scholarly journals Hybrid system «layered magnesium silicate – chlorin е6 13(1),15(2),17(3)-N,N',N''-(2-hydroxyethyl)triamide»

2020 ◽  
Vol 62 (4) ◽  
pp. 12-18
Author(s):  
Inna V. Loukhina ◽  
Keyword(s):  
Hybrid Systems ◽  
Methyl Ether ◽  
Visible Region ◽  
Magnesium Silicate ◽  
Organic Component ◽  
Chlorin E6 ◽  
Molar Ratio ◽  
Aggregative Stability ◽  
Hydroxyl Groups ◽  
Hybrid Particles

Matrices based on layered silicates have a set of useful properties, in particular, they are able to increase the stability and photosensitizing ability of porphyrins. Hybrid systems “layered silicate - porphyrin (metal porphyrin)” are promising as active components of systems for light collecting and artificial photosynthesis, catalysts, photocatalysts. The hybrid systems with content of 1.4∙10-6 and 4.2∙10-6 mol of the chlorin e6 13(1),15(2),17(3)-N,N',N''-(2-hydroxyethyl)triamide per 1 g of layered magnesium silicate was obtained by heat treatment method of a synthetic layered magnesium silicate of hectorite composition when treated with an aqueous-alcoholic solution of organic component. The molar ratio of the starting components is: Mg(OH)2 : SiO2 : LiF = 1 : 1.51 : 0.25 : chlorin e6 derivative = 1 : 1.51 : 0.25 : (19.93∙10-5 – 59.58∙10-5). Using dynamic light scattering and laser Doppler electrophoresis, it was shown that the introduction of chlorin e6 13(1),15(2),17 (3)-N,N',N''- (2-hydroxyethyl) triamide leads to the growth of hybrid particles (162 ± 3 nm) and a decrease in their aggregative stability (-30 ± 1 mV), compared with the initial layered magnesium silicate (133 ± 1 nm, -33 ± 1 mV). In this case, the introduction of more hydrophilic chlorin e6 13(1),15(2),17(3)-N,N',N''-(2-hydroxyethyl)triamidе, in the molecule of which there are three fragments of ethanolamine, allows to obtain smaller hybrid particles (162 ± 3 nm), compared with hybrid particles (248 ± 6 nm) formed by the action of chlorin e6 13(1),17(3)-N,N'-(2-hydroxyethyl)diamide15(2)-methyl ether, in the molecule of which there are two fragments of ethanolamine. Using the methods of X-ray phase analysis and electron spectroscopy in the UV-visible region, it was found that individual molecules of chlorin e6 13(1),15(2),17(3)-N,N',N''-(2-hydroxyethyl)triamide were sorbed on the surface of silicate particles due to the electrostatic interaction between the protonated molecules of the macrocycle and the ionized hydroxyl groups of magnesium silicate. It was shown that the higher hydrophilicity of chlorin e6 13(1),15(2),17(3)-N,N',N''-(2-hydroxyethyl)triamide, compared with chlorin e6 13(1),17(3)-N,N'-(2-hydroxyethyl)diamide15(2)-methyl ether did not contribute to the intercalation of the organic component into the interlayer space of layered magnesium silicate under the conditions of a water-alcohol medium.

scholarly journals Hybrid system «layered magnesium silicate – chlorin е6 13(1), 17(3)-N,N'-(2-hydroxyethyl)diamide 15(2)-methyl ester»

2019 ◽  
Vol 58 (4) ◽  
pp. 34-39
Author(s):  
Inna V. Loukhina ◽  
◽  
Irina S. Khudyaeva ◽  
Anna Yu. Bugaeva ◽  
Dmitry V. Belykh ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Methyl Ester ◽  
Magnesium Silicate ◽  
Soret Band ◽  
Ethanol Solution ◽  
Chlorin E6 ◽  
Molar Ratio ◽  
Hydroxyl Groups ◽  
Vis Spectroscopy ◽  
Chlorine E6

Hectorite type layered magnesium silicate have been synthesized by heat treatment of reaction mixture freshly prepared magnesium hydroxide suspension, silica sol, lithium fluoride solution. The starting Mg(OH)2 : SiO2 : LiF molar ratio was 1 : 1.51 : 0.25. Hybrid systems have been synthesized by heat treatment of synthetic layered magnesium silicate in water-ethanol solution of chlorin е6 13 (1), 17(3)-N,N'-(2-hydroxyethyl) diamide 15(2)-methyl ester. The systems contain of 0.85∙10-6 and 1.4∙10-6mol of the organic component per 1 g of layered magnesium silicate. The introduction of the chlorin e6 derivative into hectorite type layered magnesium silicate sol promotes the aggregation processes and growth particles of the hybrid samples (250±5 nm), as compared with the particles of magnesium silicate (133±1 nm). X-ray phase analysis, UV-Vis spectroscopy and laser Doppler electrophoresis studies have been allowed to establish that non-aggregated molecules of the chlorin e6 derivative are located on the surface of magnesium silicate particles.UV-Vis spectroscopy study showed protonation of nitrogen atoms of the chlorine macrocycle of the chlorin e6 derivative molecules (Soret band 405-406 nm; Q-band 642-643 nm) by hydroxyl groups of the layered magnesium silicate. Chlorin е6 13 (1), 17(3)-N,N'-(2-hydroxyethyl) diamide 15(2)-methyl ester sorption on the surface of magnesium silicate particles occurs due to electrostatic interaction between protonated chlorine e6 derivative molecules and ionized hydroxyl groups of the magnesium silicate.

scholarly journals Green Synthesis of N/Zr Co-Doped TiO2 for Photocatalytic Degradation of p-Nitrophenol in Wastewater

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 235
Author(s):  
Hayette Benkhennouche-Bouchene ◽  
Julien G. Mahy ◽  
Cédric Wolfs ◽  
Bénédicte Vertruyen ◽  
Dirk Poelman ◽  
...  
Keyword(s):  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Sol Gel ◽  
Visible Region ◽  
Chemical Properties ◽  
Pure Tio2 ◽  
Molar Ratio ◽  
Xps Spectra ◽  
Doped Tio2 ◽  
Co Doped

TiO2 prepared by a green aqueous sol–gel peptization process is co-doped with nitrogen and zirconium to improve and extend its photoactivity to the visible region. Two nitrogen precursors are used: urea and triethylamine; zirconium (IV) tert-butoxide is added as a source of zirconia. The N/Ti molar ratio is fixed regardless of the chosen nitrogen precursor while the quantity of zirconia is set to 0.7, 1.4, 2, or 2.8 mol%. The performance and physico-chemical properties of these materials are compared with the commercial Evonik P25 photocatalyst. For all doped and co-doped samples, TiO2 nanoparticles of 4 to 8 nm of size are formed of anatase-brookite phases, with a specific surface area between 125 and 280 m2 g−1 vs. 50 m2 g−1 for the commercial P25 photocatalyst. X-ray photoelectron (XPS) measurements show that nitrogen is incorporated into the TiO2 materials through Ti-O-N bonds allowing light absorption in the visible region. The XPS spectra of the Zr-(co)doped powders show the presence of TiO2-ZrO2 mixed oxide materials. Under visible light, the best co-doped sample gives a degradation of p-nitrophenol (PNP) equal to 70% instead of 25% with pure TiO2 and 10% with P25 under the same conditions. Similarly, the photocatalytic activity improved under UV/visible reaching 95% with the best sample compared to 50% with pure TiO2. This study suggests that N/Zr co-doped TiO2 nanoparticles can be produced in a safe and energy-efficient way while being markedly more active than state-of-the-art photocatalytic materials under visible light.

Control the Surface Wettability of Thermo-Responsive Poly(Ethylene Glycol Methyl Ether methacrylate-co-Triethylene Glycol Methyl Ether Methacrylate) Thin Film by Varying Temperature

2021 ◽  
Vol 873 ◽  
pp. 53-58
Author(s):  
Yang Yi Chen ◽  
Min Pan ◽  
Shan Hong Hu ◽  
Qi Huan ◽  
Chu Yang Zhang
Keyword(s):  
Thin Film ◽  
Ethylene Glycol ◽  
Methyl Ether ◽  
Triethylene Glycol ◽  
Surface Wettability ◽  
Molar Ratio ◽  
Poly Ethylene Glycol ◽  
Vis Spectroscopy ◽  
Poly Ethylene ◽  
Glycol Methyl Ether

The surface wettability of thermo-responsive random poly (ethylene glycol methyl ether methacrylate-co-triethylene glycol methyl ether methacrylate), abbreviated as P(MEOMA-co-MEO3MA), was investigated in thin film. UV-Vis spectroscopy shows that the LCST of P(MEOMA-co-MEO3MA) with molar ratios of 0:20, 6:14 and 9:11 were 43°C, 32 oC and 25 oC, respectively. LCST shifts towards lower temperature when molar ratio of MEOMA increases. ATR-FTIR indicates that P(MEOMA-co-MEO3MA) thin film experienced a collapse when the temperature passes its LCST. The contact angle of the paraffin oil on the film decreases 15o when the temperature is above its LCST, which confirms the surface wettability can be controlled. Atomic force microscopy shows the surface of the swollen thin film becomes rougher when above it LCST.

scholarly journals Preparation of Fe-DopedTiO2Nanotubes and Their Photocatalytic Activities under Visible Light

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang
Keyword(s):  
Visible Light ◽  
Visible Region ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Ultrasonic Assisted ◽  
Uv Visible

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.

scholarly journals Preparation of Ni Doped ZnO-TiO2Composites and Their Enhanced Photocatalytic Activity

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaowen Zou ◽  
Xiaoli Dong ◽  
Limei Wang ◽  
Hongchao Ma ◽  
Xinxin Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Visible Region ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Surface Hydroxyl ◽  
Simulated Solar Light ◽  
Transmission Electron ◽  
Doped Zno

Herein, Ni doped ZnO-TiO2composites were prepared by facile sol-gel approach and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectroscopy (PL). The results indicated that the Ni ions can be incorporated into the lattice of TiO2structure and replace Ti. The introduction of Ni expanded light absorption of TiO2to visible region, increased amount of surface hydroxyl groups and physically adsorbed oxygen (as the electronic scavenges), and then enhanced separation rate of photogenerated carriers. The photodegradation test of reactive brilliant blue (KN-R) under simulated solar light indicated that Ni doped ZnO-TiO2composites have better photocatalytic activities, as compared to those of TiO2and ZnO-TiO2.

Synthesis and Characterization of Carboxyl-Terminated Hyperbranched Polyester

2014 ◽  
Vol 665 ◽  
pp. 327-330
Author(s):  
Shi Jie Niu ◽  
Jian Wang ◽  
Yu Qing Bai ◽  
Ming Tao Run
Keyword(s):  
Glass Transition ◽  
Sodium Acetate ◽  
Succinic Anhydride ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Hydroxyl Groups ◽  
Hyperbranched Polyester ◽  
End Groups ◽  
Lower Glass Transition Temperature

In order to prepare carboxyl-terminated hyperbranched polyester (HBP-COOH), succinic anhydride was used to modify hydroxyl-terminated hyperbranched polyester (HBP-OH), and the influences of the solvents, catalysts and time on the product’s structure were investigated. When THF is used as the solvent, sodium acetate as the catalyst, the molar ratio of succinic anhydride and hydroxyl groups is 3:1, and the reaction time is 6 h at 65°C, the modification extent of the hydroxyl groups is about 99% with about 95% yield. HBP-COOH has much lower glass transition temperature than that of HBP-OH due to its long and flexible end-groups.

A toxic substance from Aspergillus viridi-nutans

1972 ◽  
Vol 18 (2) ◽  
pp. 193-197 ◽  
Author(s):  
E. B. Lillehoj ◽  
A. Ciegler
Keyword(s):  
Toxic Substance ◽  
Magnesium Silicate ◽  
Ultraviolet Spectrum ◽  
Hydroxyl Groups ◽  
Molecular Formula ◽  
Excitation Band ◽  
Distinctive Features ◽  
Wet Weight ◽  
Solvent Systems ◽  
Fluorescent Spot

A compound toxic to mice has been extracted from mycelia of Aspergillus viridi-nutans NRRL 4365, a member of the A. fumigatus group. After 2 weeks of growth on a Raulin-Thom medium in static culture at 28C, up to 2 g of toxin could be recovered from 300 g (wet weight) of mycelium. After the compound was isolated by chromatographic separation on activated magnesium silicate columns, the purified fraction was readily crystallized from cold benzene. A suspension of the substance in propylene glycol (administered intraperitoneally) had an LD50 of 2.8 mg/kg in 20-g mice. The toxin was highly fluorescent, exhibiting a 382-nm excitation band and an emission maximum at 450 nm. In thin-layer chromatographic analyses the crystalline compound appeared as a single fluorescent spot in two different solvent systems. The ultraviolet spectrum of the metabolite showed absorption maxima at 380 and 266 nm. Distinctive features of the infrared spectrum were the presence of chelated hydroxyl groups and a carbonyl ester function. Mass spectrometry demonstrated that the molecular weight of the toxin was 662 with a molecular formula of C34H30O14. Chemical microanalysis verified the formula and provided evidence of four methoxyl groups.

Optical properties of ZnO nanoparticles synthesized by varying the sodium hydroxide to zinc acetate molar ratios using a Sol-Gel process

Open Physics ◽  
2011 ◽  
Vol 9 (5) ◽  
Author(s):  
Francis Dejene ◽  
Abdub Ali ◽  
Hendrik Swart ◽  
Reinhardt Botha ◽  
Kittesa Roro ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Sol Gel ◽  
Visible Region ◽  
Blue Emission ◽  
Molar Ratio ◽  
Broad Emission Band ◽  
Photoluminescence Intensity ◽  
Molar Ratios ◽  
Quantum Confinement Effects ◽  
Sol Gel Process

AbstractMaterial property dependence on the OH−/Zn2+ molar ratio of the precursor was investigated by varying the amount of NaOH during synthesis of ZnO. It was necessary to control the water content and temperature of the mixture to ensure the reproducibility. It was observed that the structural properties, particle size, photoluminescence intensity and wavelength of maximum intensity were influenced by the molar ratio of the precursor. The XRD spectra for ZnO nanoparticles show the entire peaks corresponding to the various planes of wurtzite ZnO, indicating a single phase. UV measurements show the absorption that comes from the ZnO nanoparticles in visible region. The absorption edge of these ZnO nanoparticles are shifted to higher energies and the determined band gap energies are blue shifted as the OH−/Zn2 molar ration increases, due to the quantum confinement effects. The photoluminescence characterization of the ZnO nanostructures exhibited a broad emission band centred at green (600 nm) region for all molar ratios except for OH−/Zn2+ = 1.7 where a second blue emission around 468 nm was also observed. The photoluminescence properties of ZnO nanoparticles were largely determined by the size and surface properties of the nanoparticles.

Thermal Effects in Plasma Treatment of Patterned PDMS for Bonding Stacked Channels

2003 ◽  
Vol 782 ◽  
Author(s):  
Jin Zou ◽  
Peter Y. Wong
Keyword(s):  
Silicon Nitride ◽  
Hybrid Systems ◽  
Thermal Effects ◽  
Room Temperature ◽  
Work Of Adhesion ◽  
Chemical Components ◽  
Hydroxyl Groups ◽  
Processing Temperature ◽  
Plasma Oxidation ◽  
Bond Quality

ABSTRACTThis paper presents the results of a study to identify the effects of preheating for plasma oxidation (ashing) of patterned Polydimethylsiloxane (PDMS) for Bio-MEMS applications. PDMS creates an irreversible seal to itself as well as strong seals with glass, silicon, and silicon nitride. This process activates the surface by producing hydroxyl groups that last for several minutes to allow bonding. Several channels can be stacked to create 3D systems for microfluidic applications using PDMS alone or in combination with other materials to develop hybrid systems. For PDMS, bonding temperatures typically occur at room temperature. This research investigates the effect of preheating the materials prior to ashing. The investigators successfully demonstrate good bonding of PDMS to slides with a work adhesion on the order of 100 mJm-2. Preheating the samples at 65°C results in significant increase in work adhesion depending on mixture. The effects of processing temperature and chemical components on bond quality and work of adhesion are reported.

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