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Articles de revues sur le sujet « Porous silicas »

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Auteur : Grafiati
Publié le 25 mai 2024

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1

Yan, Xiang, Aurélie Cayla, Eric Devaux et Fabien Salaün. « Microstructure Evolution of Immiscible PP-PVA Blends Tuned by Polymer Ratio and Silica Nanoparticles ». Polymers 10, no 9 (17 septembre 2018) : 1031. http://dx.doi.org/10.3390/polym10091031.

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Composites of polypropylene (PP) and water soluble poly(vinyl alcohol) (PVA) can become an environmentally friendly precursor in preparing porous material, and their biphasic morphology needs to be manipulated. In this work, PP-PVA extrudates were prepared with a twin-screw extruder, and different PP/PVA ratios were employed to manipulate the morphology of the blends. Afterwards, different silicas were imbedded within the blends to further regulate the biphasic microstructure. PVA continuity, as a vital parameter in obtaining porous material, was determined by selective extraction measurement, and PP-PVA biphasic morphology was characterized by scanning microscopy analyses (SEM). Rheological measurement was also performed to correlate the microstructure evolution of the blends. First, it was found that with the increment of PVA proportion, PVA continuity is raised gradually, and the microstructure of blends containing 40–50 wt % of PVA is approaching co-continuous. Second, the localization of silicas was predicted based on the wettability of silica and polymers, and it was also confirmed by TEM that different silicas showed selective distribution. It is inspiring that R972 nanoparticles were found mainly distributed at the interface, which gives a possibility in preparing a surface-modified porous material. The shape distribution and average size of PVA nodules were examined by analyzing the SEM images. It is indicated that silicas with different wettabilities play disparate roles in tuning the biphasic microstructures, leading to heterogeneous PVA continuity.
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Choma, Jerzy, et Mietek Jaroniec. « Adsorption Potential Distributions for Silicas and Organosilicas ». Adsorption Science & ; Technology 25, no 8 (octobre 2007) : 573–81. http://dx.doi.org/10.1260/0263-6174.25.8.573.

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Adsorption potential distributions (APDs) were calculated from nitrogen adsorption isotherms for macroporous silicas, and for disordered and ordered mesoporous silicas without and with organic groups attached to the surface. It was shown that the APDs for porous silicas and organosilicas differ significantly from those obtained for carbonaceous materials, especially in the range of high adsorption potentials which correspond to low relative pressures. Although the high adsorption potential portions of APDs for porous siliceous materials are less informative than those for carbons, they are still useful for monitoring the changes in the surface properties due to the attachment of various organic groups.
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Weinberger, Christian, Tatjana Heckel, Patrick Schnippering, Markus Schmitz, Anpeng Guo, Waldemar Keil, Heinrich C. Marsmann, Claudia Schmidt, Michael Tiemann et René Wilhelm. « Straightforward Immobilization of Phosphonic Acids and Phosphoric Acid Esters on Mesoporous Silica and Their Application in an Asymmetric Aldol Reaction ». Nanomaterials 9, no 2 (12 février 2019) : 249. http://dx.doi.org/10.3390/nano9020249.

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The combined benefits of moisture-stable phosphonic acids and mesoporous silica materials (SBA-15 and MCM-41) as large-surface-area solid supports offer new opportunities for several applications, such as catalysis or drug delivery. We present a comprehensive study of a straightforward synthesis method via direct immobilization of several phosphonic acids and phosphoric acid esters on various mesoporous silicas in a Dean–Stark apparatus with toluene as the solvent. Due to the utilization of azeotropic distillation, there was no need to dry phosphonic acids, phosphoric acid esters, solvents, or silicas prior to synthesis. In addition to modeling phosphonic acids, immobilization of the important biomolecule adenosine monophosphate (AMP) on the porous supports was also investigated. Due to the high surface area of the mesoporous silicas, a possible catalytic application based on immobilization of an organocatalyst for an asymmetric aldol reaction is discussed.
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Ramsay, John D. F., et Christiane Poinsignon. « Neutron scattering investigations of porous silicas and water silica interfaces ». Langmuir 3, no 3 (mai 1987) : 320–26. http://dx.doi.org/10.1021/la00075a006.

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Charmas, Barbara, Karolina Kucio, Volodymyr Sydorchuk, Svitlana Khalameida, Magdalena Zięzio et Aldona Nowicka. « Characterization of Multimodal Silicas Using TG/DTG/DTA, Q-TG, and DSC Methods ». Colloids and Interfaces 3, no 1 (28 décembre 2018) : 6. http://dx.doi.org/10.3390/colloids3010006.

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The formation of hierarchical, multimodal porosity materials with controlled shape and size of pores is the essential challenge in materials science. Properties of silica materials depend largely on different features: crystal structure, dispersity, surface composition, and porosity as well as the method of preparation and possible modification. In this paper, multimodal silicas obtained using different additives are presented. A-50 and A-380 aerosils and wide-porous SiO2 milled at 300 rpm were used as the additives in the sol stage at 20 °C, the sol–gel stage followed by hydrothermal modification (HTT) at 200 °C, or in the mechanochemical treatment (MChT) process. The characterizations were made by application of N2 adsorption/desorption, SEM imaging, quasi-isothermal thermogravimetry (Q-TG), dynamic thermogravimetry/derivative thermogravimetry/differential thermal analysis (TG/DTG/DTA), and cryoporometry differential scanning calorimetry (DSC) methods. Results showed that such a one-step preparation method is convenient and makes it possible to obtain multimodal silicas of differentiated porous structures and surface chemistry.
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6

Hustings, A. M. L., et J. J. F. Scholten. « The Effect of Pressure on Pore Structure in Mercury Porosimetry ». Adsorption Science & ; Technology 4, no 4 (décembre 1987) : 241–50. http://dx.doi.org/10.1177/026361748700400404.

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The pore volume distributions of chrysotile, Mg3(OH)4. Si2O5, ZrO2 and of four samples of silica with pore volumes from 1.45 to 2.70 cm3/g have been measured by means of nitrogen capillary condensation and mercury penetration. It is shown that compaction of the porous structures can occur under the influence of the high mercury pressures applied. The degree of compaction depends on the mechanical strength of the sample, its initial porosity and the magnitude of the mercury pressure. The extremely strong ZrO2 sample, with its low pore volume of 0.18 cm3/g does not show any sign of cracking up to pressures as high as 190 MPa. Hollow chrysotile needles compact in the pressure range from 100 to 400 MPa. Highly porous silicas all show severe compaction. In accordance with Brown & Lard (Brown & Lard, 1974) it is concluded that silicas with pore volumes larger than 1.2 cm3/g are not suitable for study by mercury porosimetry.
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7

Gorgol, Marek, Agnieszka Kierys et Radosław Zaleski. « Positron Lifetime Annihilation Study of Porous Composites and Silicas Synthesized Using Polymer Templates ». Defect and Diffusion Forum 373 (mars 2017) : 280–83. http://dx.doi.org/10.4028/www.scientific.net/ddf.373.280.

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The porous structure of polymer-silica composites, based on three polymer templates, which differ in a porosity and hydrophobicity, was examined using positron annihilation lifetime spectroscopy. Additionally, the investigation of silicas obtained after removal of polymers during calcination of composite materials, was performed. In composites based on hydrophobic polymers, silica condensates only in larger free volumes, while SiO2 deeply penetrates spaces between polymer chains, when the template is polar. Moreover, the structure of the silica gel, obtained after polymer removal, depends on chemical character of the template, rather than its porosity.
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8

Crean, Abina M., Robert J. Ahern, Rakesh Dontireddy, Walid Faisil, John P. Hanrahan, Brendan T. Griffin et Katie B. Ryan. « Porous Silicas for Enhanced Drug Release ». Advances in Science and Technology 91 (octobre 2014) : 79–81. http://dx.doi.org/10.4028/www.scientific.net/ast.91.79.

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Low drug water-solubility is a major challenge to overcome in the development of tablet or capsule dosage forms for a large number of promising drug candidates. Strategies to improve drug solubility and dissolution involve chemical, physical and formulation approaches. An emerging formulation approach to increase drug dissolution and solubility involves the creation of solid dispersions of drug molecules on to a high surface area inorganic carrier, such as porous silica. The combined benefits of a hydrophilic inorganic substrate, increased drug surface area and a high-energy drug form facilitate rapid drug dissolution into aqueous based media and can create supersaturated drug solutions. The work presented provides a brief overview of the silica grades investigated, processes employed to load drugs onto the silica substrates, provide some examples of the ability of silica to enhance drug dissolution and highlight some of the challenges in the development of these novel drug delivery systems.
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BENEDETTI, A., S. CICCARIELLO, F. PINNA et G. STRUKUL. « SAXS study of coated porous silicas ». Le Journal de Physique IV 03, no C8 (décembre 1993) : C8–463—C8–466. http://dx.doi.org/10.1051/jp4:1993896.

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Guiton, T. A., et C. G. Pantano. « Infrared reflectance spectroscopy of porous silicas ». Colloids and Surfaces A : Physicochemical and Engineering Aspects 74, no 1 (juillet 1993) : 33–46. http://dx.doi.org/10.1016/0927-7757(93)80396-v.

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11

Kooyman, Patricia J., Markéta Slabová, Vladimír Bosáček, Jiří Čejka, Jiří Rathouský et Arnošt Zukal. « The Influence of pH on the Structure of Templated Mesoporous Silicas Prepared from Sodium Metasilicate ». Collection of Czechoslovak Chemical Communications 66, no 4 (2001) : 555–66. http://dx.doi.org/10.1135/cccc20010555.

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A recently developed homogeneous precipitation method was used for the investigation of the influence of pH on the structure of mesoporous silicas prepared from sodium metasilicate in the presence of a quaternary alkyl ammonium surfactant as a structure directing agent. The rate of pH decrease affects the assembly of mesoscopically ordered composites and, consequently, the porous structure of mesoporous silicas prepared from them by calcination. Pure MCM-41 molecular sieve was prepared by controlling the pH decrease of the reaction mixture so as to achieve the final pH 7.8. The as-made material prepared at higher pH (final value 10.1) is characterized by a lower degree of silica polycondensation. Due to the shrinkage of this material during calcination, a less well-ordered silica with extraordinary large surface area was prepared. A large decrease in pH (final value 5.2) led to non-organized polycondensation of silica species besides the organized assembly of the ordered material, which resulted in the formation of silica with a bimodal mesoporous structure.
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12

Navrotsky, Alexandra, Richard Hervig, James Lyons, Dong-Kyun Seo, Everett Shock et Albert Voskanyan. « Cooperative formation of porous silica and peptides on the prebiotic Earth ». Proceedings of the National Academy of Sciences 118, no 2 (29 décembre 2020) : e2021117118. http://dx.doi.org/10.1073/pnas.2021117118.

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Modern technology has perfected the synthesis of catalysts such as zeolites and mesoporous silicas using organic structure directing agents (SDA) and their industrial use to catalyze a large variety of organic reactions within their pores. We suggest that early in prebiotic evolution, synergistic interplay arose between organic species in aqueous solution and silica formed from rocks by dynamic dissolution–recrystallization. The natural organics, for example, amino acids, small peptides, and fatty acids, acted as SDA for assembly of functional porous silica structures that induced further polymerization of amino acids and peptides, as well as other organic reactions. Positive feedback between synthesis and catalysis in the silica–organic system may have accelerated the early stages of abiotic evolution by increasing the formation of polymerized species.
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13

Jadhav, Sushilkumar A., et Dominique Scalarone. « Thermoresponsive Polymer Grafted Porous Silicas as Smart Nanocarriers ». Australian Journal of Chemistry 71, no 7 (2018) : 477. http://dx.doi.org/10.1071/ch18229.

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Porous silica particles grafted with various stimuli-responsive polymers are investigated with great interest for their use as smart pharmaceutical nanocarriers in advanced drug delivery systems (DDS). In particular, porous silica particles grafted with thermoresponsive polymers that exhibit thermally triggered on/off gating mechanisms have shown improved performance as hybrid DDS capable of controlling the release of different drugs in various mediums which resemble complex biological environments. In addition, the tuning of the drug release profiles as per requirements has proved possible with modifications to the porous core and the grafted thermoresponsive polymers. This highlight presents a brief discussion of basic preparation techniques and some recent significant developments in the field of thermoresponsive polymer grafted porous silica particles as smart pharmaceutical nanocarriers.
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14

Gun'ko, V. M. « Confined space effects on various liquids interacting with fumed nanooxides and porous silicas ». Himia, Fizika ta Tehnologia Poverhni 13, no 1 (30 mars 2022) : 47–59. http://dx.doi.org/10.15407/hftp13.01.047.

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Interfacial phenomena at a surface of porous and highly disperse adsorbents in the systems containing strongly and weakly bound and unbound liquids depend strongly on the confined space effects. These effects as well as the temperature behavior of liquids located in pores or voids between nanoparticles depend on many factors. They are the pore size distributions, pore volume, specific surface area, surface chemistry of adsorbents, chemical structure and molecular sizes of adsorbates, accessibility of pores vs. probe molecule sizes, as well as textural instability of adsorbents. This instability can appear, e.g., as compaction of fumed oxides under action of liquid adsorbates, especially water, or due to mechanochemical activation. The aim of this study is to analyze features of the interfacial phenomena upon interactions of fumed oxides (silica, alumina, alumina/silica/titania) and porous silicas (silica gels and precipitated silica) with polar (water, dimethyl sulfoxide), weakly polar (chloroform), and nonpolar (n-decane, aromatic benzene and toluene) liquid adsorbates depending on the morphological and textural characteristics of the adsorbents, various adsorbate characteristics, and temperature. The observed effects as well as related phenomena are important because they can differently influence the efficiency of practical applications of adsorbents under various conditions (temperature, pressure, concentrations) depending on the characteristics of adsorbents and adsorbates (liquids, solvents and solutes).
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15

Coasne, Benoit, Aude Mezy, R. J. M. Pellenq, D. Ravot et J. C. Tedenac. « Zinc Oxide Nanostructures Confined in Porous Silicas ». Journal of the American Chemical Society 131, no 6 (18 février 2009) : 2185–98. http://dx.doi.org/10.1021/ja806666n.

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Rochester, Colin H., et Alistair Strachan. « The Adsorption of Dioxan by Porous Silicas ». Journal of Colloid and Interface Science 177, no 2 (février 1996) : 456–62. http://dx.doi.org/10.1006/jcis.1996.0058.

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17

Baudouin, D., H. A. van Kalkeren, A. Bornet, B. Vuichoud, L. Veyre, M. Cavaillès, M. Schwarzwälder et al. « Cubic three-dimensional hybrid silica solids for nuclear hyperpolarization ». Chemical Science 7, no 11 (2016) : 6846–50. http://dx.doi.org/10.1039/c6sc02055k.

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18

Gun'ko, V. M. « Features of the morphology and texture of silica and carbon adsorbents ». Surface 13(28) (30 décembre 2021) : 127–65. http://dx.doi.org/10.15407/surface.2021.13.127.

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The morphological and textural characteristics of various silicas (93 fumed silicas and 56 porous silicas), different carbons (230), and porous polymers (53) are analyzed using probe (nitrogen, argon, benzene, n-decane, water) adsorption, small angle X-ray scattering (SAXS), and transition (TEM), scanning (SEM) electron and atom force (AFM) microscopies. There are certain correlations between pore volume (Vp) and specific surface area (SSA, SBET) for these materials. Synthesis and treatment temperatures affect this relationship since a linear Vp - SBET approximation scatter decreases with decreasing these temperatures. Silicas are composed of nonporous nanoparticles (NPNP), but activated carbons (AC) are composed of porous nanoparticles (PNP). For different materials, NP are weakly or strongly packed in secondary structures. However, there are general features of pore size distributions (PSD) for NP-based materials, e.g., minimal contribution of narrow mesopores of 3-5 nm in radius due NP-packing effects. For AC produced using the same chars and activation agents but with varied activation time, the textural characteristics demonstrate smooth changes with increasing burn-off degree: nanopores partially transform into narrow mesopores with opposite PSD shifts of broad mesopores and macropores. Comparison of adsorption (open pores accessible for probes) and SAXS (both open and closed pores) data for carbons shows that the difference decreases with increasing burn-off degree due to decreasing contribution of closed pores. Most clear pictures on the particulate morphology and texture could be obtained in parallel analysis using adsorption, SAXS, and microscopic methods with appropriate data treatments.
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Lee, Sang Gil, Young Ho Kim, Jun Tae Bae, Chung Hee Lee, Hyeong Bae Pyo, Kuk Hyoun Kang et Dong Kyu Lee. « Fabrication of Hollow Porous Silica Using a Combined Emulsion Sol–Gel Process and Amphiphilic Triblock Copolymer for Loading of Quercetin ». Journal of Nanoscience and Nanotechnology 15, no 10 (1 octobre 2015) : 7935–41. http://dx.doi.org/10.1166/jnn.2015.11226.

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Flavonoids have recently attracted significant interest as potential reducing agents, hydrogendonating antioxidants, and singlet oxygen-quenchers. Quercetin, in particular, induces the expression of a gene, known to be associated with cell protection, in dose- and time-dependent manners. Therefore, quercetin may be used as an effective cosmeceutical material useful in the protection of dermal skin. In this study, hollow porous silica spheres used to load quercetin were prepared by using a combined emulsion sol–gel process and triblock copolymer as a template. Fabrication of hollow porous silica spheres was performed under various conditions such as the molar ratios of H2O/TEOS (w) and weight ratios of poloxamer 184/poloxamer 407. Loading of quercetin in hollow porous silica spheres was devised to improve the stability of quercetin and to consider the possibility as a raw cosmetic material. The surface of inclusion complexes of quercetin in hollow porous silicas was modified to enhance the stability of quercetin. The physicochemical properties of the samples were investigated using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA)-differential thermal analysis (DTA) and Brunauer–Emmett–Teller (BET) surface area and porosity analysis. Determination of quercetin concentration was carried out by high-performance liquid chromatography (HPLC) analysis.
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Manning, Joseph R. H., Carlos Brambila et Siddharth V. Patwardhan. « Unified mechanistic interpretation of amine-assisted silica synthesis methods to enable design of more complex materials ». Molecular Systems Design & ; Engineering 6, no 3 (2021) : 170–96. http://dx.doi.org/10.1039/d0me00131g.

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Fukuda, Miki, Nao Tsunoji, Yuya Yagenji, Yusuke Ide, Shinjiro Hayakawa, Masahiro Sadakane et Tsuneji Sano. « Highly active and selective Ti-incorporated porous silica catalysts derived from grafting of titanium(iv)acetylacetonate ». Journal of Materials Chemistry A 3, no 29 (2015) : 15280–91. http://dx.doi.org/10.1039/c5ta02975a.

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Moritz, Michał, et Małgorzata Geszke-Moritz. « The Effect of SBA-15 Surface Modification on the Process of 18β-Glycyrrhetinic Acid Adsorption : Modeling of Experimental Adsorption Isotherm Data ». Materials 12, no 22 (7 novembre 2019) : 3671. http://dx.doi.org/10.3390/ma12223671.

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This study aimed at the adsorption of 18β-glycyrrhetinic acid (18β-GA), a pentacyclic triterpenoid derivative of oleanane type, onto functionalized mesoporous SBA-15 silica and non-porous silica (Aerosil®) as the reference adsorbent. Although 18β-GA possesses various beneficial pharmacological properties including antitumor, anti-inflammatory, and antioxidant activity, it occurs is small amounts in plant materials. Thus, the efficient methods of this bioactive compound enrichment from vegetable raw materials are currently studied. Siliceous adsorbents were functionalized while using various alkoxysilane derivatives, such as (3-aminopropyl)trimethoxysilane (APTMS), [3-(methylamino)propyl]trimethoxysilane (MAPTMS), (N,N-dimethylaminopropyl)trimethoxysilane (DMAPTMS), and [3-(2-aminothylamino)propyl] trimethoxysilane (AEAPTMS). The effect of silica surface modification with agents differing in the structure and the order of amine groups on the adsorption capacity of the adsorbent and adsorption efficiency were thoroughly examined. The equilibrium adsorption data were analyzed while using the Langmuir, Freundlich, Redlich-Peterson, Temkin, Dubinin-Radushkevich, and Dubinin-Astakhov isotherms. Both linear regression and nonlinear fitting analysis were employed in order to find the best-fitted model. The adsorption isotherms of 18β-GA onto silicas functionalized with APTMS, MAPTMS, and AEAPTMS indicate the Langmuir-type adsorption, whereas sorbents modified with DMAPTMS show the constant distribution of the adsorbate between the adsorbent and the solution regardless of silica type. The Dubinin-Astakhov, Dubinin-Radushkevich, and Redlich-Peterson equations described the best the process of 18β-GA adsorption onto SBA-15 and Aerosil® silicas that were functionalized with APTMS, MAPTMS, and AEAPTMS, regardless of the method that was used for the estimation of isotherm parameters. Based on nonlinear fitting analysis (Dubinin-Astakhov model), it can be concluded that SBA-15 sorbent that was modified with APTMS, MAPTMS, and AEAPTMS is characterized by twice the adsorption capacity (202.8–237.3 mg/g) as compared to functionalized non-porous silica (118.2–144.2 mg/g).
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Kryszak, D., K. Stawicka, M. Trejda, V. Calvino-Casilda, R. Martin-Aranda et M. Ziolek. « Development of basicity in mesoporous silicas and metallosilicates ». Catalysis Science & ; Technology 7, no 22 (2017) : 5236–48. http://dx.doi.org/10.1039/c7cy00927e.

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Doghri, Hanène, Elena A. Baranova, Belén Albela, Mongia Saïd-Zina et Laurent Bonneviot. « A bio-inspired zinc finger analogue anchored in 2D hexagonal mesoporous silica for room temperature CO2activation via a hydrogenocarbonate route ». New Journal of Chemistry 41, no 14 (2017) : 6795–809. http://dx.doi.org/10.1039/c6nj03329f.

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Bebris, N. K., Yu S. Nikitin, A. A. Pyatygin et N. K. Shoniya. « Synthesis and investigation of porous pyrocarbon-modified silicas ». Journal of Chromatography A 364 (septembre 1986) : 409–24. http://dx.doi.org/10.1016/s0021-9673(00)96231-9.

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Pines, Dina, et Dan Huppert. « Excitation Transfer in Porous Silicas - A Fractal Approach ». Israel Journal of Chemistry 29, no 4 (1989) : 473–85. http://dx.doi.org/10.1002/ijch.198900058.

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López-Asensio, Raquel, Carmen Jiménez Gómez, Cristina García Sancho, Ramón Moreno-Tost, Juan Cecilia et Pedro Maireles-Torres. « Influence of Structure-modifying Agents in the Synthesis of Zr-doped SBA-15 Silica and Their Use as Catalysts in the Furfural Hydrogenation to Obtain High Value-added Products through the Meerwein-Ponndorf-Verley Reduction ». International Journal of Molecular Sciences 20, no 4 (14 février 2019) : 828. http://dx.doi.org/10.3390/ijms20040828.

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Zr-doped mesoporous silicas with different textural parameters have been synthesized in the presence of structure-modifying agents, and then characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption at −196 °C, NH3 thermoprogrammed desorption (NH3–TPD), CO2 thermoprogrammed desorption (CO2–TPD), and X-ray photoelectron spectroscopy (XPS). These porous materials were evaluated in the furfural hydrogenation through the Meerwein-Ponndorf-Verley (MPV) reaction. The catalytic results indicate that the catalyst synthesized under hydrothermal conditions and adding a pore expander agent is more active and selective to furfuryl alcohol. However, the Zr-doped porous silica catalysts that were synthesized at room temperature, which possess narrow pore sizes, tend to form i-propyl furfuryl and difurfuryl ethers, coming from etherification between furfuryl alcohol (FOL) and isopropanol molecules (used as H-donor) by a SN2 mechanism.
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Wang, Junyi, et Yousheng Tao. « Removal of Formaldehyde from the Indoor Environment Using Porous Carbons and Silicas ». Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) 13, no 3 (21 juin 2020) : 194–202. http://dx.doi.org/10.2174/2405520413666200124110348.

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Formaldehyde, carcinogenic for humans, is a common indoor air pollutant emitting from furniture coatings and flooring materials. Porous carbon and silica materials have applications in the removal of formaldehyde because of their large specific surface areas, obedience to surface modification for enhanced adsorption of pollutants, high chemical and mechanical stabilities, and reusability. This work briefly summarized available porous carbon and silica materials for the removal of formaldehyde from the indoor environment.
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Mesa, Monica, et Natalia Y. Becerra. « Silica/Protein and Silica/Polysaccharide Interactions and Their Contributions to the Functional Properties of Derived Hybrid Wound Dressing Hydrogels ». International Journal of Biomaterials 2021 (3 novembre 2021) : 1–13. http://dx.doi.org/10.1155/2021/6857204.

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Multifunctional and biocompatible hydrogels are on the focus of wound healing treatments. Protein and polysaccharides silica hybrids are interesting wound dressing alternatives. The objective of this review is to answer questions such as why silica for wound dressings reinforcement? What are the roles and contributions of silane precursors and silica on the functional properties of hydrogel wound dressings? The effects of tailoring the porous, morphological, and chemical characteristics of synthetic silicas on the bioactivity of hybrid wound dressings hydrogels are explored in the first part of the review. This is followed by a commented review of the mechanisms of silica/protein and silica/polysaccharide interactions and their impact on the barrier, scaffold, and delivery matrix functions of the derived hydrogels. Such information has important consequences for wound healing and paves the way to multidisciplinary researches on the production, processing, and biomedical application of this kind of hybrid materials.
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Roik, N. V., I. M. Trofymchuk, L. O. Belyakova et O. I. Oranska. « Hybrid template directed hydrothermal synthesis of MCM-41 silicas with surface silanol and 3-chloropropyl groups ». Himia, Fizika ta Tehnologia Poverhni 14, no 4 (30 décembre 2023) : 464–73. http://dx.doi.org/10.15407/hftp14.04.464.

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Silicas of MCM-41‑type with reactive functional groups are widely used as starting substrates in large variety of post‑synthetic chemical modification pathways. Therefore, variation of their structural characteristics in the process of templated sol‑gel synthesis or post-synthetic treatment is of great importance. The aim of this work was to elucidate the influence of template agent selection on structural features of MCM-41‑type materials with surface silanol and 3‑chloropropyl groups. For this purpose, template-assisted sol-gel condensation of structure forming silanes (tetraethyl orthosilicate and 3‑chloropropyltriethoxysilane) was carried out in the presence of decyltrimethylammonium bromide as structure-directing agent. The capability of cyclic oligosaccharide (β-cyclodextrin) to interact with surfactant micelles in the process of hydrothermal sol-gel synthesis and to influence the formation of mesoporous structure of silica materials was studied. The IR spectroscopy was applied to carry out control under the complete removal of template moieties from pores by extraction procedure and to confirm introduction of 3‑chloropropyl groups into the surface layer of synthesized silicas. Arrangement of mesoscale pores and structural parameters were estimated from the results of X‑ray diffraction and low-temperature adsorption-desorption of nitrogen. It has been found that β‑cyclodextrin as component of hybrid template has positive effect on porous structure of 3-chloropropyl-functionalized MCM-41-type silica causing increase of surface area accompanied with preservation of pore ordering. Moreover, both ionic surfactant and oligosaccharide components of hybrid template act as porogens during sol-gel condensation of structure forming silanes enable to prepare silica materials with micro-mesoporosity. Proposed approach can be useful in synthesis of MCM‑41‑type silicas with surface linker groups and controlled structural characteristics (pore size, geometry and ordering), which have great potential as substrates in design of sophisticated materials.
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Hongsawat, Parnuch, Panida Prarat, Chawalit Ngamcharussrivichai et Patiparn Punyapalakul. « Adsorption of ciprofloxacin on surface functionalized superparamagnetic porous silicas ». Desalination and Water Treatment 52, no 22-24 (17 juin 2013) : 4430–43. http://dx.doi.org/10.1080/19443994.2013.803795.

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Hartmann, Martin, et Xenia Kostrov. « Immobilization of enzymes on porous silicas – benefits and challenges ». Chemical Society Reviews 42, no 15 (2013) : 6277. http://dx.doi.org/10.1039/c3cs60021a.

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Nomura, Akihiro, et Christopher W. Jones. « Amine-Functionalized Porous Silicas as Adsorbents for Aldehyde Abatement ». ACS Applied Materials & ; Interfaces 5, no 12 (7 juin 2013) : 5569–77. http://dx.doi.org/10.1021/am400810s.

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de Keizer, A., E. M. van der Ent et L. K. Koopal. « Surface and volume charge densities of monodisperse porous silicas ». Colloids and Surfaces A : Physicochemical and Engineering Aspects 142, no 2-3 (décembre 1998) : 303–13. http://dx.doi.org/10.1016/s0927-7757(98)00268-4.

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Tortajada, Marta, Daniel Ramón, Daniel Beltrán et Pedro Amorós. « Hierarchical bimodal porous silicas and organosilicas for enzyme immobilization ». Journal of Materials Chemistry 15, no 35-36 (2005) : 3859. http://dx.doi.org/10.1039/b504605j.

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Shcherban, Nataliya D., Svitlana M. Filonenko, Pavel S. Yaremov, Sergii A. Sergiienko, Volodymir G. Ilyin et Dmitry Yu Murzin. « Carbothermal synthesis of porous silicon carbide using mesoporous silicas ». Journal of Materials Science 52, no 7 (9 décembre 2016) : 3917–26. http://dx.doi.org/10.1007/s10853-016-0652-7.

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Fadeev, Alexander Y., et Valentine A. Eroshenko. « Study of Penetration of Water into Hydrophobized Porous Silicas ». Journal of Colloid and Interface Science 187, no 2 (mars 1997) : 275–82. http://dx.doi.org/10.1006/jcis.1996.4495.

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Mendes, Thiago Melanda, et Wellington Longuini Repette. « Nano-silica added to Portland cement ». Acta Scientiarum. Technology 43 (14 juin 2021) : e51699. http://dx.doi.org/10.4025/actascitechnol.v43i1.51699.

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For a controlled particle size distribution, nano-silica was added to three different cements. The chemical and mineralogical compositions of the cements were characterized by fluorescence and X-ray diffraction. The granulometric distributions of cements and nano-silicas were obtained by laser granulometry and dynamic lightning scattering. The specific surface area of the raw materials was determined by gas adsorption. The effect of nano-silica and type of cement on rheological behavior was evaluated by rotational rheometry. The mechanical performance was investigated through the compression strength. The microstructural analysis was performed by scanning electron microscopy. The water demand and the consumption of dispersant increases according to the nano-silica content. The reduction in the inter-particle separation, and the agglomeration of nano-silica led to an increase in the viscosity of the suspension. The mechanical performance was directly affected by the specific surface area of the cements. Microstructural analysis showed that nano-silica changed from a layered adsorbed structure, to a porous or agglomerated structure.
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Asefa, Tewodros, et Zhimin Tao. « Mesoporous silica and organosilica materials — Review of their synthesis and organic functionalization ». Canadian Journal of Chemistry 90, no 12 (décembre 2012) : 1015–31. http://dx.doi.org/10.1139/v2012-094.

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Mesoporous silica and organosilica materials are a class of nanostructured materials that have porous structures with tunable nanometer pores, large surface areas, high pore volumes, and, in some cases, well-ordered mesostructures. Furthermore, in the case of mesoporous organosilicas, the materials possess various types of organic functional groups. This review highlights the different synthetic methods developed for mesoporous silica and organosilica nanomaterials. The review also discusses the various synthetic strategies used to functionalize the surfaces of mesoporous silica materials and produce highly functionalized mesoporous materials. Rational design and synthetic methods developed to place judiciously chosen one or more than one type of functional group(s) on the surfaces of mesoporous silica materials and generate monofunctional and multifunctional mesoporous silica materials are also introduced. These organic functionalization methods have made possible the synthesis of organically functionalized mesoporous silicas and mesoporous organosilicas with various interesting properties and many potential applications in different areas, ranging from catalysis to drug delivery and biosensing.
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Peng, Lu, Antonio Doménech-Carbó, Ana Primo et Hermenegildo García. « 3D defective graphenes with subnanometric porosity obtained by soft-templating following zeolite procedures ». Nanoscale Advances 1, no 12 (2019) : 4827–33. http://dx.doi.org/10.1039/c9na00554d.

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By applying the templating mechanism employed for the synthesis of mesoporous silicas to the structuration of sodium alginate, a novel defective 3D tubular graphene material (graphenolite) with hierarchical porous structure, very high powder specific surface area (1820 m2 g−1) has been obtained.
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Ivashchenko, N., V. Tertykh, J. Skubiszewska-Zięba, R. Leboda, S. Khainakov et O. Oranska. « Novel Route for Incorporation of Palladium Nanoparticles into Mesostructured Silicas Sba 15 and Sba-16 ». Advanced Composites Letters 22, no 3 (mai 2013) : 096369351302200. http://dx.doi.org/10.1177/096369351302200301.

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Palladium nanoparticles with controlled size were synthesized within the pores of the mesoporous SBA-15 and SBA-16 silicas with grafted silicon hydride groups. Nitrogen adsorption-desorption method, X-ray diffraction and transmission electron microscopy (TEM) were used for characterization of palladium-containing composites. Results of material study clearly revealed that Pd nanoparticles prepared by this method were located inside the porous channels and were quite uniform in size (mostly 5–6 nm). The influence of metal content on the particles size and porous structure of supports was investigated.
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Okada, K., H. Yoshizaki, Y. Kameshima, A. Nakajima et K. J. D. Mackenzie. « Porous properties of mesoporous silicas from two silica sources (acid-leached kaolinite and Si-alkoxide) ». Journal of Porous Materials 17, no 1 (22 janvier 2009) : 19–25. http://dx.doi.org/10.1007/s10934-008-9260-5.

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Tanev, P. T., et T. J. Pinnavaia. « Biomimetic Templating of Porous Lamellar Silicas by Vesicular Surfactant Assemblies ». Science 271, no 5253 (1 mars 1996) : 1267–69. http://dx.doi.org/10.1126/science.271.5253.1267.

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Pires, João, Susana Borges, Ana P. Carvalho et Ana R. Silva. « Porous Silicas and Respective Carbon Replicates for Adsorption and Catalysis ». Adsorption Science & ; Technology 28, no 8-9 (novembre 2010) : 717–26. http://dx.doi.org/10.1260/0263-6174.28.8-9.717.

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Schulz-Ekloff, Günter, Dieter Wöhrle, Bast van Duffel et Robert A. Schoonheydt. « Chromophores in porous silicas and minerals : preparation and optical properties ». Microporous and Mesoporous Materials 51, no 2 (janvier 2002) : 91–138. http://dx.doi.org/10.1016/s1387-1811(01)00455-3.

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Moragues, Alaina, Carmen Guillem, Adela Mauri-Aucejo, Marta Tortajada, Aurelio Beltrán, Daniel Beltrán et Pedro Amorós. « Enlarged pore size in nanoparticulated bimodal porous silicas : Improving accessibility ». Microporous and Mesoporous Materials 221 (février 2016) : 150–58. http://dx.doi.org/10.1016/j.micromeso.2015.09.037.

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Tzialla, O., G. Kakosimos, C. Athanasekou, E. Galata, G. E. Romanos, G. Pilatos, L. F. Zubeir et al. « Porous carbons from ionic liquid precursors confined within nanoporous silicas ». Microporous and Mesoporous Materials 223 (mars 2016) : 163–75. http://dx.doi.org/10.1016/j.micromeso.2015.11.002.

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Frisch, Harry L., Jay M. West, Christine G. Göltner et George S. Attard. « Pseudo IPNs and IPNs of two porous silicas and polystyrene ». Journal of Polymer Science Part A : Polymer Chemistry 34, no 9 (15 juillet 1996) : 1823–26. http://dx.doi.org/10.1002/(sici)1099-0518(19960715)34:9<1823 ::aid-pola22>3.0.co;2-7.

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N. Hay, John, David Porter et Hema M. Raval. « A versatile route to organically-modified silicas and porous silicas via the non-hydrolytic sol–gel process ». Journal of Materials Chemistry 10, no 8 (2000) : 1811–18. http://dx.doi.org/10.1039/a908900d.

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Sydorchuk, V., S. Khalameida, V. Zazhigalov, J. Skubiszewska-Zięba, R. Leboda et K. Wieczorek-Ciurowa. « Influence of mechanochemical activation in various media on structure of porous and non-porous silicas ». Applied Surface Science 257, no 2 (novembre 2010) : 446–50. http://dx.doi.org/10.1016/j.apsusc.2010.07.009.

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