Development of red luminescent nanocomposite based on calcium doped α-Zn2SiO4 nanoparticles embedded in silica matrix

Self-standing macrocellular titanosilicate monolith foams are obtained using a one-pot sol-gel route and show excellent performance in the epoxidation of cyclohexene. Thanks to the High Internal Phase Emulsion (HIPE) templating method, the materials feature a high void fraction, a hierarchically porous texture and good mechanical strength. Highly dispersed Ti species can be incorporated in tetrahedral coordination the silica matrix. These characteristics allow the obtained ‘SiTi(HIPE)’ materials to reach high catalytic turnover in the epoxidation of cyclohexene. The monoliths can advantageously be used to run the reaction in continuous flow mode.<br>

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DETERMINATION OF A SUITABLE CONDITION OF GRAFT COPOLYMERIZATION OF VINYLTRIETHOXYSILANE ONTO NR TO FORM NANOMATRIX STRUCTURE

Rubber Chemistry and Technology ◽

10.5254/rct.18.81545 ◽

2018 ◽

Vol 91 (4) ◽

pp. 767-775 ◽

Cited By ~ 2

Author(s):

Yuanbing Zhou ◽

Yoshimasa Yamamoto ◽

Seiichi Kawahara

Keyword(s):

Silica Nanoparticles ◽

Graft Copolymerization ◽

Monomer Concentration ◽

Minor Component ◽

Suitable Condition ◽

Average Diameter ◽

Silica Matrix ◽

Rubber Particles ◽

Hydrolysis And Condensation ◽

Nanomatrix Structure

ABSTRACT Graft copolymerization of vinyltriethoxysilane (VTES) onto NR particles in the latex stage is a unique reaction, since it occurs together with hydrolysis and condensation of the triethoxysilane group of VTES to form a colloidal silica linking to the rubber particles. These reactions may contribute to the formation of a silica nanomatrix structure that consists of a dispersoid of rubber particles as the major component and a silica matrix as the minor component. Here, the graft copolymerization of VTES followed by hydrolysis and condensation is investigated to determine a suitable condition to prepare NR with a silica nanomatrix structure. The mechanical properties of the resulting graft copolymer are discussed in relation to the morphology, silica content, and gel content of the rubber. Based on morphological observations, NR particles with an average diameter of approximately 1 μm are well dispersed in a nanomatrix consisting of silica nanoparticles. The thickness of the silica nanomatrix increases as the monomer concentration increases, and a long incubation time generates large silica nanoparticles. The tensile strength and viscoelastic properties are significantly improved by forming the silica nanomatrix structure, with its continuous structure that prevents the NR particles from merging.

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Insight into Active Centers and Anti-Coke Behavior of Niobium-Containing SBA-15 for Glycerol Dehydration

Catalysts ◽

10.3390/catal11040488 ◽

2021 ◽

Vol 11 (4) ◽

pp. 488

Author(s):

Katarzyna Stawicka ◽

Maciej Trejda ◽

Maria Ziolek

Keyword(s):

Coke Formation ◽

Catalytic Performance ◽

Acid Sites ◽

Silica Matrix ◽

High Concentration ◽

Active Centers ◽

Acidic Sites ◽

Glycerol Dehydration ◽

Adsorption Desorption ◽

Insight Into

Niobium containing SBA-15 was prepared by two methods: impregnation with different amounts of ammonium niobate(V) oxalate (Nb-15/SBA-15 and Nb-25/SBA-15 containing 15 wt.% and 25 wt.% of Nb, respectively) and mixing of mesoporous silica with Nb2O5 followed by heating at 500 °C (Nb2O5/SBA-15). The use of these two procedures allowed obtaining materials with different textural/surface properties determined by N2 adsorption/desorption isotherms, XRD, UV-Vis, pyridine, and NO adsorption combined with FTIR spectroscopy. Nb2O5/SBA-15 contained exclusively crystalline Nb2O5 on the SBA-15 surface, whereas the materials prepared by impregnation had both metal oxide and niobium incorporated into the silica matrix. The niobium species localized in silica framework generated Brønsted (BAS) and Lewis (LAS) acid sites. The inclusion of niobium into SBA-15 skeleton was crucial for the achievement of high catalytic performance. The strongest BAS were on Nb-25/SBA-15, whereas the highest concentration of BAS and LAS was on Nb-15/SBA-15 surface. Nb2O5/SBA-15 material possessed only weak LAS and BAS. The presence of the strongest BAS (Nb-25/SBA-15) resulted in the highest dehydration activity, whereas a high concentration of BAS was unfavorable. Silylation of niobium catalysts prepared by impregnation reduced the number of acidic sites and significantly increased acrolein yield and selectivity (from ca. 43% selectivity for Nb-25/SBA-15 to ca. 61% for silylated sample). This was accompanied by a considerable decrease in coke formation (from 47% selectivity for Nb-25/SBA-15 to 27% for silylated material).

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Crystallization, Luminescence and Cytocompatibility of Hexagonal Calcium Doped Terbium Phosphate Hydrate Nanoparticles

Nanomaterials ◽

10.3390/nano11020322 ◽

2021 ◽

Vol 11 (2) ◽

pp. 322

Author(s):

Jaime Gómez-Morales ◽

Raquel Fernández-Penas ◽

Ismael Romero-Castillo ◽

Cristóbal Verdugo-Escamilla ◽

Duane Choquesillo-Lazarte ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Doping Concentration ◽

Hydration Number ◽

Maturation Time ◽

Human Carcinoma ◽

Inductively Coupled ◽

Carcinoma Cell Lines ◽

Carbonate Solutions ◽

Human Carcinoma Cell ◽

Calcium Doped

Luminescent lanthanide-containing biocompatible nanosystems represent promising candidates as nanoplatforms for bioimaging applications. Herein, citrate-functionalized calcium-doped terbium phosphate hydrate nanophosphors of the rhabdophane type were prepared at different synthesis times and different Ca2+/Tb3+ ratios by a bioinspired crystallization method consisting of thermal decomplexing of Ca2+/Tb3+/citrate/phosphate/carbonate solutions. Nanoparticles were characterized by XRD, TEM, SEM, HR-TEM, FTIR, Raman, Thermogravimetry, inductively coupled plasma spectroscopy, thermoanalysis, dynamic light scattering, electrophoretic mobility, and fluorescence spectroscopy. They displayed ill-defined isometric morphologies with sizes ≤50 nm, hydration number n ~ 0.9, tailored Ca2+ content (0.42–8.11 wt%), and long luminescent lifetimes (800–2600 µs). Their relative luminescence intensities in solid state are neither affected by Ca2+, citrate content, nor by maturation time for Ca2+ doping concentration in solution below 0.07 M Ca2+. Only at this doping concentration does the maturation time strongly affect this property, decreasing it. In aqueous suspensions, neither pH nor ionic strength nor temperature affect their luminescence properties. All the nanoparticles displayed high cytocompatibility on two human carcinoma cell lines and cell viability correlated positively with the amount of doping Ca2+. Thus, these nanocrystals represent promising new luminescent nanoprobes for potential biomedical applications and, if coupled with targeting and therapeutic moieties, they could be effective tools for theranostics.

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Application of modified green algae Nannochloropsis sp. as adsorbent in the simultaneous adsorption of Methylene Blue and Cu(II) cations in solution

Sustainable Environment Research ◽

10.1186/s42834-021-00090-y ◽

2021 ◽

Vol 31 (1) ◽

Author(s):

Buhani ◽

Tri Agus Wijayanti ◽

Suharso ◽

Sumadi ◽

Muslim Ansori

Keyword(s):

Heavy Metals ◽

Methylene Blue ◽

Green Algae ◽

Contact Time ◽

Organic Dyes ◽

Silica Matrix ◽

Particle Coating ◽

Adsorption Data ◽

Magnetite Particles ◽

Simultaneous Sorption

AbstractBiomass of algae is a very potent adsorbent for absorbing aqueous waste containing heavy metals and organic dyes. This study purposes to confirm the ability of adsorbents from green algae Nannochloropsis sp. modified with silica (ASN) and followed by coating magnetite particles (ASN-MPs) to absorb simultaneously the mixture of Methylene Blue (ME) and Cu(II) cations in aqueous solution. Simultaneous sorption of ME and Cu(II) cations to ASN and ASN-MPs was carried out by the batch method with the interaction pH condition 7, contact time 90 min, and initial concentrations of ME and Cu(II) cations (0.1–1.0 mM). Based on adsorption data, Cu(II) cations have a greater adsorption rate and capacity (qm) compared to ME at the same contact time and initial concentration. The adsorption capacity (qm) values of the bi-component ME and Cu(II) cation mixture in ASN and ASN-MPs were 1.39 × 10− 1 and 5.32 × 10− 1 mmol g− 1, respectively, with the binary Langmuir adsorption isotherm constant for Cu(II) cations greater than ME. Modified adsorbent from algae Nannochloropsis sp. with silica matrix and magnetite particle coating is an adsorbent that has a high effectiveness in the collective sorption of ME and Cu(II) cations. Therefore, these adsorbents can be used for the adsorption of cation mixtures of heavy metals and organic dyes that are cationic in solution.

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Intercalation synthesis of functional hybrid materials based on layered simple hydroxide hosts and ionic liquid guests – a pathway towards multifunctional ionogels without a silica matrix?

Dalton Transactions ◽

10.1039/c1dt10841g ◽

2011 ◽

Vol 40 (39) ◽

pp. 9977 ◽

Cited By ~ 19

Author(s):

Emilie Delahaye ◽

Zailai Xie ◽

Andreas Schaefer ◽

Laurent Douce ◽

Guillaume Rogez ◽

...

Keyword(s):

Ionic Liquid ◽

Hybrid Materials ◽

Silica Matrix

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Tantalum doped SiO2-CaO-P2O5 based bioactive glasses: Investigation of in vitro bioactivity and antibacterial activities

Biomedical glasses ◽

10.1515/bglass-2020-0002 ◽

2020 ◽

Vol 6 (1) ◽

pp. 10-22

Author(s):

Zakaria Tabia ◽

Sihame Akhtach ◽

Khalil El Mabrouk ◽

Meriame Bricha ◽

Khalid Nouneh ◽

...

Keyword(s):

Antibacterial Activities ◽

Silica Matrix ◽

Morphological Properties ◽

Metallic Ions ◽

X Ray Diffraction ◽

Bioactive Glasses ◽

E Coli ◽

Fourier Transformed Infrared Spectroscopy ◽

Electron Scanning Microscopy

AbstractMultifunctionality can be achieved for bioactive glasses by endowing them with multiple other properties along with bioactivity. One way to address this topic is by doping these glasses with therapeutic metallic ions. In this work, we put under investigation a series of bioactive glasses doped with tantalum. We aim to study the effect of tantalum, on the structure, bioactivity and antibacterial property of a ternary bioactive glass composition based on SiO2-CaO-P2O5. Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Electron Scanning Microscopy (SEM) were used to assess the structural and morphological properties of these glasses and monitor their changes after in vitro acellular bioactivity test. Antibacterial activity was tested against gram positive and negative bacteria. Characterization results confirmed the presence of calcium carbonate crystallites along with the amorphous silica matrix. The assessment of bioactivity in SBF indicated that all compositions showed a fast bioactive response after only six hours of immersion period. However, analytical characterization revealed that tantalum introduced a slight latency in hydroxyapatite deposition at higher concentrations (0.8-1 %mol). Antibacterial test showed that tantalum ions had an inhibition effect on the growth of E. coli and S. aureus. This effect was more pronounced in compositions where mol% of tantalum is superior to 0.4%. These results proved that tantalum could be used, in intermediate proportions, as a promising multifunctional dopant element in bioactive glasses for bone regeneration applications.

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Synthesis, Structural, Morphological and Thermal Characterization of Five Different Silica-Polyethylene Glycol-Chlorogenic Acid Hybrid Materials

Polymers ◽

10.3390/polym13101586 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1586

Author(s):

Michelina Catauro ◽

Pavel Šiler ◽

Jiří Másilko ◽

Roberta Risoluti ◽

Stefano Vecchio Ciprioti

Keyword(s):

Polyethylene Glycol ◽

Chlorogenic Acid ◽

Hybrid Materials ◽

Sol Gel ◽

Antibacterial Properties ◽

Silica Matrix ◽

Sem Images ◽

Fixed Amount ◽

Organic Components ◽

Free Material

The present study investigated the structure, morphology, thermal behavior, and bacterial growth analysis of novel three-component hybrid materials synthesized by the sol-gel method. The inorganic silica matrix was weakly bonded to the network of two organic components: a well-known polymer such as polyethylene glycol (PEG, average molar mass of about 4000 g/mol), and an antioxidant constituted by chlorogenic acid (CGA). In particular, a first series was made by a 50 wt% PEG-based (CGA-free) silica hybrid along with two 50 wt% PEG-based hybrids containing 10 and 20 wt% of CGA (denoted as SP50, SP50C10 and SP50C20, respectively). A second series contained a fixed amount of CGA (20 wt%) in silica-based hybrids: one was the PEG-free material (SC20) and the other two contained 12 and 50 wt% of PEG, respectively (SP12C20 and SP50C20, respectively), being the latter already included in the first series. The X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images of freshly prepared materials confirmed that all the materials were amorphous and homogeneous regardless of the content of PEG or CGA. The thermogravimetric (TG) analysis revealed a higher water content was adsorbed into the two component hybrids (SP50 and SC20) because of the availability of a larger number of H-bonds to be formed with water with respect to those of silica/PEG/CGA (SPC), where silica matrix was involved in these bonds with both organic components. Conversely, the PEG-rich materials (SP50C10 and SP50C20, both with 50 wt% of the polymer) retained a lower content of water. Decomposition of PEG and CGA occurred in almost the same temperature interval regardless of the content of each organic component. The antibacterial properties of the SiO2/PEG/CGA hybrid materials were studied in pellets using either Escherichia coli and Enterococcus faecalis, respectively. Excellent antibacterial activity was found against both bacteria regardless of the amount of polymer in the hybrids.

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