scholarly journals One-Step Synthesis of Hollow Titanate (Sr/Ba) Ceramic Fibers for Detoxification of Nerve Agents

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Satya R. Agarwal ◽  
Subramanian Sundarrajan ◽  
Arunachalam Venkatesan ◽  
Seeram Ramakrishna
Keyword(s):  
Electron Microscope ◽  
Surface Area ◽  
Sol Gel ◽  
Analytical Techniques ◽  
Titanium Isopropoxide ◽  
Hollow Fibers ◽  
Vinyl Pyrrolidone ◽  
Composite Fibers ◽  
Electrospinning Technique ◽  
Bet Analysis

Poly(vinyl pyrrolidone)(PVP)/(strontium/barium acetate)/titanium isopropoxide composite fibers were prepared by electrospinning technique via sol-gel process. Diameters of fibers prepared by calcinations of PVP composite fibers were 80–140 nm (solid) and 1.2-2.2 μm (hollow fibers prepared by core-shell method). These fibers were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM) analytical techniques. XRD results showed better crystalline nature of the materials when calcined at higher temperatures. SEM and TEM results clearly showed the formation of hollow submicrometer tubes. The surface area of the samples determined by BET analysis indicated that hollow fibers have ~20% higher surface area than solid fibers. The UV studies indicate better detoxification properties of the hollow fibers compared to solid fibers.

scholarly journals Tuning the Morphological Properties of Cellulose Aerogels: An Investigation of Salt-Mediated Preparation

2021 ◽  
Author(s):  
Prakash Parajuli ◽  
Sanjit Acharya ◽  
Julia Shamshina ◽  
Noureddine Abidi
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Earth Metal ◽  
Morphological Properties ◽  
Cellulose Solution ◽  
Bet Analysis ◽  
Sol Gel Transition ◽  
Gel Transition

Abstract In this study, alkali and alkaline earth metal chlorides with different cationic radii (LiCl, NaCl, and KCl, MgCl2, and CaCl2) were used to gain insight into the behavior of cellulose solutions in the presence of salts. The specific focus of the study was evaluation of the effect of salts’ addition on the sol-gel transition of the cellulose solutions and on their ability to form monoliths, as well as evaluation of the morphology (e.g., specific surface area, pore characteristics, and microstructure) of aerocelluloses prepared from these solutions. The effect of the salt addition on the sol-gel transition of cellulose solutions was studied using rheology, and morphology of resultant aerogels was evaluated by Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, while the salt influence on the aerocelluloses’ crystalline structure and thermal stability was evaluated using powder X-Ray Diffraction (pXRD) and Thermogravimetric Analysis (TGA), respectively. The study revealed that the effect of salts’ addition was dependent on the component ions and their concentration. The addition of salts in the amount below certain concentration limit significantly improved the ability of the cellulose solutions to form monoliths and reduced the sol-gel transition time. Salts of lower cationic radii had a greater effect on gelation. However, excessive amount of salts resulted in the formation of fragile monoliths or no formation of gels at all. Analysis of surface morphology demonstrated that the addition of salts resulted in a significant increase in porosity and specific surface area, with salts of lower cationic radii leading to aerogels with much larger (~1.5 and 1.6-fold for LiCl and MgCl2, respectively) specific surface area compared to aerocelluloses prepared with no added salt. Thus, by adding the appropriate salt into the cellulose solution prior to gelation, the properties of aerocelluloses that control material’s performance (specific surface area, density, and porosity) could be tailored for a specific application.

SYNTHESIS AND CHARACTERIZATION OF NEEM-BASED ZINC OXIDE PHOTOCATALYST

2021 ◽  
Vol 36 (1) ◽  
pp. 9-15
Author(s):  
I.N Gana ◽  
V.U Ohageria ◽  
U.G Akpan ◽  
I.J Ani
Keyword(s):  
Zinc Oxide ◽  
Green Synthesis ◽  
Surface Area ◽  
Leaf Extract ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Sem Analysis ◽  
X Ray ◽  
Bet Analysis ◽  
Neem Leaf Extract

The use of chemicals for the synthesis of photocatalyts poses threat to the environment. In this study, an active photocatalyst, Dalbejiya Dongoyaro (Azadirachta indica)-based zinc oxide (ZnO) was biosynthesized from zinc acetate dihydrate using sol gel and precipitation methods. The synthesized samples were characterized using Fourier Transfer InfraRed (FTIR), X-Ray Diffractometry (XRD), Brunauer Emmet Teller (BET), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) characterization techniques. The XRD and SEM analysis of the green synthesized and non-green synthesized ZnO demonstrated the formation of hexagonal wurtzite crystalline structure and agglomerated morphology. EDX analysis demonstrated the existence of Zn and O as the major constituents of the as-synthesized nanoparticles with traces of carbon which could be attributed to the carbon tape of the sample holder. The BET analysis displayed that the surface area of the ZnO nanoparticles increased from 23.75 to 97.08 cm3/g after the green synthesis. Based on the surface area values, it can be derived that neem leaf extract enhanced the surface area of the green synthesized sample. Green synthesis is a promising route for the synthesis of photocatalyst nanoparticle which is environmentally friendly and sustainable method. Keywords: Zinc oxide, Neem leaf extract, Photocatalyt, Degradation, Bio-synthesis

Microscopic Characterization and Analysis of Electrospun TiO2-PVP and TiO2-PVDF Fibers

2017 ◽  
Vol 264 ◽  
pp. 33-37 ◽  
Author(s):  
Joshua Zheyan Soo ◽  
Bee Chin Ang ◽  
Boon Hoong Ong
Keyword(s):  
Molecular Weight ◽  
Polyvinylidene Fluoride ◽  
Sol Gel ◽  
Titanium Isopropoxide ◽  
Electrospinning Technique ◽  
X Ray ◽  
Suitable Material ◽  
Fibre Network ◽  
Weight Concentration ◽  
Polymer Decomposition

Titanium dioxide (TiO2) is a suitable material to be used in the field of photocatalytic water treatment. In this research, TiO2 membrane fibers were synthesized using a combination of non-aqueous sol gel method and electrospinning technique. Titanium isopropoxide (TTIP) was used as the precursor for the TiO2 filler of the fibers. Both polyvinylpyrrolidone (PVP) and polyvinylidene fluoride (PVDF) were used as the polymer base to obtain the respective membrane fibers. The effects of weight concentration of TTIP as well as the type and molecular weight of the polymer on the morphology of the fibers were studied. Microscopic characterization using field-emission scanning electron microscopy (FESEM) and Energy Dispersive X-Ray (EDX) analysis was performed to obtain the morphology and elemental composition of the fibers. Sub-micron range fibers with a continuous network were generally obtained. Fibers that are subjected to post-electrospinning calcination have a lower fiber diameter. Polymer decomposition is shown to occur during calcination which yielded higher purity TiO2 fibers. The use of higher molecular weight polymers can produce a stronger fibre network for membranes.

Physical and Structural Evolution of Sol-Gel Derived TiO2-SiO2 Glasses

1988 ◽  
Vol 121 ◽  
Author(s):  
Yeu-Chyi CHENG ◽  
Larry L. Hench
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Radius ◽  
Sol Gel ◽  
Structural Evolution ◽  
Titanium Isopropoxide ◽  
Hydrolysis Method ◽  
Densification Temperature ◽  
Gel Glasses

ABSTRACTA method for producing large TiO2-SiO2 gel-glass monoliths using the sol-gel method has been developed. The gel-glasses are prepared by a pre-hydrolysis method using tetramethylorthosilicate and titanium isopropoxide as precursors. The microhardness, specific surface area and pore radius of the gel-glasses do not change significantly below 600°C. Above 600°C, these properties increase rapidly with densification temperature. At lower TiO2concentration, the glasses obtained by heating to 900°C for 15 hours were not crystallized, while for 15 wt % TiO2 glass, anatase precipitated.

Synthesis of Sn4+ Doped TiO2 Nanotube and its Photocatalytic Activity

2012 ◽  
Vol 724 ◽  
pp. 21-24
Author(s):  
Hong Ying Dong ◽  
Yan Ping Ren ◽  
Kai Ming Huang ◽  
Wei Yan He ◽  
Wen Ma
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
Stable Phase ◽  
Visible Light Region ◽  
Composite Fibers ◽  
Small Particles ◽  
Electrospinning Technique ◽  
Photodegradation Efficiency ◽  
Light Region

The PVP+Ti (OC4H9)4+SnCl4·5H2O/sesame oil composite fibers were successfully prepared by a sol-gel method combined with a coaxial electrospinning technique. The Sn4+/TiO2 nanotubes were obtained by calcining the above-mentioned composite fibers and characterized by XRD and TEM. XRD results show that increasing reaction temperature facilitates to form a stable phase. TEM results show that the Sn4+/TiO2 nanotubes have smooth surface with wall thickness of ~120 nm and are composed of small particles of ~5 nm. The photocatalytic activity of Sn4+/TiO2 nanotubes was investigated. The photodegradation efficiency of Sn4+/TiO2 nanotubes decreases in UV region but increases in visible light region. The photocatalytic properties of three 0.52at% Sn4+/TiO2 nanomaterials with different morphologies were also evaluated. The photodegradation efficiencies of Sn4+/TiO2 nanopowers, Sn4+/TiO2 nanofibers and Sn4+/TiO2 nanotubes increase in visible light region in sequence. In summary, chemical modification by doping Sn4+ and morphology changing for TiO2 can improve its photocatalytic activity in visible light region significantly.

Electrospun barium titanate/cobalt ferrite composite fibers with improved magnetoelectric performance

RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55217-55223 ◽  
Author(s):  
Avinash Baji ◽  
Yiu-Wing Mai ◽  
Rattikorn Yimnirun ◽  
Sujitra Unruan
Keyword(s):  
Barium Titanate ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Composite Fibers ◽  
Electrospinning Technique ◽  
Magnetoelectric Response

In this study, we use a versatile sol–gel based electrospinning technique to fabricate nanostructured barium titanate (BaTiO3)/cobalt ferrite (CoFe2O4) composite fibers and analyze their magnetoelectric response.

scholarly journals Nickel Nanofibers Manufactured via Sol-Gel and Electrospinning Processes for Electrically Conductive Adhesive Applications

2020 ◽  
Vol 4 (2) ◽  
pp. 26
Author(s):  
Darunee Aussawasathien ◽  
Erol Sancaktar
Keyword(s):  
Ag Nanoparticles ◽  
Sol Gel ◽  
Synergetic Effect ◽  
Volume Resistivity ◽  
Hydrogen Gas ◽  
Vinyl Pyrrolidone ◽  
Metallic Nickel ◽  
Electrospinning Technique ◽  
Epoxy Nanocomposite ◽  
Electrically Conductive Adhesive

The electrospun fibers of poly(vinyl pyrrolidone) (PVP)-nickel acetate (Ni(CH3COO)2·4H2O) composite were successfully prepared by using sol-gel processing and electrospinning technique. Nickel oxide (NiO) nanofibers were obtained afterwards by high temperature calcinations of the precursor fibers, PVP/Ni acetate composite nanofibers, at 700 °C for 10 h. Following with the reduction of NiO nanofibers at 400 °C using hydrogen gas (H2) under inert atmosphere, the metallic nickel (Ni) nanofibers were subsequently produced. In addition, as-prepared Ni nanofibers were chemically coated with silver (Ag) nanoparticles to enhance their electrical property and prevent the surface oxidation. The characteristics of as-prepared fibers, such as surface morphology, fiber diameters, purity, the amount of NiO nanofibers, and metal crystallinity, were determined using a scanning electron microscope (SEM), a Fourier transform infrared spectrometer (FT-IR), a thermogravimetric analyzer (TGA), and a wide-angle x-ray diffractometer (WAXD). The volume resistivity of epoxy nanocomposite filled with Ag-coated short Ni nanofibers was lower than the one containing short Ni nanofibers with no coating due to the synergetic effect of Ag nanoparticles created during the coating process. We also demonstrated that the volume resistivity of epoxy nanocomposite filled with Ni nanofibers could be dramatically decreased by using Ni nanofibers in the non-woven mat form due to their small fiber diameter and high fiber aspect ratio, which yield a high specific surface area, and high interconnecting network.

scholarly journals Influence of polyvinyl alcohol amount on producing in situ photo-crosslinked thioamide functionalized nanofiber membranes

2015 ◽  
Vol 80 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Bihter Zeytuncu ◽  
Mehmet Morcali ◽  
Suleyman Akman ◽  
Onuralp Yucel
Keyword(s):  
Surface Area ◽  
Poly Vinyl Alcohol ◽  
Electrospinning Technique ◽  
Durability Test ◽  
Average Mass ◽  
Water Durability ◽  
Surface Areas ◽  
Bet Analysis ◽  
Nanofiber Membranes

Poly(vinyl alcohol)/maleic anhydride/acryloyl thioamide monomer (PVA/MA/ATM) photo-cured nanofiber membranes and pure PVA nanofiber membranes were produced by electrospinning technique. In situ UV radiation was applied during the electrospinning in order to provide polymerization during the jet flight and promote crosslinking of ATM and MA with PVA. The cross-linking was examined by Fourier-transform infrared spectroscopy (FTIR). The morphology and thermal behavior of electrospun nanofiber were characterized by scanning electron microscope (SEM) and thermogravimetric analysis (TGA), respectively. The surface area of nanofiber membranes was measured by Brunauer-Emmert-Teller (BET) analysis. Furthermore, water durability test was examined. Water durability test demonstrated that in situ photo-cured PVA/MA/ATM nanofiber membrane had the least average mass loss. The surface areas of PVA/MA/ATM nanofiber membranes were 160-280 m2/g. The surface area and diameter of PVA/MA/ATM nanofibers decreased as the PVA content increased. The diameter of nanofibers was obtained less than 100 nm. The results showed that the water-insoluble nanofiber membranes with better chemical and thermal resistance were obtained. These nanofiber membranes may be a promising candidate for the usage of water treatment.

scholarly journals Synthesis and Transformation of Hollow Rutile Titania Wires by Single Spinneret Electrospinning with Sol-Gel Chemistry

Fibers ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 18
Author(s):  
Chin-Shuo Kang ◽  
Edward Evans
Keyword(s):  
Sol Gel ◽  
Electrospun Nanofibers ◽  
Particle Growth ◽  
Titanium Isopropoxide ◽  
Solid Particles ◽  
Calcination Time ◽  
Hollow Nanofibers ◽  
Electrospinning Technique ◽  
Polymer Hybrid ◽  
Rutile Titania

The work described below was carried out to understand how to control the morphology of nanostructured titania calcined from electrospun nanofibers. This is the first report of hollow rutile nanofibers synthesized from electrospun nanofibers with short calcination time. Titanium isopropoxide was incorporated into the nanofibers as the titania precursor. The electrospinning technique was used to fabricate ceramic/polymer hybrid nanofibers. The electrospun nanofibers were then calcined to produce rutile titania nanofibers with different morphologies (hollow or solid nanofibers), which were characterized by SEM and TEM. The initial concentration of ceramic precursor and the calcination time were shown to control the morphology of the nanofiber. The hollow morphology was only obtained with a concentration of the precursor within a certain level and with short calcination times. The heat treatment profile contributed to particle growth. At longer times, the particle growth led to the closure of the hollow core and all the nanofibers resembled strings of solid particles. A formation mechanism for the hollow nanofibers is also proposed.

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