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- Ekstrand-Hammarström, Barbro, et al.
(author)
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Human Primary Bronchial Epithelial Cells are more Responsive to Titanium Dioxide Nanoparticles than the Lung Epithelial Cell Lines A549 and BEAS-2B
- 2012
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In: Nanotoxicology. - : Informa Healthcare. - 1743-5390 .- 1743-5404. ; 6:6, s. 623-634
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Journal article (peer-reviewed)abstract
- We have compared the cellular uptake and responses of fivepreparations of nanocrystalline titanium dioxide (TiO2) betweennormal human bronchial epithelial (NHBE) cells and epithelialcell lines (A549 and BEAS-2B). The P25 nanoparticles, containingboth anatase and rutile modifications, induced reactive oxygenspecies (ROS) and secretion of the neutrophil chemoattractantIL-8 in all three cell types used. Pure anatase and rutile particlesprovoked differential IL-8 response in A549 and no response inBEAS-2B cells despite similar formation of ROS. The pure TiO2modifications also provoked release of the inflammatorymediators: IL-6, G-CSF and VEGF, in NHBE cells but not in the twocell lines. We conclude that the responsiveness of lung epithelialcells is strongly dependent on both the physicochemicalproperties of TiO2 nanoparticles and the type of responder cells.The differential pro-inflammatory responsiveness of primarylung epithelial cells compared with immortalized cell linesshould be considered in the assessment of adverse reactions toinhaled nanoparticles.
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- Ghaly, Montaser, et al.
(author)
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ZnO/spiral-shaped glass for solar photocatalytic oxidation of Reactive Red 120
- 2014
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In: Arabian Journal of Chemistry. - : Elsevier BV. - 1878-5352 .- 1878-5379.
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Journal article (peer-reviewed)abstract
- ZnO/glass spiral (GS) was prepared by immobilization of ZnO on GS with facilemethod, and was characterized by X-ray diffraction analysis (XRD), scanning electron microscope(SEM) and the crystallite size of ZnO on GS surface was calculated. SEM showed rod-like shape ofZnO particles on GS surface. Photocatalytic activity of prepared immobilized photocatalyst wasinvestigated for decolourization and degradation of C.I. Reactive Red 120 (RR-120) dye under sunlight.The kinetics of decolourization and degradation removal has been investigated. The effect ofpH on decolourization and degradation of dye was studied. The decolourization and degradation ofdye were followed by pseudo-first order reaction. The decolourization and degradation of RR-120dye were enhanced by H2O2 addition to definite dosage beyond that the effect is diminished. Also,the reusability of immobilized ZnO on GS was tested for photocatalytic degradation of dye and itwas worth noting that it has high efficiency with slight decrease (5%) after five successive runs.
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- Jamil, Tarek S., et al.
(author)
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Enhancement of TiO2 behavior on photocatalytic oxidation of MO dye using TiO2/AC under visible irradiation and sunlight radiation
- 2012
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In: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 98, s. 270-279
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Journal article (peer-reviewed)abstract
- The activated carbon loaded TiO2 photocatalyst was prepared and characterized by FT-IR, scanning electron micrograph (SEM) and X-ray diffraction (XRD). The photocatalytic efficiency of activated carbon loaded TiO2 was evaluated by photocatalytic oxidation of Methyl Orange (MO) dye in aqueous medium using visible and solar light. TiO2/AC exhibited higher photocatalytic oxidation efficiency of MO than that of naked TiO2. The various experimental parameters like initial dye concentration, amount of catalyst and solution pH for efficient dye degradation are investigated. Activity measurements performed under visible light and solar irradiation have shown good results for the photo degradation of MO in aqueous solution. The higher efficiency of TiO2/AC is due to synergy effect of activated carbon. Addition of high adsorption capacity activated carbon to photoactive titanium dioxide in photocatalytic degradation of dyes improves the efficiency of dye mineralization. The present catalysts show high adsorptivity and high photoactivity for the degradation of the MO dye and can be very easily separated from the solution by sedimentation or simple filtration and it can be used repeatedly for MO removal with preservation of its photoactivity.
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- Khattab, Ibrahim A., et al.
(author)
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Photocatalytic degradation of azo dye Reactive Red 15 over synthesized titanium and zinc oxides photocatalysts : a comparative study
- 2012
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In: Desalination and Water Treatment. - : Informa UK Limited. - 1944-3994 .- 1944-3986. ; 48:1-3, s. 120-129
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Journal article (peer-reviewed)abstract
- Nanoparticle TiO2 and ZnO were prepared by facile method. The XRD pattern study shows that there is no obvious difference in crystal composition of various shapes of TiO2 and ZnO. The photocatalytic degradation of Reactive Red 15, commonly used as a textile dye, using synthesized titanium and zinc oxides was investigated. The effects of influential parameters such as initial pH, catalyst loading, initial dye concentration and addition of hydrogen peroxide were studied. The degradation efficiency was expressed by the removal of color and chemical oxygen demand (COD). The study reveals that: (1) Both catalysts, under corresponding optimal conditions, can be employed as an effective photocatalyst for the elimination of color and COD from dye wastewater. Also, ZnO is more efficient catalyst than TiO2; (2) Addition of proper amount of hydrogen peroxide improves both the decolorization and the degradation of the dye; (3) The photocatalytic degradation of Reactive Red 15, in the presence of both photocatalysts, obeyed pseudo-first order kinetics. The biodegradability ratio BOD5/COD increases from original zero up to 0.52 and 0.6 within 90 minutes irradiation time using 1 and 0.75 g/L TiO2 and ZnO, respectively.
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- Lejon, Christian, et al.
(author)
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Influence of quantum confinement, hydrostatic pressure and critical Zr dopant concentration on the Raman vibrational properties of Zr doped anatase TiO2 nanoparticles
- 2011
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In: Journal of Raman Spectroscopy. - : John Wiley & Sons. - 0377-0486 .- 1097-4555. ; 42:11, s. 2026-2035
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Journal article (peer-reviewed)abstract
- We present a comprehensive analysis of the Ramanspectra of pure and zirconium-doped anatase TiO2 nanoparticles. To accountfor the wavenumber shifts of the Eg(ν6)mode as a function of particle size (L) and dopant concentration (x), a modification of the standard phonon confinement model (PCM) is introduced, which takes into account the contribution of surface stress by means of the Laplace–Young equation. Together with X-ray diffraction (XRD) and transmission electronmicroscopy data, our analysis shows that the surface stress contribution to the observed blue shift of the Ramanwavenumber is of the same magnitude as the spatial phonon confinement effect. Annealing experiments show that Zr-doped nanoparticles exhibit retarded grain growth and delayed anatase-to-rutile phase transition by up to 200 K compared to pure anatase TiO2. XRD shows that Zr doping leads to a unit cell expansion of the anatase structure. Applying themodified PCM to the x-dependent variations of the Eg(ν6) Raman mode, the mode-Gr ¨ uneisen parameter is found to increase abruptly at x > 0.07 with a concomitant mode softening. This coincides with the x range over which the Zr cations are reported to be displaced from their position in the tetrahedral lattice, and where Zr precipitation occurs upon annealing. The results have implications for the interpretation of Raman spectra of ionic metal oxide nanoparticles and how these are modified upon cation doping
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