scholarly journals Synthesis of Silica-Based Materials Using Bio-Residues through the Sol-Gel Technique

2021 ◽  
Vol 2 (4) ◽  
pp. 670-685
Author(s):  
Karine Zanotti ◽  
Katerine Igal ◽  
María Belen Colombo Migliorero ◽  
Vânia Gomes Zuin ◽  
Patricia Graciela Vázquez
Keyword(s):  
Food Processing ◽  
Sol Gel ◽  
Ammonium Hydroxide ◽  
Food Processing Industry ◽  
Sem Images ◽  
Orange Peels ◽  
Pure Silica ◽  
Ft Ir ◽  
Gel Technique ◽  
Alkali Hydrolysis

This study focused on the use of citrus bio-waste and obtention of silica-based materials through the sol-gel technique for promoting a greener and more sustainable catalysis. The sol-gel method is a versatile synthesis route characterized by the low temperatures the materials are synthesized in, which allows the incorporation of organic components. This method is carried out by acid or alkali hydrolysis combined with bio-waste, such as orange and lemon peels, generated as co-products in the food processing industry. The main objective was to obtain silica-based materials from the precursor TEOS with different catalysts—acetic, citric and hydro-chloric acids and ammonium hydroxide—adding different percentages of lemon and orange peels in order to find the influence of bio-waste on acids/alkali precursor hydrolysis. This was to partially replace these catalysts for orange or lemon peels. The solids obtained were characterized with different techniques, such as SEM, FT₋IR, potentiometric titration and XRD. SEM images were compared with pure silica obtained to contrast the morphology of the acidic and alkali hydrolysis. However, until now, few attempts have been made to highlight the renewability of reagents used in the synthesis or to incorporate bio-based catalytic processes on larger scales.

Characterization of SrBi2Nb2O9 Thin Films Prepared by Sol Gel Technique

1996 ◽  
Vol 459 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Band ◽  
Sol Gel ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Gel Technique ◽  
High Degree ◽  
First Time

ABSTRACTThin films of SrBi2Nb2O9 (SBN) with thicknesses of 0.1, 0.2, and 0.4 μ were grown by Sol-gel technique on silicon, and annealed at 650°C. The SBN films were investigated by Raman scatering for the first time. Raman spectra in some of the samples present bands around 60, 167, 196, 222, 302, 451, 560, 771, 837, and 863 cm−1, which correspond to the SBN formation. The study indicates that the films are inhomogeneous, and only in samples with thicknesses 0.4 μ the SBN material was found in some places. The prominent Raman band around 870 cm−1, which is the A1g mode of the orthorhombic symmetry, is assigned to the symmetric stretching of the NbO6 octahedrals. The frequency of this band is found to shift in different places in the same sample, as well as from sample to sample. The frequency shifts and the width of the Raman bands are discussed in term of ions in non-equilibrium positions. FT-IR spectra reveal a sharp peak at 1260 cm−1, and two broad bands around 995 and 772 cm−1. The bandwidths of the latter two bands are believed to be associated with the presence of a high degree of defects in the films. The experimental results of the SBN films are compared with those obtained in SBT (T=Ta) films. X-ray diffraction and SEM techniques are also used for the structural characterization.

scholarly journals Enhanced Magnetic Properties of Co-Doped BiFeO3 Thin Films via Structural Progression

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1798
Author(s):  
Liang Bai ◽  
Mingjie Sun ◽  
Wenjing Ma ◽  
Jinghai Yang ◽  
Junkai Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Sol Gel ◽  
Sem Images ◽  
Size Mismatch ◽  
Structural Progression ◽  
Gel Technique ◽  
Average Size ◽  
Perovskite Lattice ◽  
Co Doped

Co3+ doping in BiFeO3 is expected to be an effective method for improving its magnetic properties. In this work, pristine BiFeO3 (BFO) and doped BiFe1-xCoxO3 (BFCxO, x = 0.01, 0.03, 0.05, 0.07 and 0.10) composite thin films were successfully synthesized by a sol–gel technique. XRD and Raman spectra indicate that the Co3+ ions are substituted for the Fe3+ ion sites in the BFO rhombohedral lattice. Raman vibration of oxygen octahedron is obviously weakened due to the lattice distortion induced by the size mismatch between two B-site cations (Fe3+ and Co3+ ions), which has an impact on the magnetic properties of BFCxO. SEM images reveal a denser agglomeration in Co-doped samples. TEM results indicate that the average size of grains is reduced due to the Co3+ substitution. XPS measurements illustrate that the replacement of Fe3+ with Co3+ effectively suppresses the generation of oxygen defects and increases the concentration of Fe3+ ions at the B-site of perovskite lattice. Vibrating sample magnetometer (VSM) measurements show that the remanent magnetization (Mr) of BFC0.07O (3.6 emu/cm3) and the saturation magnetization (Ms) of BFC0.10O (48.84 emu/cm3) thin film both increase by approximately two times at room temperature, compared with that of the pure BFO counterpart.

Catalytic Application of H4SiW12O40/SiO2 in Synthesis of Acetals and Ketals

2011 ◽  
Vol 284-286 ◽  
pp. 2374-2379 ◽  
Author(s):  
Shui Jin Yang ◽  
Yong Kui Huang ◽  
Li Yu
Keyword(s):  
Reaction Time ◽  
High Activity ◽  
Sol Gel ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
Catalytic Application ◽  
Ft Ir ◽  
Gel Technique ◽  
Catalyst Dosage ◽  
Novel Catalyst

A novel catalyst, H4SiW12O40/SiO2was synthesized by a sol-gel technique, and characterized by FT-IR and XRD. Catalytic application of H4SiW12O40/SiO2for synthesis of acetals and ketals were tested. The variation of different reaction parameters, such as mole ratio of aldehyde/ketone to alcohols, catalyst dosage and reaction time on the yield of acetals and ketals were also studied. The results reveal that the H4SiW12O40/SiO2catalysis generally results in good yields of acetals and ketals under mild reaction conditions and the high activity and stability of the catalyst is well retained on recycling.

Synthesis of Imprinted Polysiloxanes for Immobilization of Metal ions

2014 ◽  
Vol 1675 ◽  
pp. 209-214
Author(s):  
Adnan Mujahid ◽  
Faisal Amin ◽  
Tajamal Hussain ◽  
Naseer Iqbal ◽  
Asma Tufail Shah ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Binding Capacity ◽  
Sol Gel ◽  
Cost Effective ◽  
Inorganic Materials ◽  
Sem Images ◽  
Target Analytes ◽  
Ion Imprinted ◽  
Ft Ir

ABSTRACTImprinting is a well-established technique to induce recognition features in both organic and inorganic materials for a variety of target analytes. In this study, ion imprinted polysiloxanes with varying percentage of coupling agent i.e. 3-chloro propyl trimethoxy silane (CPTM) were synthesized by sol-gel method for imprinting of Cr3+. The imprinting of Cr3+ in cross-linked siloxane network was investigated by FT-IR which indicates the metal ion is coordinated with oxygen atoms of polysiloxanes. SEM images revealed that imprinted polysiloxanes possess uniform particles of submicron size. It was experienced that by increasing the concentration of CPTM up to 10% (v/v) substantially improves the binding capacity of polysiloxanes which allows us to recognized Cr3+ down to 50µg/L. Furthermore, the selectivity of Cr3+-imprinted polysiloxanes was evaluated by treating them with other competing metal ions of same concentration i.e. Cr6+, Pb2+ and Ni2+. In this regard, polysiloxanes showed much higher binding for imprint ion i.e. Cr3+ in comparison to above mentioned metal ions. Finally, the regenerated polysiloxanes were studied in order to reuse them thus, developing cost effective biomimetic sensor coatings.

scholarly journals Synthesis and Characterizations of LaMnO3 Perovskite Powders Using Sol-Gel Method 

2021 ◽  
Author(s):  
Deniz ÇOBAN ÖZKAN ◽  
Ahmet Türk ◽  
Erdal Celik
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Dye Sensitized Solar Cells ◽  
Ammonium Hydroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Sensitized ◽  
Gel Technique ◽  
Sensitized Solar Cells

Abstract The present research demonstrates the synthesis and characterization of LaMnO3 perovskite powders using the sol-gel technique for dye-sensitive solar cell applications. With this respect, transparent solutions were prepared from La and Mn based precursors, distilled water and citric acid monohydrate. Ammonium hydroxide was incorporated into the La-Mn solution in order to neutralize/precipitate at 24oC for 1 hour in the air. The solution was allowed to evaporate on a hot plate device at 90 °C in the air. The obtained solutions were dried at 90 oC for 24 hours to form a xerogel structure, dried at 200 oC for 2 hours and consequently annealed at 500 and 850 oC for 2 hours in the air. Thermal, structural, microstructural, optical and magnetic properties of the powders were characterized through differential thermal analysis-thermogravimetry (DTA-TG), Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM), Malvern zeta sizer (PSD), UV-vis spectrometer and vibrating sample magnetometer (VSM). The obtained results indicate promise, especially the low band range, that LaMnO3 powders can be used in dye-sensitized solar cells and can positively affect performance and efficiency.

Kramers–Kronig method for determination of optical properties of PZT nanotubes fabricated by sol–gel method and porous anodic alumina with high aspect ratio

2018 ◽  
Vol 32 (08) ◽  
pp. 1850096 ◽  
Author(s):  
Esmaeil Pakizeh ◽  
Mahmood Moradi
Keyword(s):  
Aspect Ratio ◽  
Optical Constants ◽  
Sol Gel ◽  
Transformation Method ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Sem Images ◽  
Gel Method ◽  
Sol Gel Method ◽  
Ft Ir

Ferroelectric Pb(ZrTi)O3 (PZT) nanotubes were prepared by sol–gel method and porous anodic alumina (PAA) membrane using spin-coating technique. This method is based on filling-pyrolysis-filling process and the use of one-stage alumina membranes. One of the advantages of this method is its rapidity, which takes only 1 h time before the calcination step. The effect of repeated pores filling was investigated to get the required size of nanotubes. The field emission scanning electron microscope (FE-SEM) images were shown that the PZT nanotubes have inner diameters in the range of 65–90 nm and length of about 50–60 [Formula: see text]m. This means that the samples have a significant aspect ratio (700–800). Also the FE-SEM image confirmed that the highly ordered, hexagonally distributed PAA membranes with the pore diameter about 140–150 nm were formed. The X-ray diffraction (XRD) results showed that the PZT nanotubes have a tetragonal structure. The metal oxide bands like ZrO6 and TiO6 of the final PZT nanotubes were detected by Fourier transform infrared (FT-IR) analysis and confirmed the formation of perovskite structure. By using FT-IR spectroscopy and Kramers–Kronig transformation method, the optical constants like real [Formula: see text]([Formula: see text]) and imaginary [Formula: see text]([Formula: see text]) parts of dielectric function, extinction coefficient k([Formula: see text]) and refractive index n([Formula: see text]) were determined. It was shown that the optical constants of PZT nanotubes are different from PZT nanoparticles.

Effects of Epoxy/SiO2 Hybrid Sizing on the Mechanical Properties of Carbon Fiber Composites

2007 ◽  
Vol 121-123 ◽  
pp. 1253-1256 ◽  
Author(s):  
Chun Hong Zhang ◽  
Z.Q. Zhang ◽  
H.L. Cao
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Sol Gel ◽  
Fiber Surface ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
Impact Properties ◽  
Ft Ir ◽  
Gel Technique ◽  
Interlaminar Shear

A novel epoxy/SiO2 hybrid sizing for carbon fiber surface was prepared through sol-gel technique, the structure of the sizing were analyzed, and the effects of the sizing on mechanical properties of carbon fiber composites were also investigated. The analyses by FT-IR and SEM indicated that epoxy/SiO2 hybrid sizing was prepared successfully, SiO2 particles dispersed in the hybrid sizing film homogeneously with nanoscale. The analyses on interlaminar shear strength (ILSS) and impact properties of composites showed that the epoxy/nano-SiO2 hybrid sizing increased ILSS and improved impact properties obviously at the same time.

The Study of nano-SiO2/Polyacrylate Core-Shell Hybrid Emulsions

2014 ◽  
Vol 881-883 ◽  
pp. 986-989
Author(s):  
Fa Qiu Hou ◽  
Ning Qing ◽  
Yong Jun Chen
Keyword(s):  
Contact Angle ◽  
Fourier Transform ◽  
Glass Transition ◽  
Water Contact Angle ◽  
Sol Gel ◽  
Core Shell ◽  
Water Contact ◽  
Glass Transition Temperatures ◽  
Ft Ir ◽  
Gel Technique

nano-SiO2 modified core-shell polyacrylate composite emulsion was synthesized by seeded semi-continuous starved pre-emulsion polymerization and sol-gel technique. The influence of 3-methacryloxypropyltrimethoxysilane(KH-570), tetraethoxysilane(TEOS) on the properties of emulsion and film were studied. The SiO2/silicone polyacrylate composite latex and the resultant films were characterized by fourier transform infrared spectroscopy(FT-IR), differential scanning calorimeter(DSC), thermogravimetric analysis(TGA), water contact angle goniometer (WCAG). The results showed that organic silicon and nano-SiO2 were effectively grafted to the polyacrylate molecular chain. We can observed there are two glass transition temperatures (Tg) in the DSC curve. The water contact angle (WCA) on the PAE film and SSPAE film separately attained 62.5°and 85.5°.

scholarly journals Synthesis of Mg-Ferrite nanoparticles via auto combustion method and investigation their structural, morphological and magnetic properties

2019 ◽  
Vol 24 (7) ◽  
pp. 52
Author(s):  
Ibrahim F. Waheed ◽  
Faiz M. AL-Abady ◽  
Baidaa M. Ali
Keyword(s):  
Sol Gel ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Small Particles ◽  
Sem Images ◽  
X Ray ◽  
Ferrite Structure ◽  
Auto Combustion ◽  
Ft Ir ◽  
Crystalline Microstructure

Magnesium ferrite (MgFe2O4) nanoparticles is prepared by sol-gel auto combustion method and calcinated at (200,450, 900) °C. The capping agent was urea and (Mg(NO3)2.6H2O) and (Fe(NO3)3.9H2O) nitrates as sources of metal. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) characteristic show clear modes of the cubic Mg-ferrite structure formation. Infrared spectrum of metal-oxygen vibration at (703-636) and (574-433) cm−1 show the tetrahedral and octahedral site of Mg-ferrite structure. Scanning Electron Microscope (SEM) images shown pure crystalline microstructure with polyhedral shapes and very small numbers of globular small particles. The crystallite size of Mg-ferrite is calculated using Debye-Scherrer relation and was in the range of 29 nm.   http://dx.doi.org/10.25130/tjps.24.2019.129

scholarly journals Structural, Morphological and Impedance Spectroscopic Analyses of Nano Li(Li0.05Ni0.4Co0.3Mn0.25)O2 Cathode Material Prepared by Sol-Gel Method

2014 ◽  
Vol 17 (3) ◽  
pp. 153-158
Author(s):  
A. Nichelson ◽  
S. Thanikaikarasan ◽  
Pratap Kollu ◽  
P. J. Sebastian ◽  
T. Mahalingam ◽  
...  
Keyword(s):  
Cathode Material ◽  
Sol Gel ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Diffusion Path ◽  
X Ray Diffraction ◽  
Electrical Studies ◽  
Ft Ir ◽  
Gel Technique ◽  
Ft Ir Spectroscopy

In the present work, layered lithium rich Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode materials were synthesized and its structural and electrical studies were analyzed. Layered Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was prepared by sol-gel technique using citric acid as chelating agent. The prepared sample was characterized by X-ray diffraction, SEM-EDS studies. The crystallite size of the Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was about 57 nm in which the diffusion path of lithium ion is effectively possible. The complexation behavior of prepared cathode material was analyzed by FT-IR spectroscopy. The electrical properties of the prepared Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was studied by impedance and dielectric spectral analyzes. The maximum ionic conductivity of LiLi0.05Ni0.4Co0.3Mn0.25)O2 was found to be in the order of 10-3.4 S/cm. The dielectric analysis of cathode material confirms the non-Debye type behavior.

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