The Selective Protein Separations with Polyaminofunctionality on Controlled Silica Coating-Layers of Magnetic Nanoparticles

2007 ◽  
Vol 124-126 ◽  
pp. 903-906 ◽  
Author(s):  
Moo Eon Park ◽  
Ki Ho Kang ◽  
Kyung Ja Kim ◽  
Jeong Ho Chang
Keyword(s):  
Magnetic Nanoparticles ◽  
Protein Separation ◽  
Separation Efficiency ◽  
Sol Gel ◽  
Silica Coating ◽  
Chemical Precipitation ◽  
Molar Ratio ◽  
Basic Solution ◽  
Particle Sizes ◽  
Protein Separations

This work reported the development of the high throughput protein separation process with molecularly assembled silica-coated magnetic nanoparticles as a function of amino group numbers such as mono-, di-, and tri-aminofunctionality, in which the range of silica coating thicknesses were optimized to be interacted with protein. The protein separation efficiency was demonstrated as a function of each aminofunctional group and the particle sizes of the silica coated magnetic nanoparticles. The particles were prepared by the chemical precipitation of Fe2+ and Fe3+ salts with a molar ratio of 1:2 under basic solution. The silica coated magnetic nanoparticles were directly produced by the sol-gel reaction of a tetraethyl orthosilicate (TEOS) precursor, in which the coating layer serves as a biocompatible and versatile group for further biomolecular functionalization. To effectively capture the proteins, silica coated magnetic nanoparticles need to be functionalized reproducibly on the silica surface, and three kinds of amino functional groups were adapted as a function of number of amine using the mono-, di-, and tri-aminopropylalkoxysilanes.

Effect of Catalyst Type on Structural, Morphological, and Optical Properties of SiO2 Thin Film Applied by Sol-Gel Method

2013 ◽  
Vol 829 ◽  
pp. 446-450
Author(s):  
Najme Lari ◽  
Shahrokh Ahangarani ◽  
Ali Shanaghi
Keyword(s):  
Sol Gel ◽  
Silica Coating ◽  
Molar Ratio ◽  
Antireflective Coatings ◽  
Adhesive Properties ◽  
Gel Method ◽  
Sol Gel Method ◽  
Catalyst Type ◽  
Solar Thermal Collectors ◽  
Infrared Spectrophotometer

The application of antireflective coatings to the glass covers of solar thermal collectors, allows increasing the efficiency of the whole system. Among the methods for applying nanostructure coatings, sol-gel method was selected in this study. Via this method, an antireflective silica coating deposited on glass and the solar transmittance was investigated. The precursor solutions were made by mixing tetraethylorthosilicate (TEOS), ethanol, water and alkali (NH3) or acid (HNO3) catalyst in the molar ratio of 1:3.5:0.35:0.005. In addition, the role of two types of catalysts was examined. UV-visible spectroscopy, Fourier-transformed infrared spectrophotometer, Scanning electron and Optical microscopy were used for the characterization of silica thin films. Results showed that nanoporous silica layers cause to considerable reduction of these light reflections compared with uncoated glasses. It was found that the amount of reduction as well as the adhesive properties is depending on the type of catalyst. Results revealed that not only solar transmittance of acidic-catalyzed coatings is higher than of alkali-catalyzed coatings, but also acidic-catalyzed coatings possess adhesive-resistance higher than alkali-catalyzed coatings. However, at high pH condition, the condensation rate is very fast, and the growth tends to form spherically expanding clusters cause to increasing porosity. The dense and strong binding acidic-catalyzed films have a good antireflective property; because of that, the nanoporousity appears on the surface.

scholarly journals Sol-Gel Syntheses of Zinc Oxide and Hydrogenated Zinc Oxide (ZnO:H) Phases

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Joshua Lelesi Konne ◽  
Bright Obum Christopher
Keyword(s):  
Zinc Oxide ◽  
Gas Flow ◽  
Sol Gel ◽  
Glass Tube ◽  
Chemical Precipitation ◽  
Particle Sizes ◽  
Absorption Bands ◽  
Main Components ◽  
P Type ◽  
Ir Bands

ZnO synthesized by chemical precipitation with varying starch concentrations (0.00, 0.01, 0.02, 0.05, 0.10, 0.15, and 0.20%) as stabilizing agent was used in making ZnO:H when placed in a glass tube under mild heat and hydrogen (H2) gas flow for 2 mins. Observations showed that the sample colour changed from white to light brown and finally to dark brown during the process particularly for the ZnO-starch samples. XRD data of ZnO (0.02%) and ZnO:H (0.02%) showed ZnO as the major phase with Zn(OH)2 impurity phase and a new ZnO:H peak at 2θ, 29.60° for ZnO and ZnO:H, respectively. The estimated particle sizes determined from XRD were 47 and 30 nm, respectively. The SEM of the 0.02% ZnO appeared more microporous and needle-like than those of 0.01%, while the EDX of both confirmed Zn and O as the main components. Different conductivities of 30.90 and 27.50 μS/cm were obtained for ZnO and ZnO:H samples in ethanol, respectively. Also, the UV-Vis absorption for both showed n-type and p-type material absorption bands at 310 cm−1, while the intensities of all the characteristic ZnO IR bands at 430–552 (ZnO vibrations) and 1500–1640 cm−1 (Zn-O stretching) increased for the corresponding ZnO:H samples.

Influence of Calcination Temperature on Synthesis of Magnetite (Fe3O4) Nanoparticles by Sol-Gel Method

2014 ◽  
Vol 979 ◽  
pp. 208-211 ◽  
Author(s):  
Apichaya Worawong ◽  
Tula Jutarosaga ◽  
Wandee Onreabroy
Keyword(s):  
Magnetic Nanoparticles ◽  
Calcination Temperature ◽  
Sol Gel ◽  
Ferric Nitrate ◽  
Particle Sizes ◽  
Sem Images ◽  
Gel Method ◽  
Sol Gel Method ◽  
Size And Morphology ◽  
Xrd Patterns

Magnetite (Fe3O4) nanoparticles were successfully synthesized by the sol-gel method from ferric nitrate-EG (EG=ethylene glycol) gel. The precursors were calcined in argon under an atmospheric pressure at the temperatures varied from 400°C to 500°C. The synthesized magnetic nanoparticles were characterized by X-ray diffractrometer (XRD), field emission scanning electron microscope (FE-SEM) and vibrating sample magnetometer (VSM). The XRD patterns of powder calcined temperature at 400๐C showed clearer Fe3O4phase than those calcined at other temperatures. The particle size and morphology of magnetic nanoparticles were studied using FE-SEM. The FE-SEM images showed that the particle sizes varied from 30-108 nm. The particle sizes increased with the increase of calcination temperature. VSM measurements indicated that the Fe3O4nanoparticles were soft ferrite with the maximum magnetization (Mm) and coercivity (Hc) of 35 emu/g and 17 Oe, respectively.

scholarly journals Synthesis and characterization of magnetic nanoparticles coated with silica through a sol-gel approach

Cerâmica ◽  
2009 ◽  
Vol 55 (336) ◽  
pp. 420-424 ◽  
Author(s):  
A. L. Andrade ◽  
D. M. Souza ◽  
M. C. Pereira ◽  
J. D. Fabris ◽  
R. Z. Domingues
Keyword(s):  
Fourier Transform ◽  
Magnetic Nanoparticles ◽  
Magnetite Nanoparticles ◽  
Sol Gel ◽  
Reaction Medium ◽  
Fourier Transform Infrared ◽  
Silica Coating ◽  
Precipitation Method ◽  
Pure Silica

This paper investigates the influence of reaction medium pH on silica-coating of magnetite nanoparticles. Magnetite nanoparticles were prepared by means of a reduction-precipitation method using ferric chloride as a starting material, which was partially reduced to ferrous salts by Na2SO3 before alkalinizing with ammonia. The particles were coated by sol-gel method with either ammonia or HCl aqueous solutions for either base- or acid-catalyzed hydrolysis, respectively. Powder X-ray diffraction, Fourier-transform infrared, and Zeta Potential were used for the characterization of oxides and of the coated magnetic nanoparticles. The observed difference of pH IEP in KCl solution for pure silica (2.0), magnetite (5.0), and silica-coated magnetite (2.3) samples confirms that the coating process was effective since the charge surface properties of coated magnetic nanoparticles are close to that of pure silica, even though the Fourier-transform infrared spectra did not evidence the formation of Fe-O-Si bonds.

Synthesis and Characterization of ZnO, CuO and CuO/ZnO Nanostructures by a Novel Sol-Gel Route under Ultrasonic Conditions

2012 ◽  
Vol 545 ◽  
pp. 64-70 ◽  
Author(s):  
I.B. Abdul Rahman ◽  
M.T.M. Ayob ◽  
Faizal Mohamed ◽  
Norinsan Kamil Othman ◽  
R.L. Mohd Lawi ◽  
...  
Keyword(s):  
Sol Gel ◽  
Metal Nitrate ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Particle Sizes ◽  
Oxide Materials ◽  
Metallic Oxides ◽  
Fine Powders ◽  
Ultrasonic Conditions

Great interests in metallic oxides have emerged because of the possibility to modify the properties of these materials for different applications such as catalysis or sensors. In this work, CuO, ZnO and CuO-ZnO nanoparticles were prepared by a novel sol-gel route under ultrasonic condition using triethanolamine as an emulsifying surfactant. Fine powders were obtained when the pH of the sols were increased to 13 using NaOH. Particle sizes of the produced oxide materials were in the range of 3-4 nm, 40-50 x 100-150 nm (diameter x length) and 100-200 nm for CuO, ZnO and CuO-ZnO, respectively. The molar ratio of triethanolamine to metal nitrate precursors was set at 2:3. TEM micrographs of these particles were obtained to elucidate the morphology of the nanoparticles. Experimental results show that the band gap energies (Eg) for CuO, ZnO and CuO-ZnO were found to be 2.71, 3.35 and 2.82 eV, respectively.

Efficient Micromixing for Continuous Biodiesel Production from Jatropha Oil

2018 ◽  
Vol 9 (1) ◽  
pp. 133-139
Author(s):  
Waleed S. Mohammed ◽  
Ahmed H. El-Shazly ◽  
Marwa F. Elkady ◽  
Masahiro Ohshima
Keyword(s):  
Methyl Esters ◽  
Continuous Process ◽  
Sol Gel ◽  
Average Diameter ◽  
Biodiesel Production ◽  
High Mass ◽  
Molar Ratio ◽  
Jatropha Oil ◽  
Energy Deficiency ◽  
Gel Preparation

Introduction: The utilization of biodiesel as an alternative fuel is turning out to be progressively famous these days because of worldwide energy deficiency. The enthusiasm for utilizing Jatropha as a non-edible oil feedstock is quickly developing. The performance of the base catalyzed methanolysis reaction could be improved by a continuous process through a microreactor in view of the high mass transfer coefficient of this technique. Materials & Methods: Nanozirconium tungstovanadate, which was synthetized using sol-gel preparation method, was utilized in a complementary step for biodiesel production process. The prepared material has an average diameter of 0.066 &µm. Results: First, the NaOH catalyzed methanolysis of Jatropha oil was investigated in a continuous microreactor, and the efficient mixing over different mixers and its impact on the biodiesel yield were studied under varied conditions. Second, the effect of adding the nanocatalyst as a second stage was investigated. Conclusion: The maximum percentage of produced methyl esters from Jatropha oil was 98.1% using a methanol/Jatropha oil molar ratio of 11 within 94 s using 1% NaOH at 60 &°C. The same maximum conversion ratio was recorded with the nanocatalyst via only 0.3% NaOH.

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.

scholarly journals Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1417
Author(s):  
Min Zhuang ◽  
Wen Shi ◽  
Hui Wang ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Surface Passivation ◽  
Bimetallic Nanoparticles ◽  
Zero Valent Iron ◽  
Molar Ratio ◽  
Particle Sizes ◽  
Iron Corrosion ◽  
Graphitized Carbon ◽  
Nanoscale Zero Valent Iron ◽  
Iron Nickel

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

Sol-Gel Synthesis and Characterization of Ultrafine ZrSiO4 Powder

2014 ◽  
Vol 906 ◽  
pp. 66-71
Author(s):  
Zhen Quan Li ◽  
Qiang Zhen ◽  
Ya Li Wang
Keyword(s):  
Wavelength Range ◽  
High Purity ◽  
Raw Materials ◽  
Formation Rate ◽  
Sol Gel ◽  
Molar Ratio ◽  
Sem And Tem ◽  
Homogeneous Product ◽  
Sol Gel Synthesis ◽  
Calcined Temperature

High purity ZrSiO4 powder were synthesized using Si (C2H5O)4 and ZrOCl2·8H2O as raw materials by the sol-gel method, LiCl was added as mineralizer to promote crystallization of zircon. The influences of molar ratio of Zr:Si, calcined time and calcined temperature on the synthesis of ZrSiO4 powder were investigated. XRD, SEM and TEM were used to characterize the powders. It was found that when the molar ratio of Zr:Si was 1:1.2, the calcined temperature was 1600°C and the calcined time was 4h, the high purity ZrSiO4 ultrafine powder was obtained. The ZrSiO4 formation began at 1300°C and when the gel was calcined at 1600°Cfor 4 h, the formation rate of ZrSiO4 was up to 95%. SEM and TEM studies reveal a homogeneous product with particle sizes on the order of 0.1-1μm. The IR emissivity of ultrafine ZrSiO4 is 0.892 at the whole wavelength range, and that is up to 0.951 at the wavelength range of 8-14 μm.

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