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Author: search.filters.author.Koetniyom, WantanaSubject: search.filters.subject.green synthesis

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    Influence of Dragon Fruit Peels on the Synthesis of Antibacterial Nano Zinc Oxide (Nano-ZnO) via Green Synthesis Method
    (2026-05-20)
    Sakulpeeb, Natchayaporn
    ;
    Koetniyom, Wantana
    ;
    Chutipaijit, Sutee
    ;
    Rahong, Sakon
    ;
    Kayunkid, Navaphun
    This research focused on adding value to dragon fruit peel waste by utilizing it in the synthesis of antibacterial nano zinc oxide (Nano-ZnO) through a green synthesis process. In this study, all the dragon fruit peels were extracted using the solvent extraction technique with three different solvents (deionized water, ethanol, and methanol) for 1, 2, 3, 4, and 5 h, respectively. The amount of flavonoids from the extract was determined using UV-Vis spectrophotometer to obtain the optimum extraction time, which was 4 h for DI water as the solvent. Moreover, antibacterial Nano-ZnO was synthesized successfully by a green synthesis process using zinc nitrate Zn(NO3)2 and the extracts. The molecular vibrations as well as the crystal structure and morphology were investigated by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM), respectively. Additionally, the antibacterial efficacy of the nano-zinc oxide samples was evaluated using disc diffusion method. Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were the test agents. The research shows that the X-ray diffraction patterns of all synthesized ZnO nanoparticles (NPs) exhibited a wurtzite (hexagonal) crystal structure. FT-IR spectroscopy confirmed the presence of Zn-O stretching vibrations at approximately 500 cm⁻¹. Furthermore, the FE-SEM reveals that ZnO-yellow particles displayed spherical morphologies with an average particle size of 145 nm. At the same time, ZnO-White and ZnO-Red nanoparticles exhibited a combination of rod-like and elliptical morphologies, with average particle sizes of 168 nm and 321 nm, respectively. In addition, the antibacterial activity demonstrates effective inhibition against S. aureus and E. coli in all three ZnO nanoparticle conditions.
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    Flavonoid Extraction from Mango Peels for Nanoparticles by Green Synthesis Process
    (2025-09-03)
    Wirunchit, Supamas
    ;
    Sakulpeeb, Natchayaporn
    ;
    Chutipaijit, Sutee
    ;
    Nukaew, Jiti
    ;
    Koetniyom, Wantana
    This research study explored the extraction of flavonoids from ripe and raw mango peels using different solvents (deionized water, methyl alcohol, and ethyl alcohol) over varying durations. The extracted compounds were then employed in synthesizing titanium dioxide nanoparticles (TiO2 NPs) via a green chemical process using titanium isopropoxide. Optimal extraction, yielding the highest flavonoid content, was achieved with deionized water after 3 h for ripe peels and 4 h for raw peels. The titanium dioxide nanoparticles synthesized exhibited an anatase crystal structure, as confirmed by XRD, Raman, and FTIR techniques. SEM images showed that the nanoparticles were evenly distributed and had a smooth surface. The titanium dioxide nanoparticles demonstrated stronger antibacterial activity against Escherichia coli than Staphylococcus aureus. Furthermore, raw mangoes were found to be more effective in inhibiting bacterial growth than ripe mangoes.
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    GREEN SYNTHESIS OF ZINC OXIDE NANOPARTICLES FROM LEMON PEEL EXTRACT AND THEIR ANTIBACTERIAL ACTIVITY
    (2024-01-01)
    Wirunchit, Supamas
    ;
    Sakulpeeb, Natchayaporn
    ;
    Chutipaijit, Sutee
    ;
    Nukaew, Jiti
    ;
    Koetniyom, Wantana
    This research project aimed to study the extraction of flavonoids from lemon peels using different solvents, namely deionized water (DI water), isopropanol, ethanol, and methanol. Among these, DI water yielded the highest amount of flavonoids. The extracted compounds were then utilized for the synthesis of zinc oxide nanoparticles (ZnO NPs) through a green chemical method. Various amounts of lemon peel extract (10, 15, 20, 25, and 30 ml) were mixed with Zn(NO3)2 during the synthesis process. The ZnO NPs were characterized using UV-VIS spectrophotometry, X-ray diffractometry (XRD), Fourier transform-infrared spectrometry (FT-IR), and Raman spectrometry. The results revealed successful synthesis of ZnO NPs, except for those produced using DI water extract, which exhibited a different structure (wurtzite). Subsequently, the antibacterial properties of the ZnO NPs were tested against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) using the disc diffusion method. The ZnO NPs synthesized from different solvent extracts demonstrated effective inhibition zones against both bacterial strains, indicating their potential as antibacterial agents.