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Bedřich Smetana - One of the best experts on this subject based on the ideXlab platform.
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Role of vermiculite and zirconium–vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: Marta Valaskova, M. Hundáková, Jana Zdrálková, Jonas Tokarský, Bedřich SmetanaAbstract:Abstract The Zr 4 + –vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr 4 + –vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr 4 + –vermiculite led to new findings that water molecules are attracted more strongly by Mg 2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr 4 (OH) 14 (H 2 O) 10 ] 2 + and [Zr 4 (OH) 8 (H 2 O) 16 ] 8 + may be present in the interlayer space of the Zr 4 + –vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the Zirconyl Chloride (ZrOCl 2 –30% solution in HCl) and the prepared Zr 4 + –vermiculites were designated as Zr 4 + –Verm1 and Zr 4 + –Verm2, respectively. Influence of the Zr 4 + –Verm1 and Zr 4 + –Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the Zirconyl Chloride (ZrOCl 2 –30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr 4 + –Verm1 and Zr 4 + –Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with Zirconyl Chloride solution. The type of vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.
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Role of vermiculite and zirconium–vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: Marta Valaskova, M. Hundáková, Jana Zdrálková, Jonas Tokarský, Bedřich SmetanaAbstract:The Zr4 +–vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr4 +–vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr4 +–vermiculite led to new findings that water molecules are attracted more strongly by Mg2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr4(OH)14(H2O)10]2 + and [Zr4(OH)8(H2O)16]8 + may be present in the interlayer space of the Zr4 +–vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the Zirconyl Chloride (ZrOCl2–30% solution in HCl) and the prepared Zr4 +–vermiculites were designated as Zr4 +–Verm1 and Zr4 +–Verm2, respectively. Influence of the Zr4 +–Verm1 and Zr4 +–Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the Zirconyl Chloride (ZrOCl2–30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr4 +–Verm1 and Zr4 +–Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with Zirconyl Chloride solution. The type of vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.Web of Science75-7610810
Katherine Trego - One of the best experts on this subject based on the ideXlab platform.
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Spectrophotometric determination of iron in zirconium metal and in Zirconyl Chloride
Analytica Chimica Acta, 2002Co-Authors: Louis Silverman, Katherine TregoAbstract:Abstract Iron, present in zirconium metal or in Zirconyl Chloride, may be determined spectrophotometrically in 1 : 1 hydrochloric acid solution without prior separation from the zirconium. In a 1 : 1 hydrochloric acid solution, at the solubility limit of Zirconyl Chloride (0.28 g zirconium per 25 ml), 20 p.p.m. of iron may be detected. When smaller amounts of iron are to be determined (4 p.p.m.), a larger starting sample (5 g) of zirconium is crystallized from a 3 : 1 hydrochloric acid solution which reduces the lower limit of detection of iron to 4 p.p.m.
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GRAVIMETRIC DETERMINATION OF BARIUM IN ZIRCONIUM METAL AND IN CERTAIN ZIRCONIUM SALTS
Analytica Chimica Acta, 2002Co-Authors: Louis Silverman, Katherine TregoAbstract:Abstract Barium may be determined gravimetrically in quantities ranging from 0.2 to 2.0 mg (± o.1 mg) in hydrated Zirconyl Chloride and in zirconium metal after complete separation of the zirconium. As much as 10 g of zirconium may be removed by a double precipitation in a (3 to 1) hydrochloric acid medium followed by a cupferron precipitation-chloroform extraction of the residual zirconium. The barium is then determined gravimetrically as barium sulfate in the iron-free, zirconium-free filtrate by precipitation with an excess of ammonium sulfate. As much as 0.015% barium has been found in impure Zirconyl Chloride, 0.004% in commercial “purified” Zirconyl Chloride, 0.000% barium in crystal bar zirconium metal and 0.003% barium in zirconium metal sheet. Reproducibility is 0.001%.
Ki June Yoon - One of the best experts on this subject based on the ideXlab platform.
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The catalyst for oxidative coupling of methane prepared from Zirconyl Chloride and sodium pyrophosphate
Applied Catalysis A-general, 1997Co-Authors: Ki June Yoon, Sang Won SeoAbstract:Abstract The catalysts prepared from Zirconyl Chloride and sodium pyrophosphate exhibited high activity and selectivity for the oxidative coupling of methane. We suggest that the catalytically active substances are most likely to be NaCl-promoted sodium zirconium phosphates and NaCl plays a key role in activity and selectivity of the catalyst system. The highest C 2+ selectivity was 79% at the methane conversion of 28% (C 2+ yield 22%) and the highest C 2+ yield was about 30% with the C 2+ selectivity of 66–70% at the methane conversion of 41–44%. The ethene/ethane ratio higher than 10 and the C 3+ selectivity of about 10–20% were obtained. Over the catalysts with the Na/Zr ratio greater than about 2, the C 2+ selectivity did not decrease much with time on-stream in spite of the significant decrease of the activity. The main reason for the catalyst deactivation is probably the disappearance of NaCl.
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Oxidative coupling of methane over Na^+-ZrO_2-C1^-/Al_2O_3 catalysts
Korean Journal of Chemical Engineering, 1997Co-Authors: Sun Ho Kim, Sung Min Cho, Ki June YoonAbstract:Oxidative coupling of methane (OCM) was carried out over Na^+-ZrO_2-Cl /A1[_2O_3 catalysts in a temperature range from 1023 to 1123 K. The catalysts were prepared by impregnating the α- or γ-Al_2O_3 supports with sodium carbonate and/or Zirconyl Chloride. The OCM activity was examined using the catalysts prepared by three different preparation procedures. The best catalyst was the one prepared by subsequent impregnation of sodium carbonate-preimpregnated γ-Al_2O_3 with a mixed solution of sodium carbonate and Zirconyl Chloride. It was found that preimpregnated sodium played an important role in reducing the combustion activity of the γ-Al_2O_3. The catalyst with an optimal composition showed the highest C_2 selectivity and yield of 40.8% and 15.1%, respectively. From the X-ray diffraction analysis it was found that tetragonal ZrO_2 was formed and that NaCl existed in the catalysts with relatively high sodium contents.
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Oxidative coupling of methane over Na+-ZrO2-C1-/Al2O3 catalysts
Korean Journal of Chemical Engineering, 1997Co-Authors: Sun Ho Kim, Sung Min Cho, Ki June YoonAbstract:Oxidative coupling of methane (OCM) was carried out over Na+-ZrO2-Cl /A1[2O3 catalysts in a temperature range from 1023 to 1123 K. The catalysts were prepared by impregnating the α- or γ-Al2O3 supports with sodium carbonate and/or Zirconyl Chloride. The OCM activity was examined using the catalysts prepared by three different preparation procedures. The best catalyst was the one prepared by subsequent impregnation of sodium carbonate-preimpregnated γ-Al2O3 with a mixed solution of sodium carbonate and Zirconyl Chloride. It was found that preimpregnated sodium played an important role in reducing the combustion activity of the γ-Al2O3. The catalyst with an optimal composition showed the highest C2 selectivity and yield of 40.8% and 15.1%, respectively. From the X-ray diffraction analysis it was found that tetragonal ZrO2 was formed and that NaCl existed in the catalysts with relatively high sodium contents.
Marta Valaskova - One of the best experts on this subject based on the ideXlab platform.
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Role of vermiculite and zirconium–vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: Marta Valaskova, M. Hundáková, Jana Zdrálková, Jonas Tokarský, Bedřich SmetanaAbstract:Abstract The Zr 4 + –vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr 4 + –vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr 4 + –vermiculite led to new findings that water molecules are attracted more strongly by Mg 2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr 4 (OH) 14 (H 2 O) 10 ] 2 + and [Zr 4 (OH) 8 (H 2 O) 16 ] 8 + may be present in the interlayer space of the Zr 4 + –vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the Zirconyl Chloride (ZrOCl 2 –30% solution in HCl) and the prepared Zr 4 + –vermiculites were designated as Zr 4 + –Verm1 and Zr 4 + –Verm2, respectively. Influence of the Zr 4 + –Verm1 and Zr 4 + –Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the Zirconyl Chloride (ZrOCl 2 –30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr 4 + –Verm1 and Zr 4 + –Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with Zirconyl Chloride solution. The type of vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.
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Role of vermiculite and zirconium–vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: Marta Valaskova, M. Hundáková, Jana Zdrálková, Jonas Tokarský, Bedřich SmetanaAbstract:The Zr4 +–vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr4 +–vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr4 +–vermiculite led to new findings that water molecules are attracted more strongly by Mg2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr4(OH)14(H2O)10]2 + and [Zr4(OH)8(H2O)16]8 + may be present in the interlayer space of the Zr4 +–vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the Zirconyl Chloride (ZrOCl2–30% solution in HCl) and the prepared Zr4 +–vermiculites were designated as Zr4 +–Verm1 and Zr4 +–Verm2, respectively. Influence of the Zr4 +–Verm1 and Zr4 +–Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the Zirconyl Chloride (ZrOCl2–30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr4 +–Verm1 and Zr4 +–Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with Zirconyl Chloride solution. The type of vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.Web of Science75-7610810
Zong-whie Shih - One of the best experts on this subject based on the ideXlab platform.
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SOL PREPARATION FROM Zirconyl Chloride OCTAHYDRATE IN AMINE-AMMONIA SOLUTION
Journal of The Chinese Institute of Engineers, 1999Co-Authors: Maw-ling Wang, Chi‐chung Ren, Biing-lang Liu, Zong-whie ShihAbstract:Abstract Several non‐acid amines including diethylenediamine (DEDA), trimethylenediamine (TEDA), monoethanolamine (MEA), diethanol‐amine (DEA) and triethanolamine (TEA), were examined in order to understand their suitability for being used as complex agents in the reaction with ammonium hydroxide to form ionized complex agents in the sol preparation from Zirconyl Chloride octahydrate. Only DEA and TEA amongst the non‐acid complex agents could produce the sol of the precursor of zirconium oxide, by reaction of Zirconyl Chloride octahydrate (ZrOCl2 • 8H2O) and TEA (or DEA) in ammonia solution. The reaction mechanism of sol formation, which includes sequential hydrolysis and condensation, has been proposed here. A tetranuclear complex molecule ([Zr4(OH)8(OH2)16)8+]) is first produced in the aqueous solution via hydrolysis, and a larger complex molecule ([Zr4(OH)8(OH2)16–2n]8+(HN(R‐O‐)2 2‐)n and [Zr4(OH)8–2n(OH2)16]8+ (HN(R‐O‐)2 2‐)n for DEA, and [Zr4(OH)8(OH2)16–3n]8+(N(R‐O‐)3 3‐)n and [Zr4(OH)8–3n(OH2)16](N...
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Sol synthesis from Zirconyl Chloride octahydrate in NTA-ammonia solution
Journal of Crystal Growth, 1998Co-Authors: Maw-ling Wang, Biing-lang Liu, Zong-whie ShihAbstract:This work first synthesized sol of the precursor of zirconium oxide by reacting Zirconyl Chloride octahydrate (ZrOCl2 · 8H2O) with nitrilotriacetic acid (NTA) in ammonia solution. NTA (R(COO−)n), acts as the complex compound, reacts with ammonium hydroxide to produce an ionized complex agent R(COO−)n. Reaction of ZrOCl2 · 8H2O and R(COO−)n was achieved through sequential hydrolysis and condensation, i.e., tetramer product ([Zr4(OH)8(OH2)16]8+) was produced via hydrolysis and a large complex molecule ([Zr4(OH)8 − n(OH2)16(−OOC)nR]8+ or [Zr4(OH)8(OH2)16 − n(OOC-)nR]8+) was generated via condensation. In addition, the effects of the reaction conditions including the temperature, the molar concentration of ZrOCl2 · 8H2O, the amount of ammonia and the agitation speed on the average size of sol particle and the viscosity of the sol were investigated. Rational reaction mechanism, accounting for the formation, growth of the particles, and the viscosity of the sol, was also proposed to satisfactorily account for the experimental results.
