In this study the characterization of an aluminosilicate synthesized from commercial Al2(SO4)3 and colloidal SiO2 is presented, as well as its capacity for the removal of copper from aqueous solution. Characterization...In this study the characterization of an aluminosilicate synthesized from commercial Al2(SO4)3 and colloidal SiO2 is presented, as well as its capacity for the removal of copper from aqueous solution. Characterization of the synthesized material was performed using X-ray diffraction, BET nitrogen adsorption-desorption, mass titration and the Boehm method. In order to obtain stable agglomeration and enhance its surface area (165 - 243 m2/g) and solid adsorbing capabilities, the molar ratio SiO2:Al2O3 (1:3, 1:1 and 3:1) was studied, the solubility of the preparation material, synthesis-procedure time and solution pH function were also examined. The maximum capacity to remove copper ions from an aqueous solution by synthesized aluminosilicate was 16 mg/g at pH 4 and 25℃. The Langmuir model fitted better to the copper adsorption experimental data.展开更多
Mesoporous aluminosilicates (MAS) bearing microporous zeolite units and mesoporous structures were synthesized by the hydrothermal method. Adsorptive desulfurization ability of model oil and hy-drotreated diesel was s...Mesoporous aluminosilicates (MAS) bearing microporous zeolite units and mesoporous structures were synthesized by the hydrothermal method. Adsorptive desulfurization ability of model oil and hy-drotreated diesel was studied. The effects of template concentration, crystalization time and calcination time were investigated. The desulfurization ability of adsorbents was improved by transitional metal ion-exchanging. The adsorptive desulfurization of diesel was carried out on a fixed-bed system. The results show that the adsorptive capacity is MAS>MCM-41>NaY. The improvement of desulfurization ability of MAS by Cu+ is more significant than that of Ag+.展开更多
以β沸石在Na2SiO3水溶液中选择性脱硅降解所得沸石次级结构单元、脱除的硅物种及Na2SiO3共同作为硅铝源,十六烷基三甲基溴化铵为模板剂,水热法合成出介孔硅铝分子筛BM。采用XRD、N2吸附-脱附、TEM、FT-IR、27 Al MAS NMR、Py-IR、XRF及...以β沸石在Na2SiO3水溶液中选择性脱硅降解所得沸石次级结构单元、脱除的硅物种及Na2SiO3共同作为硅铝源,十六烷基三甲基溴化铵为模板剂,水热法合成出介孔硅铝分子筛BM。采用XRD、N2吸附-脱附、TEM、FT-IR、27 Al MAS NMR、Py-IR、XRF及NH3-TPD手段对BM进行了表征,并以异丙苯裂化为探针反应,对比考察了Hβ、HBM和HAl-MCM-41分子筛的催化性能。结果表明,BM为孔壁含有β沸石结构单元的介孔分子筛。与常规方法合成的Al-MCM-41分子筛相比,其表面硅羟基数量明显减少,孔壁增厚,且四配位铝比例明显增加,酸中心密度、强酸中心比例、B/L酸比值及水热稳定性都明显提高。采用HBM分子筛催化异丙苯裂化反应的苯收率约为采用HAl-MCM-41分子筛时的3倍,且前者的催化稳定性高于Hβ沸石。展开更多
A unique templating approach for the synthesis of hexagonal mesoporous aluminosilicates via self assembly of pre formed aluminosilcate nanoclusters with the templating micella formed by cetyltrimethylammonium bromid...A unique templating approach for the synthesis of hexagonal mesoporous aluminosilicates via self assembly of pre formed aluminosilcate nanoclusters with the templating micella formed by cetyltrimethylammonium bromide (CTAB) is described. The obtained materials of MAS 5 are hydrothermally stable, which is shown by X ray diffraction (XRD) analysis. Furthermore, as characterized by NMR technique, MAS 5 has stable tetrahedral aluminum sites that is the major contributions to the acidity of aluminosilicate molecular sieve, and on non framework aluminium species in the samples was observed.展开更多
Several 2.0 wt% nickel catalysts supported on nanometer bimodal mesoporous aluminosilicate (NBMAS), AlHMS and AlMCM-41 were prepared by means of the wetness impregnation method. The characterization tech-niques such a...Several 2.0 wt% nickel catalysts supported on nanometer bimodal mesoporous aluminosilicate (NBMAS), AlHMS and AlMCM-41 were prepared by means of the wetness impregnation method. The characterization tech-niques such as Py-FTIR and H2 chemisorption showed that the amount of Br鰊sted acid sites decreased in the order of Ni/AlHMS>Ni/AlMCM-41>Ni/NBMAS, while the nickel dispersion differed a little. In the catalytic n-dodecane hydroconversion, the highest conversion was obtained over Ni/NBMAS, and the lowest isomerization selectivity occurred over Ni/AlHMS. For the cracked products, the symmetrical carbon number distribution cen-tered at C6 was obtained on the Ni/AlMCM-41 catalyst due to the well balanced metal/acid functions, whereas the Ni/AlHMS and Ni/NBMAS catalysts led to more C3-C5 and C1+C11 products, respectively.展开更多
The acidic strength of ordered mesoporous aluminosilicates of MAS-2, MAS-3, MAS-7 and MAS-9 and mi-croporous crystals of Y, L, beta, and ZSM-5 zeolites was systemically investigated by temperature-programmed desorptio...The acidic strength of ordered mesoporous aluminosilicates of MAS-2, MAS-3, MAS-7 and MAS-9 and mi-croporous crystals of Y, L, beta, and ZSM-5 zeolites was systemically investigated by temperature-programmed desorption of ammonia (NH3-TPD). Due to the use of preformed zeolite precursors of Y, L, beta and ZSM-5, the ordered mesoporous aluminosilicates with distinguished acidic strength were obtained, being dependent on the type of preformed zeolite precursors. Therefore, the acidic strength of these mesoporous aluminosilicates could be tai-lored and controlled.展开更多
文摘In this study the characterization of an aluminosilicate synthesized from commercial Al2(SO4)3 and colloidal SiO2 is presented, as well as its capacity for the removal of copper from aqueous solution. Characterization of the synthesized material was performed using X-ray diffraction, BET nitrogen adsorption-desorption, mass titration and the Boehm method. In order to obtain stable agglomeration and enhance its surface area (165 - 243 m2/g) and solid adsorbing capabilities, the molar ratio SiO2:Al2O3 (1:3, 1:1 and 3:1) was studied, the solubility of the preparation material, synthesis-procedure time and solution pH function were also examined. The maximum capacity to remove copper ions from an aqueous solution by synthesized aluminosilicate was 16 mg/g at pH 4 and 25℃. The Langmuir model fitted better to the copper adsorption experimental data.
基金Supported by National Basic Research Program of China (Grant No. 2006CB202507)National High-tech R&D Program (Grant No. 2006AA02Z209)the National Natural Science Foundation of China (Grant No. 20806086)
文摘Mesoporous aluminosilicates (MAS) bearing microporous zeolite units and mesoporous structures were synthesized by the hydrothermal method. Adsorptive desulfurization ability of model oil and hy-drotreated diesel was studied. The effects of template concentration, crystalization time and calcination time were investigated. The desulfurization ability of adsorbents was improved by transitional metal ion-exchanging. The adsorptive desulfurization of diesel was carried out on a fixed-bed system. The results show that the adsorptive capacity is MAS>MCM-41>NaY. The improvement of desulfurization ability of MAS by Cu+ is more significant than that of Ag+.
文摘以β沸石在Na2SiO3水溶液中选择性脱硅降解所得沸石次级结构单元、脱除的硅物种及Na2SiO3共同作为硅铝源,十六烷基三甲基溴化铵为模板剂,水热法合成出介孔硅铝分子筛BM。采用XRD、N2吸附-脱附、TEM、FT-IR、27 Al MAS NMR、Py-IR、XRF及NH3-TPD手段对BM进行了表征,并以异丙苯裂化为探针反应,对比考察了Hβ、HBM和HAl-MCM-41分子筛的催化性能。结果表明,BM为孔壁含有β沸石结构单元的介孔分子筛。与常规方法合成的Al-MCM-41分子筛相比,其表面硅羟基数量明显减少,孔壁增厚,且四配位铝比例明显增加,酸中心密度、强酸中心比例、B/L酸比值及水热稳定性都明显提高。采用HBM分子筛催化异丙苯裂化反应的苯收率约为采用HAl-MCM-41分子筛时的3倍,且前者的催化稳定性高于Hβ沸石。
文摘A unique templating approach for the synthesis of hexagonal mesoporous aluminosilicates via self assembly of pre formed aluminosilcate nanoclusters with the templating micella formed by cetyltrimethylammonium bromide (CTAB) is described. The obtained materials of MAS 5 are hydrothermally stable, which is shown by X ray diffraction (XRD) analysis. Furthermore, as characterized by NMR technique, MAS 5 has stable tetrahedral aluminum sites that is the major contributions to the acidity of aluminosilicate molecular sieve, and on non framework aluminium species in the samples was observed.
基金Project supported by the National Key Fundamental Research and Development Projects of China (No. G1999022402).
文摘Several 2.0 wt% nickel catalysts supported on nanometer bimodal mesoporous aluminosilicate (NBMAS), AlHMS and AlMCM-41 were prepared by means of the wetness impregnation method. The characterization tech-niques such as Py-FTIR and H2 chemisorption showed that the amount of Br鰊sted acid sites decreased in the order of Ni/AlHMS>Ni/AlMCM-41>Ni/NBMAS, while the nickel dispersion differed a little. In the catalytic n-dodecane hydroconversion, the highest conversion was obtained over Ni/NBMAS, and the lowest isomerization selectivity occurred over Ni/AlHMS. For the cracked products, the symmetrical carbon number distribution cen-tered at C6 was obtained on the Ni/AlMCM-41 catalyst due to the well balanced metal/acid functions, whereas the Ni/AlHMS and Ni/NBMAS catalysts led to more C3-C5 and C1+C11 products, respectively.
基金the National Natural Science Foundation of China (Nos. 29825108, 20173022 and 20121103), the Major State Basic Research Development Program (No. 20000077507) and the National Advanced Materials Committee of China.
文摘The acidic strength of ordered mesoporous aluminosilicates of MAS-2, MAS-3, MAS-7 and MAS-9 and mi-croporous crystals of Y, L, beta, and ZSM-5 zeolites was systemically investigated by temperature-programmed desorption of ammonia (NH3-TPD). Due to the use of preformed zeolite precursors of Y, L, beta and ZSM-5, the ordered mesoporous aluminosilicates with distinguished acidic strength were obtained, being dependent on the type of preformed zeolite precursors. Therefore, the acidic strength of these mesoporous aluminosilicates could be tai-lored and controlled.
