The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Young Hwa Jung - One of the best experts on this subject based on the ideXlab platform.
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solvothermal synthesis of tungsten Oxide nanorod nanowire nanosheet
Journal of the American Ceramic Society, 2005Co-Authors: Hong Goo Choi, Young Hwa JungAbstract:A simple process enables to synthesize tungsten Oxide with various nanomorphologies, i.e. nanorods, nanowires, and nanosheets. The tungsten hexachloride (WCl6) was used as a raw material and the tungsten Oxide nanoparticles were obtained by solvothermal treatment with solvents, i.e., ethanol, mixed solvent (ethanol1water), and water, at 2001C for 10 h. The various crystalline phases of tungsten Oxide, such as monoclinic W 18O49 nanorods, hexagonal WO3 platelets, and monoclinic WO3 nanosheets, were synthesized by simply changing the composition of the solvent. The oxygen, which was contained in water, played an important role in the final tungsten Oxide phase. Especially, W18O49 nanorods grew to nanowires as the concentration of WCl6 was decreased. Using this simple process, it will be possible to control the crystalline phase and morphologies of nanostructured tungsten Oxide System.
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Solvothermal Synthesis of Tungsten Oxide Nanorod/Nanowire/Nanosheet
Journal of the American Ceramic Society, 2005Co-Authors: Hong Goo Choi, Young Hwa JungAbstract:A simple process enables to synthesize tungsten Oxide with various nanomorphologies, i.e. nanorods, nanowires, and nanosheets. The tungsten hexachloride (WCl6) was used as a raw material and the tungsten Oxide nanoparticles were obtained by solvothermal treatment with solvents, i.e., ethanol, mixed solvent (ethanol1water), and water, at 2001C for 10 h. The various crystalline phases of tungsten Oxide, such as monoclinic W 18O49 nanorods, hexagonal WO3 platelets, and monoclinic WO3 nanosheets, were synthesized by simply changing the composition of the solvent. The oxygen, which was contained in water, played an important role in the final tungsten Oxide phase. Especially, W18O49 nanorods grew to nanowires as the concentration of WCl6 was decreased. Using this simple process, it will be possible to control the crystalline phase and morphologies of nanostructured tungsten Oxide System.
Hong Goo Choi - One of the best experts on this subject based on the ideXlab platform.
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solvothermal synthesis of tungsten Oxide nanorod nanowire nanosheet
Journal of the American Ceramic Society, 2005Co-Authors: Hong Goo Choi, Young Hwa JungAbstract:A simple process enables to synthesize tungsten Oxide with various nanomorphologies, i.e. nanorods, nanowires, and nanosheets. The tungsten hexachloride (WCl6) was used as a raw material and the tungsten Oxide nanoparticles were obtained by solvothermal treatment with solvents, i.e., ethanol, mixed solvent (ethanol1water), and water, at 2001C for 10 h. The various crystalline phases of tungsten Oxide, such as monoclinic W 18O49 nanorods, hexagonal WO3 platelets, and monoclinic WO3 nanosheets, were synthesized by simply changing the composition of the solvent. The oxygen, which was contained in water, played an important role in the final tungsten Oxide phase. Especially, W18O49 nanorods grew to nanowires as the concentration of WCl6 was decreased. Using this simple process, it will be possible to control the crystalline phase and morphologies of nanostructured tungsten Oxide System.
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Solvothermal Synthesis of Tungsten Oxide Nanorod/Nanowire/Nanosheet
Journal of the American Ceramic Society, 2005Co-Authors: Hong Goo Choi, Young Hwa JungAbstract:A simple process enables to synthesize tungsten Oxide with various nanomorphologies, i.e. nanorods, nanowires, and nanosheets. The tungsten hexachloride (WCl6) was used as a raw material and the tungsten Oxide nanoparticles were obtained by solvothermal treatment with solvents, i.e., ethanol, mixed solvent (ethanol1water), and water, at 2001C for 10 h. The various crystalline phases of tungsten Oxide, such as monoclinic W 18O49 nanorods, hexagonal WO3 platelets, and monoclinic WO3 nanosheets, were synthesized by simply changing the composition of the solvent. The oxygen, which was contained in water, played an important role in the final tungsten Oxide phase. Especially, W18O49 nanorods grew to nanowires as the concentration of WCl6 was decreased. Using this simple process, it will be possible to control the crystalline phase and morphologies of nanostructured tungsten Oxide System.
M. Georgieva - One of the best experts on this subject based on the ideXlab platform.
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Mixed Ni-Mn-Oxide Systems as catalysts for complete oxidation: Part I. Preparation and characterization
Applied Catalysis A: General, 2003Co-Authors: M. Stoyanova, St.g. Christoskova, M. GeorgievaAbstract:A method for synthesis of new Ni-Mn-Oxide Systems is proposed. The synthesized Systems have been characterised by a variety of methods including chemical analysis, infrared (IR) spectroscopy, X-ray diffraction (XRD) analysis, thermal analysis, and X-ray photoelectron spectroscopy (XPS). The results obtained reveal that the synthesized catalytic System can be successfully applied as an active phase in low temperature catalysts for complete oxidation carried out both in aqueous medium and in gas phase. The synthesis operating conditions yield hydrophilic and amorphous catalytic Systems with high active oxygen (∼8%), taking part in oxidation processes. The Ni-Mn-Oxide System is characterized by high thermal stability and its composition is kept constant up to 550 °C. Experimental data indicate that modifying a separate Ni-Oxide System with Mn one can prepare new catalytic Systems with high active oxygen content, larger specific area and higher thermal stability.
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Low-temperature iron-modified cobalt Oxide System: Part I. Preparation and characterisation
Applied Catalysis A-general, 2001Co-Authors: St.g. Christoskova, M. Stoyanova, M. GeorgievaAbstract:Abstract The cobalt Oxide System, modified with Fe was prepared by a solution technique at a room temperature. The periodic method of precipitation with inverse order of feeding the precipitator to the System (Me 2+ →OH − +OCl − ) is used, which favors the formation of amorphous and highly disperse Oxide System with non-stationary surface properties. The fresh sample as well as the samples obtained by its thermal treatment at different temperatures were characterized by Mossbauer and Infrared spectral analysis, X-ray diffraction and chemical analyses. A comparative consideration of the composition and structure of individual and modified with Fe cobalt Oxide System has been carried out in order to clarify the influence of Fe as a modifying additive on the activity and selectivity of the sample. The results obtained show that the inclusion of Fe leads to the appearance of new active sites in the fresh samples — Fe(III) ions in octahedral coordination and to increasing the mobility of the reactive oxygen. The synthesized Oxide System shows suitable properties for catalytic oxidation of toxic organic and inorganic compounds in an aqueous medium.
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Low-Temperature Catalytic Oxidation of Sulfide Ions in Aqueous Solutions on a Ni-Oxide System
Reaction Kinetics and Catalysis Letters, 2000Co-Authors: St. Christoskova, M. Stoyanova, M. GeorgievaAbstract:Catalytic oxidation of sulfide ions in aqueous solutions by air oxygen has been investigated using a Ni-Oxide System as a catalyst. The kinetics and the selectivity of the oxidation process were studied by varying the pH, catalyst amount and reaction temperature. A reduction/oxidation mechanism of the reaction has been supposed comprising interaction between the surface active oxygen of the catalyst and HS− and reoxidizing of the reduced catalyst by the dissolved oxygen. The results obtained show that the Ni-Oxide System is a promising catalyst for practical application.
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Study on the thermal stability of a high Co-Oxide used as low-temperature catalyst and oxidant for complete oxidation
Thermochimica Acta, 1997Co-Authors: St. Christoskova, M. Stojanova, M. Georgieva, D. MehandzhievAbstract:Abstract A new higher Co-Oxide has been synthesized. Its features are presented by means of IR-spectroscopy, X-ray analysis, XPS-spectroscopy, EPR, magnetic measurements and chemical analysis in a separate paper by the present authors. On the grounds of the obtained results the following formula, determining the content of the higher Co-Oxide, has been put forward: Co +2 1− x Co +4 x O y ·(OH) y · m H 2 O, with the Co-ions being in their highest oxidation degrees (i.e. +4) and in an octahedral position. The synthesized Co-Oxide System can be utilized as an active phase of a low-temperature catalyst as well as a strong oxidant for a complete oxidation in liquid and gas mediums. The present paper also studies the thermal stability of the synthesized Co-Oxide System by means of thermal analysis, IR-spectroscopy, X-ray and chemical analysis. The results show that both the freshly obtained higher Co-Oxide and the thermally treated (up to 250°C) samples maintain their composition, structure and activity in the oxidation processes. Heated at temperature above 250°C, the Co-Oxide System undergoes changes in its composition and structure, turning it into a cobaltite with a spinel structure. This is the reason for the sharp decrease of the activity of the studied System in the oxidation processes.
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Investigation of a nickel Oxide System for heterogeneous oxidation of organic compounds
Applied Catalysis A: General, 1995Co-Authors: St.g. Christoskova, M. Georgieva, N. Danova, O.k. Argirov, D. MehandzhievAbstract:The structure of a nickel Oxide System, which is an efficient oxidant for organic compounds, has been studied by spectroscopic methods such as IR, X-ray photoelectron spectroscopy, electron spin resonance, X-ray spectroscopy as well as by thermal and chemical analyses. It has been clearly shown that the reagent is not a perOxide, but a higher nickel Oxide. An oxidation reaction mechanism of organic compounds has been proposed.
Teofil Jesionowski - One of the best experts on this subject based on the ideXlab platform.
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treatment of model and galvanic waste solutions of copper ii ions using a lignin inorganic Oxide hybrid as an effective sorbent
Journal of Hazardous Materials, 2017Co-Authors: Filip Ciesielczyk, łukasz Klapiszewski, Przemyslaw Bartczak, Teofil JesionowskiAbstract:A study was made concerning the removal of copper(II) ions from model and galvanic waste solutions using a new sorption material consisting of lignin in combination with an inorganic Oxide System. Specific physicochemical properties of the material resulted from combining the activity of the functional groups present in the structure of lignin with the high surface area of the synthesized Oxide System (585m2/g). Analysis of the porous structure parameters, particle size and morphology, elemental composition and characteristic functional groups confirmed the effective synthesis of the new type of sorbent. A key element of the study was a series of tests of adsorption of copper(II) ions from model solutions. It was determined how the efficiency of the adsorption process was affected by the process time, mass of sorbent, concentration of adsorbate, pH and temperature. Potential regeneration of adsorbent, which provides the possibility of its reusing and recovering the adsorbed copper, was also analyzed. The sorption capacity of the material was measured (83.98mg/g), and the entire process was described using appropriate kinetic models. The results were applied to the design of a further series of adsorption tests, carried out on solutions of real sewage from a galvanizing plant.
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Treatment of model and galvanic waste solutions of copper(II) ions using a lignin/inorganic Oxide hybrid as an effective sorbent
Journal of Hazardous Materials, 2017Co-Authors: Filip Ciesielczyk, łukasz Klapiszewski, Przemyslaw Bartczak, Teofil JesionowskiAbstract:Abstract A study was made concerning the removal of copper(II) ions from model and galvanic waste solutions using a new sorption material consisting of lignin in combination with an inorganic Oxide System. Specific physicochemical properties of the material resulted from combining the activity of the functional groups present in the structure of lignin with the high surface area of the synthesized Oxide System (585 m 2 /g). Analysis of the porous structure parameters, particle size and morphology, elemental composition and characteristic functional groups confirmed the effective synthesis of the new type of sorbent. A key element of the study was a series of tests of adsorption of copper(II) ions from model solutions. It was determined how the efficiency of the adsorption process was affected by the process time, mass of sorbent, concentration of adsorbate, pH and temperature. Potential regeneration of adsorbent, which provides the possibility of its reusing and recovering the adsorbed copper, was also analyzed. The sorption capacity of the material was measured (83.98 mg/g), and the entire process was described using appropriate kinetic models. The results were applied to the design of a further series of adsorption tests, carried out on solutions of real sewage from a galvanizing plant.
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Adsorption of Ni(II) from model solutions using co-precipitated inorganic Oxides
Adsorption-journal of The International Adsorption Society, 2013Co-Authors: Filip Ciesielczyk, Karolina Wieszczycka, Przemyslaw Bartczak, Magdalena Nowacka, Katarzyna Siwińska-stefańska, Teofil JesionowskiAbstract:The aim of this work was to obtain an inorganic Oxide System containing silica and magnesium Oxide, and characterized by specific physicochemical properties, in particular well-defined adsorption parameters. The preparation process was carried out according to a co-precipitation method using solutions of sodium silicate and selected inorganic magnesium salt. The Oxide System obtained (MgO·SiO2) was used as a support (adsorbent) of nickel(II) ions, whose precursors were model solutions of nitrates. The effectiveness of the adsorption process was evaluated using many different analytical techniques, including atomic absorption spectroscopy, energy dispersive X-ray spectroscopy and equivalent point titration. Moreover the stability of adsorbent/adsorbate bonding was estimated. The Oxide Systems—adsorbents—used in the process were also analyzed according to their physicochemical properties, especially changes in adsorption parameters. The last part of the study involved evaluation of the kinetics of the adsorption process depending on time and the pH of the reaction System.
Filip Ciesielczyk - One of the best experts on this subject based on the ideXlab platform.
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treatment of model and galvanic waste solutions of copper ii ions using a lignin inorganic Oxide hybrid as an effective sorbent
Journal of Hazardous Materials, 2017Co-Authors: Filip Ciesielczyk, łukasz Klapiszewski, Przemyslaw Bartczak, Teofil JesionowskiAbstract:A study was made concerning the removal of copper(II) ions from model and galvanic waste solutions using a new sorption material consisting of lignin in combination with an inorganic Oxide System. Specific physicochemical properties of the material resulted from combining the activity of the functional groups present in the structure of lignin with the high surface area of the synthesized Oxide System (585m2/g). Analysis of the porous structure parameters, particle size and morphology, elemental composition and characteristic functional groups confirmed the effective synthesis of the new type of sorbent. A key element of the study was a series of tests of adsorption of copper(II) ions from model solutions. It was determined how the efficiency of the adsorption process was affected by the process time, mass of sorbent, concentration of adsorbate, pH and temperature. Potential regeneration of adsorbent, which provides the possibility of its reusing and recovering the adsorbed copper, was also analyzed. The sorption capacity of the material was measured (83.98mg/g), and the entire process was described using appropriate kinetic models. The results were applied to the design of a further series of adsorption tests, carried out on solutions of real sewage from a galvanizing plant.
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Treatment of model and galvanic waste solutions of copper(II) ions using a lignin/inorganic Oxide hybrid as an effective sorbent
Journal of Hazardous Materials, 2017Co-Authors: Filip Ciesielczyk, łukasz Klapiszewski, Przemyslaw Bartczak, Teofil JesionowskiAbstract:Abstract A study was made concerning the removal of copper(II) ions from model and galvanic waste solutions using a new sorption material consisting of lignin in combination with an inorganic Oxide System. Specific physicochemical properties of the material resulted from combining the activity of the functional groups present in the structure of lignin with the high surface area of the synthesized Oxide System (585 m 2 /g). Analysis of the porous structure parameters, particle size and morphology, elemental composition and characteristic functional groups confirmed the effective synthesis of the new type of sorbent. A key element of the study was a series of tests of adsorption of copper(II) ions from model solutions. It was determined how the efficiency of the adsorption process was affected by the process time, mass of sorbent, concentration of adsorbate, pH and temperature. Potential regeneration of adsorbent, which provides the possibility of its reusing and recovering the adsorbed copper, was also analyzed. The sorption capacity of the material was measured (83.98 mg/g), and the entire process was described using appropriate kinetic models. The results were applied to the design of a further series of adsorption tests, carried out on solutions of real sewage from a galvanizing plant.
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Adsorption of Ni(II) from model solutions using co-precipitated inorganic Oxides
Adsorption-journal of The International Adsorption Society, 2013Co-Authors: Filip Ciesielczyk, Karolina Wieszczycka, Przemyslaw Bartczak, Magdalena Nowacka, Katarzyna Siwińska-stefańska, Teofil JesionowskiAbstract:The aim of this work was to obtain an inorganic Oxide System containing silica and magnesium Oxide, and characterized by specific physicochemical properties, in particular well-defined adsorption parameters. The preparation process was carried out according to a co-precipitation method using solutions of sodium silicate and selected inorganic magnesium salt. The Oxide System obtained (MgO·SiO2) was used as a support (adsorbent) of nickel(II) ions, whose precursors were model solutions of nitrates. The effectiveness of the adsorption process was evaluated using many different analytical techniques, including atomic absorption spectroscopy, energy dispersive X-ray spectroscopy and equivalent point titration. Moreover the stability of adsorbent/adsorbate bonding was estimated. The Oxide Systems—adsorbents—used in the process were also analyzed according to their physicochemical properties, especially changes in adsorption parameters. The last part of the study involved evaluation of the kinetics of the adsorption process depending on time and the pH of the reaction System.
