New insights into the formation mechanism of Ag, Au and AgAu nanoparticles in aqueous alkaline media: alkoxides from alcohols, aldehydes and ketones as universal reducing agents

2015 ◽  
Vol 17 (33) ◽  
pp. 21683-21693 ◽  
Author(s):  
Janaina F. Gomes ◽  
Amanda C. Garcia ◽  
Eduardo B. Ferreira ◽  
Cleiton Pires ◽  
Vanessa L. Oliveira ◽  
...  
Keyword(s):  
Alkaline Medium ◽  
Formation Mechanism ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Alkaline Media ◽  
Aldehydes And Ketones

Alkoxide from alcohols, aldehydes and ketones in alkaline medium is the actual and universal reducing agent of silver and gold ions.

scholarly journals The Influence of Water Reducing Agents on Early Hydration Property of Ferrite Aluminate Cement Paste

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 731
Author(s):  
Chunlong Huang ◽  
Zirui Cheng ◽  
Jihui Zhao ◽  
Yiren Wang ◽  
Jie Pang
Keyword(s):  
Setting Time ◽  
Critical Role ◽  
Hydration Product ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Hydration Process ◽  
Early Hydration ◽  
Cement Pastes ◽  
Hydration Rate ◽  
Aluminate Cement

The ferrite aluminate cement (FAC) could rapidly lose fluidity or workability due to its excessive hydration rate, and greatly reduce the construction performance. Chemical admixtures are commonly used to provide the workability of cement-based materials. In this study, to ensure required fluidity of FAC, chemically different water reducing agents are incorporated into the FAC pastes. The experiments are performed with aliphatic water reducing agent (AP), polycarboxylic acid water reducing agent (PC) and melamine water reducing agent (MA), respectively. Influence of the water reducing agents on fluidity, setting time, hydration process, hydration product and zeta potential of the fresh cement pastes is investigated. The results show that PC has a better dispersion capacity compared to AP and MA. Besides decreasing water dosage, PC also acts as a retarder, significantly increasing the setting times, delaying the hydration rate and leading to less ettringite in the hydration process of FAC particles. The water reducing agents molecules are adsorbed on the surface of positively charged minerals and hydration products, however, for PC, steric hindrance from the long side chain of PC plays a critical role in dispersing cement particles, whereas AP and MA acting through an electrostatic repulsion force.

scholarly journals Synthesis of Gold Nanoparticles Using p-Aminobenzoic Acid and p-Aminosalicylic Acid as Reducing Agent

2019 ◽  
Vol 19 (1) ◽  
pp. 68
Author(s):  
Abdul Aji ◽  
Eko Sri Kunarti ◽  
Sri Juari Santosa
Keyword(s):  
Gold Nanoparticles ◽  
Optimum Condition ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Hydroxyl Group ◽  
Synthesis Process ◽  
Aminobenzoic Acid ◽  
Aminosalicylic Acid ◽  
Amino Groups ◽  
Transmission Electron

Synthesis of gold nanoparticles (AuNPs) by reduction of HAuCl4 with p-aminobenzoic acid and p-aminosalicylic acid as a reducing agent was investigated. This work was conducted in order to determine the optimum condition of AuNPs synthesis and examine the effect of the hydroxyl group in p-aminosalicylic acid towards the size, shape, and stability of the synthesized gold nanoparticles (AuNPs). The optimum condition of the gold nanoparticles synthesis was determined by UV/Vis spectrophotometer, the shape and size of gold nanoparticles were measured by Transmission Electron Microscope (TEM). The synthesis process was started by reacting HAuCl4 and the reducing agents in an aqueous solution at 86 ºC. The initial gold concentration, reducing agents concentration and pH were varied in order to obtain the optimum condition. In the optimum condition, the results showed that p-aminosalicylic acid containing both hydroxyl and amino groups performed higher reduction ability compared to p-aminobenzoic acid that only containing an amino group. Reducing agents which have a hydroxyl group (p-aminosalicylic acid) could produce AuNPs with a smaller concentration of HAuCl4 than p-aminobenzoic acid. Gold nanoparticles that were synthesized with p-aminosalicylic acid were more stable and had a smaller particle size compared to its counterpart that is synthesized with p-aminobenzoic acid.

scholarly journals Effects of reducing reagents and temperature on conversion of nitrite and nitrate to nitric oxide and detection of NO by chemiluminescence

1997 ◽  
Vol 43 (4) ◽  
pp. 657-662 ◽  
Author(s):  
Fan Yang ◽  
Eric Troncy ◽  
Martin Francœur ◽  
Bernard Vinet ◽  
Patrick Vinay ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Effect Of Temperature ◽  
Fixed Amount ◽  
Increased Temperature

Abstract To measure the concentration of nitrites and nitrates by chemiluminescence, we examined the efficiency of five reducing agents [V(III), Mo(VI) + Fe(II), NaI, Ti(III), and Cr(III)] to reduce nitrite (NO2−) and (or) nitrate (NO3−) to nitric oxide (NO). The effect of each reducing agent on the conversion of different amounts of NO2− and (or) NO3−(100–500 pmol, representing concentrations of 0.4 to 2 μmolar) to NO was determined at 20 °C for NO2− and at 80 °C for NO3−. The effect of temperature from 20 to 90 °C on the conversion of a fixed amount of NO2− or NO3− (400 pmol or 1.6 μmolar) to NO was also determined. These five reducing agents are similarly efficient for the conversion of NO2− to NO at 20 °C. V(III) and Mo(VI) + Fe(II) can completely reduce NO3− to NO at 80 °C. NaI and Cr(III) were unable to convert NO3− to NO. Increased temperature facilitated the conversion of NO3− to NO, rather than that of NO2− to NO. We evaluated the recovery of NO2− and NO3− from plasmas of pig and of dog. Recovery from plasma of both animals was reproducible and near quantitative.

scholarly journals Mechanism of copper-mediated inactivation of herpes simplex virus.

1997 ◽  
Vol 41 (4) ◽  
pp. 812-817 ◽  
Author(s):  
J L Sagripanti ◽  
L B Routson ◽  
A C Bonifacino ◽  
C D Lytle
Keyword(s):  
Hydrogen Peroxide ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Mammalian Cells ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Free Radical Scavengers ◽  
Protective Effects ◽  
Relative Level ◽  
Simplex Virus

The inactivation of herpes simplex virus (HSV) by copper was enhanced by the following reducing agents at the indicated relative level: ascorbic acid > hydrogen peroxide > cysteine. Treatment of HSV-infected cells with combinations of Cu(II) and ascorbate completely inhibited virus plaque formation to below 0.006% of the infectious virus input, while it maintained 30% viability for the host mammalian cells. The logarithm of the surviving fraction of HSV mediated by 1 mg of Cu(II) per liter and 100 mg of reducing agent per liter followed a linear relationship with the reaction time, in which the kinetic rate constant for each reducing agent was -0.87 min(-1) (r = 0.93) for ascorbate, -0.10 min(-1) (r = 0.97) for hydrogen peroxide, and -0.04 min(-1) (r = 0.97) for cysteine. The protective effects of metal chelators and catalase, the lack of effect of superoxide dismutase, and the partial protection conferred by free-radical scavengers suggest that the mechanism of copper-mediated HSV inactivation is similar to that previously reported for copper-mediated DNA damage. The sensitivity exhibited by HSV to Cu(II) and reducing agents, particularly ascorbate, might be useful in the development of therapeutic antiviral agents.

scholarly journals Artificial Sweeteners and Sugar Ingredients as Reducing Agent for Green Synthesis of Silver Nanoparticles

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Shohreh Hemmati ◽  
Erin Retzlaff-Roberts ◽  
Corren Scott ◽  
Michael T. Harris
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Green Synthesis ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Artificial Sweeteners ◽  
Silver Nanostructures ◽  
Artificial Sweetener ◽  
Transmission Electron ◽  
Vis Spectroscopy

An environmentally friendly technique has been developed to produce metal nanoparticles using green synthesis methods. In this study, silver nanostructures were synthesized using different sugar substitutes and artificial sweeteners as green reducing agents in an aqueous solution at low temperature. The main ingredients (such as maltodextrin, sucrose, saccharin, and sucralose) of the artificial sweeteners acting as reducing agents were used to reduce Ag+ ions to Ag0. The pH of the solution was controlled during synthesis through the addition of sodium hydroxide (NaOH) to increase the strength of the reducing agents by converting nonreducing sugars to reducing ones and consequently increasing the rate of silver nanoparticle formation. The size and morphology of the synthesized nanostructures were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The formation of nanostructures during the course of the reactions was investigated by UV-visible (UV-vis) spectroscopy characterization of an aliquot of sample at specific intervals. The function of each artificial sweetener and corresponding ingredients as a reducing agent and capping agent was investigated by Fourier-transform infrared spectroscopy (FTIR) and mass spectrometry (MS).

Haze Formation and the Influence of Ethanol Gasoline of Severe Cold Area on Haze

2014 ◽  
Vol 665 ◽  
pp. 528-533
Author(s):  
Li Bai ◽  
Wen Tao Chang
Keyword(s):  
Particulate Matter ◽  
Formation Mechanism ◽  
Aerosol Particles ◽  
Combustion Products ◽  
Cold Winter ◽  
Aldehydes And Ketones ◽  
Cold Area ◽  
Regional Haze ◽  
Haze Formation ◽  
The Impact

By analyzing the composition of haze and its formation mechanism, this thesis studies the impact of ethanol gasoline combustion products: aerosol particles, particulate matter, additional products (aldehydes and ketones, etc.) and water on severe cold area regional haze formation. The results show that the effect of ethanol gasoline combustion products on haze formation is also very serious. Therefore, this article does not recommend excessive use of ethanol gasoline in the cold winter.

Some Observations on a Perigo-Type Inhibition of Clostridium botulinum in a Simplified Medium

1975 ◽  
Vol 38 (12) ◽  
pp. 762-763 ◽  
Author(s):  
C. N. HUHTANEN
Keyword(s):  
Yeast Extract ◽  
Clostridium Botulinum ◽  
Type A ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Sensitive Assay ◽  
Vegetative Cells ◽  
Botulinum Type ◽  
Better Than

A rapid and sensitive assay for Perigo factor was developed using a medium of 0.5% yeast extract and tryptone, 0.2% glucose, 0.12% K2HPO4 and 0.1% cysteine HCI or sodium thioglycollate and vegetative cells of Clostridium botulinum type A. Yeast extract or tryptone, together with a reducing agent (cysteine, sodium thioglycollate, or glucose autoclaved with the medium), produced a Perigo inhibitor when autoclaved at 15 psi for 15 min with NaNO2. Tryptone was more active than yeast extract as a source of the Perigo inhibitor; of the reducing agents tested cysteine was more effective in producing Perigo-type inhibition than thioglycollate and either was better than glucose autoclaved with the medium.

Synthesis of Silver Nanoparticles Using o-Hydroxybenzoic, p-Hydroxybenzoic, and o,p-Dihydroxybenzoic Acids as Reducing Agents

2017 ◽  
Vol 901 ◽  
pp. 26-31 ◽  
Author(s):  
Dian Susanthy ◽  
Fadliah ◽  
Endang Tri Wahyuni ◽  
Sri Juari Santosa
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Para Position ◽  
Hydroxyl Groups ◽  
Hydroxybenzoic Acid ◽  
Dihydroxybenzoic Acid ◽  
Transmission Electron ◽  
Shape And Size

Synthesis of silver nanoparticles (AgNPs) by reduction of AgNO3 with o-hydroxybenzoic, p-hydroxybenzoic and o,p-dihydroxybenzoic acids as reducing agents was investigated. This research was conducted to determine the effect of the position and number of hydroxyl groups towards the size, shape and stability of the resulted AgNPs. Surface Plasmon Resonance (SPR) of AgNPs was characterized by UV/Vis spectrophotometer, the shape and size of AgNPs was determined by Transmission Electron Microscope (TEM). The results showed that the reducing agent that has substituents in the para position (p-hydroxybenzoic acid) has the higher reduction ability than the others. AgNPs were yielded by all types of reducing agents in alkaline system. Reducing agents which have greater number of substituents (o,p-dihydroxybenzoic acid) could produce AgNPs with smaller concentration of AgNO3 than the others. AgNPs that was produced by reducing agent having substituents on the para position (p-hydroxybenzoic acid) was more stable and smaller particle size, i.e. 34 ± 1.78 nm than reducing agent that has substituent on the ortho para positions (with particle size 45 + 3.67 nm) and ortho positions (with particle size 70 ± 4.96 nm).

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