Direct synthesis and characterization of LaSBA-15 mesoporous molecular sieves

Luz, Geraldo E.; Lima, Stevie H.; Melo, Ana C. R.; Araújo, Antônio S.; Fernandes, Valter J.

doi:10.1007/s10853-009-4054-y

Cited by 23 publications

(5 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4(a-d) All samples exhibited a typical irreversible type-IV adsorption/desorption isotherm with a H1 hysteresis loop, as defined by the International Union of Pure and Applied Chemistry (IUPAC) [70]. These isotherm profiles are typical features of mesoporous materials with cylindrical pores, like the SBA-15 [43,44], and are in agreement with XRD results. Furthermore, indicate that TiO 2 nanocrystals employing by in-situ anchoring (ISA) method did not block the mesoporous of SBA-15 matrix.…”

Section: Micro-ramam Spectrocopy Analysessupporting

confidence: 77%

“…The preparation conditions of mesoporous SBA-15 using direct synthesis method with pH adjustment have been reported in our previous papers [43,44]. A typical synthesis method of pure SBA-15 matrix is described as follows: 4 g of amphiphilic triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol), Pluronic P123 (average molecular weight 5800), 97% purity (Sigma-Aldrich), was dissolved in 148.3 mL of hydrochloric acid (HCl − Vetec) solution (pH < 0.1) under stirring for 2 h at 40 • C. In the sequence, 8.8 mL of tetraethyl orthosilicate (TEOS), 98% purity (Sigma-Aldrich), was added to initial mixture, which was maintained at 40 • C for 24 h under constant stirring.…”

Section: Synthesis Of Pure Sba-15 Matrixmentioning

confidence: 99%

See 1 more Smart Citation

Anatase TiO2 nanocrystals anchored at inside of SBA-15 mesopores and their optical behavior

Araújo

Silva

Sczancoski

et al. 2016

Applied Surface Science

View full text Add to dashboard Cite

In this paper, a new synthesis method was proposed to obtain anatase titanium oxide (TiO 2) nanocrystals anchored into SBA-15 molecular sieve, as a matrix assigned by the in-situ anchoring (ISA) method. Pure SBA-15 and modified with TiO 2 nanocrystals at different Si/Ti molar ratios (R = 75, 50, and 25) were structurally characterized by X-ray diffraction (XRD), Micro-Raman and Fourier Transform infrared (FTIR) spectroscopies. Specific surface area, pore volume and average pore diameter were estimated using both Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods, respectively. Morphological aspects of these samples were observed by means of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Optical properties were investigated by ultravioletvisible (UV-vis) diffuse reflectance spectroscopy. XRD patterns, Micro-Raman and FT-IR spectra indicate the TiO 2 nanocrystals crystallized in a tetragonal structure anchored into the SBA-15 mesopores. BET and BJH methods prove a large amount of TiO 2 nanocrystals were anchored inside of SBA-15 mesopores due to increase in surface area and average pore size of SBA-15 matrix. FE-SEM and TEM images showed the pure SBA-15 has an elongated hexagon-shaped microstructure, and an average size of 7.34 nm for 2D hexagonal mesopores. Moreover, ISA method was able to avoid blocking of mesopores, in addition promotes a significant increasing the impregnation rate of anatase TiO 2 nanocrystals in SBA-15 matrix. A growth mechanism was proposed in order to explain the stages involved in the formation of TiO 2-SBA mesoporous. UV-vis spectra revealed a dependence of the optical band gap energy (E gap) with the decreasing of Si/Ti molar ratios.

show abstract

Section: Micro-ramam Spectrocopy Analysessupporting

confidence: 77%

Section: Synthesis Of Pure Sba-15 Matrixmentioning

confidence: 99%

Anatase TiO2 nanocrystals anchored at inside of SBA-15 mesopores and their optical behavior

Araújo

Silva

Sczancoski

et al. 2016

Applied Surface Science

View full text Add to dashboard Cite

show abstract

“…In this context, in order to obtain a biocatalyst with high catalytic performance, it is necessary to immobilize it on a support that possesses as main characteristics: insolubility in water, high porosity or high surface area, inertness to the enzymatic activity and the reaction, thus providing the biocatalysts with the desired kinetic, mechanic and biochemical properties [18][19][20]. Among the several available supports, potential importance has been given to the exploitation of inorganic materials, as SBA-15 (Santa Barbara Amorphous), which has mesopores hexagonally ordered and interconnected by micropores that enables the accommodation or diffusion of large molecules, which gives this material vast applicability in the area of catalysis [21,22] and adsorption [23][24][25]. In addition, SBA-15 can be functionalized via silane derivatives followed by activation with several compounds.…”

Section: Introductionmentioning

confidence: 99%

“…Following our earlier publications [24,31] in the present work, SBA-15 was prepared, characterized and tested as support to immobilize Burkholderia cepacia lipase by two different procedures (covalent linkage and physical adsorption). The effect of the immobilization procedure on the biocatalyst activity was assessed in the synthesis of biodiesel from palm kernel oil.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Procedure to Immobilize Lipase on SBA-15 for Biodiesel Production from Palm Kernel Oil

et al. 2021

View full text Add to dashboard Cite

Microbial lipase from Burkholderia cepacia was immobilized by covalent bond and physical adsorption on SBA-15 mesoporous support and its catalytic efficiency was measured in the formation of fatty acids ethyl esters from palm kernel oil. The immobilized biocatalyst and its support were characterized by X-ray Diffraction, Fourier Transform Infrared Spectroscopy, N 2 Adsorption-desorption, and thermal analysis TG/DTG. The immobilization of the enzyme onto the support maintained the typical structure of the SBA-15. From the TG measurements, it can be deduced that about 25% of lipase was immobilized in SBA-15 via covalent bond and 15% was incorporated via physical adsorption. Both immobilized lipase preparations were used to perform the transesterification reactions using different oil: ethanol molar ratios and time. The biocatalyst prepared by physical adsorption promoted better results, measured by the apparent yield (> 90%) and conversion (98.9%) in all reactions, which were also confirmed by viscosity and density data. The regeneration of SBA-15 support was found to be feasible and demonstrated efficiency for 5 times, reducing the associated costs of the process.Luiz Di Souza-In memoriam.

show abstract

“…Despite of the interest of the scientific community and researches accomplished, the functionalization of SBA-15 is challenging task because the heteroatoms can be introduced into the silica wall by replacing Si 4+ , within the mesopores or on the outer surface and modify the original properties of the support [15]. Literature report several methods of SBA-15 functionalization such as: direct synthesis or "one pot" procedure [25,[38][39][40][41], wetness impregnation [40,[42][43][44], deposition-precipitation (DP) [45][46][47], graft hybrid (GH) [48,49], colloid immobilization (CI) [50][51][52][53], nanoparticles encapsulation (NE) [54,55]. We briefly reviewed already mentioned methods of SBA-15 functionalization, because it is are the most reported in the literature, to verify if such methods are satisfactory or if we need of new functionalization method/strategies.…”

Section: Introductionmentioning

confidence: 99%

Functionalization methods of SBA-15 mesoporous molecular sieve: a brief overview

et al. 2019

View full text Add to dashboard Cite

SBA-15 molecular mesoporous sieve has attracted great interest of researchers since its discovery in 1998, owing large area surface, well-defined pores, uniform pore size, high thermal and hydrothermal stability, well-defined pore structure and ability to be functionalized with diverse metal oxides (active phase of catalyst). This work contains a brief review of the main SBA-15 functionalization methods: direct synthesis, post-synthesis or post-grafting, deposition-precipitation, graft hybrid, colloid immobilization and nanoparticle encapsulation showing the advantages and disadvantages of each. We also approach some synthetic strategies to overcome the shortcomings of the mentioned methods, as well as some parameters to choose the best method. Here, we showed that these methods don't provide the functionalization of SBA-15 keeping all the peculiar properties of support and that the new strategies or alternatives routes are important to overcome some challenges of the functionalization of SBA-15. This is a challenging point that needs to be further explored by promoting greater advances in materials science and catalysis.

show abstract

Direct synthesis and characterization of LaSBA-15 mesoporous molecular sieves

Cited by 23 publications

References 26 publications

Anatase TiO2 nanocrystals anchored at inside of SBA-15 mesopores and their optical behavior

Anatase TiO2 nanocrystals anchored at inside of SBA-15 mesopores and their optical behavior

Influence of the Procedure to Immobilize Lipase on SBA-15 for Biodiesel Production from Palm Kernel Oil

Functionalization methods of SBA-15 mesoporous molecular sieve: a brief overview

Contact Info

Product

Resources

About