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Nonlocal XANES pre-edge feature of FeTiO3 ilmenite-type at Ti and Fe K-edge
(2020-09-01)
Phoohinkong, Weerachon
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Boonyarattanakalin, Kanokthip
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Mekprasart, Wanichaya
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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.
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Optical absorption and FTIR study of cellulose/tio2hybrid composites
(2019-05-01)
Plermjai, Kittiya
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Boonyarattanakalin, Kanokthip
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Mekprasart, Wanichaya
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Phoohinkong, Weerachon
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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.
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ACTIVE-ILMENITE SURFACE STRUCTURE INFLUENCE ON ACID-ASSISTED BALL MILLING
(2018-12-01)
Phoohinkong, Weerachon
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Pavasupree, Sorapong
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Boonyarattanakalin, Kanokthip
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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.
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Extraction and characterization of nanocellulose from sugarcane bagasse by ball-milling-assisted acid hydrolysis
(2018-09-05)
Plermjai, Kittiya
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Boonyarattanakalin, Kanokthip
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Mekprasart, Wanichaya
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Pavasupree, Sorapong
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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.
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Adsorbed protein on P25 nanoparticles-synthesis, characterization and electrochemical property
(2018-09-05)
Phoohinkong, Weerachon
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Sukonket, Thitinart
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Boonyarattanakalin, Kanokthip
Keratin modification on surface of titanium dioxide P25 was carried out from titanium dioxide suspension and keratin solution extracted from swine wool. The existence of amide component, protein functional groups dissociated to active protein moieties and attached to titanium dioxide surface in form of hybrid nanomaterial were characterized by Fourier-transform infrared spectroscopy (FT-IR). The keratin protein decorated on particle surfaces was observed by Field Emission Scanning Electron Microscopy (FESEM). Chemical states and bonding at the nano-biomolecule interfaces with titanium dioxide were investigated using X-ray Photoelectron Spectroscopy (XPS). Protein concentration is considered as roles for protein modification, surface bonding, chemical states and protein adsorption. The Ti3+ and Ti2+ surface and high adsorption degree can be obtained at low concentration of protein solution with P25. However, the strong bonding between protein and TiO<inf>2</inf> obtained in high protein concentration with Ti3+ and Ti2+ species result disappear for Ti3+ and Ti2+ XPS peaks. The adsorbed protein reveals secondary structure of random coil keratin with strong bonding conjugated to the titanium dioxide surface. The strong binding between protein and TiO<inf>2</inf> surface in this novel protein-TiO<inf>2</inf> hybrid material shows a promising alternative way for advance tunable electronic structure and charge transport mechanism which enhance electrochemical capacitance by mean of double layer and pseudo-capacitive behavior.
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Synthesis of low-cost titanium dioxide-based heterojunction nanocomposite from natural ilmenite and leucoxene for electrochemical energy storage application
(2018-08-01)
Phoohinkong, Weerachon
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Pavasupree, Sorapong
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Mekprasart, Wanichaya
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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.
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Uv shielding properties of cellulose/tio 2 composite film
(2018-05-01)
Plermjai, Kittiya
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Phoohinkong, Weerachon
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Pavasupree, Sorapong
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Mekprasart, Wanichaya
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Pecharapa, Wisanu
Cellulose/TiO <inf>2</inf> composite film was prepared for UV shielding applications. Cellulose was extracted from sugarcane bagasse by ball milling process. The cellulose/ TiO <inf>2</inf> composite film with different concentrations of cellulose showed a synergic feature of optical transparency and UV-blocking. The crystalline structure of cellulose was characterized by X-ray diffraction (XRD). The treated cellulose has higher crystallinity than the untreated cellulose. Fourier transform infrared spectroscopy ( FT-IR) analysis shows the evidence of chemical treatment hemicellulose and lignin removal from sugarcane bagasse. The optical properties were measured by UV-Vis spectrometer, the results of TiO <inf>2</inf> and cellulose solution correspond to UV-A and UV-C absorbance regions with high transparent of cellulose composite films. The revealed results are essential for UV protecting materials application.
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Anatase/Rutile TiO2 composite thin films prepared via dip coating technique and their hydrophilicity, stability and photocatalytic activity
(2018-01-01)
Ibrahim, Ammar
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Phoohinkong, Weerachon
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Mekprasart, Wanichaya
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Pecharapa, Wisanu
In this work, titanium dioxide (TiO<inf>2</inf>) mixed-phase powders were prepared by sonochemical process in combination with calcination at different temperature in range of 400C to 1000C. The as-prepared powders were dispersed with tetraethyl orthosilicate (TEOS) as supported matrix of TiO<inf>2</inf> for homogeneous colloid and used as starting precursor for thin film coating. The designated thin films were deposited onto glass substrates by dip coating process. X-ray diffraction technique was employed to evaluate TiO<inf>2</inf> phase ratio meanwhile the film morphologies and hydrophilicity were investigated using scanning electron microscope and water contact angle, respectively. UV-Vis spectrophotometer was used to analyse the photcatalytic properties of the films. Photocatalytic activity of the prepared film was performed by mean of the decolorization of Rhodamine B dye solution under solar irradiation. The photocatalytic performance of assigned films was investigated and correlated mechanisms responsible for the activity are discussed.
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Synthesis and characterization of copper zinc oxide nanoparticles obtained via metathesis process
(2017-09-01)
Phoohinkong, Weerachon
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Foophow, Tita
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Pecharapa, Wisanu
Copper-doped zinc oxide nanoparticles were successfully synthesized by grinding copper acetate and zinc acetate powder with different starting molar ratios in combined with sodium hydroxide. The effect of initial copper and zinc molar ratios on the product samples was investigated and discussed. Relevant ligand coordination type of reactant acetate salt precursors and product samples were investigated by Fourier transform infrared spectroscopy (FTIR). The particle shapes and surface morphologies were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Phase structures of prepared samples were studied by x-ray powder diffraction (XRD) and x-ray absorption near-edge spectroscopy (XANES) was applied to investigate the local structure of Cu and Zn environment atoms. The results demonstrate that the, particle size of as-synthesized products affected by copper concentration in the precursor trend to gradually decreases from nanorod shape with diameter around 50-100 nm to irregular particle structure around 5 nm associated with an increase in the concentration of copper in precursor. Moreover, it is noticed that shape and morphology of the products are strongly dependent on Cu:Zn ratios during the synthesis. Nanocrystallines Cu-doped ZnO by the substitution in Zn site with a high crystallization degree of hexagonal wurtzite structure were obtained. This synthesis technique is suggested as a potential effective technique for preparing copper zinc oxide nanoparticles with various atomic ratio in wide range of applications.
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Characterization and x-ray absorption spectroscopy of ilmenite nanoparticles derived from natural ilmenite ore via acidassisted mechanical ball-milling process
(2017-09-01)
Phoohinkong, Weerachon
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Pavasupree, Sorapong
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Wannagon, Anucha
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Sanguanpak, Samunya
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Boonyarattanakalin, Kanokthip
In this work activated ilmenite nanoparticles were prepared by chemical-assisted in mechanical ball-milling process from ilmenite ore as starting raw material. The effect of milling process on their phase composition, particle size, surface morphology and local structure were investigated. Phase identification and crystalline structure of ilmenite mineral, milled samples and subsequent leached residues were characterized by x-ray diffraction (XRD). Meanwhile, the distorted octahedral structure and the oxidation state of relevant elements in ilmenite ore and activated ilmenite obtained by different process conditions were analyzed by x-ray absorption spectroscopy (XAS). Particle size and morphologies of the samples were monitored by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Three dominant peaks of TiO2 rutile, FeTiO<inf>3</inf>, and Fe<inf>2</inf>TiO<inf>4</inf> are obviously adulterated in XRD patterns after mechanical milling with water and acid solution when comparing to precursor mineral. However, the contaminated phase of FeTiO3 and Fe<inf>2</inf>TiO<inf>4</inf> was readily decreased by acid-assisted mechanical ball-milling. The enhancement in leaching process of ilmenite residue after milling can be obtained with sulfuric acid. This result suggests that iron contaminated phase could be leached from the sample resulting to the decrease in Fe environment around Ti atom.

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