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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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    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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    Comparison study of photocatalytic activity of titanium-rich materials derived from natural minerals ores using acidic leaching
    (2017-01-01)
    Kansaard, Thanaphon
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    Phoohinkong, Weerachon
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    Sanguanpak, Samanya
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    Wannakon, Anucha
    Over past decades, titanium dioxide-based materials have been recognized as effectively practical photocatalysts for purification of toxicity waste. However, pure TiO<inf>2</inf> photocatalyst is highly active under ultraviolet illumination. In this work, the effort has been focused on the synthesis of titanium-rich materials starting from minerals ores ilmenite ores and leucoxene ores by ball-milling process in combined with hydrochloric acid leaching method with optimized conditions. Crystallinity and morphologies of as-prepared samples were characterized by X-rays diffraction technique and scanning electron microscope. The photocatalytic activities of both derived-materials were studied and compared by degradation of Rhodamine B organic dye as organic toxicity compound under ultraviolet light and visible light. The results illustrate that the leucoxene-derived sample exhibits superior catalytic performance to the sample derived from ilmenite ores due to the greater Ti-content of the starting leucoxene ores.
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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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    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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    Photocatalytic performance of ball-milled anatase/rutile mixed phase TiO2 composite powders
    (2016-01-01)
    Phoohinkong, Weerachon
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    ;
    Mixed-phase anatase/rutile titanium dioxide (TiO<inf>2</inf>) composite powder is an important material due to the unique properties of photocatalytic activity, which the photocatalytic efficiency of mixed-phase is higher than the only single anatase or rutile phase. In this study, the anatase/rutile mixed phase TiO<inf>2</inf> composite powders were prepared by ball milling of TiO<inf>2</inf> commercial grade powders. Effect of the anatase/rutile phase ratio on photocatalytic performance was investigated. The sample phase ratio is evaluated using X-ray diffraction (XRD) meanwhile the composite morphology is characterized using field emission scanning electron microscope (FE-SEM). The overall results revealed that the mixed-phase anatase/rutile provided significant enhancement in photocatalytic performance compared with only anatase or rutile single phase. In addition, this ballmilling technique is considered an effective process, cost-effectively on energy saving, and suitable for preparing anatase/rutile TiO<inf>2</inf> mixed-phase for photocatalytic application.
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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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    ; ;
    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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    Effect of cobalt dopant on structural and optical properties of co-precipitated TiO2 nanopowders
    (2016-01-01)
    Junlabhut, Prasopporn
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    Wattanawikkam, Chakkaphan
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    Phoohinkong, Weerachon
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    The effects of cobalt (Co) addition on structural and optical properties of TiO<inf>2</inf> nanopowders have been investigated. A co-precipitation method was employed to synthesize TiO<inf>2</inf> nanoparticles with various Co additives from 0-10 mol% using tetrabutyl titanate and Cobalt (II) nitrate hexahydrate as starting precursors for Ti and Co source, respectively. The crystallinity of Co-doped TiO<inf>2</inf> nanopowders is heightened by calcination process. The crystal structure, phase formation and the corresponding functional groups of Co-doped TiO2 were analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The scanning electron microscope (SEM) was taken to observe their morphologies. The chemical compositions of Co additive into TiO<inf>2</inf> matrix are confirmed by EDAX. Their optical properties were investigated by diffuse reflectance spectroscopy. Diffuse reflectance spectra of samples exhibit the increasing absorption in visible region with an increasing Co content. The overall characterization results indicated that the crystallinity and optical properties of TiO<inf>2</inf> nanoparticles are significantly affected by Co dopant.
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    Optical absorption and FTIR study of cellulose/tio2hybrid composites
    (2019-05-01)
    Plermjai, Kittiya
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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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    Nonlocal XANES pre-edge feature of FeTiO3 ilmenite-type at Ti and Fe K-edge
    (2020-09-01)
    Phoohinkong, Weerachon
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    ; ;
    Pavasupree, Sorapong
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    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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    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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    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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    CPC photocatalytic reactor in presence of immobilized tio 2 and photocatalytic activity
    (2017-07-01)
    Ibrahim, Ammar
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    Phoohinkong, Weerachon
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    In this present work, compound parabolic collector (CPC) combined with tubular reactors was designed to accept both directly incident and reflected light. The light collecting of CPC reflecter was analysed via light reflection modeling. Titanium isopropoxide was used as a precursor to prepare immobilized titanium dioxide on the borosilicate beads which was used as supporter. The coated beads were prepared via dip coating technique. The photocatalytic activity of immobilized TiO <inf>2</inf> was performed to decolorize the Rhodamine B dye solution under solar irradiation. UV-Vis spectrophotometer was used to characterize the degradation of rhodamine B dye solution and to analyse the photocatalytic performance. The analysis of reflecting on CPC reflector indicates that all incidents are reflected to reactor tube according to the defined concentration ratio as equal one. The photodegradation of rhodamine B dye solution under solar irradiation is clearly observed by over 90% in presence of immobilized TiO <inf>2</inf> on glass beads.