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Author: search.filters.author.Mekprasart, WanichayaSubject: search.filters.subject.TiO2

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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
    ;
    Pavasupree, Sorapong
    ;
    Wannagon, Anucha
    ;
    Sanguanpak, Samunya
    ;
    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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    Influence of milling time, NH3 additive and annealing temperature on physical properties of modified commercial TiO2 powders via ball milling process
    (2014-01-01)
    Techitdheera, Wicharn
    ;
    Rattanarak, Jiravat
    ;
    Mekprasart, Wanichaya
    ;
    Pecharapa, Wisanu
    N-doped TiO<inf>2</inf> were prepared via ball milling process with different operating times and annealing temperatures. Commercial TiO<inf>2</inf> anatase powders used as TiO<inf>2</inf> precursor were dispersed in ammonia solution for nitrogen source. Ball milled TiO<inf>2</inf> powders at various times were annealed in nitrogen atmosphere at different temperatures. Physical properties and surface morphologies after ball milling process were monitored by X-ray diffraction (XRD) and scanning electron microscope (SEM). The component of samples was characterized by energy-dispersive X-ray spectroscopy (EDX). The active surface area of the samples was investigated by Brunauer Emmet Teller method. SEM result indicated that large particle of TiO<inf>2</inf> precursor could be reduced via ball milling process leading to high active surface area by the increase of milling time. XRD result showed the crystalline structures of TiO<inf>2</inf> after milling process and nitrogen annealing were identical to TiO<inf>2</inf> precursor structure. Meanwhile, the appearance of impurity phase in TiO<inf>2</inf> precursor was also depreciated via ball milling process with ammonia solution and annealing under nitrogen atmosphere.
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    Photocatalytic activities under UV light of ball-milled TiO2photocatalysts
    (2013-10-29)
    Rattanarak, Jiravat
    ;
    Mekprasart, Wanichaya
    ;
    Pecharapa, Wisanu
    ;
    Techitdheera, Wicharn
    Anatase TiO<inf>2</inf> powders used as photocatalysts were prepared by ball milling process at various milling time and annealed in nitrogen atmosphereat different temperatures. Commercial TiO<inf>2</inf> powders were ball-milled with ethanol at room temperature. After ball milling process, the samples were annealed in nitrogen atmosphere. The particle sizes and surface area of milled powders were measured by particle analyzer and Brunauer Emmet Teller method(BET). Effect of milling time and annealing temperature on structural properties of TiO<inf>2</inf> powders was investigated by X-ray diffraction(XRD) and scanning electron microscope(SEM). The degradation of aquous RhB dye by ball-milled TiO<inf>2</inf> powder photocatalyst was investigated under UV light irradiation. Comparing to P-25, TiO<inf>2</inf> powder prepared via ball milling process at 24 hr demonstrated significant enhancement in its photocatalytic activity under UV light due to the increasing active surface area after ball milling process. © (2013) Trans Tech Publications, Switzerland.