scholarly journals Synthesis of Silver Nanoparticles Dispersed in Various Aqueous Media Using Laser Ablation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. Tajdidzadeh ◽  
B. Z. Azmi ◽  
W. Mahmood M. Yunus ◽  
Z. Abidin Talib ◽  
A. R. Sadrolhosseini ◽  
...  
Keyword(s):  
Particle Size ◽  
Aqueous Media ◽  
Chitosan Solution ◽  
Ag Nps ◽  
Spherical Form ◽  
Visible Absorption ◽  
Silver Nps ◽  
The Media ◽  
The Stability ◽  
Average Size

The particle size, morphology, and stability of Ag-NPs were investigated in the present study. A Q-Switched Nd: YAG pulsed laser (λ= 532 nm, 360 mJ/pulse) was used for ablation of a pure Ag plate for 30 min to prepare Ag-NPs in the organic compound such as ethylene glycol (EG) and biopolymer such as chitosan. The media (EG, chitosan) permitted the making of NPs with well dispersed and average size of Ag-NPs in EG is about 22 nm and in chitosan is about 10 nm in spherical form. Particle size, morphology, and stability of NPs were compared with distilled water as a reference. The stability of the samples was studied by measuring UV-visible absorption spectra of samples after one month. The result indicated that the formation efficiency of NPs in chitosan was higher than other media and NPs in chitosan solution were more stable than other media during one month storage. This method for synthesis of silver NPs could be as a green method due to its environmentally friendly nature.

scholarly journals Biomimetic Synthesis of Silver Nanoparticles from Aqueous Extract of Saraca indica and its Profound Antibacterial Activity

2020 ◽  
Vol 11 (1) ◽  
pp. 8110-8120
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Aqueous Extract ◽  
Silver Nanoparticle ◽  
Pathogenic Bacteria ◽  
Drug Formulation ◽  
Biomimetic Synthesis ◽  
Visible Absorption ◽  
The Stability ◽  
Average Size

The present findings were focused on green synthesis of silver nanoparticles through an aqueous extract of Saraca indica. The stability of the nanoparticle was achieved through the optimization of physico-chemical parameters. The sharp UV-visible absorption maximum at 400 was observed for biological synthesized silver nanoparticles. The spectroscopic analysis was thus used to assess the formation of silver nanoparticles. The AFM analysis did analyze the morphology of the nanocomposite, which was further confirmed through TEM micrograph. The electron micrograph image discloses that silver nanoparticles were polydispersed and dominantly as spherical with size ranges from 40nm to 100nm. The average size distribution was 49nm. The chemical reductions of Ag+ ions were further confirmed through FTIR. The biogenic silver nanoparticle and their drug formulation showed profound antibacterial activity against pathogenic bacteria. The flavonoids rich binding of silver nanoparticle showed great medicinal potential and can be used for the treatment of several harmful infectious diseases. Hence, plant-based metal nanoparticles meet the demand for less toxic formulation during drug development and its delivery.

Fabrication of TiO2/Ag/Ag2O Nanoparticles to Enhance the Photocatalytic Activity of Degussa P25 Titania

2016 ◽  
Vol 69 (1) ◽  
pp. 41 ◽  
Author(s):  
Safyan A. Khan ◽  
Shahid Ali ◽  
Manzar Sohail ◽  
Mohamed A. Morsy ◽  
Zain H. Yamani
Keyword(s):  
Chemical Reduction ◽  
Visible Region ◽  
Spherical Shape ◽  
Ag Nps ◽  
X Ray ◽  
Transmission Electron ◽  
Silver Nps ◽  
Degussa P25 ◽  
Average Size ◽  
Ag2o Nanoparticles

A simple chemical reduction approach was used to synthesize Ag nanoparticles (NPs) over a reputed photocatalyst, Degussa P25 (TiO2). Silver doping extended the P25 absorption wavelength from the ultraviolet to the visible region. The synthesized silver NPs (Ag NPs) were of spherical shape and had an average size of ~4.6 nm. In the next stage, Ag NPs were partially oxidized by treatment with hydrogen peroxide. The resulting P25/Ag/Ag2O nanocomposites were characterized by X-ray powder diffraction, transmission electron microscopy, energy dispersive X-ray analysis, Brunauer–Emmett–Teller analysis, and UV-visible spectroscopy. The photocatalytic activities of the P25, P25/Ag, and P25/Ag/Ag2O catalysts were investigated for the degradation of non-biodegradable dyes, methylene blue and rhodamine 6G. The P25/Ag/Ag2O nanocomposite exhibited better photodegradation activity than P25, as well as the commonly used Ag3PO4, under visible light irradiation.

scholarly journals Size Effect of Fe3O4 Nanoparticles on Magnetism and Dispersion Stability of Magnetic Nanofluid

2021 ◽  
Vol 9 ◽  
Author(s):  
Fang Chen ◽  
Nasir Ilyas ◽  
Xiaobing Liu ◽  
Zhenggui Li ◽  
Shengnan Yan ◽  
...  
Keyword(s):  
Particle Size ◽  
Saturation Magnetization ◽  
Reaction Temperature ◽  
Impurity Phase ◽  
Dispersion Stability ◽  
Dead Layer ◽  
Magnetic Nanofluids ◽  
Potential Applications ◽  
The Stability ◽  
Average Size

It is well known that magnetic nanofluids are widely applied in various fields ranging from heat transfer to miniature cooling, and from damping to sealing, due to the mobility and magnetism under magnetic field. Herein, the PFPE-oil based magnetic nanofluids with superior magnetization and dispersion stability were obtained via regulating reaction temperature. The structures of particles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The size effects of particles on the magnetism and coating effect of particles, and on the stability and saturation magnetization of the fluids were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM) and density instrument, respectively. The results indicate that the impurity phase FeOOH only appear in the sample prepared at 18°C and the average size of Fe3O4 nanoparticles reduces from 120 to 20 nm with raising reaction temperature. The saturation magnetization of Fe3O4 particles increases firstly and then reduces with increasing particle size, which is affected by the thickness of magnetic dead layer and impurity phase FeOOH. The Fe3O4 particles could be chemically coated by PFPE-acids, and the coated mass is a little affected by particle size. The stability of the nanofluids lowers while the saturation magnetization increases firstly and then decrease with increasing particle size. At reaction temperature of 60°C, Fe3O4 particles of 25 nm and the nanofluids with superior stability and saturation magnetization were obtained. Our results indicate that the control of nanoparticles size by regulating reaction temperature can be a useful strategy for preparing magnetic nanofluids with desirable properties for various potential applications.

scholarly journals Statistical Optimization of Co-stabilized Growth of Ag NPs by Liquid Plasma Interaction Method for Study of Antibacterial Activity

2021 ◽  
Author(s):  
Noorul Huda ◽  
M. Y. Naz ◽  
M. Ayyaz ◽  
S. Shukrullah
Keyword(s):  
Antibacterial Activity ◽  
Metal Salt ◽  
Xrd Analysis ◽  
P Value ◽  
Ftir Analysis ◽  
Interaction Method ◽  
Ag Nps ◽  
Silver Nps ◽  
Average Size ◽  
Fcc Structure

Abstract In this study, a plasma jet of argon gas was impinged with a solution of metal salt and stabilizers for production of silver NPs. To optimize the absorbance parameter, a simplex centroid design (SCD) was used to optimize the experiments. The combined and individual effect of stabilizers on the synthesis of Ag NPs was significant when P-value < 0.05. SCD optimization of UV results showed a sharp SPR band at 302 nm. In FTIR analysis, bond absorption at 1633 cm−1 attributed to C=O was shifted to higher wavelength due to saccharides addition. XRD analysis confirmed the FCC structure of Ag NPs having average size of 15 nm. SEM- EDX revealed the formation of spherical shaped Ag NPs with strong absorption at 3 keV confirming the presence of the Ag content. Antibacterial activity of Ag NPs was significant against both bacteria, with slightly stronger activity against Staph. aureus than Escherichia coli.

scholarly journals Green Synthesis of Metal Nanostructures and Its Nonlinear Optical Properties

2021 ◽  
Author(s):  
Emusani Ramya
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Nonlinear Optical ◽  
Electric Dipole Transition ◽  
Metal Nanostructures ◽  
Ag Nps ◽  
Nonlinear Optical Susceptibility ◽  
Visible Absorption ◽  
Luminescence Enhancement ◽  
Silver Nps

Simple green synthesis of metal nanoparticles (Ag NPs) was prepared by using Raphanussativus leaf extract. This extract acts as reduce and stabilizing agent. The formation of silver NPs was confirmed and characterized by XRD, UV–visible absorption spectrum, TEM, and FTIR. The luminescence enhancement and quenching of Eu3+and Sm3+ ions were observed in the presence of silver NPs. The luminescence enhancement is owing to arise in the electric-dipole transition with alteration of the field around Ln3+ ions. Nonlinear studies in femtosecond (fs) and picosecond (ps) time scales have been studied by using the Z-scan technique. Third-order nonlinear optical susceptibility of silver nanoparticles was obtained with Degenerate Four-Wave Mixing (DFWM) in the fs regime. The lifetimes of lanthanum complexes were increased by the concentration of silver NPs and decreased for further silver. The high enhanced luminescence and nonlinear studies of green synthesized silver nanoparticles can be used in optics and bio applications.

Host-Guest Interactions on Electrode Surfaces for Immobilization of Molecular Catalysts

2020 ◽  
Author(s):  
Laurent Sévery ◽  
Jacek Szczerbiński ◽  
Mert Taskin ◽  
Isik Tuncay ◽  
Fernanda Brandalise Nunes ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Heterogeneous Systems ◽  
Catalytic Systems ◽  
New Approach ◽  
Molecular Systems ◽  
Electrode Surfaces ◽  
Catalytic Surfaces ◽  
Oxide Electrodes ◽  
The Stability ◽  
Molecular Catalysts

The strategy of anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. The stability of molecular catalysts is, however, far less than that of traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here, we apply a non-covalent “click” chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces via host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and allows the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and readsorption of fresh guest. This strategy represents a new approach to practical molecular-based catalytic systems.

SINTESIS DAN KARAKTERISASI NANOPARTIKEL KITOSAN – EKSTRAK KULIT BUAH MANGGIS (Garcinia Mangostana)

2013 ◽  
Vol 14 (3) ◽  
Author(s):  
Eriawan Rismana ◽  
Susi Kusumaningrum ◽  
Olivia Bunga P ◽  
Idah Rosidah ◽  
Marhamah Marhamah
Keyword(s):  
Particle Size ◽  
Sodium Tripolyphosphate ◽  
Chitosan Solution ◽  
The Other ◽  
Ionic Gelation ◽  
Garcinia Mangostana ◽  
Particle Size Analyzer ◽  
Cadmium Lead ◽  
Solvent Residue ◽  
Mold And Yeast

The chitosan – Garcinia Mangostana extract nanoparticles has been prepared by ionic gelation reaction by mixture 0.2 % chitosan solution in acetic acid with Garcinia Mangostana extract and it’s continued by reaction process with 0.1 % sodium tripolyphosphate. The particle size of material was determined by Particle Size Analyzer (PSA) that it showed in the range of 200 – 500 nm. The color, pH, water, α- mangostin, mercury, arsenic, cadmium, lead, totally microbe aerobic, totally mold and yeast, and solvent residue contents of nanoparticles were also examined by many methods that these resulted are yellow, 4.50 – 5.50, 89 – 90 %, 1.05 %, < 0.005 ppm, < 0.01 ppm, < 0.01 ppm, < 0.05 ppm, < 10 CFU/g, < 10 CFU/g and not detected, respectively. The other characterization was also observed that it’sincluded stability andTLC chromatogram. A mixture of nanoparticles with cosmetics bases was showed that it’s increased stability, homogeneity and easy to formed.

scholarly journals Nitration of Jharia basin coals, India: a study of structural modifications by XRD and FTIR techniques

2021 ◽  
Author(s):  
Prabal Boral ◽  
Atul K. Varma ◽  
Sudip Maity
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Linear Relationship ◽  
Glacial Acetic Acid ◽  
Vitrinite Reflectance ◽  
Aqueous Media ◽  
Interlayer Spacing ◽  
Acetic Acid Medium ◽  
X Ray ◽  
The Media

AbstractFour coal samples from Jharia basin, India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical, petrographic and spatial structure of the organic mass by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. X-ray parameters of coal like interlayer spacing (d002), crystallite size (Lc), aroamticity (fa), average number of aromatic layers (Nc), and coal rank (I26/I20) have been determined using profile-fitting software. Considerable variation is observed in treated coals in comparison to the demineralized coals. The d002 values of treated coals have increased in both the media showing increase in disordering of organic moieties. A linear relationship has been observed between d002 values with the volatile matter of the coals. Similarly, the d002 values show linear relationship with Cdmf contents for demineralized as well as for the treated coals in both the media. The Lc and Nc values have decreased in treated coals corresponding to demineralized coals. The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity (fa) increases with increase in rank and shows a linear relationship with the vitrinite reflectance. The corresponding I26/I20 values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium. FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals (SMCs) in both the media, the corresponding bands at 1550–1490 and 1355–1315 cm−1 respectively. FTIR study confirms that nitration is the predominant phenomenon, though, oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs. In comparison to raw coals, the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.

scholarly journals Chitosan Nanocarrier Entrapping Hydrophilic Drugs as Advanced Polymeric System for Dual Pharmaceutical and Cosmeceutical Application: A Comprehensive Analysis Using Box-Behnken Design

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 677
Author(s):  
Sara A. Abosabaa ◽  
Aliaa N. ElMeshad ◽  
Mona G. Arafa
Keyword(s):  
Particle Size ◽  
Sodium Tripolyphosphate ◽  
Chitosan Nanoparticles ◽  
Optimization Procedure ◽  
Entrapment Efficiency ◽  
Chitosan Solution ◽  
Polydispersity Index ◽  
Successful Implementation ◽  
Solution Ph ◽  
Box Behnken Design

The objective of the present research is to propose chitosan as a nanocarrier for caffeine—a commonly used drug in combating cellulite. Being a hydrophilic drug, caffeine suffers from insufficient topical penetration upon application on the skin. Chitosan nanoparticles loaded with caffeine were prepared via the ionic gelation technique and optimized according to a Box–Behnken design. The effect of (A) chitosan concentration, (B) chitosan solution pH, and (C) chitosan to sodium tripolyphosphate mass ratio on (Y1) entrapment efficiency percent, (Y2) particle size, (Y3) polydispersity index, and (Y4) zeta potential were studied. Subsequently, the desired constraints on responses were applied, and validation of the optimization procedure was confirmed by the parameters exhibited by the optimal formulation. A caffeine entrapment efficiency percent of 17.25 ± 1.48%, a particle size of 173.03 ± 4.32 nm, a polydispersity index of 0.278 ± 0.01, and a surface charge of 41.7 ± 3.0 mV were attained. Microscopical evaluation using transmission electron microscope revealed a typical spherical nature of the nanoparticles arranged in a network with a further confirmation of the formation of particles in the nano range. The results proved the successful implementation of the Box–Behnken design for optimization of chitosan-based nanoparticles in the field of advanced polymeric systems for pharmaceutical and cosmeceutical applications.

scholarly journals ZnWO4 Nanoparticle Scintillators for High Resolution X-ray Imaging

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1721
Author(s):  
Heon Yong Jeong ◽  
Hyung San Lim ◽  
Ju Hyuk Lee ◽  
Jun Heo ◽  
Hyun Nam Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
High Resolution ◽  
Tungsten Oxide ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
X Ray ◽  
X Ray Imaging ◽  
Average Size ◽  
And Tungsten

The effect of scintillator particle size on high-resolution X-ray imaging was studied using zinc tungstate (ZnWO4) particles. The ZnWO4 particles were fabricated through a solid-state reaction between zinc oxide and tungsten oxide at various temperatures, producing particles with average sizes of 176.4 nm, 626.7 nm, and 2.127 μm; the zinc oxide and tungsten oxide were created using anodization. The spatial resolutions of high-resolution X-ray images, obtained from utilizing the fabricated particles, were determined: particles with the average size of 176.4 nm produced the highest spatial resolution. The results demonstrate that high spatial resolution can be obtained from ZnWO4 nanoparticle scintillators that minimize optical diffusion by having a particle size that is smaller than the emission wavelength.

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