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1.
Polymers (Basel) ; 16(10)2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38794589

RESUMEN

Transdermal transport can be challenging due to the difficulty in diffusing active substances through the outermost layer of the epidermis, as the primary function of the skin is to protect against the entry of exogenous compounds into the body. In addition, penetration of the epidermis for substances hydrophilic in nature and particles larger than 500 Da is highly limited due to the physiological properties and non-polar nature of its outermost layer, namely the stratum corneum. A solution to this problem can be the use of microneedles, which "bypass" the problematic epidermal layer by dispensing the active substance directly into the deeper layers of the skin. Microneedles can be obtained with various materials and come in different types. Of special interest are carriers based on biodegradable and biocompatible polymers, such as polysaccharides. Therefore, this paper reviews the latest literature on methods to obtain hyaluronic acid-based microneedles. It focuses on the current advancements in this field and consequently provides an opportunity to guide future research in this area.

2.
Chemphyschem ; 25(10): e202300823, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38353297

RESUMEN

Polymeric materials, despite their many undeniable advantages, nowadays are a major environmental challenge. Thus, in recent years biodegradable polymer matrices have been widely used in various sectors, including the medicinal, chemical, and packaging industry. Their widespread use is due to the properties of biodegradable polymer matrices, among which are their adjustable physicochemical and mechanical properties, as well as lower environmental impact. The properties of biodegradable polymers can be modified with various types of nanofillers, among which clays, organic and inorganic nanoparticles, and carbon nanostructures are most commonly used. The performance of the final product depends on the size and uniformity of the used nanofillers, as well as on their distribution and dispersion in the polymer matrix. This literature review aims to highlight new research results on advances and improvements in the synthesis, physicochemical properties and applications of biodegradable polymer matrices modified with metal nanoparticles and metal oxides.

3.
Int J Mol Sci ; 24(24)2023 Dec 17.
Artículo en Inglés | MEDLINE | ID: mdl-38139403

RESUMEN

Amorphous silica as a food additive (E 551) is used in food materials (e.g., sweeteners, dairy products) for its anti-caking properties. The physicochemical properties of SiO2 also make it suitable to serve as a carrier of active substances in functional foods, dietary supplements, and drugs. Deficiency of niacinamide (vitamin B3, niacin) leads to several pathologies in the nervous system and causes one of the nutritional diseases called pellagra. The present study focuses on the use of hybrid ordered mesoporous silicas (SBA-15/SBA-16) functionalized with amino groups introduced through grafting or co-condensation with (N-vinylbenzyl)aminoethylaminopropyltrimethoxysilane (Z-6032) as novel carriers of niacinamide. They combine the characteristics of a relatively stable and chemically inert amorphous silica matrix with well-defined structural/textural parameters and organic functional groups that give specific chemical properties. The highest degree of carrier loading with niacinamide (16 wt.%) was recorded for the unmodified SBA-15. On the other hand, the highest degree of niacinamide release characterizes the functionalized SBA-15 sample (60% after 24 h), indicating that the presence of amino groups affects the release profile of niacinamide from the structure of the mesoporous silica.


Asunto(s)
Niacina , Dióxido de Silicio , Dióxido de Silicio/química , Niacinamida
4.
Life (Basel) ; 13(10)2023 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-37895331

RESUMEN

Calendula officinalis L. promotes wound healing and might be effective in gingival fibroblast stimulation. The influence of different concentrations of Calendula officinalis L. ethanol extract on human gingival fibroblast was visualized using PANsys 3000-a fully automated cell culture device used for in vitro culture to study cells under conditions similar to in vivo. The human fibroblast cells were isolated from gingival tissue. The 100% brew of Calendula officinalis L., as well as 7% and 20% Calendula officinalis L. ethanol extract, were added to the cultured cells and observed for 72 h. The qualitative and quantitative composition of the volatile compounds of marigold Calendula officinalis L. flowers are presented in this study. The essential oil compounds of the decoction were isolated with solid-phase microextraction (SPME) and analyzed with gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The presence of terpenoids, flavonoids, and other compounds was demonstrated. The composition was correlated with the fragrance properties. Observation of gingival fibroblast showed that there were no changes in cell morphology and proliferation after 100% Calendula officinalis L. brew stimulation. The growth and cell division were not inhibited. Likewise, the addition of 7% or 20% ethanol in water extract of Calendula officinalis L. stimulation did not inhibit the fibroblast proliferation. Overall, ethanol extracts of Calendula officinalis L. decrease the alcohol cytotoxic influence on gingival fibroblasts.

5.
Materials (Basel) ; 16(15)2023 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-37570087

RESUMEN

The aim of this study was the synthesis, characterization, and catalytic application of new hierarchical materials modified with tantalum and vanadium ions. These materials exhibit secondary porosity, thus allowing the reactant molecules to access the active sites of the material while maintaining the acidity and crystallinity of the zeolites. Based on the results, these systems were found to be highly active and selective in the oxidation of cyclohexene. The performance of the catalysts was compared in oxidation processes carried out by conventional and microwave-assisted methods. Microwave-assisted experiments showed that in the presence of a hierarchical FAU zeolite containing Ta, long reaction times could be shortened with increased activity and selectivity under the same residual experimental conditions.

6.
Molecules ; 28(13)2023 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-37446593

RESUMEN

The role of nanotechnology is increasingly important in our society. Through it, scientists are acquiring the ability to understand the structure and properties of materials and manipulate them at the scale of atoms and molecules. Nanomaterials are at the forefront of the rapidly growing field of nanotechnology. The synthesis of nanostructured materials, especially metallic nanoparticles, has attracted tremendous interest over the past decade due to their unique properties, making these materials excellent and indispensable in many areas of human activity. These special properties can be attributed to the small size and large specific surface area of nanoparticles, which are very different from those of bulk materials. Nanoparticles of different sizes and shapes are needed for many applications, so a variety of protocols are required to produce monodisperse nanoparticles with controlled morphology. The purpose of this review is firstly to introduce the reader to the basic aspects related to the field of nanotechnology and, secondly, to discuss metallic nanoparticles in greater detail. This article explains the basic concepts of nanotechnology, introduces methods for synthesizing nanoparticles, and describes their types, properties, and possible applications. Of many methods proposed for the synthesis of metal nanoparticles, a chemical reduction is usually preferred because it is easy to perform, cost-effective, efficient, and also allows control of the structural parameters through optimization of the synthesis conditions. Therefore, a chemical reduction method is discussed in more detail-each factor needed for the synthesis of nanoparticles by chemical reduction is described in detail, i.e., metal precursors, solvents, reducing agents, and stabilizers. The methods that are used to characterize nanomaterials are described. Finally, based on the available literature collection, it is shown how changing the synthesis parameters/methods affects the final characteristics of nanoparticles.


Asunto(s)
Nanopartículas del Metal , Nanoestructuras , Humanos , Nanotecnología/métodos , Nanopartículas del Metal/química
7.
Sci Rep ; 13(1): 9168, 2023 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-37280270

RESUMEN

In the present paper, for the first time the ability of the porous biosilica originated from three marine diatom strains of 'Nanofrustulum spp.' viz. N. wachnickianum (SZCZCH193), N. shiloi (SZCZM1342), N. cf. shiloi (SZCZP1809), to eliminate MB from aqueous solutions was investigated. The highest biomass was achieved under silicate enrichment for N. wachnickianum and N. shiloi (0.98 g L-1 DW and 0.93 g L-1 DW respectively), and under 15 °C for N. cf. shiloi (2.2 g L-1 DW). The siliceous skeletons of the strains were purified with hydrogen peroxide and characterized by SEM, EDS, the N2 adsorption/desorption, XRD, TGA, and ATR-FTIR. The porous biosilica (20 mg DW) obtained from the strains i.e. SZCZCH193, SZCZM1342, SZCZP1809, showed efficiency in 77.6%, 96.8%, and 98.1% of 14 mg L-1 MB removal under pH 7 for 180 min, and the maximum adsorption capacity was calculated as 8.39, 19.02, and 15.17 mg g-1, respectively. Additionally, it was possible to increase the MB removal efficiency in alkaline (pH = 11) conditions up to 99.08% for SZCZP1809 after 120 min. Modelling revealed that the adsorption of MB follows Pseudo-first order, Bangham's pore diffusion and Sips isotherm models.


Asunto(s)
Diatomeas , Azul de Metileno , Dióxido de Silicio , Diatomeas/química , Diatomeas/crecimiento & desarrollo , Dióxido de Silicio/química , Dióxido de Silicio/aislamiento & purificación , Adsorción , Azul de Metileno/metabolismo , Concentración de Iones de Hidrógeno , Porosidad , Contaminantes del Agua/aislamiento & purificación , Purificación del Agua/instrumentación , Purificación del Agua/métodos
8.
Int J Mol Sci ; 24(11)2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37298152

RESUMEN

Research on the synthesis and characterization of ordered mesoporous materials with uniquely functionalized external and internal surfaces has intensified in the last decade [...].


Asunto(s)
Tecnología , Porosidad
9.
Mar Drugs ; 21(5)2023 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-37233506

RESUMEN

Industrial wastes with hazardous dyes serve as a major source of water pollution, which is considered to have an enormous impact on public health. In this study, an eco-friendly adsorbent, the porous siliceous frustules extracted from the diatom species Halamphora cf. salinicola, grown under laboratory conditions, has been identified. The porous architecture and negative surface charge under a pH of 7, provided by the various functional groups via Si-O, N-H, and O-H on these surfaces, revealed by SEM, the N2 adsorption/desorption isotherm, Zeta-potential measurement, and ATR-FTIR, respectively, made the frustules an efficient mean of removal of the diazo and basic dyes from the aqueous solutions, 74.9%, 94.02%, and 99.81% against Congo Red (CR), Crystal Violet (CV), and Malachite Green (MG), respectively. The maximum adsorption capacities were calculated from isotherms, as follows: 13.04 mg g-1, 41.97 mg g-1, and 33.19 mg g-1 against CR, CV, and MG, respectively. Kinetic and isotherm models showed a higher correlation to Pore diffusion and Sips models for CR, and Pseudo-Second Order and Freundlich models for CV and MG. Therefore, the cleaned frustules of the thermal spring-originated diatom strain Halamphora cf. salinicola could be used as a novel adsorbent of a biological origin against anionic and basic dyes.


Asunto(s)
Diatomeas , Contaminantes Químicos del Agua , Colorantes/química , Colorantes de Rosanilina/química , Rojo Congo , Agua/química , Adsorción , Cinética , Concentración de Iones de Hidrógeno , Contaminantes Químicos del Agua/química
10.
Int J Nanomedicine ; 18: 2507-2523, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37197025

RESUMEN

Introduction: Solid lipid nanoparticles (SLN) have been considered lately as promising drug delivery system in treatment of many human diseases including cancers. We previously studied potential drug compounds that were effective inhibitors of PTP1B phosphatase - possible target for breast cancer treatment. Based on our studies, two complexes were selected for encapsulation into the SLNs, the compound 1 ([VO(dipic)(dmbipy)] · 2 H2O) and compound 2 ([VOO(dipic)](2-phepyH) · H2O). Here, we investigate the effect of encapsulation of those compounds on cell cytotoxicity against MDA-MB-231 breast cancer cell line. The study also included the stability evaluation of the obtained nanocarriers with incorporated active substances and characterization of their lipid matrix. Moreover, the cell cytotoxicity studies against the MDA-MB-231 breast cancer cell line in comparison and in combination with vincristine have been performed. Wound healing assay was carried out to observe cell migration rate. Methods: The properties of the SLNs such as particle size, zeta potential (ZP), and polydispersity index (PDI) were investigated. The morphology of SLNs was observed by scanning electron microscopy (SEM), while the crystallinity of the lipid particles was analyzed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The cell cytotoxicity of complexes and their encapsulated forms was carried out against MDA-MB-231 breast cancer cell line using standard MTT protocols. The wound healing assay was performed using live imaging microscopy. Results: SLNs with a mean size of 160 ± 25 nm, a ZP of -34.00 ± 0.5, and a polydispersity index of 30 ± 5% were obtained. Encapsulated forms of compounds showed significantly higher cytotoxicity also in co-incubation with vincristine. Moreover, our research shows that the best compound was complex 2 encapsulated into lipid nanoparticles. Conclusion: We observed that encapsulation of studied complexes into SLNs increases their cell cytotoxicity against MDA-MB-231 cell line and enhanced the effect of vincristine.


Asunto(s)
Neoplasias de la Mama , Nanopartículas , Humanos , Femenino , Vincristina , Lípidos/química , Células MDA-MB-231 , Nanopartículas/química , Neoplasias de la Mama/tratamiento farmacológico , Tamaño de la Partícula , Portadores de Fármacos/química
11.
Pharmaceutics ; 15(2)2023 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-36839857

RESUMEN

Hierarchical zeolites are aluminosilicates with a crystal structure, which next to the micropores possess secondary porosity in the range of mesopores and/or small macropores. Due to their ordered structure and additional secondary porosity, they have aroused great interest among scientists in recent years. Therefore, the present work concerns the synthesis and characterization of hierarchical zeolites with secondary mesoporosity, based on commercial zeolites such as MFI (ZSM-5), BEA (ß) and FAU (Y), and modified with polysaccharides such as inulin, hyaluronic acid, and heparin. All materials were characterized by various analytical techniques and applied as a platform for delivery of selected drug molecules. On the basis of X-ray diffraction (presence of reflections in the 2θ angle range of 1.5-2.5°) and low-temperature nitrogen sorption isotherms (mixture of isotherms of I and IV type) additional secondary porosity was found in the mesopore range. Additional tests were also conducted to determine the possibility of loading selected molecules with biological activity into the aforementioned materials and then releasing them in the therapeutic process. Molecules with different therapeutic options were selected for testing, namely ibuprofen, curcumin, and ferulic acid with anti-inflammatory, potentially anticancer, antioxidant, and skin discoloration activities, respectively. Preliminary studies have confirmed the possibility of using hierarchical zeolites as potential carriers for bioactive molecules, as the loading percentage of active substances ranged from 39-79% and cumulative release for ibuprofen reached almost 100% after 8 h of testing.

12.
Int J Mol Sci ; 24(3)2023 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-36769204

RESUMEN

Bisphenol A (4,4-isopropylidenediphenol, BPA) is an organic compound widely used, e.g., in the production of epoxy resins, plastics, and thermal receipt papers. Unfortunately, bisphenol A has negative effects on human health, which has prompted the search for an effective method of its removal. One of the most promising methods of its elimination is photocatalytic removal. The aim of this study was to design an effective method for the photocatalytic removal of bisphenol A using, for the first time, hierarchical zeolites and ruthenium ion-modified diatom biosilica, and silver as photocatalysts and optimization of the reaction conditions: temperature, pH, and composition of the reaction mixture as well as the electromagnetic wavelength. Additionally, for the first time, the electromagnetic wavelength that would be most suitable for the study was selected. All materials used were initially characterized by XRD and low-temperature nitrogen adsorption/desorption isotherms. Ruthenium ion-modified biosilica proved to be the most effective catalyst for bisphenol A removal, which occurred at a rate higher than 99%.


Asunto(s)
Diatomeas , Rutenio , Contaminantes Químicos del Agua , Zeolitas , Humanos , Zeolitas/química , Contaminantes Químicos del Agua/química , Compuestos de Bencidrilo/química
13.
Materials (Basel) ; 15(18)2022 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-36143628

RESUMEN

This work shows that hierarchical zeolites are promising systems for the delivery of biologically relevant hydrophobic substances, such as curcumin. The validity of using piperine as a promoter of curcumin adsorption was also evaluated. The use of pure curcumin is not medically applicable due to its low bioavailability and poor water solubility. To improve the undesirable properties of curcumin, special carriers are used to overcome these shortcomings. Hierarchical zeolites possessing secondary mesoporosity are used as pharmaceutical carrier systems for encapsulating active substances with low water solubility. This porosity facilitates access of larger reagent molecules to the active sites of the material, preserving desirable adsorption properties, acidity, and crystallinity of zeolites. In this work, methods are proposed to synthesize hierarchical zeolites based on a commercial FAU-type zeolite. Studies on the application and adsorption kinetics of curcumin using commercial FAU-type zeolite and hierarchical zeolites based on commercial FAU-type zeolite are also included.

14.
Molecules ; 27(11)2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35684408

RESUMEN

Phytoecdysones from Serratula coronata seem to be promising agents for skincare in patients with psoriasis. The aim of the study was to determine the effects of creams containing the extract of S. coronata on psoriatic lesions. Creams with different formulas were prepared: 0-Lekobaza®, 1-Lekobaza®, S. coronata, 2-Lekobaza®, Salicylic acid, 3-Lekobaza®, S. coronata, Salicylic acid. After examination of skin penetration and biosafety, the designated cream was applied twice daily for 6 weeks on 72 psoriatic plaques located on elbows or knees. The lesions were assessed at baseline and follow-up of 6 weeks. The lesions area was measured, and severity of scaling, erythema, and infiltration was assessed using a 5-point scale (from 0-none to 4-very severe). Skin hydration and structure, pH, transepidermal water loss, erythema, and melanin index were analyzed instrumentally. Creams 1, 2, and 3 significantly reduced the area of psoriatic plaques. Improvement in erythema and infiltration was observed for creams 1 and 3. Creams 1-3 reduced scaling. Our study confirmed a beneficial effect of creams containing S. coronata extract on psoriatic lesions.


Asunto(s)
Asteraceae , Psoriasis , Eritema , Humanos , Extractos Vegetales/farmacología , Psoriasis/tratamiento farmacológico , Ácido Salicílico/uso terapéutico
15.
Molecules ; 27(7)2022 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-35408600

RESUMEN

Solid lipid nanoparticles (SLNs) have been synthesized as potential drug delivery systems. They are classified as solid lipid nanocarriers that can successfully carry both hydrophilic and hydrophobic drugs. SLNs are based on a biocompatible lipid matrix that is enzymatically degraded into natural components found in the human body. Solid lipid nanoparticles are suitable for the incorporation of hydrophobic active ingredients such as curcumin. The study included the optimization of lipid nanoparticle composition, incorporation of the active compound (curcumin), a stability evaluation of the obtained nanocarriers and characterization of their lipid matrix. Through process optimization, a dispersion of solid lipid nanoparticles (solid lipid:surfactant­2:1.25 weight ratio) predisposed to the incorporation of curcumin was developed. The encapsulation efficiency of the active ingredient was determined to be 99.80%. In stability studies, it was found that the most suitable conditions for conducting high-pressure homogenization are 300 bar pressure, three cycles and a closed-loop system. This yields the required values of the physicochemical parameters (a particle size within a 200−450 nm range; a polydispersity index of <30%; and a zeta potential of about |±30 mV|). In this work, closed-loop high-pressure homogenization was used for the first time and compared to the currently preferred open-loop method.


Asunto(s)
Curcumina , Nanopartículas , Portadores de Fármacos , Humanos , Lípidos/química , Liposomas , Nanopartículas/química , Tamaño de la Partícula
16.
Materials (Basel) ; 15(2)2022 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-35057398

RESUMEN

Currently, carriers of active ingredients in the form of particles of a size measured in nanometers are the focus of interest of research centers worldwide. So far, submicrometer emulsions, liposomes, as well as microspheres, and nanospheres made of biodegradable polymers have been used in medicine. Recent studies show particular interest in nanoparticles based on lipids, and at the present time, are even referred to as the "era of lipid carriers". With the passage of time, lipid nanoparticles of the so-called first and second generation, SLN (Solid Lipid Nanoparticles) and nanostructured lipid carriers and NLC (Nanostructured Lipid Carriers), respectively, turned out to be an alternative for all imperfections of earlier carriers. These carriers are characterized by a number of beneficial functional properties, including, among others, structure based on lipids well tolerated by the human body, high stability, and ability to carry hydro- and lipophilic compounds. Additionally, these carriers can enhance the distribution of the drug in the target organ and alter the pharmacokinetic properties of the drug carriers to enhance the medical effect and minimize adverse side effects. This work is focused on the current review of the state-of-the-art related to the synthesis and applications of popular nanoparticles in medicine, with a focus on their use, e.g., in COVID-19 vaccines.

17.
Materials (Basel) ; 16(1)2022 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-36614532

RESUMEN

Increasing demand for energy and environmental degradation are the most serious problems facing the man. An interesting issue that can contribute to solving these problems is the use of photocatalysis. According to literature, solar energy in the presence of a photocatalyst can effectively (i) be converted into electricity/fuel, (ii) break down chemical and microbial pollutants, and (iii) help water purification. Therefore, the search for new, efficient, and stable photocatalysts with high application potential is a point of great interest. The photocatalysts must be characterized by the ability to absorb radiation from a wide spectral range of light, the appropriate position of the semiconductor energy bands in relation to the redox reaction potentials, and the long diffusion path of charge carriers, besides the thermodynamic, electrochemical, and photoelectrochemical stabilities. Meeting these requirements by semiconductors is very difficult. Therefore, efforts are being made to increase the efficiency of photo processes by changing the electron structure, surface morphology, and crystal structure of semiconductors. This paper reviews the recent literature covering the synthesis and application of nanomaterials in photocatalysis.

18.
Int J Mol Sci ; 22(13)2021 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-34201641

RESUMEN

A new catalyst based on biosilica doped with palladium(II) chloride nanoparticles was prepared and tested for efficient degradation of methyl orange (MO) in water solution under UV light excitation. The obtained photocatalyst was characterized by X-ray diffraction, TEM and N2 adsorption/desorption isotherms. The photocatalytic degradation process was studied as a function of pH of the solution, temperature, UV irradiation time, and MO initial concentration. The possibilities of recycling and durability of the prepared photocatalysts were also tested. Products of photocatalytic degradation were identified by liquid chromatography-mass spectrometry analyses. The photocatalyst exhibited excellent photodegradation activity toward MO degradation under UV light irradiation. Rapid photocatalytic degradation was found to take place within one minute with an efficiency of 85% reaching over 98% after 75 min. The proposed mechanism of photodegradation is based on the assumption that both HO• and O2•- radicals, as strongly oxidizing species that can participate in the dye degradation reaction, are generated by the attacks of photons emitted from diatom biosilica (photonic scattering effect) under the influence of UV light excitation. The degradation efficiency significantly increases as the intensity of photons emitted from biosilica is enhanced by palladium(II) chloride nanoparticles immobilized on biosilica (synergetic photonic scattering effect).


Asunto(s)
Compuestos Azo/química , Diatomeas/química , Paladio/química , Contaminantes Químicos del Agua/química , Catálisis , Concentración de Iones de Hidrógeno , Cinética , Nanopartículas del Metal/química , Microscopía Electrónica de Transmisión , Fotólisis , Reciclaje , Espectrometría de Masa por Ionización de Electrospray , Temperatura , Rayos Ultravioleta , Difracción de Rayos X
19.
RSC Adv ; 11(16): 9505-9517, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-35423430

RESUMEN

Hydrodeoxygenation (HDO) carried out at high temperatures and high hydrogen pressures is one of the alternative methods of upgrading pyrolytic oils from biomass, leading to high quality biofuels. To save energy, it is important to carry out catalytic processes under the mildest possible experimental conditions. The aim of our research was the synthesis of ordered mesoporous SBA-16 type silica materials modified with transition metal atoms (Ir, Ru, Pd, Pt), their physicochemical characterization and use as catalysts in hydrodeoxygenation of model chemicals (guaiacol, syringol, creosol). The HDO process was carried out under mild experimental conditions at temperatures in the range from 90 to 130 °C and hydrogen pressures in the range from 25 to 60 bar. The catalytic tests revealed differences in the catalytic properties of the samples studied. The catalytic systems used assured highly efficient transformations of the examined molecules as well as high selectivity towards chemical compounds with lower O/C ratio and higher H/C ratio as compared to those in the initial substrates. High activity of the catalysts containing precious metals in the experimental conditions applied suggests their potential to improve bio-oil production for biofuels.

20.
Materials (Basel) ; 13(19)2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-33019709

RESUMEN

Mesoporous silicas have enjoyed great interest among scientists practically from the moment of their discovery thanks to their unique attractive properties. Many types of mesoporous silicas have been described in literature, the most thoroughly MCM-41 and SBA-15 ones. The focus of this review are the methods of syntheses, characterization and use of mesoporous silicas from SBA (Santa Barbara Amorphous) and HMM (Hybrid Mesoporous Materials) groups. The first group is represented by (i) SBA-1 of three-dimensional cubic structure and Pm3n symmetry and (ii) SBA-2 of three-dimensional combined hexagonal and cubic structures and P63/mmc symmetry. The HMM group is represented by (i) HMM-1 of two-dimensional hexagonal structure and p6mm symmetry and (ii) HMM-2 of three-dimensional structure and P63/mmc symmetry. The paper provides comprehensive information on the above-mentioned silica materials available so far, also including the data for the silicas modified with metal ions or/and organic functional groups and examples of the materials applications.

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