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Bayerite

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Zhichao Yang – 1st expert on this subject based on the ideXlab platform

  • surfactant free preparation of mesoporous solid hollow boehmite and Bayerite microspheres via double hydrolysis of naalo2 and formamide from room temperature to 180 c
    Journal of Colloid and Interface Science, 2020
    Co-Authors: Zhichao Yang

    Abstract:

    Abstract The transformation from solid boehmite microspheres to hollow Bayerite microspheres at room temperature (25 °C) was successfully realized via the double hydrolysis of NaAlO2 and formamide (FA) solution. Effects of reaction time, temperature and FA dos on the transformation process were studied in detail. The results show that hollow boehmite microspheres were obtained via increasing the temperature above 120 °C and the FA dos above 12 mL; amorphous alumina hydrate, solid boehmite and hollow Bayerite microspheres were also obtained at 25 °C for 1 h, 2 h and 24 h reactions, respectively; solid Bayerite microspheres were obtained by decreasing the FA dos below 4 mL at 25 °C. Because of the slow change of pH from 12.9 to 8.7, simultaneous dissolution and regeneration for different aluminum hydroxide were the key factors for forming hollow boehmite/Bayerite microspheres. The Al yield for boehmite microspheres reached 41.4% at 25 °C for a 2 h reaction; when increasing the temperature to 180 °C, the Al yield for hollow boehmite microspheres with higher crystallinity increased to 82.7%. Moreover, the solid/hollow boehmite microspheres with high surface areas showed outstanding adsorption capacities of 751.9 mg/g and 694.4 mg/g, respectively, for Congo red. This significant transformation of structure and morphology provides an effective strategy for preparing mono-phase hydrated alumina with excellent adsorption performance.

  • Surfactant-free preparation of mesoporous solid/hollow boehmite and Bayerite microspheres via double hydrolysis of NaAlO2 and formamide from room temperature to 180 °C.
    Journal of Colloid and Interface Science, 2019
    Co-Authors: Zhichao Yang

    Abstract:

    Abstract The transformation from solid boehmite microspheres to hollow Bayerite microspheres at room temperature (25 °C) was successfully realized via the double hydrolysis of NaAlO2 and formamide (FA) solution. Effects of reaction time, temperature and FA dos on the transformation process were studied in detail. The results show that hollow boehmite microspheres were obtained via increasing the temperature above 120 °C and the FA dos above 12 mL; amorphous alumina hydrate, solid boehmite and hollow Bayerite microspheres were also obtained at 25 °C for 1 h, 2 h and 24 h reactions, respectively; solid Bayerite microspheres were obtained by decreasing the FA dos below 4 mL at 25 °C. Because of the slow change of pH from 12.9 to 8.7, simultaneous dissolution and regeneration for different aluminum hydroxide were the key factors for forming hollow boehmite/Bayerite microspheres. The Al yield for boehmite microspheres reached 41.4% at 25 °C for a 2 h reaction; when increasing the temperature to 180 °C, the Al yield for hollow boehmite microspheres with higher crystallinity increased to 82.7%. Moreover, the solid/hollow boehmite microspheres with high surface areas showed outstanding adsorption capacities of 751.9 mg/g and 694.4 mg/g, respectively, for Congo red. This significant transformation of structure and morphology provides an effective strategy for preparing mono-phase hydrated alumina with excellent adsorption performance.

Ray L Frost – 2nd expert on this subject based on the ideXlab platform

  • xps study of the major minerals in bauxite gibbsite Bayerite and pseudo boehmite
    Journal of Colloid and Interface Science, 2006
    Co-Authors: Theo J Kloprogge, Loc V Duong, Barry J Wood, Ray L Frost

    Abstract:

    Synthetic corundum (Al2O3), gibbsite (Al(OH)(3)), Bayerite (Al(OH)(3)), boehmite (AlO(OH)) and pseudoboehmite (AlO(OH)) have been studied by high resolution XPS. The chemical compositions based on the XPS survey scans were in good agreement with the expected composition. High resolution A12p scans showed no significant changes in binding energy, with all values between 73.9 and 74.4 eV. Only Bayerite showed two transitions, associated with the presence of amorphous material in the sample. More information about the chemical and crystallographic environment was obtained from the 0 Is high resolution spectra. Here a clear distinction could be made between oxygen in the crystal structure, hydroxyl groups and adsorbed water. Oxygen in the crystal structure was characterised by a binding energy of about 530.6 eV in all minerals. Hydroxyl groups, present either in the crystal structure or on the surface, exhibited binding energies around 531.9 eV, while water on the surface showed binding energies around 533.0 eV. A distinction could be made between boehmite and pseudoboehmite based on the slightly lower ratio of oxygen to hydroxyl groups and water in pseudoboehmite. (c) 2005 Elsevier Inc. All rights reserved.

  • comparison of the raman spectra of Bayerite boehmite diaspore and gibbsite
    Journal of Raman Spectroscopy, 2001
    Co-Authors: Ray L Frost, Huada Ruan, Theo J Kloprogge

    Abstract:

    Gibbsite and Bayerite are alumina trihydrate (Al(OH) 3). Gibbsite occurs abundantly in nature, usually as a major mineral component in bauxite whereas Bayerite is rarely found in nature. Boehmite and diaspore are alumina oxohydroxide (AlOOH) and are two other important minerals in bauxite. The Raman spectra of these four minerals were obtained using a Fourier transform Raman spectrometer operating at 1064 nm. Bayerite spectrum shows five absorption bands, 3652, 3542, 3449, 3438, and 3421 cm-1 and the gibbsite spectrum shows four strong and sharp absorption bands, 3619, 3523, 3433 and 3363 cm-1 in the hydroxyl stretching region. Four broad bands, 3426, 3365, 3229 and 2935 cm-1 and three weak bands, 3420, 3216 and 3090 cm-1 are present in this region for diaspore and boehmite, respectively. The Raman bands correspond well with the infrared absorption bands at 3620, 3525 cm-1 for gibbsite, 3365 cm-1 for diaspore and 3423, 3096 cm-1 for boehmite and these bands are assigned to be Raman and infrared active. The spectra of Bayerite, gibbsite and diaspore are complex while the spectrum of boehmite only illustrates four absorption bands in the low frequency region. Common bands of RT-Raman spectra at 1019, 892, 816, 710, 568, 539, 506, 429, 395, 379, 321, 306, 255 and 242 cm-1 were observed for gibbsite, 1079, 1068, 898, 866, 545, 434, 388, 322, 292, 250 and 239 cm-1 for Bayerite, 705, 608, 446, 260 and 216 cm-1 for diaspore, and 674, 495 and 360 cm-1 for boehmite. The differences in the vibrational spectra of Bayerite, gibbsite, diaspore and boehmite are interpreted as being due to the differences in the molecular structure of these minerals.

  • comparison of raman spectra in characterizing gibbsite Bayerite diaspore and boehmite
    Journal of Raman Spectroscopy, 2001
    Co-Authors: Huada Ruan, Ray L Frost, J T Kloprogge

    Abstract:

    High-quality Raman spectra were used for the characterization of alumina phases of gibbsite, Bayerite, diaspore and boehmite. The Raman spectrum of gibbsite shows four strong, sharp bands at 3617, 3522, 3433 and 3364 cm in the hydroxyl stretching region. The spectrum of Bayerite shows seven bands at 3664, 3652, 3552, 3542, 3450, 3438 and 3420 cm. Five broad bands at 3445, 3363, 3226, 3119 and 2936 cm and four broad and weak bands at 3371, 3220, 3085 and 2989 cm-1 are present in the Raman spectrum of the hydroxyl stretching region of diaspore and boehmite. The hydroxyl stretching bands are related to the surface structure of the minerals. The Raman spectra of Bayerite, gibbsite and diaspore are complex whereas the Raman spectrum of boehmite shows only four bands in the low-wavenumber region. These bands are assigned to deformation and translational modes of the alumina phases. A comparison of the Raman spectrum of bauxite with those of boehmite and gibbsite showed the possibility of using Raman spectroscopy for on-line processing of bauxites that contain a mixture of alumina phases.

Theo J Kloprogge – 3rd expert on this subject based on the ideXlab platform

  • xps study of the major minerals in bauxite gibbsite Bayerite and pseudo boehmite
    Journal of Colloid and Interface Science, 2006
    Co-Authors: Theo J Kloprogge, Loc V Duong, Barry J Wood, Ray L Frost

    Abstract:

    Synthetic corundum (Al2O3), gibbsite (Al(OH)(3)), Bayerite (Al(OH)(3)), boehmite (AlO(OH)) and pseudoboehmite (AlO(OH)) have been studied by high resolution XPS. The chemical compositions based on the XPS survey scans were in good agreement with the expected composition. High resolution A12p scans showed no significant changes in binding energy, with all values between 73.9 and 74.4 eV. Only Bayerite showed two transitions, associated with the presence of amorphous material in the sample. More information about the chemical and crystallographic environment was obtained from the 0 Is high resolution spectra. Here a clear distinction could be made between oxygen in the crystal structure, hydroxyl groups and adsorbed water. Oxygen in the crystal structure was characterised by a binding energy of about 530.6 eV in all minerals. Hydroxyl groups, present either in the crystal structure or on the surface, exhibited binding energies around 531.9 eV, while water on the surface showed binding energies around 533.0 eV. A distinction could be made between boehmite and pseudoboehmite based on the slightly lower ratio of oxygen to hydroxyl groups and water in pseudoboehmite. (c) 2005 Elsevier Inc. All rights reserved.

  • comparison of the raman spectra of Bayerite boehmite diaspore and gibbsite
    Journal of Raman Spectroscopy, 2001
    Co-Authors: Ray L Frost, Huada Ruan, Theo J Kloprogge

    Abstract:

    Gibbsite and Bayerite are alumina trihydrate (Al(OH) 3). Gibbsite occurs abundantly in nature, usually as a major mineral component in bauxite whereas Bayerite is rarely found in nature. Boehmite and diaspore are alumina oxohydroxide (AlOOH) and are two other important minerals in bauxite. The Raman spectra of these four minerals were obtained using a Fourier transform Raman spectrometer operating at 1064 nm. Bayerite spectrum shows five absorption bands, 3652, 3542, 3449, 3438, and 3421 cm-1 and the gibbsite spectrum shows four strong and sharp absorption bands, 3619, 3523, 3433 and 3363 cm-1 in the hydroxyl stretching region. Four broad bands, 3426, 3365, 3229 and 2935 cm-1 and three weak bands, 3420, 3216 and 3090 cm-1 are present in this region for diaspore and boehmite, respectively. The Raman bands correspond well with the infrared absorption bands at 3620, 3525 cm-1 for gibbsite, 3365 cm-1 for diaspore and 3423, 3096 cm-1 for boehmite and these bands are assigned to be Raman and infrared active. The spectra of Bayerite, gibbsite and diaspore are complex while the spectrum of boehmite only illustrates four absorption bands in the low frequency region. Common bands of RT-Raman spectra at 1019, 892, 816, 710, 568, 539, 506, 429, 395, 379, 321, 306, 255 and 242 cm-1 were observed for gibbsite, 1079, 1068, 898, 866, 545, 434, 388, 322, 292, 250 and 239 cm-1 for Bayerite, 705, 608, 446, 260 and 216 cm-1 for diaspore, and 674, 495 and 360 cm-1 for boehmite. The differences in the vibrational spectra of Bayerite, gibbsite, diaspore and boehmite are interpreted as being due to the differences in the molecular structure of these minerals.