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Mehran Rezaei - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis of Nanocrystalline CeO2 with High Surface Area by the Taguchi Method and its Application in Methanation
    Chemical Engineering & Technology, 2014
    Co-Authors: Behzad Nematollahi, Mehran Rezaei, Ebrahim Nemati Lay
    Abstract:

    Mesoporous nanocrystalline cerium(IV) oxide (CeO2) with High Surface Area was synthesized by precipitation using a cationic surfactant and employed as support for a nickel catalyst in CO methanation. The preparation factors of CeO2 were optimized by the Taguchi method to achieve a sample with High Surface Area. The obtained results reveal that the sample prepared under optimized conditions has a mesoporous structure with High Surface Area and crystallite size. The addition of a surfactant significantly influences the structural properties of CeO2 and improves the specific Surface Area. The optimized sample was employed as support for a nickel catalyst in CO methanation reaction. The prepared catalyst possessed a High activity compared to a commercial methanation catalyst.

  • synthesis of High Surface Area nanocrystalline mgo by pluronic p123 triblock copolymer surfactant
    Powder Technology, 2011
    Co-Authors: Mehran Rezaei, Majid Khajenoori, Behzad Nematollahi
    Abstract:

    Abstract Nanocrystalline magnesium oxide with High Surface Area was prepared by a simple precipitation method using pluronic P123 triblock copolymer (Poly(ethylene glycol)-block, Poly(propylene glycol)-block, Poly(ethylene glycol)) as surfactant. The prepared samples were characterized by X-ray Diffraction (XRD), N2 adsorption (BET), Fourier transform infrared spectroscopy (FTIR), Thermal, differential thermal gravimetric and differential thermal analyses (TG/DTG/DTA) and Scanning electron microscopy (SEM). The obtained results revealed that the addition of surfactant is effective to prepare magnesium oxide with High Surface Area and affects the morphology of the prepared samples. The results showed that the magnesium oxide calcined at different temperatures ranging from 600 to 800 °C possessed a High Surface Area in the range of 133.9–78.1 m2 g−1. In addition, the magnesium oxide prepared with the addition of surfactant showed a narrower pore size distribution compared to the sample prepared without the addition of a surfactant.

  • synthesis of High Surface Area nanocrystalline mgo by pluronic p123 triblock copolymer surfactant
    Powder Technology, 2011
    Co-Authors: Mehran Rezaei, Majid Khajenoori, Behzad Nematollahi
    Abstract:

    Abstract Nanocrystalline magnesium oxide with High Surface Area was prepared by a simple precipitation method using pluronic P123 triblock copolymer (Poly(ethylene glycol)-block, Poly(propylene glycol)-block, Poly(ethylene glycol)) as surfactant. The prepared samples were characterized by X-ray Diffraction (XRD), N2 adsorption (BET), Fourier transform infrared spectroscopy (FTIR), Thermal, differential thermal gravimetric and differential thermal analyses (TG/DTG/DTA) and Scanning electron microscopy (SEM). The obtained results revealed that the addition of surfactant is effective to prepare magnesium oxide with High Surface Area and affects the morphology of the prepared samples. The results showed that the magnesium oxide calcined at different temperatures ranging from 600 to 800 °C possessed a High Surface Area in the range of 133.9–78.1 m2 g−1. In addition, the magnesium oxide prepared with the addition of surfactant showed a narrower pore size distribution compared to the sample prepared without the addition of a surfactant.

  • Synthesis of pure tetragonal zirconium oxide with High Surface Area
    Journal of Materials Science, 2007
    Co-Authors: Mehran Rezaei, Seyed Mehdi Alavi, Saeed Sahebdelfar, Hans Teunissen, J. H. Jacobsen, Zifeng Yan, Jakob Sehested
    Abstract:

    Zirconium oxide (ZrO2) with High Surface Area and High content of the tetragonal polymorph was prepared by precipitation from aqueous solutions under basic conditions in the presence of hexadecyltrimethylammonium bromide as surfactant. The surfactant to zirconium molar ratio, pH of precipitation, aging time and zirconium concentration in aqueous solution were optimized by the Taguchi method. The sample, prepared under optimized conditions had a High Surface Area of 168 m2 g−1 after calcination at 600 °C for 10 h. Pellets, prepared by pressing this sample and after calcination at 800 °C for 0.5 h had a Surface Area of 105 m2 g−1. X-ray diffraction analyses showed that both heat treatments gave pure tetragonal zirconium oxide.

  • tetragonal nanocrystalline zirconia powder with High Surface Area and mesoporous structure
    Powder Technology, 2006
    Co-Authors: Mehran Rezaei, Seyed Mehdi Alavi, Saeed Sahebdelfar
    Abstract:

    Nanocrystalline zirconia powder with High Surface Area, pure tetragonal phase and mesoporous structure was prepared by a surfactant-assisted route by using Pluronic P123 block copolymer as the surfactant. The zirconium to surfactant molar ratio, pH of precipitation, aging time and zirconium molarity were optimized by the Taguchi method of experimental design. The sample prepared under optimized conditions showed a High Surface Area of 175 m2 g− 1, pure tetragonal crystallite phase and a mesoporous structure after calcination at 600 °C for 5 h. The X-ray diffraction and nitrogen adsorption analyses showed that the mesoporous structure and tetragonal phase were stable towards Higher temperatures.

Behzad Nematollahi - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis of Nanocrystalline CeO2 with High Surface Area by the Taguchi Method and its Application in Methanation
    Chemical Engineering & Technology, 2014
    Co-Authors: Behzad Nematollahi, Mehran Rezaei, Ebrahim Nemati Lay
    Abstract:

    Mesoporous nanocrystalline cerium(IV) oxide (CeO2) with High Surface Area was synthesized by precipitation using a cationic surfactant and employed as support for a nickel catalyst in CO methanation. The preparation factors of CeO2 were optimized by the Taguchi method to achieve a sample with High Surface Area. The obtained results reveal that the sample prepared under optimized conditions has a mesoporous structure with High Surface Area and crystallite size. The addition of a surfactant significantly influences the structural properties of CeO2 and improves the specific Surface Area. The optimized sample was employed as support for a nickel catalyst in CO methanation reaction. The prepared catalyst possessed a High activity compared to a commercial methanation catalyst.

  • synthesis of High Surface Area nanocrystalline mgo by pluronic p123 triblock copolymer surfactant
    Powder Technology, 2011
    Co-Authors: Mehran Rezaei, Majid Khajenoori, Behzad Nematollahi
    Abstract:

    Abstract Nanocrystalline magnesium oxide with High Surface Area was prepared by a simple precipitation method using pluronic P123 triblock copolymer (Poly(ethylene glycol)-block, Poly(propylene glycol)-block, Poly(ethylene glycol)) as surfactant. The prepared samples were characterized by X-ray Diffraction (XRD), N2 adsorption (BET), Fourier transform infrared spectroscopy (FTIR), Thermal, differential thermal gravimetric and differential thermal analyses (TG/DTG/DTA) and Scanning electron microscopy (SEM). The obtained results revealed that the addition of surfactant is effective to prepare magnesium oxide with High Surface Area and affects the morphology of the prepared samples. The results showed that the magnesium oxide calcined at different temperatures ranging from 600 to 800 °C possessed a High Surface Area in the range of 133.9–78.1 m2 g−1. In addition, the magnesium oxide prepared with the addition of surfactant showed a narrower pore size distribution compared to the sample prepared without the addition of a surfactant.

  • synthesis of High Surface Area nanocrystalline mgo by pluronic p123 triblock copolymer surfactant
    Powder Technology, 2011
    Co-Authors: Mehran Rezaei, Majid Khajenoori, Behzad Nematollahi
    Abstract:

    Abstract Nanocrystalline magnesium oxide with High Surface Area was prepared by a simple precipitation method using pluronic P123 triblock copolymer (Poly(ethylene glycol)-block, Poly(propylene glycol)-block, Poly(ethylene glycol)) as surfactant. The prepared samples were characterized by X-ray Diffraction (XRD), N2 adsorption (BET), Fourier transform infrared spectroscopy (FTIR), Thermal, differential thermal gravimetric and differential thermal analyses (TG/DTG/DTA) and Scanning electron microscopy (SEM). The obtained results revealed that the addition of surfactant is effective to prepare magnesium oxide with High Surface Area and affects the morphology of the prepared samples. The results showed that the magnesium oxide calcined at different temperatures ranging from 600 to 800 °C possessed a High Surface Area in the range of 133.9–78.1 m2 g−1. In addition, the magnesium oxide prepared with the addition of surfactant showed a narrower pore size distribution compared to the sample prepared without the addition of a surfactant.

W. Weisweiler - One of the best experts on this subject based on the ideXlab platform.

  • A new route for the synthesis of High Surface Area γ-aluminium oxide xerogel
    Applied Catalysis A-general, 2002
    Co-Authors: S. Kureti, W. Weisweiler
    Abstract:

    Abstract A new sol–gel method has been developed to synthesize High Surface Area γ-aluminium oxide. The preparation was carried out at ambient temperature using a special reactor which allowed the dosing of gaseous water for the hydrolysis of aluminium alcoxide. Aluminium tri- sec -butoxide was used as precursor and acetone as solvent, since this mixture leads to a stable lyogel. After drying and pyrolysis a High Surface Area γ-aluminium oxide xerogel was formed. The effect of heating on the morphology and structure was examined by nitrogen sorption (BET and pore size distribution), SEM, XRD and 27 Al MAS NMR. The results indicate that the xerogel is a Highly stable material at elevated temperatures. Moreover, the High Surface Area xerogel exhibits an enlarged amount of acid sites which leads to an enhanced catalytic activity for example in the propene oxidation.

  • A new route for the synthesis of High Surface Area -aluminium oxide xerogel
    2002
    Co-Authors: S. Kureti, W. Weisweiler
    Abstract:

    A new sol–gel method has been developed to synthesize High Surface Area-aluminium oxide. The preparation was carried out at ambient temperature using a special reactor which allowed the dosing of gaseous water for the hydrolysis of aluminium alcoxide. Aluminium tri-sec-butoxide was used as precursor and acetone as solvent, since this mixture leads to a stable lyogel. After drying and pyrolysis a High Surface Area -aluminium oxide xerogel was formed. The effect of heating on the morphology and structure was examined by nitrogen sorption (BET and pore size distribution), SEM, XRD and 27 Al MAS NMR. The results indicate that the xerogel is a Highly stable material at elevated temperatures. Moreover, the High Surface Area xerogel exhibits an enlarged amount of acid sites which leads to an enhanced catalytic activity for example in the propene oxidation. © 2002 Elsevier Science B.V. All rights reserved.

M.p. Srinivasan - One of the best experts on this subject based on the ideXlab platform.

  • Mesoporous High-Surface-Area activated carbon
    Microporous and Mesoporous Materials, 2001
    Co-Authors: M.p. Srinivasan
    Abstract:

    Coconut shells and palm seeds have been used as raw materials to obtain activated carbons with High Surface Area by simultaneous treatment with zinc chloride and carbon dioxide as the physical and chemical agents, respectively. Both the Surface Area and the mesopore content could be tuned by controlling the experimental parameters, viz., ZnCl2-to-raw material ratio, duration of exposure to the carbon dioxide atmosphere and temperature of activation. In particular, ZnCl2-to-shell ratios above 1 yielded High Surface Areas, and ratios above 2 resulted in High mesopore content. The adsorption capacity and nature of the porosity were investigated by adsorption experiments using adsorbates with different molecular sizes (viz., phenol, methylene blue and erythrosine red). The capacities of the mesoporous activated carbons were much Higher than those of microporous carbons for larger adsorbates, confirming the presence of large amounts of mesopores in the former. The measured adsorption capacities for the prepared samples conformed to the expectations based on micropore and mesopore Area and volume estimations.

  • Preparation of High-Surface-Area activated carbons from coconut shell
    Microporous and Mesoporous Materials, 1999
    Co-Authors: M.p. Srinivasan
    Abstract:

    Abstract High-Surface-Area activated carbons were prepared by chemical activation of coconut shell with KOH as active agent. The influence of activation parameters on the final products was studied by varying the KOH-to-shell ratio, activation temperature and pre-heat temperatures. The samples were characterized by nitrogen adsorption isotherms at 77 K. The Surface Area and pore volume of the carbons were estimated by BET, the Langmuir equation and the t-plot method. Pre-treatment at 600°C favored the product with good yield, High Surface Area and granular form. The BET Surface Area and pore volume were as High as 2451 m2/g and 1.21 cm3/g, respectively. The activated carbons exhibited a much Higher adsorption capacity for phenol, 4-chlorophenol and 4-nitrophenol from aqueous solution than did a commercial activated carbon.

Saeed Sahebdelfar - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis of pure tetragonal zirconium oxide with High Surface Area
    Journal of Materials Science, 2007
    Co-Authors: Mehran Rezaei, Seyed Mehdi Alavi, Saeed Sahebdelfar, Hans Teunissen, J. H. Jacobsen, Zifeng Yan, Jakob Sehested
    Abstract:

    Zirconium oxide (ZrO2) with High Surface Area and High content of the tetragonal polymorph was prepared by precipitation from aqueous solutions under basic conditions in the presence of hexadecyltrimethylammonium bromide as surfactant. The surfactant to zirconium molar ratio, pH of precipitation, aging time and zirconium concentration in aqueous solution were optimized by the Taguchi method. The sample, prepared under optimized conditions had a High Surface Area of 168 m2 g−1 after calcination at 600 °C for 10 h. Pellets, prepared by pressing this sample and after calcination at 800 °C for 0.5 h had a Surface Area of 105 m2 g−1. X-ray diffraction analyses showed that both heat treatments gave pure tetragonal zirconium oxide.

  • tetragonal nanocrystalline zirconia powder with High Surface Area and mesoporous structure
    Powder Technology, 2006
    Co-Authors: Mehran Rezaei, Seyed Mehdi Alavi, Saeed Sahebdelfar
    Abstract:

    Nanocrystalline zirconia powder with High Surface Area, pure tetragonal phase and mesoporous structure was prepared by a surfactant-assisted route by using Pluronic P123 block copolymer as the surfactant. The zirconium to surfactant molar ratio, pH of precipitation, aging time and zirconium molarity were optimized by the Taguchi method of experimental design. The sample prepared under optimized conditions showed a High Surface Area of 175 m2 g− 1, pure tetragonal crystallite phase and a mesoporous structure after calcination at 600 °C for 5 h. The X-ray diffraction and nitrogen adsorption analyses showed that the mesoporous structure and tetragonal phase were stable towards Higher temperatures.