Stability Studies of Magnetite Nanoparticles in Environmental Solutions

In the presented paper, studies of magnetite nanoparticle stability in selected environmental solutions are reported. The durability tests were performed in four types of liquids: treated and untreated wastewater, river water, and commercial milk (0.5% fat). Nanoparticles before and after deposition in the testing conditions were measured by transmission electron microscopy, X-ray diffraction, infrared spectroscopy, and Mössbauer spectroscopy. The amount of Fe atoms transferred into the solutions was estimated on the basis of flame atomic absorption spectroscopy. The analysis of the obtained results shows good stability of the tested nanoparticles in all water solutions. They do not change their structure or magnetic properties significantly, which makes them a good candidate to be used as, for example, detectors of specific compounds or heavy metals. On the other hand, studies show that particles are stable in environmental conditions for a long period of time in an unchanged form, which can cause their accumulation; therefore, they may be hazardous to living organisms.

Download Full-text

Effect of MWCNT doping on the structural and optical properties of PVC/PVDF polymer blend

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v13i2.5702 ◽

2017 ◽

Vol 13 (2) ◽

pp. 4640-4647

Author(s):

A. M. Abdelghany ◽

M.S. Meikhail ◽

S.I. Badr ◽

A. S. Momen

Keyword(s):

Surface Damage ◽

X Ray Diffraction ◽

Dopant Content ◽

Casting Technique ◽

Transmission Electron ◽

Dopant Level ◽

Before And After ◽

Carbon Nano Tubes ◽

Small Band ◽

Vibrational Bands

Thin film samples of pristine polyvinyl chloride (PVC), poly vinyldine fluoride (PVDF) in combination with their blend in addition to samples containing factorial mass fraction of multi wall carbon nano-tubes (MWCNTs) in the dopant level were prepared via routine casting technique using tetrahydrofurane (THF) as a common solvent. X-ray diffraction and transmission electron microscopy (TEM) depict the nano-scale (15-25 nm) of functionalized MWCNTs with no surface damage results from functionalization process.X-ray diffraction (XRD) shows a semi-crystalline nature of PVDF with evidence for more than one phase namely a and b phases. The fraction of b phase was calculated and correlated to the dopant content. FTIR optical absorption spectra revels a preservation of the main vibrational bands before and after addition of MWCNTs in the doping level with a presence of new small band 1151 cm-1 assigned for the interaction and complexation between constituents.

Download Full-text

Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

Journal of Nanomaterials ◽

10.1155/2013/650725 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 20

Author(s):

Mashael Alshabanat ◽

Amal Al-Arrash ◽

Waffa Mekhamer

Keyword(s):

Electron Microscopy ◽

Thermal Stability ◽

Solution Method ◽

Sonication Time ◽

X Ray Diffraction ◽

Transmission Electron ◽

Polystyrene Matrix ◽

Before And After ◽

Silicate Layers ◽

Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

Download Full-text

Modification of Titanium Dioxide Nanoparticles with 3-(Trimethoxysilyl)propyl Methacrylate Silane Coupling Agent

Journal of Chemistry ◽

10.1155/2020/1381407 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Thuy-Chinh Nguyen ◽

Tien-Dung Nguyen ◽

Duc-Toan Vu ◽

Duc-Phuong Dinh ◽

Anh-Hiep Nguyen ◽

...

Keyword(s):

Electron Microscopy ◽

Tio2 Nanoparticles ◽

Coupling Agent ◽

Titanium Dioxide Nanoparticles ◽

X Ray Diffraction ◽

Nano Tio2 ◽

Propyl Methacrylate ◽

Transmission Electron ◽

Before And After ◽

Modification Of Titanium

This paper presents some characteristics, properties, and morphology of TiO2 nanoparticles (nano-TiO2) modified with various contents of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) coupling agent. The treatment process was carried out in ethanol solvent at 50oC using ammonia as a catalyst for hydrolysis reaction of silane to silanol. Infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, ultraviolet-visible spectroscopy, and X-ray diffraction methods were used for determination of the characteristics, properties of nano-TiO2 before and after treatment. In addition, the contact angle and grafting efficiency of TMSPM on the surface of TiO2 nanoparticles was also evaluated. The obtained results confirmed that TMSPM was grafted to the TiO2 nanoparticles, the agglomeration of nano-TiO2 was decreased, and surface of TiO2 nanoparticles became hydrophobic after modification by TMSPM.

Download Full-text

Peroxide Electrochemical Sensor and Biosensor Based on Nanocomposite of TiO2 Nanoparticle/Multi-Walled Carbon Nanotube Modified Glassy Carbon Electrode

Nanomaterials ◽

10.3390/nano10010064 ◽

2019 ◽

Vol 10 (1) ◽

pp. 64 ◽

Cited By ~ 5

Author(s):

L. Andrés Guerrero ◽

Lenys Fernández ◽

Gema González ◽

Marjorie Montero-Jiménez ◽

Rafael Uribe ◽

...

Keyword(s):

Modified Electrode ◽

Glassy Carbon ◽

Sodium Dodecylsulfate ◽

Modified Electrodes ◽

Dimethyl Formamide ◽

X Ray Diffraction ◽

Transmission Electron ◽

Before And After ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

A hydrogen peroxide (H2O2) sensor and biosensor based on modified multi-walled carbon nanotubes (CNTs) with titanium dioxide (TiO2) nanostructures was designed and evaluated. The construction of the sensor was performed using a glassy carbon (GC) modified electrode with a TiO2–CNT film and Prussian blue (PB) as an electrocalatyzer. The same sensor was also employed as the basis for H2O2 biosensor construction through further modification with horseradish peroxidase (HRP) immobilized at the TiO2–fCNT film. Functionalized CNTs (fCNTs) and modified TiO2–fCNTs were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray DifFraction (XRD), confirming the presence of anatase over the fCNTs. Depending on the surface charge, a solvent which optimizes the CNT dispersion was selected: dimethyl formamide (DMF) for fCNTs and sodium dodecylsulfate (SDS) for TiO2–fCNTs. Calculated values for the electron transfer rate constant (ks) were 0.027 s−1 at the PB–fCNT/GC modified electrode and 4.7 × 10−4 s−1 at the PB–TiO2/fCNT/GC electrode, suggesting that, at the PB–TiO2/fCNT/GC modified electrode, the electronic transfer was improved. According to these results, the PB–fCNT/GC electrode exhibited better Detection Limit (LD) and Quantification Limit (LQ) than the PB–TiO2/fCNT/GC electrode for H2O2. However, the PB film was very unstable at the potentials used. Therefore, the PB–TiO2/fCNT/GC modified electrode was considered the best for H2O2 detection in terms of operability. Cyclic Voltammetry (CV) behaviors of the HRP–TiO2/fCNT/GC modified electrodes before and after the chronoamperometric test for H2O2, suggest the high stability of the enzymatic electrode. In comparison with other HRP/fCNT-based electrochemical biosensors previously described in the literature, the HRP–fCNTs/GC modified electrode did not show an electroanalytical response toward H2O2.

Download Full-text

Microwave Sintering of Nanocrystalline TiO2

MRS Proceedings ◽

10.1557/proc-189-273 ◽

1990 ◽

Vol 189 ◽

Cited By ~ 8

Author(s):

J. A. Eastman ◽

K. E. Sickafus ◽

J. D. Katz ◽

S. G. Boeke ◽

R. D. Blake ◽

...

Keyword(s):

Microwave Sintering ◽

Phase Changes ◽

Microwave Cavity ◽

Oxygen Stoichiometry ◽

X Ray Diffraction ◽

Nanocrystalline Tio2 ◽

Transmission Electron ◽

Before And After ◽

Maximum Temperatures ◽

Short Time

ABSTRACTNanocrystalline TiO2 compacts having initial approximate mean grain sizes of 14 nm and approximate green densities of 70% of theoretical were sintered by short-time exposure in a 2.45 GHz microwave cavity to maximum temperatures of 800, 1000 or 1200 ºC. Sample densities were measured before and after exposure to microwaves using Archimede's method. Transmission electron microscopy and x-ray diffraction were utilized to monitor grain growth and phase changes. Rutherford backscattering was used to monitor any changes in oxygen stoichiometry. The results of this study indicate that enhanced densification behavior is obtained for microwavesintered samples relative to samples sintered using conventional pressureless-sintering techniques.

Download Full-text

Microstructure of Pyrolytic Carbon Matrix in Carbon/Carbon Composites after Graphitization

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1270 ◽

2007 ◽

Vol 336-338 ◽

pp. 1270-1273 ◽

Cited By ~ 1

Author(s):

Wan Chang Sun ◽

He Jun Li ◽

Shou Yang Zhang ◽

Yong Huang

Keyword(s):

Polarized Light ◽

Carbon Matrix ◽

Pyrolytic Carbon ◽

Interplanar Distance ◽

Carbon Composites ◽

X Ray Diffraction ◽

Transmission Electron ◽

Before And After ◽

The Matrix ◽

Microstructure Parameters

The morphologies and textures of the pyrolytic carbon matrix in 2D-C/C composites after graphitization were investigated by means of polarized light microscope (PLM) and high resolution transmission electron microscope (HRTEM). The microstructure parameters of the pyrolytic carbon matrix before and after graphitization were characterized with X-ray diffraction (XRD) technology. It was found that the interplanar distance of (002) planes (d002) of pyrolytic carbon matrix decreases, and the microcrystalline stack height (LC) increases after graphitization. Graphitization treatment resulted in a coarsening of the surface texture and in the formation of circumferential cracks within the matrix. The lattice fringes of the pyrolytic carbon matrix are continuous and longer in each domain and the (002) peak spot is smaller and more intense after graphitization.

Download Full-text

Synthesis and Characterization of Porous Mo-W Oxide Nanostructures

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.18404 ◽

2008 ◽

Vol 8 (12) ◽

pp. 6445-6450

Author(s):

F. Paraguay-Delgado ◽

Y. Verde ◽

E. Cizniega ◽

J. A. Lumbreras ◽

G. Alonso-Nuñez

Keyword(s):

Electron Microscopy ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Synthesis Method ◽

Atomic Ratio ◽

High Specific Surface Area ◽

X Ray Diffraction ◽

Transmission Electron ◽

Before And After

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 °C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 °C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.

Download Full-text

Preparation of Cellulose Acetate Ultra-Fine Fibers Containing Quasi-Spherical Gold Nanoparticles by Electrospinning Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.391-392.400 ◽

2011 ◽

Vol 391-392 ◽

pp. 400-403

Author(s):

Dong Mei Zhao ◽

Li Guo Sun ◽

Li Li Lv ◽

Jian Li

Keyword(s):

Electron Microscopy ◽

Gold Nanoparticles ◽

Cellulose Acetate ◽

Trisodium Citrate ◽

X Ray Diffraction ◽

Au Nps ◽

Transmission Electron ◽

Electrospinning Method ◽

Before And After ◽

Spherical Gold Nanoparticles

Quasi-spherical gold nanoparticles(Au NPs) prepared by trisodium citrate reduction of HAuCl4were dispersed into cellulose acetate(CA) ultra-fine fibers by electrospinning. The optical properties of Au NPs before and after electrospinning were measured by UV-vis spectrometer. The morphology and distribution of Au NPs in CA ultra-fine fibers were observed by transmission electron microscopy (TEM). The morphology and diameter of Au NPs/CA fibers were studied by scanning electron microscopy (SEM). The crystallinity change of CA fiber before and after adding Au NPs was characterized by X-ray diffraction (XRD).

Download Full-text

Removal of Cd (II) in Water Samples Using Modified Magnetic Iron Oxide Nanoparticle

Iranian Jornal of Toxicology ◽

10.32598/ijt.10.1.299.1 ◽

2016 ◽

Vol 10 (1) ◽

pp. 9-14

Author(s):

Ahmad Kakaei ◽

◽

Mohammad Kazemeini ◽

Keyword(s):

Water Samples ◽

High Capacity ◽

Absorption Spectrometry ◽

Iron Oxide Nanoparticle ◽

Maximum Adsorption Capacity ◽

Magnetite Nanoparticle ◽

Cadmium Ions ◽

Flame Atomic Absorption ◽

Low Concentrations ◽

Living Organisms

Background: Heavy metals, even at low concentrations, are harmful to human health and environment. Cadmium as a heavy metal is highly toxic and can cause serious threat to living organisms. This research was designed to evaluate the adsorption potential of modified magnetic iron nanoparticles by 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol ligand for the removal of cadmium ions from water solutions. Methods: This study was conducted in Ilam Branch, Islamic Azad University, Iran, in 2014. Modified magnetic iron nanoparticle was used as adsorbent for the removal of cadmium from aqueous solution. In batch extraction, the effects of parameters like pH of sample solution (3.0-11.0), initial metal concentrations (50-300) mgL-1), contact time (1.0-10 min) and adsorbent dose (10.0-60.0 mg) were studied on the adsorption process. Modified magnetite nanoparticle was presented as the adsorbent for the removal of cadmium ions from aqueous samples and later was confirmed by flame atomic absorption spectrometry. Results: The adsorption of cadmium ions on modified magnetite nanoparticles strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations. The removal process followed the Langmuir isotherm. Maximum adsorption capacity for the adsorption of cadmium ions by the sorbent was 24.09 mgg-1. Conclusion: The method was successfully applied to adsorption of cadmium in water samples with satisfactory results. Other advantages include high capacity, good stability and fast adsorption kinetics. High pre-concentration factor was obtained easily by this method (120) and low analysis cost.

Download Full-text

Characterization of Cu-Al alloy/SiO2 interface microstructure

MRS Proceedings ◽

10.1557/proc-615-g7.5.1 ◽

2000 ◽

Vol 615 ◽

Cited By ~ 1

Author(s):

Pei-I Wang ◽

S. P. Murarka ◽

G.-R. Yang ◽

E. Barnat ◽

T.-M. Lu ◽

...

Keyword(s):

Interfacial Layer ◽

Alloy Film ◽

Al Alloy ◽

X Ray Diffraction ◽

Adhesion Promoter ◽

Adhesion Promoters ◽

Barrier Formation ◽

Transmission Electron ◽

Before And After ◽

Sputter Deposited

ABSTRACTCu-Al alloys have been recommended for application as the diffusion barriers/adhesion promoters for advanced copper based metallization schemes. This approach to barrier formation is to generate an ultra-thin interfacial layer through Cu alloying without significantly affecting the resistivity of Cu. In this paper the microstructure of the bilayers of Cu/Cu-5 at%Al and Cu-5 at%Al/Cu sputter deposited on SiO2 before and after thermal annealing is investigated by transmission electron microscopy (TEM). Interfacial layer is observed in both cases. The variation of the resistance of the Cu-Al alloy film is consistent with its microstructure. The x-ray diffraction (XRD) spectra of Cu-5 at%Al on SiO2 shows that the addition of Al into Cu intends to favor the Cu (111) texture. These results will be presented and discussed showing that films of Cu doped with Al appear to act as a suitable barrier and adhesion promoter between SiO2 and Cu.

Download Full-text