Green Synthesis and Multi-technique Characterization of Copper Nanoparticles Mediated by Citrus sinensis Peel Essential Oil
Amarachi Keziah Ezeike
Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria.
Valentine Chukwuma Ezenwa *
Integrity Research Laboratory, Oko. Anambra State, Nigeria.
Simon Pierre Yinyang Danga
Department of Biological Sciences, Faculty of Science, University of Garoua, Garoua, Cameroon.
Chinaza Favour Chukas
Integrity Research Laboratory, Oko. Anambra State, Nigeria.
C. Nwangwu Udoka
Federal Ministry of Health, National Arbovirus and Vectors Research Centre Enugu, Enugu State, Nigeria.
A. Dogunro Festus
Federal Ministry of Health, National Arbovirus and Vectors Research Centre Enugu, Enugu State, Nigeria.
Chukwuebuka Michael Nwosu
Federal Ministry of Health, National Arbovirus and Vectors Research Centre Enugu, Enugu State, Nigeria.
Malachy Chigozie Ugwu
Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria.
Angus Nnamdi Oli
Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria.
Charles Okechukwu Esimone
Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Green synthesis of nanoparticles using plant-derived materials has gained increasing attention due to environmental and safety concerns associated with conventional chemical methods. Citrus sinensis essential oil, obtained from agro-waste citrus peels, contains bioactive phytochemicals capable of acting as natural reducing and stabilizing agents. This study aimed to synthesize copper-based nanoparticles via a green route and evaluate their physicochemical properties.
Methods: Copper nanoparticles were synthesized via a green, biogenic route using Citrus sinensis essential oil. The synthesized nanoparticles were characterized using UV-Visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and gas chromatography-mass spectrometry (GC-MS).
Results: UV-Visible spectroscopy showed a characteristic absorption band at 300-320 nm, indicating nanoparticle formation. FTIR analysis revealed functional groups such as hydroxyl, carbonyl, and aliphatic moieties, confirming phytochemical involvement in reduction and stabilization. SEM images (8000×-10,000×) showed agglomerated clusters with irregular and porous morphology, while the primary particle size was inferred to be nanoscale. XRD patterns exhibited diffraction peaks consistent with nanocrystalline copper-based structures; however, peak broadening and low intensity suggest weak crystallinity and possible phase overlap. GC-MS identified 40 phytochemical constituents, predominantly oxygenated monoterpenes and sesquiterpenes, including cis-(-)-1,2-epoxy-p-menth-8-ene, decanal, D-carvone, and α-copaene, which likely contributed to nanoparticle formation and stabilization.
Conclusion: Citrus sinensis essential oil serves as an effective biogenic agent for the synthesis of copper-based nanostructures, providing an eco-friendly approach for agro-waste valorization. The characterized properties suggest potential applications in agriculture, environmental management, and vector control; however, further studies are required to validate their biological and functional performance.
Keywords: Copper nanoparticles, green synthesis, essential oil, physicochemical characterization, GC-MS