Ultrafine silver nanoparticles supported on a covalent carbazole framework as high-efficiency nanocatalysts for nitrophenol reduction

2019 ◽  
Vol 7 (22) ◽  
pp. 13449-13454 ◽  
Author(s):  
Wei Gong ◽  
Qianqian Wu ◽  
Guoxing Jiang ◽  
Guangji Li
Keyword(s):  
Silver Nanoparticles ◽  
Rate Constant ◽  
High Efficiency ◽  
Reduction Reaction ◽  
Porous Polymer ◽  
Ag Nps ◽  
Nitrophenol Reduction

A novel covalent micro/macro-porous polymer (CMP), CZ–TEB, is synthesized and then Ag NPs are immobilized on it, and the normalized rate constant (knor) of the Ag0@CZ–TEB catalyzed reduction reaction of 4-NP to 4-AP reaches up to 21.49 mmol−1 s−1.

scholarly journals Single-Step Green Synthesis of Highly Concentrated and Stable Colloidal Dispersion of Core-Shell Silver Nanoparticles and Their Antimicrobial and Ultra-High Catalytic Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1007
Author(s):  
Azam Ali ◽  
Mariyam Sattar ◽  
Fiaz Hussain ◽  
Muhammad Humble Khalid Tareen ◽  
Jiri Militky ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Tannic Acid ◽  
Rate Constant ◽  
Catalytic Properties ◽  
Colloidal Dispersion ◽  
Alkaline Condition ◽  
Core Shell ◽  
Average Particle ◽  
Ag Nps

The versatile one-pot green synthesis of a highly concentrated and stable colloidal dispersion of silver nanoparticles (Ag NPs) was carried out using the self-assembled tannic acid without using any other hazardous chemicals. Tannic acid (Plant-based polyphenol) was used as a reducing and stabilizing agent for silver nitrate in a mild alkaline condition. The synthesized Ag NPs were characterized for their concentration, capping, size distribution, and shape. The experimental results confirmed the successful synthesis of nearly spherical and highly concentrated (2281 ppm) Ag NPs, capped with poly-tannic acid (Ag NPs-PTA). The average particle size of Ag NPs-PTA was found to be 9.90 ± 1.60 nm. The colloidal dispersion of synthesized nanoparticles was observed to be stable for more than 15 months in the ambient environment (25 °C, 65% relative humidity). The synthesized AgNPs-PTA showed an effective antimicrobial activity against Staphylococcus Aureus (ZOI 3.0 mM) and Escherichia coli (ZOI 3.5 mM). Ag NPs-PTA also exhibited enhanced catalytic properties. It reduces 4-nitrophenol into 4-aminophenol in the presence of NaBH4 with a normalized rate constant (Knor = K/m) of 615.04 mL·s−1·mg−1. For comparison, bare Ag NPs show catalytic activity with a normalized rate constant of 139.78 mL·s−1·mg−1. Furthermore, AgNPs-PTA were stable for more than 15 months under ambient conditions. The ultra-high catalytic and good antimicrobial properties can be attributed to the fine size and good aqueous stability of Ag NPs-PTA. The unique core-shell structure and ease of synthesis render the synthesized nanoparticles superior to others, with potential for large-scale applications, especially in the field of catalysis and medical.

Gold nanoparticles-coated chemically-reactive polymer colloids and the study of their catalytic kinetics

2014 ◽  
Vol 1641 ◽  
Author(s):  
Maolin Li ◽  
Vivian Zhong ◽  
Guofang Chen
Keyword(s):  
Gold Nanoparticles ◽  
Reaction Time ◽  
Rate Constant ◽  
Apparent Rate Constant ◽  
Reaction Rate ◽  
Catalytic Efficiency ◽  
Reduction Reaction ◽  
Assembly Method ◽  
Nitrophenol Reduction ◽  
Time Average

ABSTRACTRaspberry-like composite spheres based on chemically-reactive poly(glycidyl methacrylate) (PGMA) colloids as the cores coated with tunable size of gold nanoparticles were synthesized via a controlled assembly method. Kinetic study of 4-nitrophenol reduction by NaBH4 in the presence of poly(allylamine hydrochloride)-modified PGMA composite with tunable size of AuNPs (PGMA@PAH@AuNPs) was demonstrated. Effects of gold nanoparticles size and PGMA colloid diameter on the reaction time, average reaction rate and average turnover frequency (TOF), order of reaction (n) and apparent rate constant (kapp) were systematically investigated. Experimental results of our study showed composites with 3.4 ± 0.9 nm AuNPs have the best catalytic efficiency with the highest reaction order and apparent rate constant. The poisoning of product 4-aminophenol on PAH-modified PGMA colloid-supported gold nanocatalysts was evaluated using 4-nitrophenol/NaBH4 reduction reaction for the reaction time, average reaction rate, average TOF, order of reaction and apparent rate constant.

Role of dissolved oxygen in nitroarene reduction by a heterogeneous silver textile catalyst in water

2020 ◽  
Vol 44 (41) ◽  
pp. 17780-17790
Author(s):  
Sembanadar Karuppusamy ◽  
Frank Marken ◽  
Manickam Anbu Kulandainathan
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Rate Constant ◽  
Reduction Reaction ◽  
Dissolved Oxygen Concentration ◽  
Nitrophenol Reduction ◽  
Nitroarene Reduction

The effects of dissolved oxygen concentration on the rate constant of the 4-nitrophenol reduction reaction with a silver-coated textile as a ‘dip-catalyst’ were studied.

scholarly journals Synthesis and Application of Silver Nanoparticles (Ag NPs) for the Prevention of Infection in Healthcare Workers

2019 ◽  
Vol 20 (15) ◽  
pp. 3620 ◽  
Author(s):  
Shingo Nakamura ◽  
Masahiro Sato ◽  
Yoko Sato ◽  
Naoko Ando ◽  
Tomohiro Takayama ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Healthcare Workers ◽  
High Efficiency ◽  
Particle Surface ◽  
Silver Ions ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Medical Field ◽  
Ag Nps ◽  
Environment Friendly

Silver is easily available and is known to have microbicidal effect; moreover, it does not impose any adverse effects on the human body. The microbicidal effect is mainly due to silver ions, which have a wide antibacterial spectrum. Furthermore, the development of multidrug-resistant bacteria, as in the case of antibiotics, is less likely. Silver ions bind to halide ions, such as chloride, and precipitate; therefore, when used directly, their microbicidal activity is shortened. To overcome this issue, silver nanoparticles (Ag NPs) have been recently synthesized and frequently used as microbicidal agents that release silver ions from particle surface. Depending on the specific surface area of the nanoparticles, silver ions are released with high efficiency. In addition to their bactericidal activity, small Ag NPs (<10 nm in diameter) affect viruses although the microbicidal effect of silver mass is weak. Because of their characteristics, Ag NPs are useful countermeasures against infectious diseases, which constitute a major issue in the medical field. Thus, medical tools coated with Ag NPs are being developed. This review outlines the synthesis and utilization of Ag NPs in the medical field, focusing on environment-friendly synthesis and the suppression of infections in healthcare workers (HCWs).

Green Synthesis of Silver Nanoparticles with Exceptional Colloidal Stability and its Catalytic Activity Toward Nitrophenol Reduction

NANO ◽  
2016 ◽  
Vol 11 (04) ◽  
pp. 1650046 ◽  
Author(s):  
Manisha Sharma ◽  
Amit Mishra ◽  
Vinod Kumar ◽  
Soumen Basu
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Colloidal Stability ◽  
Ag Nps ◽  
Step Process ◽  
Synthesis Parameters ◽  
Salt Addition ◽  
Nitrophenol Reduction ◽  
Vis Spectroscopy ◽  
One Step

Silver nanoparticles (Ag NPs) were synthesized by one-step process in the presence of kollicoat as capping, reducing and stabilizing mediator. The synthesized NPs were characterized by using FTIR, TEM, DLS, XRD, EDS and UV-Vis spectroscopy. The resulting Ag NPs had an incomparable colloidal stability against the salt addition and change of pH. The effect of different synthesis parameters and the catalytic property of the NPs were examined.

Testing of photocatalytic potential of silver nanoparticles produced through nonthermal plasma reduction reaction and stabilized with saccharides

2021 ◽  
pp. 1-14
Author(s):  
N.U.H. Altaf ◽  
M.Y. Naz ◽  
S. Shukrullah ◽  
H.N. Bhatti
Keyword(s):  
Silver Nanoparticles ◽  
Band Gap ◽  
Light Exposure ◽  
Argon Plasma ◽  
Silver Ions ◽  
Reduction Reaction ◽  
Diameter Distribution ◽  
Light Spectrum ◽  
Plasma Reduction ◽  
Narrow Diameter Distribution

In this study, silver nanoparticles (AgNPs) were produced through an atmospheric pressure plasma reduction reaction and tested for photodegradation of methyl blue (MB) under sunlight exposure. The argon plasma born reactive species were used to reduce silver ions to AgNPs in the solution. Glucose, fructose and sucrose were also added in the solution to stabilize the growth process. The glucose stabilized reaction produced the smallest nanoparticles of 12 nm, while sucrose stabilized reaction produced relatively larger nanoparticles (14 nm). The nanoparticles exhibited rough morphology and narrow diameter distribution regardless of stabilizer type. The narrow diameter distribution and small band gap helped activating majority of nanoparticles at a single wavelength of light spectrum. The band gap energy of AgNPs varied from 2.22 eV to 2.41 eV, depending on the saccharide type. The photoluminescence spectroscopy of AgNPs produced emission peaks at 413 nm, 415 nm, and 418 nm. The photocatalytic potential of AgNP samples was checked by degrading MB dye under sunlight. The degradation reaction reached a saturation level of 98% after 60 min of light exposure.

scholarly journals Antibacterial activity of royal jelly-mediated green synthesized silver nanoparticles

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Susanna Gevorgyan ◽  
Robin Schubert ◽  
Mkrtich Yeranosyan ◽  
Lilit Gabrielyan ◽  
Armen Trchounian ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Green Synthesis ◽  
Royal Jelly ◽  
Fluorescence Emission ◽  
Spherical Particles ◽  
Ag Nps ◽  
Gram Negative ◽  
Green Synthesized Silver Nanoparticles ◽  
Higher Sensitivity

AbstractThe application of green synthesis in nanotechnology is growing day by day. It’s a safe and eco-friendly alternative to conventional methods. The current research aimed to study raw royal jelly’s potential in the green synthesis of silver nanoparticles and their antibacterial activity. Royal jelly served as a reducing and oxidizing agent in the green synthesis technology of colloidal silver nanoparticles. The UV–Vis maximum absorption at ~ 430 nm and fluorescence emission peaks at ~ 487 nm confirmed the presence of Ag NPs. Morphology and structural properties of Ag NPs and the effect of ultrasound studies revealed: (i) the formation of polydispersed and spherical particles with different sizes; (ii) size reduction and homogeneity increase by ultrasound treatment. Antibacterial activity of different concentrations of green synthesized Ag NPs has been assessed on Gram-negative S. typhimurium and Gram-positive S. aureus, revealing higher sensitivity on Gram-negative bacteria.

scholarly journals Toxicity and chemical transformation of silver nanoparticles in A549 lung cells: dose-rate-dependent genotoxic impact

2021 ◽  
Author(s):  
Laure Bobyk ◽  
Adeline Tarantini ◽  
David Beal ◽  
Giulia Veronesi ◽  
Isabelle Kieffer ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Silver Nanoparticles ◽  
Dose Rate ◽  
Cell Metabolism ◽  
A549 Cells ◽  
Dna Integrity ◽  
Lung Cells ◽  
Ag Nps ◽  
Rate Dependent ◽  
A549 Lung

Acute exposure of A549 cells to Ag-NPs induces stronger effects on DNA integrity, ROS level, cell metabolism and cell cycle than repeated exposure. Ag-NPs dissolves in both exposure conditions and Ag ions recombine with thiolated proteins.

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