scholarly journals INFLUENCE OF SYNTHESIS CONDITIONS ON AGGREGATIVE STABILITY OF Ag ALCOSOLS

2020 ◽  
pp. 25-32
Author(s):  
Андрей Владимирович Блинов ◽  
Александр Александрович Кравцов ◽  
Владислав Викторович Раффа ◽  
Василий Николаевич Крамаренко ◽  
Святослав Олегович Крандиевский ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Isopropyl Alcohol ◽  
Aggregative Stability ◽  
Selective Absorption ◽  
Synthesis Conditions ◽  
Nanoparticle Stability ◽  
Sodium Chloride Solutions ◽  
Stable Particles ◽  
First Time ◽  
Electroacoustic Spectroscopy

Впервые в работе представлены результаты исследования влияния типа спиртовой среды на свойства высококонцентрированных золей наночастиц серебра. С помощью спектрофотометрии установлено наличие селективной полосы поглощения, обусловленной поверхностным плазмонным резонансом наночастиц серебра. Измерение дзета-потенциала показало, что вне зависимости от типа среды поверхность наночастиц серебра заряжена отрицательно. Обнаружено, что наиболее агрегативно устойчивые частицы, сохраняющие стабильность в концентрированных растворах хлорида натрия, получены в среде изопропилового спирта и характеризуются дзета-потенциалом, равным -99,8 мВ. For the first time, the paper presents the results of investigation the effect of the type of alcoholic medium on the properties of highly concentrated sols of silver nanoparticles. Spectrophotometry revealed the presence of a selective absorption band corresponding to the surface plasmon resonance of silver nanoparticles. Measurement of the zetta potential showed that, regardless of the type of medium, the surface of silver nanoparticles is negatively charged. It was found that the most aggregatively stable particles that retain stability even in concentrated sodium chloride solutions were obtained in isopropyl alcohol and are characterized by the zetta potential equal to -99,8 mV. Keywords: silver nanoparticles, optical properties, electroacoustic spectroscopy, zeta potential, nanoparticle stability.

Novel Baddeleyite-Based Zirconia Ceramics for Biomedical Applications

2017 ◽  
Vol 13 ◽  
pp. 9-14
Author(s):  
Alexander I. Tyurin ◽  
Andrey O. Zhigachev ◽  
Alexey V. Umrikhin ◽  
Vyacheslav V. Rodaev ◽  
Tatyana S. Pirozhkova
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tetragonal Phase ◽  
Biomedical Applications ◽  
Zirconia Ceramics ◽  
Engineering Ceramics ◽  
Synthesis Conditions ◽  
Microstructure And Mechanical Properties ◽  
First Time

For the first time nanostructured engineering ceramics were prepared from natural zirconia mineral (baddeleyite) with CaO as a tetragonal phase stabilizer. The effect of synthesis conditions on microstructure and mechanical properties of the baddeleyite-based ceramics is reported, furthermore, the effect of calcia content on hardness and fracture toughness is studied. Optimal calcia concentration and synthesis conditions are found, corresponding hardness and fracture toughness values are 10,8 GPa and 13,3 MPa×m1/2. The reported mechanical properties are comparable to those typically reported for yttria-stabilized engineering zirconia ceramics, prepared from chemically synthesized zirconia.

scholarly journals A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
M. A. El-Sheikh
Keyword(s):  
Silver Nanoparticles ◽  
Room Temperature ◽  
Colloidal Solution ◽  
Synthesis Method ◽  
Silver Ions ◽  
Water Soluble ◽  
Synthesis Process ◽  
Carboxymethyl Starch ◽  
Round Shape ◽  
First Time

The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride is used for the first time in the synthesis of silver nanoparticles (AgNPs). A new green synthesis method involves using PI/UV system, carboxymethyl starch (CMS), silver nitrate, and water. A mechanism of the reduction of silver ions to AgNPs by PI/UV system as well as by the newly born aldehydic groups was proposed. The synthesis process was assessed by UV-vis spectra and TEM of AgNPs colloidal solution. The highest absorbance was obtained using CMS, PI and AgNO3concentrations of 10 g/L, 1 g/L, and 1 g/L, respectively; 40°C; 60 min; pH 7; and a material : liquor ratio 1 : 20. AgNPs so-obtained were stable in aqueous solution over a period of three weeks at room temperature (~25°C) and have round shape morphology. The sizes of synthesized AgNPs were in the range of 1–21 nm and the highest counts % of these particles were for particles of 6–10 and 1–3 nm, respectively.

scholarly journals Optimization of Green Synthesis of Silver Nanoparticles from Leaf Extracts ofPimenta dioica(Allspice)

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Akshay Rajeev Geetha ◽  
Elizabeth George ◽  
Akshay Srinivasan ◽  
Jameel Shaik
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Leaf Extract ◽  
Synthesis Method ◽  
Leaf Extracts ◽  
Synthesis Of Nanoparticles ◽  
Hot Air ◽  
Vis Spectroscopy ◽  
Pimenta Dioica ◽  
First Time

Production of silver nanoparticles from the leaf extracts ofPimenta dioicais reported for the first time in this paper. Three different sets of leaves were utilized for the synthesis of nanoparticles—fresh, hot-air oven dried, and sun-dried. These nanoparticles were characterized using UV-Vis spectroscopy and AFM. The results were diverse in that different sizes were seen for different leaf conditions. Nanoparticles synthesized using sun-dried leaves (produced using a particular ratio (1 : 0.5) of the leaf extract sample and silver nitrate (1 mM), resp.) possessed the smallest sizes. We believe that further optimization of the current green-synthesis method would help in the production of monodispersed silver nanoparticles having great potential in treating several diseases.

scholarly journals Dissolution of iron in sodium chloride solution during alternating current polarization

2021 ◽  
Vol 318 (3) ◽  
pp. 51-62
Author(s):  
A. Bayeshova ◽  
◽  
A. Bayeshov ◽  
A. Kadirbayeva ◽  
F. Zhumabay ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Iron Hydroxide ◽  
Alternating Current ◽  
Iron Electrode ◽  
Half Cycle ◽  
Iron Compounds ◽  
Titanium Electrode ◽  
Sodium Chloride Solutions ◽  
Multi Stage ◽  
First Time

Iron compounds are widely used in many industries and engineering, and even in medicine. The existing methods of obtaining iron compounds are multi-stage and complex. The purpose of this work is to obtain iron (II) hydroxide and oxide from metal waste under alternating current action using one and two half-cycles. For the first time, the electrochemical behavior of iron electrode was studied by electrolysis method during alternating current polarization of industrial frequency in sodium chloride solutions. The iron polarization was carried out in pair with titanium, while the current density on the iron electrode varied in the range of 200-1200 A/m2, and on the titanium is in the range of 20-100 kA/m2. It is established that in the anode half-cycle of alternating current, iron is oxidized to form divalent ions. At this moment, the titanium electrode is in the cathode half-cycle, hydrogen is released on it, hydroxyl ions are formed in the cathode space. In the solution, ions interact with iron (II) ions to produce iron hydroxide. At temperatures above 600C, iron (II) hydroxide is dehydrated with the production of iron (II) oxide. The electrolysis was carried out in two electrolyzers connected to each other in parallel with the immersion of pair of “titanium-iron” electrodes into each electrolyzer. The iron dissolution occurs simultaneously in two half-cycles of alternating current and this approach is proposed for the first time. The process productivity increases by more than 1.5 times.

scholarly journals Eco-friendly microwave-enhanced green synthesis of silver nanoparticles using Aloe vera leaf extract and their physico-chemical and antibacterial studies

2018 ◽  
Vol 7 (3) ◽  
pp. 231-240 ◽  
Author(s):  
Omid Ahmadi ◽  
Hoda Jafarizadeh-Malmiri ◽  
Naeimeh Jodeiri
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Exposure Time ◽  
Leaf Extract ◽  
Aloe Vera ◽  
Synthesis Conditions ◽  
Stabilizing Agents ◽  
Microwave Exposure ◽  
Mean Particle Size ◽  
Vis Spectroscopy

Abstract Silver nanoparticles (AgNPs) were synthesized using Aloe vera leaf extract as both reducing and stabilizing agents via microwave irradiation method. The effects of the microwave exposure time and the amount of AgNO3 solution on the mean particle size and concentration of the synthesized AgNPs solution were investigated using response surface methodology. The synthesized AgNPs were characterized by transmission electron microscopy, UV-Vis spectroscopy, and dynamic light scattering. Well-dispersed and spherically fabricated AgNPs with mean particle size (46 nm) and maximum concentration (64 ppm) and zeta potential (+15.5 mV), were obtained at optimal synthesis conditions, using 9 ml of AgNO3 (1 mm) and 0.1 ml of Aloe vera extract during microwave exposure time of 360 s. The antibacterial activity of the synthesized AgNPs was tested using Escherichia coli and Staphylococcus aureus bacteria and the obtained results indicated their significant inhibitory effects against these two Gram-negative and Gram-positive bacteria.

Evaluating the mechanism of nucleation and growth of silver nanoparticles in a polymer membrane under continuous precursor supply: tuning of multiple to single nucleation pathway

2019 ◽  
Vol 21 (8) ◽  
pp. 4193-4199 ◽  
Author(s):  
Apurva N. Naik ◽  
Sabyasachi Patra ◽  
Debasis Sen ◽  
Asok Goswami
Keyword(s):  
Silver Nanoparticles ◽  
Nucleation And Growth ◽  
Polymer Membrane ◽  
First Time ◽  
Precursor Supply

LaMer type nucleation curve has been experimentally studied for the first time for synthesis of membrane hosted silver nanoparticles under continuous precursor supply. Radiotracer has been uniquely used as a probe in this investigation.

scholarly journals Fabrication of C60Fullerene Nanofibers by Volatile Diffusion Method

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Bingzhe Wang ◽  
Xin Gao ◽  
Guangzhe Piao
Keyword(s):  
Crystal Growth ◽  
Self Assembly ◽  
Growth Process ◽  
Room Temperature ◽  
Isopropyl Alcohol ◽  
Diffusion Method ◽  
Short Fibers ◽  
Aspect Ratios ◽  
Crystal Growth Process ◽  
First Time

C60fullerene nanofibers (FNFs) were for the first time prepared by a volatile diffusion method using toluene as solvent and isopropyl alcohol as precipitation agent in room temperature, 25°C. FNFs with different lengths, aspect ratios, and morphologies could be fabricated by changing incubation time. Meanwhile, as for a crystal growth process, a possible mechanism of the formation of the crystal of FNFs was proposed in which the short and thin FNFs are the result of crystal growth, and self-assembly happens between the short fibers and thus leads to the formation of thick and long bundles of the FNFs.

Effect of silver nanoparticles on human primary keratinocytes

2013 ◽  
Vol 394 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Radoslaw Szmyd ◽  
Anna Grazyna Goralczyk ◽  
Lukasz Skalniak ◽  
Agnieszka Cierniak ◽  
Barbara Lipert ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Properties ◽  
Wound Dressings ◽  
Epidermal Keratinocytes ◽  
Primary Keratinocytes ◽  
Human Epidermal Keratinocytes ◽  
Normal Human ◽  
Physical And Chemical ◽  
First Time ◽  
Human Primary Keratinocytes

Abstract Silver nanoparticles (AgNPs) have many biological applications in biomedicine, biotechnology and other life sciences. Depending on the size, shape and the type of carrier, AgNPs demonstrate different physical and chemical properties. AgNPs have strong antimicrobial, antiviral and antifungal activity, thus they are used extensively in a range of medical settings, particularly in wound dressings but also in cosmetics. This study was undertaken to examine the potential toxic effects of 15 nm polyvinylpyrrolidone-coated AgNPs on primary normal human epidermal keratinocytes (NHEK). Cells were treated with different concentrations of AgNPs and then cell viability, metabolic activity and other biological and biochemical aspects of keratinocytes functioning were studied. We observed that AgNPs decrease keratinocyte viability, metabolism and also proliferatory and migratory potential of these cells. Moreover, longer exposure resulted in activation of caspase 3/7 and DNA damage. Our studies show for the first time, that AgNPs may present possible danger for primary keratinocytes, concerning activation of genotoxic and cytotoxic processes depending on the concentration.

Time resolved growth of membrane stabilized silver NPs and their catalytic activity

RSC Advances ◽  
2014 ◽  
Vol 4 (103) ◽  
pp. 59379-59386 ◽  
Author(s):  
Sabyasachi Patra ◽  
Debasis Sen ◽  
Ashok K. Pandey ◽  
J. Bahadur ◽  
S. Mazumder ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Growth Kinetics ◽  
Nanocomposite Membranes ◽  
Time Resolved ◽  
Catalytic Application ◽  
Silver Nps ◽  
First Time ◽  
Kinetics Of

Growth kinetics of membrane stabilized silver nanoparticles have been studied for the first time with time resolved in situ SAXS. The catalytic application of nanocomposite membranes thus formed has also been explored.

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