Papers by Keyword: SBA-15

Abstract: In this study, we report the functionalization of imidazolium-based ionic liquids (ImIL) onto mesoporous silica SBA-15 nanomaterial with a larger surface area of 737.96 m²/g and an interpore distance of 10.68 nm. Imidazolium-based ionic liquids, 1-(3-triethoxysilylpropyl)-methylimidazolium chloride was functionalized with concentration of 1.0, 2.0, 4.0, 6.0, 8.0 and 10.0 mmol onto SBA-15 via a sol-gel method to obtain xImIL-SBA-15 nanocomposites. Small-angle X-ray scattering (SAXS), N₂ adsorption/desorption analysis and field emission scanning electron microscopy (FESEM) were used to characterize the ImIL-SBA-15 nanocomposites. SAXS patterns of ImIL-SBA-15 nanocomposites possessed (1 0 0), (1 1 0) and (2 0 0) diffractions respectively, which indicated that the well-ordered hexagonal mesostructure of SBA-15 support remained intact after functionalization of ImIL. The total surface area, total pore volume and BJH pore size distribution of all ImIL-SBA-15 nanocomposites decreasing with the increasing amount of ImIL from 393.27 to 354.39 m²/g which indicated that the pore channel and/or surface of SBA-15 were occupied by ImIL without significant reduction of the quality. It was found that the grafted amount of ImIL on SBA-15 nanocomposites increased from 0.60 to 0.97 mmol/g when amount of ImIL content in the mixture was increased from 1.0 to 10.0 mmol. FESEM micrographs showed a similar pattern as SBA-15 indicating that the mesoporous hexagonal structure of SBA-15 was still retained. Thus, it can be concluded that xImIL-SBA-15 nanocomposites was successfully synthesized by functionalization of ImIL onto mesoporous silica SBA-15.

Abstract: SBA-15 was modified with strontium before being functionalized with HPW acid to investigate its performance and stability in the glycerolysis of lauric acid. The physical and chemical characteristics of the catalyst were analyzed using Fourier Transformed Infrared (FTIR), Scanning Electron Morphology (SEM), BET surface analysis, Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). The collective evidence and finding from material characterizations, including the successfully formed and retained SBA-15 mesopores after modification twice, SrO formation and disappearance, post-SrO modification and HPW incorporation, respectively, further strengthen the claim of the strong anchoring of HPW onto the SBA-15 via the strontium-salt bridge. The reusability of the lauric acid conversion was also evaluated. The superior stability of the synthesized catalyst (HPW/SrSBA-15) was demonstrated with minimal to no change in both lauric acid conversion (75.34%) and monolaurin yield (38.9%). Such a result was attributed to the good interaction between HPW and SBA-15 via strontium modification and proved that the catalyst does not undergo severe deactivation and showed good catalytic activity in recycled use.

Abstract: Ordered carbon was prepared via nanocasting method with Santa Barbara Amorphous (SBA)-15 as the template and sucrose as the carbon precursor. The ordered carbon surface was then modified with oxygen and nitrogen species to alter its chemical and physical properties. All surface-modified ordered carbon samples were evaluated using nitrogen adsorption-desorption analyser and electrochemical impedance spectroscopy. Post modifications, the KOH electrolyte ion transportation are affected due to significant change in the ordered carbon structural properties.

Abstract: Molecular sieves have been applied to the triacylglycerides processing in the production of biodiesel through transesterification reaction. The purpose of obtain a material that has characteristics favorable to higher biodiesel conversion, this paper aims to synthesize molecular sieves SBA-15 and Al-SBA-15 on two reasons Si/Al (Si/Al= 10 and 100) evaluated in the transesterification reaction of soybean oil and investigate the potential of Si/Al ratios in the reaction over the acid each material. The catalysts were prepared by conventional hydrothermal method by varying the composition of the aluminum consequently altering the acidity of the material, since this reaction takes place in acid medium. The samples were characterized by X-Ray Diffraction (XRD), scanning electron microscopy (SEM), Spectroscopy in the infrared region by Fourier transform (FTIR). The results of the characterization of the catalysts have shown that the materials were successfully obtained, from the characterization observed. The biodiesel syntheses were conducted with soybean oil using ethyl alcohol 12: 1 relative to the oil and 5% of catalyst in the reactor with autogenous pressure. Were realized viscosity analyzes as conversion parameter of the vegetable oil into biodiesel. From the results of biodiesel viscosity was obtained a yield of 13% on average by using the Al-SBA-15. However, even not have remained within the specifications the standards of the National Petroleum, Natural Gas and Biofuels, catalysts showed efficiency compared with the SBA-15 in biodiesel synthesis.

Abstract: The high interest in the synthesis of mesoporous catalyst demands that novel materials are developed with simple methods capable of improving process yields. In this work, a novel heterogeneous mesoporous catalyst support has been synthesized using mesoporous SBA-15 loaded with mixed bimetal oxides of CeO₂ and MgO. Formation of the SBA-15 was actuated in air at room temperature (25°C) and in oven conditions at 100°C after which cerium nitrate and magnesium nitrate precursors were then impregnated into the SBA-15 framework and calcined at 550°C for each of the air and oven crystallization processes. XRD peak patterns confirmed SBA-15 formation and dispersion of nanocrystallites of CeO₂ and MgO within the porous framework of SBA-15. Both the air and oven dried processes produced mesoporous MgO-CeO₂/SBA-15 catalysts with isotherms that exhibit typical H1 type hysteresis confirming that they possess open-ended cylindrical mesopores. The structural data extracted gave average pore size, pore volume and surface area values in the ranges of 3-5.2 nm, 0.600-2.500 cc/g and 400-500 m²/g respectively which is ideal for several industrial applications.

Abstract: Fe-SBA-15 materials with different Fe content have been prepared using tetraethyl orthosilicate (TEOS) and iron nitrate (Fe (NO₃)_3·H₂O as precursors and Pluronic P123 as structure directing agent through evaporation-induced self-assembly (EISA) method. The materials were characterized by nitrogen sorption, powder X-ray diffraction and TEM. All the Fe-SBA-15 samples appeared ordered 2D hexagonal mesostructure. The BET surface area and pore diameter were about 500 m²/g and 4 nm respectively. In the reaction of phenol hydroxylation to dihydroxybenzenes, the Fe-SBA-15 materials showed good catalytic activity, giving 20.2% of phenol conversion, 58.2% of selectivity for o-dihydroxy benzene and 41.8% of selectivity for p-dihydroxy benzene. After five cycles, the product yield was 25.2%, while selectivities of o-dihydroxy benzene and p-dihydroxy benzene were 58.2% and 41.8%, respectively. All these findings indicated the potential of Fe-SBA-15-10 could be used as a cost-effective, environment-friendly catalyst.

Abstract: Activated carbon (AC), the KOH-modified activated carbon (KAC) and mesoporous material SBA-15 before and after pore expansion (SBA-15k) were modified using triethylenetetramine (TETA) and tetraethylenepentamine (TEPA) as modifiers. The CO₂ adsorption capacities of adsorbents were determined by thermogravimetric method. The results show that at 60 °C and the atmosphere of 15% CO₂ (volume fraction), with the increasing of amine loading amount, the CO₂ adsorption capacities of AC and KAC decreased gradually. While those of SBA-15 and SBA-15k increase at first stage and decrease subsequently. Cyclic CO₂ adsorption capacities and mass of the adsorbents show no obvious changes, so the adsorbents have excellent stability.

Abstract: The mesoporous silica SBA-15 molecular sieve has been widely studied due to its unidirectional mesoporous structure, its high average pore diameter, its high thermal and hydrothermal stability and its ability to absorb metal ions, allowing its use as support material for catalysts. This study aimed to synthesize the Co/SBA-15 catalyst, and characterize it through the techniques of X-ray diffraction, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The SBA-15 support was synthesized from the following molar composition of reaction mixture: 1TEOS: 0.017 P123: 5.7 HCl: 173 H2O: 40 EtOH, and after calcined at 550 °C for 6 hours. The Co/SBA-15 catalyst was prepared by incorporating 10% cobalt by wet impregnation. Through the X-ray diffractograms, it was found that the impregnation has not changed the structure of the material. RTP profiles showed the presence of peaks at different temperatures that may be caused by dispersion of the cobalt.

Abstract: Silica glass was prepared via the spark plasma sintering (SPS) method by using SBA-15 as the starting material. Five temperatures (1000, 1010, 1020, 1030 and 1040°C) were selected as the final sintering temperature above 600°C. The transparent silica glass was prepared by SPS sintering of mesoporous silica SBA-15 at 1040°C. The impact of temperature structure collapse of SBA-15, the structure and transmittance of the glass were studied using X ray diffraction, SEM, TEM, Infrared analysis, Raman analysis and UV-VIS spectrophotometer. Results show that SBA-15 collapsed completely at 1040°C, the sintered glass had high transmittance of above 90% in visible spectra, and its hardness was 6.96 Gpa, and that the sintered transparent sample was silica glass. The work demonstrated a novel strategy to use SPS to prepare highly transparent silica glass by sintering of SBA-15.

Abstract: A graphitic mesoporous carbon-based material (GMC) was prepared using a nano-casting process by using SBA-15 as a hard template and sucrose as a carbon precursor. Modification of GMC was carried out by chemical oxidation with nitric acid in order to generate surface functionalities. The oxidized GMC material was then used as adsorbent for Basic Red 2 (BR2) in aqueous solutions. The morphology, pore structure, and surface functional groups of GMC samples were evaluated by field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller method (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Boehm titration. N2 adsorption-desorption analysis revealed a type IV isotherm characteristic of mesoporous materials with BET surface area approximately 1000 m2g-1 and pore volume 0.9 cm3g-1. The effects of different adsorption parameters such as initial pH, initial dye aqueous solution concentration and temperature on BR2 removal were investigated. After modification, the BET surface area slightly decreased but the adsorption capacity of BR2 increased with optimum adsorption in 200 ppm initial concentration, pH of 10 at 60 °C.