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Zhongmin Liu - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of ti mcm 41 using Colloidal Silica and titanium trichloride iii catalytic activity of ti mcm 41 molecular sieve
    2001
    Co-Authors: Q Xin, Zhongmin Liu
    Abstract:

    The catalytic properties of the Ti-MCM-41 molecular sieve synthesized from Colloidal Silica and TiCl3 were tested in the epoxidation of styrene, alpha -methyl styrene and cyclohexene using 30% H2O2 solution as the oxidant. The catalysts show excellent catalytic properties and the substrate conversion and the product selectivity are comparable with those in the case of Ti-MCM-41 synthesized from organic precursors. The results obtained from the three olefins with different structure indicate that the main procedure of the oxidation of olefins with terminal C=C bond is the oxidative cleavage, while that of cyclohexene is the epoxidation.

  • ti mcm 41 synthesized from Colloidal Silica and titanium trichloride synthesis characterization and catalysis
    Chemistry of Materials, 2001
    Co-Authors: Zhaochi Feng, Q Xin, Zhongmin Liu
    Abstract:

    Titanium-containing mesoporous molecular sieve Ti−MCM-41 has been synthesized using Colloidal Silica as the silicon source and TiCl3 solution as the titanium source and was characterized by X-ray diffraction, N2 adsorption, UV−vis, and UV−Raman spectroscopies. The formation of anatase TiO2 can be avoided during the synthesis and the crystallization of the molecular sieve because of the relatively low hydrolysis rate of an inorganic TiCl3 solution. The characterization results confirm that most Ti4+ ions are isolated and tetrahedrally coordinated in the framework of MCM-41. Different auxiliary templates, tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrabutylammonium hydroxide, and NH3·H2O were used to synthesize the Ti−MCM-41 molecular sieve. Among them, TMAOH and TEAOH were found to be the most effective auxiliary templates to improve the long-ranged order of the molecular sieves.

Elza Bontempi - One of the best experts on this subject based on the ideXlab platform.

  • inertisation of heavy metals in municipal solid waste incineration fly ash by means of Colloidal Silica a synchrotron x ray diffraction and absorption study
    RSC Advances, 2013
    Co-Authors: Rudolf Paul Wilhelm Jozef Struis, Laura Borgese, Alessandra Gianoncelli, Laura E. Depero, Michela Pasquali, Marcello Gelfi, Paolo Colombi, Dominique Thiaudiere, Giuseppe Rizzo, Elza Bontempi
    Abstract:

    Many efforts have been undertaken in past decades to minimize pollution from municipal solid waste incineration fly ash (MSWI FA). This residue is toxic, because of its high concentration of heavy metals, mainly Pb and Zn. A new method for heavy metals entrapment with MSWI FA was proposed recently. The method is based on the use of Colloidal Silica and it was applied to other FA typologies (flue gas desulfurization and coal fly ashes). The first results, in terms of material recovery, are very promising. The present paper is dedicated to the study of the mechanism of entrapment of heavy metals as promoted by the use of Colloidal Silica in the inertisation process by means of X-ray Absorption Spectroscopy (XAS) and by synchrotron-based XRD. Only XAS allowed focussing on the local environmental changes for Pb and Zn atoms on a molecular level. Chemical equilibrium calculations predict that, without Silica, water-soluble Pb and Zn salts form stable phases, such as carbonates. XAS analysis showed that, despite carbonation of alkaline earth metals such as Ca, Colloidal Silica promotes the stabilisation of major heavy metals in phases other than carbonates and most likely in the more inert Silicate form.

  • a new method for municipal solid waste incinerator mswi fly ash inertization based on Colloidal Silica
    Journal of Environmental Monitoring, 2010
    Co-Authors: Elza Bontempi, R Ardesi, Laura Borgese, Annalisa Zacco, Alessandra Gianoncelli, Laura E. Depero
    Abstract:

    Municipal solid waste incineration (MSWI) is a straightforward way to manage waste, however the disposal of process byproducts, mainly bottom and fly ash, is still a problem, because of their hazardous contents. Fly ash is a byproduct of many other processes that involve combustion to produce energy. In this paper we present and discuss a new method for MSWI fly ash inertization, mainly based on the use of Colloidal Silica as a stabilization agent for metals. In the patented procedure, fly ash of different provenance can be used to produce an inert and non-hazardous material, that can be reused. In fact to make the recovery process more efficient, landfilling should be totally avoided. For this reason, to enhance the possibility of reuse, a washing process, for salts recovery, is proposed as a final step of the inertization procedure. The obtained inert material is called COSMOS (Colloidal Silica Medium to Obtain Safe inert), and it is composed of calcium carbonate, calcium sulfate, silicon oxide and a wide quantity of non-soluble amorphous compounds. COSMOS does not contain any corrosive salts. This makes it extremely interesting for cement industry applications with several other advantages, and environmental benefits. The new proposed inertization procedure appears very promising, because it allows MSWI fly ash to be considered a valuable resource. Thanks to the obtained results, a demonstration project, in the frame of LIFE+, has been funded by the European Commission (LIFE+ 2008 project ENV/IT/000434, http://www.cosmos.csmt.eu).

Laura E. Depero - One of the best experts on this subject based on the ideXlab platform.

  • inertisation of heavy metals in municipal solid waste incineration fly ash by means of Colloidal Silica a synchrotron x ray diffraction and absorption study
    RSC Advances, 2013
    Co-Authors: Rudolf Paul Wilhelm Jozef Struis, Laura Borgese, Alessandra Gianoncelli, Laura E. Depero, Michela Pasquali, Marcello Gelfi, Paolo Colombi, Dominique Thiaudiere, Giuseppe Rizzo, Elza Bontempi
    Abstract:

    Many efforts have been undertaken in past decades to minimize pollution from municipal solid waste incineration fly ash (MSWI FA). This residue is toxic, because of its high concentration of heavy metals, mainly Pb and Zn. A new method for heavy metals entrapment with MSWI FA was proposed recently. The method is based on the use of Colloidal Silica and it was applied to other FA typologies (flue gas desulfurization and coal fly ashes). The first results, in terms of material recovery, are very promising. The present paper is dedicated to the study of the mechanism of entrapment of heavy metals as promoted by the use of Colloidal Silica in the inertisation process by means of X-ray Absorption Spectroscopy (XAS) and by synchrotron-based XRD. Only XAS allowed focussing on the local environmental changes for Pb and Zn atoms on a molecular level. Chemical equilibrium calculations predict that, without Silica, water-soluble Pb and Zn salts form stable phases, such as carbonates. XAS analysis showed that, despite carbonation of alkaline earth metals such as Ca, Colloidal Silica promotes the stabilisation of major heavy metals in phases other than carbonates and most likely in the more inert Silicate form.

  • a new method for municipal solid waste incinerator mswi fly ash inertization based on Colloidal Silica
    Journal of Environmental Monitoring, 2010
    Co-Authors: Elza Bontempi, R Ardesi, Laura Borgese, Annalisa Zacco, Alessandra Gianoncelli, Laura E. Depero
    Abstract:

    Municipal solid waste incineration (MSWI) is a straightforward way to manage waste, however the disposal of process byproducts, mainly bottom and fly ash, is still a problem, because of their hazardous contents. Fly ash is a byproduct of many other processes that involve combustion to produce energy. In this paper we present and discuss a new method for MSWI fly ash inertization, mainly based on the use of Colloidal Silica as a stabilization agent for metals. In the patented procedure, fly ash of different provenance can be used to produce an inert and non-hazardous material, that can be reused. In fact to make the recovery process more efficient, landfilling should be totally avoided. For this reason, to enhance the possibility of reuse, a washing process, for salts recovery, is proposed as a final step of the inertization procedure. The obtained inert material is called COSMOS (Colloidal Silica Medium to Obtain Safe inert), and it is composed of calcium carbonate, calcium sulfate, silicon oxide and a wide quantity of non-soluble amorphous compounds. COSMOS does not contain any corrosive salts. This makes it extremely interesting for cement industry applications with several other advantages, and environmental benefits. The new proposed inertization procedure appears very promising, because it allows MSWI fly ash to be considered a valuable resource. Thanks to the obtained results, a demonstration project, in the frame of LIFE+, has been funded by the European Commission (LIFE+ 2008 project ENV/IT/000434, http://www.cosmos.csmt.eu).

Wen-chang Chen - One of the best experts on this subject based on the ideXlab platform.

  • transparent organic inorganic hybrid thin films prepared from acrylic polymer and aqueous monodispersed Colloidal Silica
    Materials Chemistry and Physics, 2003
    Co-Authors: Yangyen Yu, Wen-chang Chen
    Abstract:

    Highly transparent hybrid films containing nano-sized Silica domain were synthesized from acrylic polymer and aqueous monodispersed Colloidal Silica (CS) with a coupling agent, 3-(trimethoxysilyl)propyl methacrylate (MSMA). The Silica content in the hybrid thin films was varied from 0 to 50 wt.%. The experimental results showed that the Silica particle size in the precursor solution and the hybrid films was varied from 20 to 40 nm. It could be controlled by the mole ratio of MSMA to Silica. The results of scanning electron microscope (SEM), transmission electron microscope (TEM), and elemental analysis support the above conclusion. The prepared hybrid films showed high film uniformity and optical transparence. The thermal stability of the prepared hybrid films increased with the increasing Silica content. The refractive index decreased linearly with the increasing Silica fraction in the hybrid films. The experimental results suggest that the hybrid thin films have potential applications as passive films for optical devices.

  • synthesis and characterization of organic inorganic hybrid thin films from poly acrylic and monodispersed Colloidal Silica
    Polymer, 2003
    Co-Authors: Ching Yi Chen, Wen-chang Chen
    Abstract:

    Abstract Hybrid thin films containing nano-sized inorganic domain were synthesized from poly(acrylic) and monodispersed Colloidal Silica with coupling agent. The 3-(trimethoxysilyl)propyl methacrylate (MSMA) was bonded with Colloidal Silica first, and then polymerized with acrylic monomer to form a precursor solution. Then, the precursor was spin coated and cured to form the hybrid films. The Silica content in the hybrid thin films was varied from 0 to 50 wt%. The experimental results showed that the coverage area of Silica particle by the MSMA decreased with increasing Silica content and resulted in the aggregation of Silica particle in the hybrid films. Thus, the Silica domain in the hybrid films was varied from 20 to 35 nm by the different mole ratios of MSMA to Silica. The results of scanning electron microscope, transmission electron microscope, and elemental analysis support the above results. The prepared hybrid films from the crosslinked acrylic polymer moiety showed much better film uniformity, thermal stability and mechanical properties than the poly(methyl methacrylate) (PMMA) based hybrid materials. Large pin-holes were found in the PMMA–Silica hybrid films probably due to the significant difference on thermal properties between the two moieties or the evaporation of solvent. The refractive index decreased linearly with increasing the Silica fraction in the hybrid films. Excellent optical transparence was obtained in the prepared hybrid films. These results show that the hybrid thin films have potential applications as passive films for optical devices.

Q Xin - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of ti mcm 41 using Colloidal Silica and titanium trichloride ii characterization of ti mcm 41 molecular sieve
    2001
    Co-Authors: Q Xin
    Abstract:

    The Ti-MCM-41 molecular sieve synthesized with Colloidal Silica and titanium trichloride has been characterized by nitrogen adsorption, TG-DTA and spectroscopies of FT-IR, UV-Vis and UV-Raman. N-2 adsorption isotherms reveal that with the incorporation of titanium into the framework of the molecular sieve, the pore size decreases and the wall thickness increases. TG and DTA profiles suggest that different template sorption sites exist in the framework of Ti-MCM-41. FT-IR, UV-Vis and UV-Raman spectra indicate that the formation of anatase TiO2 can be avoided during the preparation of the synthesis gel and the crystallization of the molecular sieve. Most Ti4(+) ions are isolated and tetrahedrally coordinated in the framework of MCM-41.

  • synthesis of ti mcm 41 using Colloidal Silica and titanium trichloride iii catalytic activity of ti mcm 41 molecular sieve
    2001
    Co-Authors: Q Xin, Zhongmin Liu
    Abstract:

    The catalytic properties of the Ti-MCM-41 molecular sieve synthesized from Colloidal Silica and TiCl3 were tested in the epoxidation of styrene, alpha -methyl styrene and cyclohexene using 30% H2O2 solution as the oxidant. The catalysts show excellent catalytic properties and the substrate conversion and the product selectivity are comparable with those in the case of Ti-MCM-41 synthesized from organic precursors. The results obtained from the three olefins with different structure indicate that the main procedure of the oxidation of olefins with terminal C=C bond is the oxidative cleavage, while that of cyclohexene is the epoxidation.

  • ti mcm 41 synthesized from Colloidal Silica and titanium trichloride synthesis characterization and catalysis
    Chemistry of Materials, 2001
    Co-Authors: Zhaochi Feng, Q Xin, Zhongmin Liu
    Abstract:

    Titanium-containing mesoporous molecular sieve Ti−MCM-41 has been synthesized using Colloidal Silica as the silicon source and TiCl3 solution as the titanium source and was characterized by X-ray diffraction, N2 adsorption, UV−vis, and UV−Raman spectroscopies. The formation of anatase TiO2 can be avoided during the synthesis and the crystallization of the molecular sieve because of the relatively low hydrolysis rate of an inorganic TiCl3 solution. The characterization results confirm that most Ti4+ ions are isolated and tetrahedrally coordinated in the framework of MCM-41. Different auxiliary templates, tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrabutylammonium hydroxide, and NH3·H2O were used to synthesize the Ti−MCM-41 molecular sieve. Among them, TMAOH and TEAOH were found to be the most effective auxiliary templates to improve the long-ranged order of the molecular sieves.