scholarly journals Facile Synthesis and Surface Characterization of Titania-Incorporated Mesoporous Organosilica Materials

2019 ◽  
Vol 3 (3) ◽  
pp. 77
Author(s):  
Chamila Gunathilake ◽  
Chandrakantha Kalpage ◽  
Murthi Kadanapitiye ◽  
Rohan S. Dassanayake ◽  
Amanpreet S. Manchanda ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Triblock Copolymer ◽  
Surface Characterization ◽  
Titanium Isopropoxide ◽  
Ethanol Solution ◽  
Molar Ratio ◽  
Initial Reaction ◽  
Pluronic P123 ◽  
Synthesis Strategy ◽  
Bridging Groups

Titania-incorporated organosilica-mesostructures (Ti-MO) were synthesized using tris [3-(trimethoxysilyl)propyl]isocyanurate, tetraethylorthosilicate as silica precursors, and titanium isopropoxide as the titanium precursor via a co-condensation method in the presence of the triblock copolymer, Pluronic P123. The triblock copolymer was completely removed by extraction with a 95% ethanol solution, followed by a thermal treatment at 350 °C under flowing nitrogen without decomposing isocyanurate bridging groups. The molar ratio of titanium to silica in the mesostructures was gradually changed by increasing the amount of tetraethylorthosilicate in the initial reaction mixture. Our synthesis strategy also allowed us to tailor both adsorption and structural properties, including a well-developed specific surface area, high microporosity, and large pore volume. A portion of the samples was thermally treated at 600 °C to remove both the block copolymer and bridging groups. The thermal treatment at 600 °C was used to convert the amorphous titania into a crystalline anatase form. The Ti-MO materials were characterized using a N2 adsorption desorption analysis, thermogravimetric analysis (TGA), solid state nuclear magnetic resonance (NMR), transmission electron microscope (TEM), and X-ray powder diffraction (XRD). CO2 adsorption studies were also conducted to determine the basicity of the Ti-MO materials. The effect of the surface properties on the CO2 sorption was also identified.

Mesoporous alumina–zirconia–organosilica composites for CO2 capture at ambient and elevated temperatures

2015 ◽  
Vol 3 (6) ◽  
pp. 2707-2716 ◽  
Author(s):  
Chamila Gunathilake ◽  
Mietek Jaroniec
Keyword(s):  
Co2 Capture ◽  
Triblock Copolymer ◽  
Elevated Temperatures ◽  
Mesoporous Alumina ◽  
Pluronic P123 ◽  
Bridging Groups ◽  
Binary Composite

New ternary and binary composite mesostructures consisting of alumina, zirconia and organosilica with isocyanurate bridging groups were synthesized via co-condensation of suitable precursors in the presence of a triblock copolymer, Pluronic P123.

Periodic Mesoporous Organosilicas PMOs with Different Organic Bridging Groups: Synthesis and Characterization

2002 ◽  
Vol 726 ◽  
Author(s):  
Vivian Rebbin ◽  
Olaf Muth ◽  
Michael Fröba
Keyword(s):  
Ir Spectroscopy ◽  
Triblock Copolymer ◽  
Synthesis And Characterization ◽  
Structure Directing Agent ◽  
Periodic Mesoporous Organosilicas ◽  
Pluronic P123 ◽  
Mesoporous Organosilicas ◽  
Bridging Groups

AbstractWe present results on new periodic mesoporous organosilicas synthesized with 1,4-bis(triethoxysilyl)benzene (BTEB), 1,2-bis(trimethoxysilyl)ethane (BTME) and bis[3-(trimethoxysilyl)propyl]amine (BTMPA). The materials show high inner surfaces up to 830 m2/g and pore diameters in the range of 2.7 to 3.7 nm depending on the structure directing agent used. In case of BTEB as precursor and triblock copolymer Pluronic P123 as structure directing agent exceptional thick pore walls were obtained (7.2 nm). Characterization was carried out by P-XRD, nitrogen physisorption analysis, thermoanalytical methods and IR spectroscopy.

scholarly journals Pure hydroxyapatite synthesis originating from amorphous calcium carbonate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michika Sawada ◽  
Kandi Sridhar ◽  
Yasuharu Kanda ◽  
Shinya Yamanaka
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Molar Ratio ◽  
Final Phase ◽  
Amorphous Calcium Carbonate ◽  
Phosphate Compound ◽  
Synthesis Strategy ◽  
Phosphorylation Reaction ◽  
Subsequent Calcination

AbstractWe report a synthesis strategy for pure hydroxyapatite (HAp) using an amorphous calcium carbonate (ACC) colloid as the starting source. Room-temperature phosphorylation and subsequent calcination produce pure HAp via intermediate amorphous calcium phosphate (ACP). The pre-calcined sample undergoes a competitive transformation from ACC to ACP and crystalline calcium carbonate. The water content, ACC concentration, Ca/P molar ratio, and pH during the phosphorylation reaction play crucial roles in the final phase of the crystalline phosphate compound. Pure HAp is formed after ACP is transformed from ACC at a low concentration (1 wt%) of ACC colloid (1.71 < Ca/P < 1.88), whereas Ca/P = 1.51 leads to pure β-tricalcium phosphate. The ACP phases are precursors for calcium phosphate compounds and may determine the final crystalline phase.

scholarly journals Influence of Alumina Precursor Properties on Cu-Fe Alumina Supported Catalysts for Total Toluene Oxidation as a Model Volatile Organic Air Pollutant

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 252
Author(s):  
Tadej Žumbar ◽  
Alenka Ristić ◽  
Goran Dražić ◽  
Hristina Lazarova ◽  
Janez Volavšek ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Iron Concentration ◽  
Catalytic Performance ◽  
Air Pollutant ◽  
Molar Ratio ◽  
Homogeneous Distribution ◽  
Total Oxidation ◽  
Alumina Support ◽  
Determining Factors ◽  
Volatile Organic

The structure–property relationship of catalytic supports for the deposition of redox-active transition metals is of great importance for improving the catalytic efficiency and reusability of the catalysts. In this work, the role of alumina support precursors of Cu-Fe/Al2O3 catalysts used for the total oxidation of toluene as a model volatile organic air pollutant is elucidated. Surface characterization of the catalysts revealed that the surface area, pore volume and acid site concentration of the alumina supports are important but not the determining factors for the catalytic activity of the studied catalysts for this type of reaction. The determining factors are the structural order of the support precursor, the homogeneous distribution of the catalytic sites and reducibility, which were elucidated by XRD, NMR, TEM and temperature programed reduction (TPR). Cu–Fe/Al2O3 prepared from bayerite and pseudoboehmite as highly ordered precursors showed better catalytic performance compared to Cu-Fe/Al2O3 derived from the amorphous alumina precursor and dawsonite. Homogeneous distribution of FexOy and CuOx with defined Cu/Fe molar ratio on the Al2O3 support is required for the efficient catalytic performance of the material. The study showed a beneficial effect of low iron concentration introduced into the alumina precursor during the alumina support synthesis procedure, which resulted in a homogeneous metal oxide distribution on the support.

scholarly journals Promising Immobilization of Industrial-Class Phospholipase A1 to Attain High-Yield Phospholipids Hydrolysis and Repeated Use with Optimal Water Content in Water-in-Oil Microemulsion Phase

2021 ◽  
Vol 11 (4) ◽  
pp. 1456
Author(s):  
Yusuke Hayakawa ◽  
Ryoichi Nakayama ◽  
Norikazu Namiki ◽  
Masanao Imai
Keyword(s):  
Water Content ◽  
Reaction Rate ◽  
Enzyme Reaction ◽  
Initial Reaction Rate ◽  
Industrial Applications ◽  
Molar Ratio ◽  
High Yield ◽  
Initial Reaction ◽  
Phospholipase A1 ◽  
Repeated Use

In this study, we maximized the reactivity of phospholipids hydrolysis with immobilized industrial-class phospholipase A1 (PLA1) at the desired water content in the water-in-oil (W/O) microemulsion phase. The optimal hydrophobic-hydrophilic condition of the reaction media in a hydrophobic enzyme reaction is critical to realize the maximum yields of enzyme activity of phospholipase A1. It was attributed to enzymes disliking hydrophobic surroundings as a special molecular structure for reactivity. Immobilization of PLA1 was successfully achieved with the aid of a hydrophobic carrier (Accurel MP100) combination with the treatment using glutaraldehyde. The immobilized yield was over 90% based on simple adsorption. The hydrolysis reaction was kinetically investigated through the effect of glutaraldehyde treatment of carrier and water content in the W/O microemulsion phase. The initial reaction rate increased linearly with an increasing glutaraldehyde concentration and then leveled off over a 6% glutaraldehyde concentration. The initial reaction rate, which was predominantly driven by the water content in the organic phase, changed according to a typical bell-shaped curve with respect to the molar ratio of water to phospholipid. It behaved in a similar way with different glutaraldehyde concentrations. After 10 cycles of repeated use, the reactivity was well sustained at 40% of the initial reaction rate and the creation of the final product. Accumulated yield after 10 times repetition was sufficient for industrial applications. Immobilized PLA1 has demonstrated potential as a biocatalyst for the production of phospholipid biochemicals.

scholarly journals Polydopamine-Assisted Surface Modification of Ti-6Al-4V Alloy with Anti-Biofilm Activity for Dental Implantology Applications

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1385
Author(s):  
Ioana Cristina Marinas ◽  
Bianca Maria Tihauan ◽  
Andreea Gabriela Diaconu ◽  
Xenia Filip ◽  
Anca Petran ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Surface Characterization ◽  
Molar Ratio ◽  
Antibiofilm Activity ◽  
Microbial Adhesion ◽  
Microbial Biofilms ◽  
No Release ◽  
Logarithmic Reduction ◽  
Solid State 13C Nmr

Coating the surfaces of implantable materials with various active principles to ensure inhibition of microbial adhesion, is a solution to reduce infections associated with dental implant. The aim of the study was to optimize the polydopamine films coating on the Ti-6Al-6V alloy surface in order to obtain a maximum of antimicrobial/antibiofilm efficacy and reduced cytotoxicity. Surface characterization was performed by evaluating the morphology (SEM, AFM) and structures (Solid-state 13C NMR and EPR). Antimicrobial activity was assessed by logarithmic reduction of CFU/mL, and the antibiofilm activity by reducing the adhesion of Escherichia coli, Staphylococcus aureus, and Candida albicans strains. The release of NO was observed especially for C. albicans strain, which confirms the results obtained for microbial adhesion. Among the PDA coatings, for 0.45:0.88 (KMnO4:dopamine) molar ratio the optimal compromise was obtained in terms of antimicrobial activity and cytotoxicity, while the 0.1:1.5 ratio (KMnO4:dopamine) led to higher NO release and implicitly the reduction of the adhesion capacities only for C. albicans, being slightly cytotoxic but with moderate release of LDH. The proposed materials can be used to reduce the adhesion of yeast to the implantable material and thus inhibit the formation of microbial biofilms.

Titanium and Ti-13Nb-13Zr Alloy Porous Implants Obtained by Space-Holder Technique with Addition of Albumin

2012 ◽  
Vol 529-530 ◽  
pp. 574-579
Author(s):  
Tamiye Simone Goia ◽  
Kalan Bastos Violin ◽  
José Carlos Bressiani ◽  
Ana Helena de Almeida Bressiani
Keyword(s):  
Thermal Treatment ◽  
Surface Characterization ◽  
High Vacuum ◽  
Pure Titanium ◽  
Vacuum Furnace ◽  
Metal Powders ◽  
Space Holder ◽  
Significant Difference ◽  
13Zr Alloy ◽  
Hydride Titanium

Titanium and its alloys are the main metals studied as porous metallic implants by their excellent mechanical properties and biological interactions. Production methods of porous metallic materials are based on powder metallurgy (PM), because it allows the manufacturing of parts with complex shapes and dimensions close to the finals (near-net shape), and the addition of alloying elements reaching a satisfactory structural homogeneity, and porosity. The pore production by space-holder technique constitutes of mixing organic compounds with metal powder, which when removed by thermal treatment prior structures are kept in place. The objective of this study is to obtain porous implants of commercially pure titanium (cpTi) and Ti-13Nb-13Zr alloy by PM with space-holder technique and albumin as an additive. For the processing of the samples were used hydride titanium powder (TiH2) to obtain cpTi samples, and metal powders of Ti, Nb and Zr in the stoichiometric proportions for obtaining the alloy samples. The samples were prepared by mixing the metallic powder to the albumin (30wt%) and filling a silicone model that was pressed isostatically (140 MPa). The thermal treatment was performed in an oxidizing atmosphere (350°C/1h) for the decomposition of organic material. The sintering was performed at a temperature of 1300°C (1h/cpTi, 3h/Alloy) in high vacuum furnace (10-5 mBar) to all samples. The calculated porosity showed a significant difference between the samples cpTi (40%) and alloy (60%). The samples surface characterization showed very rough with high specific surface area. Samples of cpTi presented formation of necks arising from sintering. In the alloy samples were observed homogenous microstructure with the presence of α and β phases composing the Widmanstätten structure. It is possible to conclude that the same amount albumin allowed the formation of pores in the microstructure of cpTi and alloy although in different proportions, without harming the sintering of both and allowing diffusion of the alloy elements.

RETRACTED: Morphological Control of CaCO3 Particles by Pluronic P123 Triblock Copolymer in Aqueous Solution

2007 ◽  
Vol 23 (10) ◽  
pp. 1487-1492 ◽  
Author(s):  
X JIANG ◽  
J CAO ◽  
M ZHENG ◽  
J GUO ◽  
S DENG ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Triblock Copolymer ◽  
Morphological Control ◽  
Pluronic P123

scholarly journals Uniform Sb2S3 optical coatings by chemical spray method

2019 ◽  
Vol 10 ◽  
pp. 198-210 ◽  
Author(s):  
Jako S Eensalu ◽  
Atanas Katerski ◽  
Erki Kärber ◽  
Ilona Oja Acik ◽  
Arvo Mere ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Spray Pyrolysis ◽  
Deposition Temperature ◽  
Treatment Temperature ◽  
Molar Ratio ◽  
Optical Coatings ◽  
Phase Reaction ◽  
X Ray ◽  
Chemical Spray ◽  
Post Deposition

Antimony sulfide (Sb2S3), an environmentally benign material, has been prepared by various deposition methods for use as a solar absorber due to its direct band gap of ≈1.7 eV and high absorption coefficient in the visible light spectrum (1.8 × 105 cm−1 at 450 nm). Rapid, scalable, economically viable and controllable in-air growth of continuous, uniform, polycrystalline Sb2S3 absorber layers has not yet been accomplished. This could be achieved with chemical spray pyrolysis, a robust chemical method for deposition of thin films. We applied a two-stage process to produce continuous Sb2S3 optical coatings with uniform thickness. First, amorphous Sb2S3 layers, likely forming by 3D Volmer–Weber island growth through a molten phase reaction between SbCl3 and SC(NH2)2, were deposited in air on a glass/ITO/TiO2 substrate by ultrasonic spraying of methanolic Sb/S 1:3 molar ratio solution at 200–210 °C. Second, we produced polycrystalline uniform films of Sb2S3 (E g 1.8 eV) with a post-deposition thermal treatment of amorphous Sb2S3 layers in vacuum at 170 °C, <4 × 10−6 Torr for 5 minutes. The effects of the deposition temperature, the precursor molar ratio and the thermal treatment temperature on the Sb2S3 layers were investigated using Raman spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and UV–vis–NIR spectroscopy. We demonstrated that Sb2S3 optical coatings with controllable structure, morphology and optical properties can be deposited by ultrasonic spray pyrolysis in air by tuning of the deposition temperature, the Sb/S precursor molar ratio in the spray solution, and the post-deposition treatment temperature.

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