UV-Vis spectrophotometry, which revealed a characteristic absorption peak at 368 nm. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the ZnO-NPs, showing a hexagonal wurtzite structure with an average crystallite size of 24 nm. Fourier-transform infrared (FT-IR) spectroscopy indicated that hydroxyl and carbonyl groups from the plant polyphenols and flavonoids were actively involved in stabilizing the nanoparticle matrix. The photocatalytic efficiency of the synthesized ZnO-NPs was evaluated by monitoring the degradation of Methyl Orange dye under natural solar irradiation. The biosynthesized nanoparticles achieved 94.2% decolorization of the dye within 90 minutes of exposure. Kinetic modeling established that the photocatalytic breakdown followed the Langmuir-Hinshelwood pseudo-first-order model with a rate constant of 0.028 min⁻¹, proving that these green catalysts are highly efficient for treating textile industry organic pollutants.

Keywords: Zinc oxide nanoparticles; Green synthesis; Citrus sinensis; Crystalline structure; Photocatalytic degradation; Methyl orange

Manuscript Timeline: Received: June 05, 2011; Revised: July 18, 2011; Accepted: August 12, 2011; Published: February 03, 2012.

Citation: Musa, S. I., & Popoola, O. R. (2012). Green Synthesis of Zinc Oxide Nanoparticles Using Aqueous Leaf Extract of Citrus sinensis and Their Photocatalytic Activity. International Journal of Chemistry, 3(2), 10–17.

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