scholarly journals Sintesis dan karakterisai kitosan dari limbah cangkang udang sebagai stabilizer terhadap Ag nanopartikel

2019 ◽  
Vol 4 (2) ◽  
pp. 86
Author(s):  
Astuti Amin ◽  
Nur Khairi ◽  
Eko Allo

The research of manufacturing chitosan from shrimp shell waste , and their use as a stabilizer in the manufacture of silver nanoparticles has been done. The aim of the research was to synthesize silver nanoparticles using chitosan as a stabilizer by chemical reduction method and determine the effect of chitosan concentration on the stability of Ag nanoparticles. In this study, the raw material used is shrimp shell powder and then processed in several stages, eliminating proteins, demineralization, and deacetylation. Chitosan obtained is 16.4 % of shrimp shell powder, with a degree of deacetylation of 85 %. Chitosan is used to synthesize silver nanoparticles as a reducing agent of silver ions in silver nitrate solution and is expected to be stabilizer. Sample containing 45 mg of chitosan and 1000 ppm AgNO3 has 421,60 nm of maximum wavelength, and the average particle size is 154.07 nm.

Author(s):  
Liem Le ◽  
The Nguyen ◽  
Dieu Nguyen

In this work, silver nanoparticles (AgNPs) were synthesized rapidly and eco-friendlily using the extract of Mulberry leaves and aqueous solution of silver nitrate without any toxic chemical [1,2]. The Mulberry leaves extract acts as both reducing agent and stabilizing agent. The UV-Vis spectrum shows peak at 430 nm. The TEM image of synthesized AgNPs sample shows spherical shaped particles whose size range from 15 to 20 nm. TEM image of nano silver solution sample synthesized by microwave assisted method shows nearly spherical particles with an average particle size of 10 nm. The absorption UV-vis spectrum of silver nanoparticles synthesized by microwave assisted method (AgNPsmw) shows a sharp absorption band around 415 nm. After two month storage of AgNPsmw, the absorption spectrum of AgNPsmw was taken again. The UV-Vis spectrum shows negligible peak changes of silver nanoparticles have occurred after two months of storage. The synthesized AgNPs material could be used as an antimicrobial, used in the field of textile and in wastewater treatment.


2018 ◽  
Vol 55 (1A) ◽  
pp. 45
Author(s):  
Le Thi An Nhien

In this study, silver nanoparticles (AgNPs) were prepared by gamma rays irradiation of 1.0, 2.5, 5.0 and 10 mM silver nitrate solution using chitosan as a stabilizer. UV spectra, morphology and size of AgNPs irradiated at different doses were characterized by using UV-vis spectrophotometer and TEM images. The obtained results indicated that the average size of AgNPs increased by the increase of silver concentration in irradiated solution or the degree of acetylation of chitosan, while the increase of chitosan concentration was found to be a functional key for reducing the average size of particles in AgNPs product. In vitro test, AgNPs inhibited the growth of Corynespora cassiicola. In particularly, the inhibitory efficiency of AgNPs on the growth of C. cassiicola on rubber leaf extract media increased from 52.1 to 100 % when the average particle size of particles in AgNPs product decreased from 15 to 5 nm at the concentration of 50 ppm. In addition, the increase of AgNPs concentration from 10 to 90 ppm also enhanced the antifungal activity to be from 6.3 to 100 %, respectively. It suggests that the silver nanoparticles/chitosan (AgNPs/chitosan) synthesized by γ-rays irradiation method is a very promising fungicidal product applying for treating C. cassiicola, a serious pathogen fungus on rubber trees.


2013 ◽  
Vol 1 (04) ◽  
pp. 16-24 ◽  
Author(s):  
Anu Kumar ◽  
Kuldeep Kaur ◽  
Sarika Sharma

The present study reports the synthesis of silver nanoparticle using Morus nigra leaf extract were used as reducing agent for reduction of silver nitrate solution. The synthesis of silver nanoparticles was analyzed by UV-Visible spectroscopy, Scanning Electron Microscopy. The SEM analysis has shown that size of silver nanoparticles synthesized from leaves extract of M.nigra was 200 nm and seems to be spherical in morphology. Morphology of chemically synthesized silver nanoparticles is nearly spherical and of size ranges from 300-500 nm. The average particle size analyzed from SEM analysis was observed to be 350 nm. This article has discussed the synthesis of silver nanoparticles generated from plant extract, characterization and antibacterial analysis. In this study the antibacterial activity was examined against six MTCC cultures collected from IMTECH Chandigarh, Including both gram positive and gram negative bacteria such as P.aeruginosa, S.aureus, B.subtilis, E.coli, P.flourescens and Streptococus mutans. Out of these strains the antimicrobial activity of the silver nanoparticles showed maximum zone of inbhition against P.flourescens (22 mm), P.aeruginosa (19 mm), S.aureus (18 mm) and least effective against E.coli (15mm). In contrast chemically synthesized silver nanoparticles were found most effective against S.aureus (13 mm) and B.subtilis (12mm) and almost ineffective against Streptococcus mutans (6 mm) and P.flourescens (4 mm). In the concluding remarks, the silver nanoparticles synthesized using M.nigra leaves extract would be a better antimicrobial effective against various bacterial species.


2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Antonio M. Brito-Silva ◽  
Luiz A. Gómez ◽  
Cid B. de Araújo ◽  
André Galembeck

Poly(vinyl-pyrrolidone) (PVP) stabilized silver nanoparticles with an average particle size ranging from 4.3 to 4.9 nm were synthesized by laser ablation in preformed colloids in methanol, acetone, ethylene glycol, and glycerin. Aqueous colloids obtained using PVP, poly(vinyl-alcohol) (PVA), and sodium citrate as stabilizing agents also lead to a good control over particle size distribution. Silver ions were reduced with sodium borohydride. The smaller average particle size and narrower dispersivity in comparison to previously reported data were ascribed to the relatively small size of the particles formed in the chemical reduction step, laser fluence, and the use of PVP, which was not previously used as the stabilizing agent in “top-down” routes. The surface plasmon resonance band maximum wavelength shifted from 398 nm in methanol to 425 nm in glycerin. This shift must be due to solvent effects since all other variables were the same.


2007 ◽  
Vol 7 (11) ◽  
pp. 3917-3919 ◽  
Author(s):  
Sung Hyun Park ◽  
Dong Seok Seo ◽  
Jong Kook Lee

Recently, PbO containing glass systems in commercial silver paste have been used due to their low glass transition temperature, good thermal and electrical properties. However, PbO is a hazardous material to both health and the environment. In this study, Pb-free silver paste was prepared by mixing commercial silver powder and silver nanoparticles. The commercial powder has an average particle size of 1.6 μm. The silver nanoparticles with particles size of 20–50 nm were synthesized by a chemical reduction method using surfactant. Pb-free frit was added into the mixed silver powder as the amounts of 3, 6 and 9 wt%. Using the obtained paste, thick films were fabricated by a screen printing on alumina substrate and the films were fired at temperature from 400 to 550 °C. The films had thickness of 6–11 μm and sheet resistivity of about 4–11 μΩ cm.


Author(s):  
SNEHA THAKUR ◽  
KRISHNA MOHAN G

Objective: The main objective of the research work is to evaluate the antityrosinase potential of onion DNA silver nanoparticles (AgNPs). Methods: The onions were procured from the local market and DNA was extracted from onions using detergent and methylated spirit. The isolated DNA was selected for synthesis of AgNPs which acts as capping and reducing agent. About 10 ml of the DNA extract was added to 90 ml of 0.1 N silver nitrate solution. After 24 h incubation, the solution turned dark brown, which indicates the formation of AgNPs. The synthesized DNA AgNPs were characterized by ultraviolet-visible, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) studies. Results: The results revealed that the particles were uniform in shape with face-centered cubic structure. The particles are 153±20.4 nm in size and were no signs of agglomeration measured by DLS studies. The FTIR spectroscopy revealed B form of DNA along with strong N-H stretching, C=N stretching, and also asymmetric vibrations of phosphate groups characteristic for DNA molecule. The XRD studies revealed the face-centered cubic structure. SEM studies revealed the spherical structure with average particle size of 150±0.1 nm for single DNA nanoparticles. The onion DNA AgNPs were further investigated for its antityrosinase activity against the standard kojic acid and were to have anticancer potential nearer to the standard. Conclusion: From the results, it is evident that the synthesized onion DNA AgNPs have antityrosinase potential and can be further investigated for in vivo anticancer potential in future.


2021 ◽  
Vol 53 (03) ◽  
pp. 190-200
Author(s):  
Sarita Kumar ◽  

Introduction: Global rise in the Aedes-borne diseases and harmful effects of synthetic insecticides has diverted research to explore secondary metabolites in plants as mosquito control agent in the form of nanoparticles. Current study investigated Clitoria ternatea-mediated nanoparticles against Aedes aegypti. Methods: The aqueous and hexane leaf extracts of C. ternatea were assayed against Ae. aegypti early fourth instars. The extract-mediated silver nanocomposites (AgNCs) were synthesized after optimizing the volume and concentration of silver nitrate solution. The synthesis was tracked by the colour change of reaction mixture from pale yellow to dark brown followed by monitoring with UV-Visible spectroscopy and Dynamic Light Scattering. Results: The biosynthesis of 3 mM, 4 mM and 5 mM AgNCs was traced at 438, 401 and 407 nm, respectively. The average particle size distribution ranged from 34.62 to 60.64 nm and polydispersity index was 0.6-0.7. The 24 h larval exposure with aqueous and hexane leaf extracts demonstrated respective LC50 values of 53.057 and 42.179 mg/L, which decreased significantly on larvicidal assay with NCs. The 5mM AgNCs showed the maximum efficiency with LC50 of 10.317 mg/L after 24 h. Scanning and transmission electron microscopy images demonstrated a spherical, poly-dispersed structure with diameter in the 1-27 nm range. The assays against non-targets; Moina and Cyclops ascertained the eco-safety of NCs. Conclusion: The study demonstrated the C. ternatea leaf extract as possible effective mosquito nano-larvicide, alternate to traditional insecticides. Field studies, which could not be held due to the current pandemic, would further ascertain the possible use of these NCs against Aedes larvae.


2007 ◽  
Vol 124-126 ◽  
pp. 639-642 ◽  
Author(s):  
Sung Hyun Park ◽  
Dong Seok Seo ◽  
Jong Kook Lee

Fabrication of paste at low temperature has been developed in order to apply for various electronic devices, such as bus electrode and address electrode in PDP, especially for enlargement of a screen size. In this study, nano-sized silver particles with 10 - 30 nm were synthesized from silver nitrate (AgNO3) by a chemical reduction method. To prepare Pb-free silver paste, the silver nanoparticles were mixed with conventional silver powder with an average particle size of 1.6 and conventional Pb-free frit. Thick films were fabricated from silver paste by a screen printing on alumina substrate and the films were fried at temperatures ranging from 550 °C to 600 °C. Microstructures of the fried thick films were analyzed by FE-SEM. Sheet resistivity of fried thick films was measured and also the relationship between sinterability and conductivity of these films were investigated.


2013 ◽  
Vol 755 ◽  
pp. 91-96
Author(s):  
A. Ruíz-Baltazar ◽  
R. Esparza ◽  
R. Pérez ◽  
G. Rosas

In this work, a spectroscopic and structural characterization of diatomaceous earth-montmorillonite clays after impregnated with silver nanoparticles were carried out. The silver nanoparticles were synthesized by chemical reduction with sodium borohydride starting from silver nitrate solution. The obtained nanoparticles were stabilized with polyvinyl-pyrrolidone as a surface agent. In order to perform the homogeneous nucleation process, Ag nanoparticles solutions at concentrations of 1, 2 and 4 parts per million were magnetically mixed in the porous material. Additionally, we assessed the porous material adsorption ability of silver by atomic absorption spectroscopy. The quantity of Ag nanoparticles adsorbed by the diatomaceous earth and the adsorption rate as function of the concentration of Ag nanoparticles were established. Other complementary techniques such as X-ray diffraction, infrared spectroscopy and transmission and scanning electron microscopy were used.


Technologies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 7 ◽  
Author(s):  
Le Ngoc Liem ◽  
Nguyen Phuoc The ◽  
Dieu Nguyen

In this work, silver nanoparticles (AgNPs) were synthesized quickly and in an eco-friendly manner using the extract of Mulberry leaves and aqueous solution of silver nitrate without any toxic chemicals (Yuet et al. Int. J. Nanomed. 2012, 7, 4263–4267; Krishnakuma and Adavallan. Adv. Nat. Sci. Nanosci. Nanotechnol. 2014, 5, 025018). The Mulberry leaves extract functions as both a stabilizing and reducing agent. The UV-Vis spectroscopy shows a peak maximum at 430 nm. The transmission electron microscopy (TEM) image illustrated of synthesized AgNPs were nearly spherical-shaped particles whose sizes range from 15 to 20 nm. The TEM image of Nano Silver solution sample synthesized by the microwave assisted method shows nearly spherical particles, with an average particle size estimated at 10 nm. The absorption UV-vis spectrum of silver nanoparticles synthesized by the microwave assisted method (AgNPsmw) shows a sharp absorption band around 415 nm. The UV-Vis spectrum of AgNPsmw after two months of storage shows negligible peak changes of silver nanoparticles.


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