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Abstract: Sulfonic acid functionalized mesoporous SBA-15 catalysts have been studied in the microwave-assisted transesterification of soybean oil with 1-butanol in order to produce low freezing point biodiesel. Small-angle powder XRD and nitrogen adsorption analysis revealed the formation of mesoporous materials with high surface area and uniform porosity. Catalytic activity was found to be largely dependent on the acid strength rather than the number of acid sites. Propyl-SO3H and arene-SO3H functionalized SBA-15 catalysts showed high activity and stability in transesterification reactions whereas perfluoro-SO3H functionalized SBA-15 catalyst exhibited a complete loss of activity after recycling due to complete leaching of perfluoro-SO3H groups in the reaction medium. The results over arene-SO3H functionalized catalysts showed that the optimal loading of arene-SO3H groups is approximately 15% (molar percent of functional group to total silicon) and the optimal oil to alcohol molar ratio is 1:6. Increases in catalyst to oil weight ratio and reaction temperature significantly enhance the reaction rates. Simultaneous transesterification and esterification of soybean oil with up to 20 wt% oleic acid over arene-SO3H functionalized catalyst indicated that this catalyst could be a promising candidate for processing low quality feedstocks containing high fraction of free fatty acids. Further modification of Ar-SO3H SBA-15 catalyst with hydrophobic groups did not significantly improve its catalytic performance. [Copyright &y& Elsevier]

Abstract: Cerium-doped MCM-41 (Ce-MCM-41) was prepared by a hydrothermal method and its catalytic activity for ozonation of p-chlorobenzoic acid (p-CBA) in aqueous solution was studied. For comparison, cerium-loaded MCM-41 (Ce/MCM-41) was prepared by a dipping method. Ce-MCM-41 was characterized by the low and wide angle X-ray powder diffraction (XRD), nitrogen adsorption–desorption, transmission electron microscopy (TEM) and ultraviolet–visible diffuse reflection spectrum (UV–vis DRS). The results showed that the material retained the highly ordered mesopore structure of MCM-41 and had a surface area of 852m2 g−1. Cerium was incorporated into the framework of MCM-41, locating at tetrahedrally coordinated sites. The cerium doping content, initial pH of aqueous solution and reaction temperature played important roles in catalytic ozonation of p-CBA. Under the chosen conditions (1.39mgl−1 ozone dosage, 10mgl−1 p-CBA solution and 1gl−1 catalyst dosage), the high mineralization rate (86%) was achieved by Ce-MCM-41/O3 process at 60min reaction time, only 52% by O3 alone. The combination of Ce-MCM-41 and O3 exhibited a significant synergetic effect. Ce-MCM-41 showed the better activity and stability than cerium-loaded MCM-41(Ce/MCM-41) during catalytic ozonation of p-CBA, its cerium leaching was greatly reduced (only 0.085mgl−1) and below detection limit after being reused, compared with that of Ce/MCM-41 (0.44mgl−1) with the presence of the same theoretical cerium content. TOC removal rate slightly decreased from 86% to 81% and kept stable after Ce-MCM-41 being re-utilized two times, which illustrated that Ce-MCM-41 was a kind of promising catalyst for ozonation of p-CBA. The addition of Ce-MCM-41 significantly improved ozone decomposition into HOus solution and reduced ozone concentration in equilibrium. [Copyright &y& Elsevier]

Abstract: Santa Barbara Amorphous (SBA-15) mesoporous materials decorated with vary amount of TiO2 (7–31% TiO2/SBA-15) were prepared by the post-synthesis method from previously synthesized SBA-15 and their photocatalytic activity toward the degradation of methylene blue (MB) was measured. Nonionic surfactant was used as liquid template and tetraethyl orthosilicate (TEOS) as SiO2 precursor for the synthesis of mesoporous silica SBA-15. The synthesized x% TiO2/SBA-15 materials were characterized by N2 adsorption–desorption isotherms, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), micro-Raman spectroscopy, infrared spectroscopy of framework vibration (IR-KBr) and X-ray photoelectron spectroscopy (XPS). The x% TiO2/SBA-15 photocatalysts were found to be more active than pure anatase titania and this increase was linear with TiO2 loading. The highest activity of 31% TiO2/SBA-15 sample was explained in terms of the combined factors such as a high crystallinity of anatase phase, preservation of a high surface area, a large amount of the surface hydroxyl groups, and a larger accessibility of photo-oxidative sites. A linear correlation between the apparent first order rate constants (k app) and the amount of TiO2 species located within porous structure of the SBA-15 substrate was found. [Copyright &y& Elsevier]

Abstract: This article presents preparation, characterization and evaluation of heterogeneous Titanium based alumina mesoporous silica catalysts for the photo degradation of chlorophenols in aqueous solution. For more economic application, a series of silica, Al2O3–SiO2 and TiO2–Al2O3–SiO2 are prepared using linear alkylbenzene sulfonic acid as a novel structure directing agent. Two Ti–Al–SiO2 samples were prepared by direct synthesis using different titanium sources. The prepared samples are characterized by combination of various physicochemical techniques, such as XRD, N2 physisorption, FT-IR, UV–vis, SEM and TEM. The prepared mesoporous materials are applied in the presence of UV irradiation for photodegradation of chlorophenols as pollutants in water. The results reveal that the photodegradation process of 4-chlorophenol (4-CP) is completed within 40min, while reach 67.3% for 2-chlorophenol (2-CP) within 130min. Moreover, the titanium precursor species and the catalyst dosage (0.1–0.4g/l) affect the photocatalytic activity of prepared catalysts for 2-chlorophenol degradation. Finally, the concentration of acetate and chloride ions formed during the degradation process can also affect the activity of the prepared catalysts. [Copyright &y& Elsevier]

Abstract: Destruction of chlorinated aromatic compounds was carried out over mesoporous Cu x Mg1−x Al2O4 spinel oxides with x =0, 0.2, 0.5 and 0.8, which were prepared by the coprecipitation method. All the catalyst samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption–desorption isotherms. The performances of these catalysts on the decomposition of hexachlorobenzene (HCB) and the catalytic formation of polychlorinated dibenzodioxin and dibenzofuran (PCDD/F) were evaluated in a closed system. The activities of these catalysts for dechlorination of HCB increased with increasing the magnesium content in them. The Cu0.2Mg0.8Al2O4 presented a higher catalytic activity for the hydrodechlorination of HCB than CuO, Al2O3, as well as the other Cu x Mg1−x Al2O4 spinels. More than 99% dechlorination efficiency of HCB was achieved at low temperatures (≤300°C) for a short time (30min) under air atmosphere over Cu0.2Mg0.8Al2O4 spinel. In comparison to air atmosphere, nitrogen atmosphere seemed to be more beneficial for the dechlorination of HCB with a dechlorination efficiency of 90% at 250°C for 10min. For the Cu0.2Mg0.8Al2O4 catalyst, the I-TEQ of PCDD/F formed was 4.5pg/g, far below the value of 15122.5pg/g on CuO. The Cu0.2Mg0.8Al2O4 catalyst inhibited the chlorination reaction and enhanced the dechlorination reaction. The catalytic behavior including catalytic dechlorination of HCB and catalytic formation of PCDD/F related to the physical characteristics of Cu x Mg1−x Al2O4 spinel was discussed. [ABSTRACT FROM AUTHOR]

Abstract: The catalytic upgrading of pyrolytic vapors derived from radiata pine sawdust was carried out over mesoporous MFI zeolite synthesized using an amphiphilic organosilane. Its catalytic activity was compared with those of conventional HZSM-5 and mesoporous material from HZSM-5 (MMZZSM-5). The effect of gallium incorporation into mesoporous MFI zeolite on the product distribution and chemical composition of bio-oil was also investigated. The catalysts synthesized were characterized using ICP, XRD, N2-sorption, NH3-TPD, and H2-TPR methods. After catalytic upgrading, products were analyzed by GC–TCD, GC–FID, GC–MS, and Karl Fischer titration. The mesoporous MFI zeolite exhibited the best activity in deoxygenation and aromatization during the upgrading of pyrolytic vapors. In particular, mesoporous MFI zeolite showed high selectivity for highly valuable aromatics, such as benzene, toluene, and xylenes (BTX), even though it decreased the overall organic fraction of the bio-oil. The incorporation of gallium into the mesoporous MFI zeolite increased both the organic fraction of the bio-oil and resistance to coke deposition. Moreover, the selectivity for BTX aromatics was enhanced when the appropriate amount of gallium was introduced. [Copyright &y& Elsevier]

Abstract: The nickel active sites were introduced into TUD-1 mesoporous molecular sieve via grafting, direct synthesis, and impregnation methods. These samples were characterized using powder X-ray diffraction, N2 physisorption, H2 temperature-programmed reduction, H2 chemisorption, TG/DTA, temperature-programmed hydrogenation, Raman spectra and transmission electron microscope to give the insight of physicochemical properties. Catalytic tests probed by the carbon dioxide reforming of methane revealed that Ni-grafted TUD-1 exhibited the highest catalytic activity and long-term stability among these catalysts. Further studies implied catalytic activity, stability and carbon formation were highly sensitive to the metallic nickel particle size which was significantly affected by the introduction method of Ni active sites. Strong anchoring effect inherent to the grafting method was suggested to be the underlying reason for the small Ni particle size and improved catalytic performance. [Copyright &y& Elsevier]

Abstract: Nanotitania supported on mesoporous silica systems were synthesized by a reliable procedure based on an incipient wetness impregnation post-synthetic approach. Characterization by X-ray diffraction, N2 physisorption, TEM, X-ray photoelectron spectroscopy, ICP has been carried out in order to investigate the chemical–physical properties of the catalysts with particular attention to the chemical nature of the titanium species. The photocatalytic activity of the samples was evaluated for the degradation of NOx in the gas phase. The influence of both the textural properties and the nature of titanium species on the photocatalytic activity is discussed. [Copyright &y& Elsevier]