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Solvent-Dependent Green Synthesis of ZnO Nanopowders Using Mitragyna speciosa Leaf Extract: Impact on Piezo-Photocatalytic and Antibacterial
(2026-07-01)
Sanyen, Thanyapa
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Songpanit, Maneerat
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Kansaard, Thanaphon
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Wirunchit, Supamas
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Chutipaijit, Sutee
ZnO nanopowders were synthesized via a solvent-mediated green route using Mitragyna speciosa Korth. leaf extract as reducing and stabilizing agents. Deionized water and methanol were employed to tailor the phytochemical composition of the extracts. The influence of extract concentration (5–20 mL) and solvent polarity on structural, morphological, and functional properties was systematically investigated. Structural analyses confirmed the formation of Zn-O bonds and a phase-pure hexagonal wurtzite ZnO without secondary phases. Surface morphology revealed solvent-dependent morphological evolution toward spherical shapes and reduced aggregation in the methanol-derived system. For antibacterial activity, green ZnO nanopowders demonstrated enhanced biocidal effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, comparable to that of commercial ZnO nanoparticles. Enhanced piezo-photocatalytic degradation of rhodamine B was achieved under combined light and ultrasonic irradiation, with superior performance observed for methanol-derived ZnO. This enhancement is attributed to the synergistic interplay of solvent-induced defect states, reduced particle size, and piezoelectric field-driven charge separation. Scavenger analysis confirmed that superoxide radicals ((Formula presented.)) dominate the degradation pathway by green-synthesized ZnO nanopowders prepared from different solvent extracts. Thus, a correlation between solvent-mediated phytochemical environments and piezo-photocatalytic activity provides new insights for the design of sustainable, high-performance ZnO-based catalysts.
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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
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Koetniyom, Wantana
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Chutipaijit, Sutee
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Rahong, Sakon
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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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Fungal Transformation and Oxalate-Mediated Mineralization of Heavy Metal Oxides by Aspergillus aculeatus
(2026-04-01)
Sawangchart, Thanakorn
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Chutipaijit, Sutee
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Meksiriporn, Bunyarit
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Narueban, Worapat
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Tilokkarn, Worrathon
Fungal transformation is increasingly recognized as an important process influencing metal solubilization and immobilization in soil environments. In this study, a fungal strain (PTW4) isolated from mining-contaminated soil was molecularly identified as Aspergillus aculeatus. The strain was evaluated for its ability to solubilize and transform several heavy metal oxides, including ZnO, Pb<inf>3</inf>O<inf>4</inf>, Cu<inf>2</inf>O, and MoO<inf>3</inf>. PTW4 produced consistent halo formation across all tested oxides, accompanied by progressive acidification of the culture medium, suggesting organic acid-mediated solubilization. Characterization of extracellular precipitates by SEM-EDS and XRD indicated mineral phases consistent with oxalate-associated biominerals, including zinc oxalate dihydrate (ZnC<inf>2</inf>O<inf>4</inf>·2H<inf>2</inf>O), lead oxalate (PbC<inf>2</inf>O<inf>4</inf>), and copper oxalate hydrate (CuC<inf>2</inf>O<inf>4</inf>·xH<inf>2</inf>O). These minerals represent low-solubility phases that may reduce metal mobility in the surrounding environment. In contrast, molybdenum did not precipitate under the experimental conditions, suggesting metal-specific constraints in fungal biomineralization processes. Although organic acid production was not directly quantified, identification of oxalate mineral phases supports an oxalate-associated mineralization mechanism. Overall, the results provide evidence for heavy metal solubilization and selective extracellular precipitation consistent with oxalate biomineral formation by A. aculeatus PTW4, highlighting its potential relevance to fungal-mediated bioremediation and selective bioleaching processes.
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Green synthesis and optimized annealing tempserature effects on zinc oxide nanoparticles using mango peel extract
(2026-01-01)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Meedech, Woradech
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Chutipaijit, Sutee
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Koetniyom, Wantana
This study presents the green synthesis of zinc oxide nanoparticles (ZnO-NPs) using mango peel extract (MgE) as a natural reducing and stabilizing agent. Phytochemical extraction was performed with deionized water, ethanol, and methanol for 1 h to 5 h, with deionized water at 4 h yielding the highest flavonoid content. Using zinc nitrate as a precursor, 25 mL of MgE successfully facilitated the synthesis of ZnO-NPs (ZnO-25MgE). It was found that annealing temperature at 400°C for 6 h produced pure ZnO. The obtained nanoparticles were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FE-SEM). XRD confirmed the crystalline structure with an average size of 6.67 nm, while FT-IR and FE-SEM analyses revealed Zn–O vibrations, residual organics, and nanoscale morphology. Thermogravimetric analysis (TGA) indicated the appropriate annealing temperature for the removal of organics. For comparison, chemically synthesized ZnO was also characterized, and its antibacterial activity was assessed via disc diffusion against Escherichia coli and Staphylococcus aureus. The results demonstrated notable inhibition, highlighting the potential of biosynthesized ZnO-NPs for antimicrobial applications.
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Flavonoid Extraction from Mango Peels for Nanoparticles by Green Synthesis Process
(2025-09-03)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Chutipaijit, Sutee
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Nukaew, Jiti
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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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Coconut Residue-Derived Nanoporous Carbon via Hydrothermal Carbonization for Nanoporous Carbon-Based Supercapacitor Electrodes
(2025-07-01)
Ruenroengrit, Kemchat
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Kunyuan, Jumpon
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Ruttanadech, Nuttapong
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Kaewtrakulchai, Napat
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Puengjinda, Pramote
The increasing demand for sustainable and cost-effective energy storage solutions has driven interest in biomass-derived carbon materials for supercapacitor electrodes. This study explores the valorization of coconut residue (CR), an abundant agricultural waste, as a carbon precursor for nanoporous carbon (NPC) production. NPC was synthesized via hydrothermal carbonization (HTC) of CR, followed by chemical activation using potassium hydroxide (KOH) at varying temperatures (700, 800, and 900 °C). The effects of activation temperature on the structure and electrochemical performance of the NPC were systematically investigated. The activated materials exhibited amorphous, highly porous structures, with surface areas increasing alongside activation temperature—reaching a maximum of 1969 m2 g−1 at 900 °C. Electrochemical characterization was conducted using a three-electrode setup through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) in a 1 M Na<inf>2</inf>SO<inf>4</inf> electrolyte. The sample activated at 900 °C with a CR:KOH weight ratio of 1:2.5 achieved the highest specific capacitance of 52 F g−1 at a specific current of 1 A g−1. These findings underscore the potential of CR as a low-cost and sustainable raw material for fabricating efficient electrode materials in energy storage applications.
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X-ray characterization, structural analysis, antibacterial activity, and self-cleaning property of Cu-doped TiO2-SiO2 nanocomposite prepared by sonochemical process
(2024-12-01)
Mekprasart, Wanichaya
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Songpanit, Maneerat
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Sanyen, Thanyapa
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Samart, Sutichai
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Chutipaijit, Sutee
TiO<inf>2</inf>-SiO<inf>2</inf> nanocomposites with different copper (Cu) precursor loadings were prepared by a one-step sonochemical process. The mole ratio of Cu precursor in TiO<inf>2</inf>-SiO<inf>2</inf> composite was varied at 0.004, 0.008, 0.020, and 0.040, respectively. The specific X-ray characterization techniques on crystalline structure, chemical composition, and chemical states of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> composite were carried out by X-ray diffraction technique (XRD), X-ray fluorescence (XRF), and X-ray photoelectron spectroscopy (XPS), respectively. Surface morphology and chemical bonding of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> composite were monitored by field emission scanning electron microscope (FE-SEM) and Fourier transform infrared spectrophotometer (FTIR). For antibacterial properties, the inhibition zone of antimicrobial activity was investigated by varying amounts of Cu precursors in the TiO<inf>2</inf>-SiO<inf>2</inf> composite. After that, Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> composite powder with different Cu precursor ratios was mixed in PMMA solution and deposited on glass slides to study the optical property and hydrophilicity by UV-VIS-NIR spectrophotometer and contact angle method. XRD patterns of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> nanocomposites show the formation of the main TiO<inf>2</inf> anatase phase with the ultrafine particles observed by FE-SEM images. FT-IR spectra of the composites are assigned to the prominent peaks of the Ti-O-Ti and Ti-O-Si bond relating to the TiO<inf>2</inf>-SiO<inf>2</inf> host matrix. Meanwhile, TiO<inf>2</inf>-SiO<inf>2</inf> composites with Cu precursor at 0.004 mol ratio can significantly enhance the antibacterial activity with a large inhibition zone. The contact angle value of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> nanocomposite film at 0.040 Cu precursor mole ratio in the TiO<inf>2</inf>-SiO<inf>2</inf> matrix resulted in the optimized composite ratio for achieving a hydrophilic surface on the substrate.
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Valorization of horse manure conversion to magnetic carbon nanofiber for dye adsorption by hydrothermal treatment coupled with carbonization
(2024-06-01)
Kaewtrakulchai, Napat
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Chanpee, Sirayu
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Pasee, Warit
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Putta, Ampol
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Chutipaijit, Sutee
Pollution of water resources has recently increased as a result of expanded industrial activity. Recycling waste biomass into bio-adsorbent material offers a cheap, easy, and eco-friendly solution. In this study, magnetic carbon nanofibers (MCNF) with a highly porous structure were developed from magnetite-preloaded horse manure by hydrothermal treatment followed by carbonization using different ratios of iron (III) nitrate and iron oxide as magnetic precursors. The produced MCNF had a very porous structure with specific surface area of 435.31 m2/g and high carbon content. The magnetic characteristics of MCNF promoted by the presence of iron oxide species. The saturated magnetization of MCNF obtained from a 5:5 ratio of the magnetic precursors (iron (III) nitrate: iron oxide) was 2.48 emu/g. Synthesized MCNF was applied as a bio-adsorbent for methylene blue (MB) removal from aqueous solution, with results showing excellent dye adsorption of 92–99 %. MB adsorption was facilitated by pore filling, electrostatic contact, hydrogen bonding, and ion complexation. Experimental results indicated that the Freundlich isotherm and pseudo-second-order kinetic models concurred with the observed MB adsorption data, suggesting that the adsorption mechanism involved multilayered micropore interactions between magnetite and MB chemisorption. The resulting magnetic adsorbent was successfully removed from the aqueous solution by physical separation. Findings indicated that horse manure-derived MCNF could be used as an efficient bio-adsorbent to remove organic contaminants in wastewater.
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The Effect of Polyvinyl Alcohol Addition on the Optical Properties and Oxygen Detection Performance of Titanium Dioxide and Methylene Blue Nanocomposite Colorimetric Indicators
(2024-05-01)
Boonyarattanakalin, Kanokthip
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Rattan, Praphaporn
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Songpanit, Maneerat
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Chutipaijit, Sutee
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Okumura, Hideyuki
In this study, we investigated the impact of polyvinyl alcohol (PVA) incorporation on the optical properties and oxygen detection performance of a titanium dioxide/methylene blue (TiO<inf>2</inf>/MB) nanocomposite colorimetric indicator for packaging applications. The nanocomposite was synthesized via mechanical milling of TiO<inf>2</inf> nanoparticles with MB and citric acid. PVA, at varying concentrations (0, 3, 9, and 14 wt%), was introduced during the wet milling process to produce a homogeneous composite film. Spin coating was employed to fabricate TiO<inf>2</inf>/MB nanocomposite films for oxygen detection evaluation. The influence of PVA loading on the films’ chemical functionalities and surface morphologies was assessed using Fourier-transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FE-SEM). The indicator’s activation process, involving a color change between bleached and colored states, and its recovery time were monitored via optical imaging and UV-VIS-NIR spectrophotometry. The results revealed that a PVA content of 9 wt% yielded well-defined films with enhanced stability of the TiO<inf>2</inf>/MB nanocomposite’s oxygen detection performance.
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GREEN SYNTHESIS OF ZINC OXIDE NANOPARTICLES FROM LEMON PEEL EXTRACT AND THEIR ANTIBACTERIAL ACTIVITY
(2024-01-01)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Chutipaijit, Sutee
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Nukaew, Jiti
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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.

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