scholarly journals Exposure Media and Nanoparticle Size Influence on the Fate, Bioaccumulation, and Toxicity of Silver Nanoparticles to Higher Plant Salvinia minima

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2305
Author(s):  
Melusi Thwala ◽  
Stephen Klaine ◽  
Ndeke Musee
Keyword(s):  
Silver Nanoparticles ◽  
Analytical Techniques ◽  
Hard Water ◽  
Higher Plant ◽  
X Ray ◽  
Chlorophyll Pigments ◽  
Size Dependent ◽  
Predicted Environmental Concentrations ◽  
Low Exposure ◽  
Toxicity Pattern

Silver nanoparticles (AgNPs) are favoured antibacterial agents in nano-enabled products and can be released into water resources where they potentially elicit adverse effects. Herein, interactions of 10 and 40 nm AgNPs (10-AgNPs and 40-AgNPs) with aquatic higher plant Salvinia minima at 600 µg/L in moderately hard water (MHW), MHW of raised calcium (Ca2+), and MHW containing natural organic matter (NOM) were examined. The exposure media variants altered the AgNPs’ surface properties, causing size-dependent agglomeration. The bio-accessibility in the ascending order was: NOM < MHW < Ca2+, was higher in plants exposed to 10-AgNPs, and across all exposures, accumulation was higher in roots compared to fronds. The AgNPs reduced plant growth and the production of chlorophyll pigments a and b; the toxic effects were influenced by exposure media chemistry, and the smaller 10-AgNPs were commonly the most toxic relative to 40-AgNPs. The toxicity pattern was linked to the averagely higher dissolution of 10-AgNPs compared to the larger counterparts. The scanning electron microscopy and X-ray fluorescence analytical techniques were found limited in examining the interaction of the plants with AgNPs at the low exposure concentration used in this study, thus challenging their applicability considering the even lower predicted environmental concentrations AgNPs.

scholarly journals Anticoagulant, thrombolytic and antibacterial activities of Euphorbia acruensis latex-mediated bioengineered silver nanoparticles

2019 ◽  
Vol 8 (1) ◽  
pp. 590-599 ◽  
Author(s):  
Kaushik Roy ◽  
Ambikesh K. Srivastwa ◽  
Chandan K. Ghosh
Keyword(s):  
Silver Nanoparticles ◽  
Analytical Techniques ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
Antibacterial Study ◽  
X Ray ◽  
Transmission Electron ◽  
Human Blood Samples ◽  
Green Synthesized Silver Nanoparticles

Abstract In this report, we present a simple and unexplored procedure for green synthesis of silver nanoparticles featuring exudation of Euphorbia acruensis along with the study of its antibacterial and anticoagulant properties. Analytical techniques like ultraviolet visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) were used to analyse the production, crystallinity and morphology of bio-reduced silver nanoparticles. The antibacterial study was performed by following standard disc diffusion method. Most importantly, the anticoagulant and thrombolytic activities of biogenic silver nanoparticles were evaluated by addition of nanoparticles to human blood samples under practical conditions. These green synthesized silver nanoparticles were found to have potent antibacterial, anticoagulant and thrombolytic properties which make them an attractive choice for future medical applications.

scholarly journals Characterization of scale deposits formed in sanitary hot water pipelines in the northern tourist zone of Agadir city

2018 ◽  
Vol 7 (2) ◽  
pp. 86-92
Author(s):  
M'barek Belattar ◽  
Abdallah Hadfi ◽  
Said Ben Aazza ◽  
Said Mohareb ◽  
Naima Hafid ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Analytical Techniques ◽  
Hard Water ◽  
Hot Water ◽  
Infrared Spectrometry ◽  
X Ray ◽  
The North ◽  
Quality Of Water ◽  
Physico Chemical ◽  
Water Pipelines

The formation of scale on surfaces in contact with water is due to many reasons as the hardness of water and its temperature. Therefore, this phenomenon of scale in water pipelines is a common and inevitable problem in the regions that exploit or use groundwater with high rigidity. The circuits fed by hot water are easily reached by hard water scaling. The deposition of encrusting curst at the level of walls in touch with water is due to many technical, economic and environmental problems. It causes a reduction in water flow and a decrease in the efficiency of heating systems.In this study, we are particularly interested in studying the phenomenon of hard water scaling caused by sanitary hot water in a tourist unit situated in the north of the seaside in the city of Agadir. First, we have evaluated the physico-chemical quality of water in use in this tourist unit. Secondly, we conducted a qualitative and quantitative analysis of the scale found in the circuits that transport sanitary hot water. Several analytical techniques were used to reach this goal namely: X-ray fluorescence (XRF) which shows that 85.50% of scale is represented by Calcium Carbonate. Whereas infrared spectrometry (IR) demonstrates the existence of the Carbonate anion CO32-. In addition, due to thermogravimetric analysis (TGA) and differential thermal analysis (DTA) we found that the endothermic event shows the decomposition of Calcium Carbonate of CaO and CO2 in the temperature range of 660 C° to 820 C°. For scanning electron microscopy (SEM), it indicates that the scale takes the form of needle-like aragonite crystals. At last, the X-ray diffraction (XRD) shows that the scale is composed essentially of Calcium Carbonate of the type aragonite.The results of the different techniques of characterisation are in concordance in the scaling of the circuits of sanitary hot water in the tourist unit under study.

scholarly journals Silver Nanoparticles on Chitosan/Silica Nanofibers: Characterization and Antibacterial Activity

2019 ◽  
Vol 21 (1) ◽  
pp. 166 ◽  
Author(s):  
Małgorzata Zienkiewicz-Strzałka ◽  
Anna Deryło-Marczewska ◽  
Yury A. Skorik ◽  
Valentina A. Petrova ◽  
Adam Choma ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Low Cost ◽  
Physicochemical Characterization ◽  
Analytical Techniques ◽  
Electrospinning Technique ◽  
X Ray ◽  
Silica Phase ◽  
Silica Nanofibers

A simple, low-cost, and reproducible method for creating materials with even silver nanoparticles (AgNP) dispersion was established. Chitosan nanofibers with silica phase (CS/silica) were synthesized by an electrospinning technique to obtain highly porous 3D nanofiber scaffolds. Silver nanoparticles in the form of a well-dispersed metallic phase were synthesized in an external preparation step and embedded in the CS/silica nanofibers by deposition for obtaining chitosan nanofibers with silica phase decorated by silver nanoparticles (Ag/CS/silica). The antibacterial activity of investigated materials was tested using Gram-positive and Gram-negative bacteria. The results were compared with the properties of the nanocomposite without silver nanoparticles and a colloidal solution of AgNP. The minimum inhibitory concentration (MIC) of obtained AgNP against Staphylococcus aureus (S. aureus) ATCC25923 and Escherichia coli (E. coli) ATCC25922 was determined. The physicochemical characterization of Ag/CS/silica nanofibers using various analytical techniques, as well as the applicability of these techniques in the characterization of this type of nanocomposite, is presented. The resulting Ag/CS/silica nanocomposites (Ag/CS/silica nanofibers) were characterized by small angle X-ray scattering (SAXS), X-ray diffraction (XRD), and atomic force microscopy (AFM). The morphology of the AgNP in solution, both initial and extracted from composite, the properties of composites, the size, and crystallinity of the nanoparticles, and the characteristics of the chitosan fibers were determined by electron microscopy (SEM and TEM).

scholarly journals Synthesis and Characterization of Silver Nanoparticles Using Alginate from the Brown Seaweed Laminaria ochroleuca: Structural Features and Antibacterial Activity

2021 ◽  
Vol 12 (5) ◽  
pp. 6046-6057
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Sodium Alginate ◽  
Brown Seaweed ◽  
Analytical Techniques ◽  
Spherical Shape ◽  
Structural Features ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Laminaria Ochroleuca

In this study, inexpensive and eco-friendly production of the silver nanoparticles (AgNPs) was explored using Laminaria ochroleuca sodium alginate as stabilizing and reducing agent. The synthesized nanoparticles were characterized by various analytical techniques such as UV–Vis spectroscopy, Energy dispersive X-ray spectrometer (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), TEM selected area electron diffraction (SAED), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The synthesis of AgNPs was elucidated by characteristic absorption peaks in the UV–Vis test. The FTIR analysis revealed the involvement of many functional groups in the bioreduction and the stabilization of AgNPs, while TEM images illustrated the spherical shape with maximum particles found in the size range of 10-20 nm. Prominent peaks and silver diffraction rings shown by the XRD spectrum and SAED pattern, respectively, confirmed the crystalline nature (fcc) of the synthesized AgNPs, which were found to be thermally stable based on TGA analysis. The AgNPs exhibited strong antibacterial activity against Gram+ and Gram– bacteria. The synthesized silver nanoparticles using Laminaria ochroleuca sodium alginate revealed interesting properties that could be potentially used for pharmaceutical applications.

scholarly journals Comparative Antibacterial Study of Silver Nanoparticles Doped Activated Carbon Prepared by Different Methods

2020 ◽  
Vol 15 (1) ◽  
pp. 187-194
Author(s):  
Pragya Pandey ◽  
Bivek Karki ◽  
Binod Lekhak ◽  
Agni R. Koirala ◽  
R. K. Sharma ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Activated Carbon ◽  
Nitrate Solution ◽  
Analytical Techniques ◽  
Silver Nitrate Solution ◽  
Carbon Powder ◽  
X Ray Diffraction ◽  
Toxic Heavy Metals ◽  
Antibacterial Study ◽  
X Ray

 Activated carbon is greatly used to adsorb toxic heavy metals from water bodies. Simultaneous removal of such pollutants and pathogenic impurities is essential for safe drinking water. In this study, silver nanoparticles (NPs) doped activated carbon (AC) composite was fabricated via hydrothermal technique and green synthesis technique using commercial activated carbon powder and silver nitrate solution. Several analytical techniques, including scanning electron microscopy (SEM), energy dispersive x-ray (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the formation of silver nanoparticles on the surface and pores of AC. The prepared composite materials were accessed for their anti-bacterial property using Escherichia coli and Staphylococcus aureus and found that such materials have good antibacterial activity which shows that as fabricated composite can be used potentially for water treatment.

scholarly journals Preparation of silver nanoparticles in a high voltage AC arc in water

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Joanna Jabłońska ◽  
Krzysztof Jankowski ◽  
Mikołaj Tomasik ◽  
Dariusz Cykalewicz ◽  
Paweł Uznański ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
High Voltage ◽  
Water Solution ◽  
Analytical Techniques ◽  
Dark Field ◽  
Atomic Scale ◽  
Mutual Distance ◽  
Chemical Mapping ◽  
X Ray ◽  
Vis Spectroscopy

AbstractThe article presents for the first time the synthesis of silver nanoparticles in an electric arc of high-voltage alternating current with a frequency of 50 Hz. In particular, the method and apparatus necessary for the preparation of nanoparticles in water solution is discussed. Current–voltage characteristics depending on the mutual distance between the electrodes are presented which show a very high stability of the generated discharge phenomena. The obtained nanoparticles were examined using various analytical techniques such as UV–Vis spectroscopy, dynamic light scattering (DLS), zeta potential, energy dispersive X-Ray analysis (EDS), X-ray diffraction (XRD), and X-ray fluorescence (EDXRF). The morphology, surface and size of the obtained nanoparticles was carried out using transmission electron microscopy (TEM) and scanning TEM (STEM) equipped with the annual dark-field imaging scanning atomic-scale chemical mapping (STEM). The designed simple power supply unit consisting of an autotransformer and a microwave oven transformer (MOT) makes the preparation of silver nanoparticles both simple and economical.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Layered and ion implantation specimens as possible reference materials for the electron-probe microanalysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1652-1653
Author(s):  
G. Remond ◽  
R.H. Packwood ◽  
C. Gilles ◽  
S. Chryssoulis
Keyword(s):  
Ion Implantation ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
X Ray ◽  
Spatially Resolved ◽  
Analytical Expressions ◽  
Original Approach ◽  
Depth Concentration

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

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