• Journal of Korean Society for Atmospheric Environment
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• v.24 no.6
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• pp.674-681
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• 2008

Silver as a metal catalyst has been used to remove odorous compounds. In this study, silver particles in nano sizes ($5{\sim}30nm$) were prepared on the surface of $NaHCO_3$, the supporting material, using a sputtering method. The silver nano-particles were dispersed by dissolving $Ag-NaHCO_3$ into water, and the dispersed silver nano-particles in the aqueous phase was applied to remove inorganic odor compounds, $NH_3$ and ${H_2}O$, in a scrubbing reactor. Since ammonia has high solubility, it was removed from the gas phase even by spraying water in the scrubber. However, the concentration of nitrate (${NO_3}^-$) ion increased only in the silver nano-particle solution, implying that the silver nano-particles oxidized ammonia. Hydrogen sulfide in the gas phase was rapidly removed by the silver nano-particles, and the concentration of sulfate (${SO_4}^{2-}$) ion increased with time due to the oxidation reaction by silver. As a result, the silver nano-particles in the aqueous solution can be successfully applied to remove odorous compounds without adding additional energy sources and producing any harmful byproducts.

• Textile Coloration and Finishing
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• v.23 no.2
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• pp.146-153
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• 2011

Silver nano-particles have been synthesized by liquid phase reduction method and alcohol reduction process. Silver nano-particles of the size 30 ~ 40 nm were formed successfully by alcohol reduction process. The formation, structure, morphology and size of silver nano-particles have been studied using FE-SEM, TEM, XRD, UV-visible spectroscopy. In particular high dispersion stability of the synthesized silver nano-particles could be obtained by PVP binding. Antibacterial activity of Ag/PET master batch sample made from its nano-silver particles showed excellent antibacterial activity against S. aureus and E. coli.

• KSBB Journal
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• v.27 no.1
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• pp.16-20
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• 2012

In this study, novel nano silver sand filtration method was compared with UV treatment and normal sand filtration method through filtering treated water from sewage treatment plant. As a result, $BOD_5$ removal rate of nano silver sand filtration showed higher approximately 31% and 23%, comparing with UV treatment and sand filtration. Moreover, $KMnO_4$ removal rate of nano silver sand was about 6.6 and 2.8 times higher than other two methods. In addition, it showed better for removing SS and total coliform, comparing with others. Also, there is no bacteria on nano silver sand after experiments. Therefore, nano silver sand filtration will be effective for advanced water treatment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2250-2255
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• 2010

An fine silver particle has a variety of uses, such as in killing micrograms and as catalysts. Many techniques have been used for the production of the fine particles. Faraday cell, consisting of two silver electrodes in an electrolyte, is unique, but it is hard to get a very fine particle by this method. A finer silver nano-particle producing cell, utilizing a dielectric bed as a lower electric current and higher field controlling means, has been proposed and investigated. The I-V characteristics of the cell and effect of the dielectric bed on the producing finer silver nano-particles have been investigated. The I-V characteristics of the cell with the dielectric bed were different from that of the same system without the bed, due to the increased cell resistance and elevated electric field intensity. It is found that the proposed cell with the dielectric bed can produce finer silver nano-particles effectively, which, however, can be used as one of effective fine silver nano-particle producing means.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1552-1555
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• 2005

We have studied the inkjet patterning of synthesized aqueous silver nano-sol on interface-controlled ITO glass substrate. Furthermore, we designed the conductive ink for direct inkjet patterning on bare ITO glass substrate. The first, the highly concentrated polymeric dispersant-assisted silver nano sol was prepared by variation of molecular weight and control of initial nucleation and growth of silver nanoparticles. The high concentration of batch-synthesized silver nano sol was possible to 40 wt%. At the same time the particle size of silver nanoparticles was below $10{\sim}20nm$. The second, the synthesized silver nano sol was inkjet - patterned on ITO glass substrate. The connectivity and width of fine line depended largely on the wettability of silver nano sol on ITO glass substrate, which was controlled by surfactant. The relationship was understood by wetting angle. The fine line of silver electrode as fine as $50{\sim}100\;{\mu}m$ was successfully formed on ITO glass substrate. The last, the direct inkjet-patternable silver nano sol on bare ITO glass substrate was designed also.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.771-776
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• 2005

In recent days, there is much interest in the biocidal activity of silver since silver is known to be safe and effective as disinfectant and biocidal material against coliforms and viruses. In particular, nano silted silver particles which can be used as effective biocidal material received more attention. Accordingly, it is important to investigate antimicrobial activity and mechanism of nano sized silver particles prepared in a cost-effective manner. In this study, nano sized silver particles were prepared via photoreduction of a silver salt ($AgNO_3$) in the bulk phase of $PEO_{20}-PPO_{70}-PEO_{20}$ (Pluronic 123) block copolymer The antimicrobial efficacy of silver nano particles against E. coli was investigated and compared with that of silver ion as the concentration of silver nano particles, pH ($5.6{\sim}8.2$), temperature ($4^{\circ}C{\sim}35^{\circ}C$) varied in aqueous system. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) was used to examine the nature of damaged microorganism with nano sized silver particles and silver ion. This study showed that antimicrobial efficacy of silver nano particles was approximately one twentieth than that of silver ion. It was more biocidal at higher pH in contrast with silver ion. In addition, nano silver particles was demonstrated to disrupt the outer membrane of E. coli, subsequently causing their aggregation. On the other hand, silver ion diffused into the cell damaging the cytoplasmic membrane without disrupting the outer membrane of E. coli.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.63-65
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• 2008

The functional non-woven fabrics have been applied in various industry fields, such as clothing, hygiene, environment, medical and so forth. The functional non-woven fabrics were manufactured by meltblown and finishing processes. These functional non-woven fabrics were made of 2,000ppm nano-silver resin composite and polypropylene resin. Silver is one of the most universal antimicrobial substances. Nano-technology enables us to expand the surface area of silver particles markedly. Nano-silver particles were successfully produced less than 10nm in size. The functional non-woven fabrics including nano-silver particles showed excellent antibacterial activities against Staphylococcus aureus(ATCC 6538) and Klebsieila pneumoniae (ATCC 4352). From the results, nano-silver particels probably will be available as a good and safe antibiotic alternative.

• Molecular & Cellular Toxicology
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• v.5 no.1
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• pp.23-31
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• 2009

To compare the effects of nanometer-sized silver ions and support materials (nano-silver coating material, NM-silver) and silver ions, we exposed zebrafish embryos to both types of nano-silver ions and compared the acute responses during embryogenesis. The amount of silver in the NM-silver (17.16%) was greater than that in the silver ion (4.56%). Both of these materials have different atomic compositions. The silver ion-exposed groups (10 and 20 ppt) showed lower survival rates than the NM-silver-exposed groups (10 and 20 ppt). NM-silver penetrated the skin and blood tube of zebrafish larvae as aggregated particles, whereas, silver ions penetrated the organelles, nucleus and yolk in a spread-out pattern. Micro-array analysis of RNA from zebrafish larvae (72 hours post-fertilization) that were treated with either NM-silver or silver ions, showed alteration in expression of the BMP, activin, TGF-$\beta$, and $GSK3{\beta}$ genes pathway. Additionally, $GSK3{\beta}$ gene pathway for apoptosis that was related with left-right asymmetry. Gene expression changes in the NM-silver or silver ions-treated zebrafish embryo led to phenotypic changes in the hatched larvae, reflecting increased apoptosis and incomplete formation of an axis.

• Journal of Science and Technology Studies
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• v.13 no.2
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• pp.173-206
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• 2013

Launched by Samsung in 2003, nano-silver washing machines were a representative application of nanotechnology in commercial products until the US Environment Protection Agency (EPA) decided to regulate companies that produce nano-silver products in 2006. A year later, however, the EPA reclassified the washing machines not as an application of nanotechnology but as an ion-generating machine. As shown by the EPA's equivocation on this issue, establishing a category for nano-silver material should be considered in the procedure of risk assessment and regulation. This paper analyzes the controversy over Samsung's nano-silver washing machines more in detail to study how the demarcation between silver ion and nano-silver can vary according to the risk perception of nanotechnology. In Korea and the US, the boundary between silver ion and nano-silver was malleable and mobilzed depending on the contexts. Based on an analysis of the recent history of nano-silver washing machines, this paper explores the influence of risk perception over the ontological perspectives on a certain material.

• Textile Coloration and Finishing
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• v.20 no.6
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• pp.18-25
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• 2008

The functional non-woven fabrics have been applied in various industry fields, such as clothing, hygiene, environment, medical and so forth. The functional non-woven fabrics were manufactured by meltblown and finishing processes. These functional non-woven fabrics were based on 5wt% masterbatch using 2,000ppm nano-silver resin composite. Silver is one of the most universal antimicrobial substances. Nano-technology enables us to expand the surface area of silver particles markedly. Silver nano particles were successfully produced less than 50nm in size. The functional non-woven fabrics including nano-silver particles showed excellent antibacterial activities against Staphylococcus aureus (ATCC 6538) and Klebsieila pneumoniae (ATCC 4352). From the results, functional non-woven fabrics including silver nano particels probably will be available as a good and safe antibiotic alternative, such as mask medium filter, water purifier filter, hygiene wet tissues, marine products pad and so forth.