KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 19

Some of the metrics are blocked by your
consent settings
Synergistic effects of biomass-derived carbon quantum dots and Cu Co-doping on TiO2 nanocomposite for enhanced visible-light photocatalysis
(2026-12-01)
Zhao, Huali
;
Noonuruk, Russameeruk
;
Bootchanont, Atipong
;
Porjai, Porramain
;
Thongpool, Voranuch
The development of sustainable approaches for enhancing the visible-light activity of TiO<inf>2</inf>-based photocatalysts has attracted considerable research interest. In this work, carbon quantum dots (CQDs)-Cu co-modified TiO<inf>2</inf> nanocomposites were synthesized via a hydrothermal method using butterfly pea ( Clitoria ternatea ) flowers as a biomass-derived carbon source. The Cu content was fixed at 1.5 mol% relative to Ti, while the CQDs loading was controlled by varying the butterfly pea precursor concentration from 0.25 to 1.25 g L−1, yielding 1C–Cu–TiO<inf>2</inf>, 3C–Cu–TiO<inf>2</inf>, and 5C–Cu–TiO<inf>2</inf> samples. The prepared materials were characterized by electron microscopy, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, photoluminescence (PL), and X-ray absorption spectroscopy (XAS). High-resolution transmission electron microscopy revealed CQDs with an average size of approximately 4.29 nm and an interplanar spacing of approximately 0.23 nm. All composites retained the anatase TiO<inf>2</inf> phase after Cu incorporation and CQDs modification. Enhanced visible-light absorption was observed and is attributed to the formation of Cu-related sub-band-gap states and the sensitization effect of CQDs. PL analysis showed an emission peak at ∼415 nm under 660 nm excitation, suggesting the presence of upconversion photoluminescence behavior in the CQDs. Conventional PL spectra further suggested reduced charge-carrier recombination in the modified composites. Photocatalytic activity was evaluated through Rhodamine B (RhB) degradation under visible-light irradiation. Among all samples, 1C–Cu–TiO<inf>2</inf> exhibited the highest performance, achieving degradation efficiency of 99.28% within 50 min. The apparent reaction rate constant reached 0.1038 min−1, which was 2.23, 1.96, and 2.90 times higher than those of pristine TiO<inf>2</inf>, Cu–TiO<inf>2</inf>, and 3C–Cu–TiO<inf>2</inf>, respectively. Radical scavenging experiments indicated that •OH and h+ were the dominant reactive species, while •O<inf>2</inf>− also participated in the degradation process. The enhanced photocatalytic performance is attributed to the synergistic effects of Cu and biomass-derived CQDs in improving visible-light harvesting and charge separation, providing an effective approach for developing visible-light-responsive TiO<inf>2</inf> photocatalysts.
Some of the metrics are blocked by your
consent settings
RSM optimization of spray-coating parameters to enhance paper strength using cellulose nanocrystals extracted from young coconut husks
(2025-09-01)
Nuthongkum, Pilaipon
;
Noonuruk, Russameeruk
;
Bootchanont, Atipong
;
Porjai, Porramain
;
Wattanawikkam, Chakkaphan
This study optimizes spray-coating parameters for cellulose nanocrystals extracted from young coconut husks onto paper substrates using response surface methodology. CNCs were produced through acid hydrolysis and mechanical grinding, yielding nanocrystals with an average size of 116 nm and a crystallinity index increase from 28.89 % to 86.13 %. XRD and FTIR analyses confirmed high purity, while UV-vis revealed significant optical absorption in the UV range. Spray-coating parameters, including CNC concentration, volume, heating temperature, and heating duration, were optimized using a central composite design. The 2FI model revealed that CNC concentration and heating duration significantly affected film thickness, where higher CNC levels and longer heating durations produced thicker coatings. However, excessive CNC content led to agglomeration, compromising film quality. The quadratic model highlighted a significant relationship between coating parameters and tensile strength. Heat treatment notably enhanced mechanical properties, with optimal tensile strength reaching 26.15 ± 0.61 MPa-15 % higher than uncoated paper-under conditions of 4 % w/v CNC concentration, 1.5 ml volume, 75 °C heating temperature, and 35 min heating duration. This research highlights the potential of CNCs from young coconut husks as a sustainable reinforcement material, promoting agricultural waste valorization and enhancing paper properties.
Some of the metrics are blocked by your
consent settings
Enhancement of an intumescent fire shield paint from the nanotube rutile mineral for the fire performance of steel structures
(2024-12-01)
Chaisaenrith, Prasan
;
Chobpattana, Varistha
;
O-charoen, Narongchai
;
Srisawat, Natee
;
Pecharapa, Wisanu
Building and construction fire safety is an important issue for the protection of people and property. This research investigates nano-TiO<inf>2</inf> from rutile minerals' synergistic role in intumescent fire shield paint (IFSP). A synergistic ingredient was introduced to intumescent fire shield paint to evaluate its impact on char morphology, fire protection test, fire propagation test, and compare it with current market products. A hydrothermal process was used to create a rutile mineral, with various techniques used to describe its structure, size, and composition. Intumescent char was found in a furnace using FESEM and X-ray fluorescence. The results showed that rutile minerals contain a rutile phase and a nanotube structure. The surface of the sample IFSP A's char showed layer and foam structures with homogenous voids during a fire test, indicating a high porosity structure. Large holes and recurring gaps were observed in the char of the IFSP B, C, and D. Sample IFSP A took more time at the structural critical temperature (about 550 °C) than other intumescent fire shield paint samples, making it a barrier layer that effectively shields the metal substrate from heat. The intumescent char residue had the highest C/O ratio of 0.57, indicating the best char yield degree and anti-oxidation abilities. The IFSP A had a phosphorous content of 36.2 %, which could combine with phosphorus and TiO<inf>2</inf> to form a ceramic barrier. The increased TiO<inf>2</inf> in IFSP A suggests that char layers with TiO<inf>2</inf> may still contain strong ceramic structures and function as effective thermal protection layers.
Some of the metrics are blocked by your
consent settings
Piezoelectric enhanced photocatalytic properties of PVDF–ZnO/Cu nanofibers prepared by electrospinning technique
(2022-01-01)
Bootchanont, Atipong
;
Porjai, Porramain
;
Noonuruk, Russameeruk
;
Wattanawikkam, Chakkaphan
;
Pavasupree, Sorapong
Piezoelectric-assisted photocatalysis technology is one of the efficient ways to achieve enhancement in photocatalytic performance by facilitating the separation of photoinduced electron and holes via internal field initiated via piezoelectricity. Herein, bi-piezoelectric integrated effect was generated by the combination of piezoelectric semiconductor photocatalyst ZnO/Cu and piezoelectric polymer polyvinylidene fluoride (PVDF). Firstly, ZnO/Cu nanoparticles were prepared by facile co-precipitation method. Then, nanoparticles (at 10–30 wt%) were loaded in PVDF for fabricating nanofibers by electrospinning technique. All PVDF–ZnO/Cu nanofibers were characterized by XRD, FE-SEM, FTIR, XAS, and UV–Vis DRS. The structural study indicates that the β- and α-phase PVDF is observed in all the prepared nanofibers. XANES technique confirms the oxidation state of 2+ for Zn and Cu ions in both nanoparticles and nanofibers. Furthermore, under the synergy action of ultrasonic and visible light irradiation, PVDF–ZnO/Cu nanofibers exhibit superior piezo-photocatalytic degradation of rhodamine B dye when compared with single light or mechanical excitation. Effects of ZnO/Cu concentration on optical, piezoelectric, and photocatalytic properties are discussed.
Some of the metrics are blocked by your
consent settings
Characterization, X-ray absorption spectroscopic analysis and photocatalytic activity of Co/Zn co-doped TiO2 nanoparticles synthesized by one-step sonochemical process
(2021-10-01)
Mekprasart, Wanichaya
;
Pavasupree, Sorapong
;
Jayasankar, C. K.
;
Ravuri, Balaji Rao
;
Wattanawikkam, Chakkaphan
A novel one-step preparation of sonochemical method was applied to synthesize Co/Zn co-doped TiO<inf>2</inf> nanoparticles using a sonicator of 750 W, 20 kHz for 30 min at room temperature. The formation of the anatase TiO<inf>2</inf> phase for all as-prepared samples was observed from XRD results with a crystalline size in nanoscale. The use of ultrasound allowed for the successful doping of both Co and Zn into the TiO<inf>2</inf> lattice, which was confirmed by Synchrotron light including X-ray near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS) spectroscopy. Ti K-edge, Co K-edge, and Zn K-edge XANES spectra exhibited the dominating +4, +2, and +2 valence state of Ti, Co, and Zn in as-prepared samples, respectively. A detailed XANES and EXAFS data analysis give strong evidence that the Co/Zn dopants partially replace the Ti atom of the TiO<inf>2</inf> host. The Co/Zn co-doping extends the light absorption of the host to the visible region and restricts the e+/h+ recombination. The photocatalytic activity of samples was tested for degradation of Rhodamine B dye solution under visible light irradiation. The as-synthesized of the co-doped catalyst was presented as highly efficient, with 2.5 and 5 times dye degradation compared with single-doped and bare TiO<inf>2</inf>.
Some of the metrics are blocked by your
consent settings
Nonlocal XANES pre-edge feature of FeTiO3 ilmenite-type at Ti and Fe K-edge
(2020-09-01)
Phoohinkong, Weerachon
;
Boonyarattanakalin, Kanokthip
;
Mekprasart, Wanichaya
;
Pavasupree, Sorapong
;
Pecharapa, Wisanu
The pre-K-edge feature of Ti and Fe XANES of ilmenite FeTiO<inf>3</inf> were investigated. The electronic structure of FeTiO<inf>3</inf> was examined based on the partial density of electronic state distribution on both local and nonlocal atoms. A strong contribution of nonlocal metal-metal intervalence electronic states of Ti and Fe pre-K-edge was observed in X-ray absorption near-edge structure (XANES) measurement. This observation agrees well with the calculated local state density. The nonlocal excitation transitions in the pre-edge feature contribute to local pre-K-edge at both Ti and Fe. Ti pre-K-edge consists of highly hybridized Ti-3d(t<inf>2g</inf>) with a small part of dipole-allowed 4p and a small 4s density transition state feature which is predominated by nonlocal of Fe-3d mixed with 4p state delocalized via O-2p as the main component peak. The peak feature at Ti-3d(e<inf>g</inf>) energy state is assigned to hybridization of Ti-3d(e<inf>g</inf>) and Ti-4p state contributed with nonlocal of the hybridized Fe-sp and the Ti-pd state. Fe pre-K-edge shows two main prominent transition peaks of hybridized Fe-pd state and the delocalized local Fe-sp with nonlocal Ti-3d(t<inf>2g</inf>) and 4p mixing states centered at 7112.38 and 7116.48 eV, respectively. The local and nonlocal excited transition energy states and density of both Ti pre-K-edge and Fe pre-K-edge features are corresponded with each other through the O-2p state transition pathway.
Some of the metrics are blocked by your
consent settings
Optical absorption and FTIR study of cellulose/tio2hybrid composites
(2019-05-01)
Plermjai, Kittiya
;
Boonyarattanakalin, Kanokthip
;
Mekprasart, Wanichaya
;
Phoohinkong, Weerachon
;
Pavasupree, Sorapong
Cellulose/TiO<inf>2</inf> composite was prepared by conventional mixing using distilled water as medium. The structure and relevant properties of cellulose/TiO<inf>2</inf> composite were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV- Vis spectroscopy. XRD results exhibit typical cellulose structure type I. The absorbance spectra of TiO<inf>2</inf>and cellulose exist in vicinity of 200 nm and 350 nm in the UV range, corresponding to the UV-C, UV-B and UV-A. In addition, the UV absorption band of the composite can be extended covering wide UV region. Corresponding FTIR results suggest the existence of chemical bonding or surface interaction between TiO<inf>2</inf> and cellulose.
Some of the metrics are blocked by your
consent settings
ACTIVE-ILMENITE SURFACE STRUCTURE INFLUENCE ON ACID-ASSISTED BALL MILLING
(2018-12-01)
Phoohinkong, Weerachon
;
Pavasupree, Sorapong
;
Boonyarattanakalin, Kanokthip
;
Mekprasart, Wanichaya
;
Pecharapa, Wisanu
Active-ilmenite powder derived from natural ilmenite sand was prepared by the ball milling process with acid-solution and Deionized (DI) water. Morphology and particle size of active-ilmenite product in acid/DI-assisted ball milling process were monitored by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). Surface atomic component and chemical bonding were investigated by X-ray photoelectron spectroscopy (XPS). Meanwhile, bulk chemical oxidation and fine structure of active-ilmenite were studied by X-ray absorption near edge structure (XANES) and extended X-ray absorption ne-structure spectroscopy (EXAFS) to confirm the oxidation state and local active species structure at surface. Active-ilmenite by acid-assisted ball milling process is a distinctive method for the preparation of active-ilmenite product with high active surface. Moreover, the distortion of TiO <inf>6</inf> and FeO <inf>6</inf> octahedral cluster on the sample surface was detected in all milled samples with acid-assisted ball milling process. The presence of Fe 2+ , Fe 3+ ions and miniature sulfate was also detected on the sample surface by milled product with acid-assisted method.
Some of the metrics are blocked by your
consent settings
Extraction and characterization of nanocellulose from sugarcane bagasse by ball-milling-assisted acid hydrolysis
(2018-09-05)
Plermjai, Kittiya
;
Boonyarattanakalin, Kanokthip
;
Mekprasart, Wanichaya
;
Pavasupree, Sorapong
;
Phoohinkong, Weerachon
This study is proposed to characterize nanocellulose extracted from sugarcane bagasse (SCB). For extracting cellulose, the bagasse was treated by chemical treatment. The nanocellulose was prepared using ball-milling with acid hydrolysis. Morphology of bagasse, cellulose and nanocellulose were characterized by scanning electron microscopy (SEM). The chemical composition of extracted cellulose and nanocellulose was investigated by Fourier-transformed infrared spectroscopy that verifying the removal of lignin and hemicellulose during cellulose isolation process from sugarcane bagasse. The crystalline structure of cellulose and nanocellulose were characterized by X-ray diffraction (XRD), indicating that the nanocellulose prepared by ball milling with acid hydrolysis has higher crystallinity than nanocellulose prepared only ball milling.
Some of the metrics are blocked by your
consent settings
Synthesis of low-cost titanium dioxide-based heterojunction nanocomposite from natural ilmenite and leucoxene for electrochemical energy storage application
(2018-08-01)
Phoohinkong, Weerachon
;
Pavasupree, Sorapong
;
Mekprasart, Wanichaya
;
Pecharapa, Wisanu
Titanium dioxide-based nanocomposites were prepared by simple mixing titanium dioxide with activated ilmenite and leucoxene. Raw ilmenite and leucoxene ore were firstly activated by modified ball-milling process by sulfuric acid assist to obtain activated ilmenite and leucoxene. The mixture between activated ilmenite/leucoxene with commercial anatase titanium dioxide and followed by heat treatment samples demonstrate enhance electrochemical capacitor performance. Phase compositions of prepared samples were confirmed by X-ray diffraction (XRD). The local structure changes were investigated by X-ray absorption spectroscopy (XAS). The particle size and morphology were studied by field emission scanning electron microscope (FE-SEM). The chemical states of the nanocomposites were investigated by X-ray photoelectron spectroscopy (XPS). Electrochemical properties of the prepared nanocomposites were conducted using cyclic voltammetry (CV). Results in this work introduce cost-effectiveness and simple route to prepare electroactive nanocomposite electrode materials from natural ore with enhanced electrochemical capability. The particle size, structure, morphology, heterojunction interface and surface characteristics show significant key to improve electron transfer activity regarding the modification of the specific active sites.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results