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Modified mesoporous SBA-15 silica materials (G-SBA-IDA, G-SBA-EDTA and G-SBA-DTPA) (where IDA, EDTA and DTPA represent iminodiacetic acid, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, respectively) were prepared by treatment of grafted monoamine or diamine or triamine mesoporous SBA-15 silica (G-SBA-N, G-SBA-NN , G-SBA-NNN) nanomaterials with ethylchloroacetate, followed by acid hydrolysis of ester groups. These materials were characterized by several techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), small angle X-ray scattering (SAXS), thermal analysis (TGA) and X-ray photoelectron spectroscopy (XPS). TEM and BET analysis revealed that the IDA functionalized amine mesoporous SBA-15 silica materials have maintained their mesostructure after modification of the amine mesoporous silica with ethylchloroacetate. Thermal analysis (TGA-DTA) and FTIR confirmed that ethylchloroacetate groups are covalently bound to the amine groups. The acid forms of IDA functionalized materials showed high potential for extraction and removal of heavy pollutant metal ions (Co 2+ , Ni 2+ , Cu 2+ and Pb 2+ ) from aqueous solutions.

In this work, a novel heterogeneous catalyst consisting of peroxophosphotungstate, microporous MOF-808, and mesoporous SBA-15 was synthesized, characterized, and used to remove sulfides from model fuel. The prepared material, PW4@MOF-808@SBA-15, exhibits excellent catalytic activity with a desulfurization efficiency of 99.8% in 60 min for multicomponent simulated fuel, and the desulfurization rate can reach more than 90% after ten consecutive cycles. The excellent catalytic activity and reusability are attributed to the hierarchically porous hybrid material MOF-808@SBA-15, which can effectively encapsulate PW4 and provide a site for the oxidation of sulfides.

A new series of binary and ternary nanocomposites contains cobalt oxide or iron/cobalt oxides were manufactured to increase silicon dioxide shielding power. XRD indicated the presence of Co as Co 2.74 O 4 (COD: 1528446) and the presence of iron as Fe 3 O 4 (COD: 9002318 and 9005814). Using Profex, the Rietveld refinements were carried out. The R w , R ex , x 2 , and G of were 4.49, 4.34, 1.07, and 1.03, respectively, indicating good refinement parameters. XPS indicated the presence of Si ( ), Fe (Fe O ) and cobalt ( and ). TEM analysis showed that all metal oxide@SBA-15 solids have characteristic and well-organized SBA-15 structures. The -radiation shielding for the prepared samples were investigated via the Monte-Carlo code (MCN) and Phy-X software. The results confirmed that, adding high concentrations of cobalt-oxide and hematite increases the linear attenuation significantly. The SiCoFe-3 sample, which contains the highest content of cobalt-oxide and hematite, has the best -radiation shielding capability among all the synthesized SiCo/SiCoFe samples.

This study investigated the removal of a typical organic pollutant methylene blue (MB) dye from wastewater by a prepared mesoporous SBA-15 adsorbent in a continuous adsorption system (fixed-bed column). The structural and textural properties of the SBA-15 adsorbent were determined using different characterization techniques. The adsorption of continuous system experiments assessed the bed height effect, initial concentration, and flow rate on a breakthrough curve. The kinetic constants and breakthrough curves were obtained using the Thomas and Yan models. The breakthrough results revealed that SBA-15 has an excellent adsorption efficiency for use in the continuous adsorption system. The findings explain that MB removal achieved the maximum uptake (84 mg/g) at 6 cm of bed height, 0.5 mL/min of flow rate, and 30 mg/L initial concentration of MB. SBA-15 can be efficiently regenerated by calcination and re-employed 5 times in a fixed-bed system without a significant loss in its adsorption capacity of MB from MB solutions. As a result, SBA-15 was determined as the appropriate media to be adsorbent for MB. This study suggests that the prepared SBA-15 is feasible to use effectively for MB removal from the wastewater.

The immobilization of Hoveyda–Grubbs form of metathesis catalyst ( Z.C .) exhibited simple non-covalent interactions with the mesoporous SBA-15. It was discovered that the Z.C . catalyst worked well to speed up the citronellene ring closing metathesis reaction. Using cyclohexane as a solvent, the citronellene ring closing metathesis reaction was performed at various temperatures. A very low (almost negligible) catalyst leaching was observed. A high turnover number (TON) was obtained by using a very small amount of catalyst. The activation energy was calculated in the case of ring closing metathesis reaction of citronellene at different temperatures. By using the high concentration of citronellene, a high TON was obtained (4674), which indicates that active catalytic centers were not demolished by a large concentration of citronellene molecule. Turnover number (264) was produced when the Ru/substrate molar ratio 1:300 used in the reaction. Graphical abstract

This study reports the synthesis and thorough characterization of a novel copper catalyst immobilized on magnetic mesoporous silica (Fe 3 O 4 @SBA-15). The catalyst preparation involved stepwise functionalization of Fe 3 O 4 @SBA-15 through sequential treatment with (3-aminopropyl)triethoxysilane (APTES), trichlorotriazine, and 2-(2-pyridyl)benzimidazole, resulting in Fe 3 O 4 @SBA-bis(PBI). Subsequent coordination with CuI in acetonitrile produced the final catalyst complex, Fe 3 O 4 @SBA-bis(PBI)-Cu. Extensive characterization was performed using standard spectroscopic techniques. The copper content of the catalyst was determined by atomic absorption spectroscopy to be 0.866 mmol g −1 (5.5 wt%). Catalytic performance evaluation demonstrated that Fe 3 O 4 @SBA-bis(PBI)-Cu effectively catalyzes the conversion of iodo-, bromo-, and chloroarenes to their respective anilines, using NaN 3 as the nitrogen source. Notably, the catalyst exhibited excellent recyclability, maintaining catalytic activity over six successive cycles with minimal deactivation, highlighting its robustness and suitability for sustainable catalytic applications in organic synthesis. The low metal leaching (0.4%) shows that the copper is firmly bound to the ligand, and the reaction was mainly carried out by a heterogeneous catalyst.

Abstract Enzymes immobilized onto substrates with excellent selectivity and activity show a high stability and can withstand extreme experimental conditions, and their performance has been shown to be retained after repeated uses. Applications of immobilized enzymes in various fields benefit from their unique characteristics. Common methods, including adsorption, encapsulation, covalent attachment and crosslinking, and other emerging approaches (e.g., MOFs) of enzyme immobilization have been developed mostly in recent years. In accordance with these immobilization methods, the present review elaborates the application of magnetic separable nanoparticles and functionalized SBA-15 and MCM-41 mesoporous materials used in the immobilization of enzymes. Resumo Enzimas imobilizadas em substratos com excelente seletividade e atividade apresentam alta estabilidade e podem suportar condições experimentais extremas, e seu desempenho foi mantido após repetidos usos. As aplicações de enzimas imobilizadas em vários campos se beneficiam de suas características únicas. Métodos comuns, incluindo adsorção, encapsulamento, ligação covalente e reticulação, e outras abordagens emergentes (por exemplo, MOFs) de imobilização de enzima, foram desenvolvidos principalmente nos últimos anos. De acordo com esses métodos de imobilização, a presente revisão elabora a aplicação de nanopartículas magnéticas separáveis e materiais mesoporosos funcionalizados SBA-15 e MCM-41 usados na imobilização de enzimas.

Mesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses.Graphic Abstract

The interaction and nature of surface sites for water and methanol sorption on MFI-type zeolites and mesoporous SBA-15 were investigated by solid-state NMR spectroscopy and correlated with the desorption enthalpies determined via TGA/DSC. For siliceous Silicalite-1, 29Si CPMAS NMR studies support stronger methanol than water interactions with SiOH groups of Q3-type. On siliceous SBA-15, SiOH groups of Q2-type are accompanied by an enhanced hydrophilicity. In aluminum-containing Na-ZSM-5, Na+ cations are strong adsorption sites for water and methanol as evidenced by 23Na MAS NMR in agreement with high desorption enthalpies of ΔH = 66–74 kJ/mol. Solid-state NMR of aluminum-containing Na-[Al]SBA-15, in contrast, has shown negligible water and methanol interactions with sodium and aluminum. Desorption enthalpies of ΔH = 44–60 kJ/mol hint at adsorption sites consisting of SiOH groups influenced by distant framework aluminum. On H-ZSM-5, Brønsted acidic OH groups are strong adsorption sites as indicated by partial protonation of water and methanol causing low-field shifts of their 1H MAS NMR signals and enhanced desorption enthalpies. Due to the small number of Brønsted acid sites in aluminum-containing H-[Al]SBA-15, water and methanol adsorption on this material is suggested to mainly occur at SiOH groups with distant framework aluminum species, as in the case of Na-[Al]SBA-15.

Improvement of the bioavailability of poorly soluble medicinal substances is currently one of the major challenges for pharmaceutical industry. Enhancing the dissolution rate of those drugs using novel methods allows to increase their bioavailability. In recent years, silica-based mesoporous materials have been proposed as drug delivery systems that augment the dissolution rate. The aim of this study was to analyse the influence of phenylbutazone adsorption on SBA-15 on its dissolution rate. Moreover, we examined the cytotoxicity of the analyzed silica. The material was characterized by SEM, TEM, DSC, 1H-NMR, XRD, and FT-IR. The phenylbutazone did not adsorb on unmodified SBA-15, while the adsorption on APTES-modified SBA-15 resulted in 50.43 mg/g of loaded phenylbutazone. Phenylbutazone adsorbed on the APTES-modified SBA-15 was then released in the hydrochloric acidic medium (pH 1.2) and phosphate buffer (pH 7.4) and compared to the dissolution rate of the crystalline phenylbutazone. The release profiles of the amorphous form of adsorbed phenylbutazone are constant in different pH, while the dissolution rate of the crystalline phenylbutazone depends on the pH. The cytotoxicity assays were performed using the Caco-2 cell line. Our results indicate that the analyzed material ensured phenylbutazone adsorption in an amorphous state inside the mesopores and increased its dissolution rate in various pH levels. Furthermore, the cytotoxicity assay proved safety of studied material. Our study demonstrated that APTES-modified SBA-15 can serve as a non-toxic drug carrier that improves the bioavailability of phenylbutazone.