• KSBB Journal
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• v.29 no.5
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• pp.353-360
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• 2014

This study targets the pollutant removal of secondary effluent from final clarifiers in wastewater treatment plant using silver nanoparticles on activated carbon. The removal efficiency and treatment characteristics of pollutant are anlayzed by perfoming experiments using granular activated carbon with silver nanoparticles and ordinary granular activated carbon. The specific surface area of granular activated carbon with silver nanoparticles is smaller than that of ordinary granular activated carbon. However, the removal efficiency of $COD_{Mn}$, T-N and T-P in experiments using activated carbon with silver nanoparticles are higher than that in experiment using ordinary granular activated carbon. That means the case of activated carbon with silver nanoparticles is much better at treatment activity. In addition, activated carbon with silver nanoparticles has antimicrobial activity because there is no microbe on the surface of it after experiments.

• Carbon letters
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• v.4 no.4
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• pp.168-174
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• 2003

Silver nitrate ($AgNO_3$) powder was mixed into a reformed pitch precursor. Then, the silver-containing pitch was melt spun to form round and "C" shape fibers. A wire mesh was inserted prior to the nozzle to improve the spinnability of the silvercontaining precursor pitch. Silver particles in the carbon fibers (CFs) were detected by XRD and TEM. These tests showed that silver particles were uniformly distributed and the total amount of silver remained constant during stabilization and carbonization. Next, the silver-containing CFs were activated by steam diluted in nitrogen gas. Silver particles accelerated the activation rate, but the specific surface areas of the silver-containing ACFs were similar to those of non-silver containing ACFs at the same burn-off levels. The specific surface area of the C-shaped activated carbon fibers was larger than that of the round activated carbon fibers. The likely reason is that the surface area of a C-shaped CF is about two times larger than that of a round CF when equivalent cross-sectional areas are compared. A small amount of silver particles in the periphery of the CFs was removed during the activation, but the remainder of silver was stayed within the ACFs.

• Analytical Science and Technology
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• v.19 no.2
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• pp.121-130
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• 2006

In this study, silver pre-treated activated carbons are transformed using sulfuric acid. From the results of adsorption, each isotherm shows a distinct knee band, which is characteristic of microporous adsorbents with capillary condensation in micropores. In order to reveal the causes of the differences in adsorption capacity and specific surface area after the samples were washed with various strengths of sulfuric acid, surface morphology and external pore structure were investigated by SEM. X-ray diffraction patterns indicated that Ag-activated carbons show better performance for silver and silver compounds removal by post-treatment with acid. The FT-IR spectra of silver-activated carbon samples show that the acid post-treatment was consequently associated with the removal of silver with an increased surface functional group containing oxygen of the activated carbon. The type and quality of oxygen groups are determined on the method proposed by Boehm. For the chemical composition microanalysis of silver-activated carbons transformed by post-treatment with sulfuric acid, samples were analyzed by EDX.

• Carbon letters
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• v.8 no.1
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• pp.30-36
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• 2007

Oxidized PAN (OXI-PAN) fibers were used for the precursors of activated carbon fiber in study. How drying temperature affected the properties of carbon fibers on activating process of carbon fibers was investigated. The specific surface areas of activated carbon fibers have been determined on a series of chemically activated carbons with KOH and NaOH. The experimental data showed variations in specific surface area, iodine and silver adsorptions by the activated carbon fibers. The amount of iodine adsorption increases with increasing specific surface areas in both activation methods. This was because the ionic radius of iodine was smaller than the interior micropore size of activated carbon fibers. Silver adsorbed well in NaOH activated carbon fibers rather than KOH activated carbon fibers in this study.

• Journal of the Korean Professional Engineers Association
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• v.20 no.3
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• pp.26-29
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• 1987

The physical and chemical characteristics of bacteriostatic water filter media are compared to granular activated carbon upon which a silver impregnated. Silver ion that has been chemically impregnated the activated carbon was the bactericidal agent in water filter media. Also, silver Ion that has teen chemically impregnated onto the activated acetate resin was the bactericidal agent in ultrasonic humidifier. Silver impregnated active carbon and silver cartridge will be able to the bactericidal agents for statical water.

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1189-1194
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• 2004

The adsorption isotherms of N2 onto the metallic silver treated activated carbon fiber samples after acid treatment are Type I with a small amount of capillary condensation hysteresis. Increasing amount of acid treatment leads to a decrease in SBETs and external surface area. But, micropore volume and average pore diameter are presented in constant regular values with increasing amount of sulfuric acid treatment. SEM observes the surface morphology and crystal grown state of metal on the fiber surface. The results of EDX of Ag-activated carbon fiber pre-treated with acid show the spectra corresponding to almost all samples rich in silver with increasing the amount of acid treated. The FT-IR spectra of Ag-activated carbon fiber show that the acid pre-treatment is consequently associated with the homogeneous dispersion of metal with the increased surface acidity of the activated carbon fiber. The type and quality of oxygen groups are determined with Boehm titration method. From the those results, a positive influence of the acidic groups on the carbon fiber surface by acid treatment is also demonstrated by an increase in the contents of metallic silver with increasing of acidic groups.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.10
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• pp.583-589
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• 2009

Activated carbon has long been used in purification processes for indoor air quality. However, the bioaerosol removal by activated carbon is not often sufficient to be used in an air control devise. In order to overcome these problems, silver nano-particles have been proposed as an antibacterial agent on the surface of activated carbon. Silver or silver ions have been known for antimicrobial activities. In this study, bioaerosol generated by using an Escherichia coli culture was introduced to a lab-scale column packed with activated carbon (AC) and silver nano-particles attached to activated carbon (Ag-AC). E. coli was almost completely removed in the Ag-AC column, whereas bioaerosol penetrated through the AC column. To determine the antibacterial effect of different filter materials in a full-scale air-handling system, another experiment was conducted using a wind tunnel equipped with a heat exchanger and three filter materials including commercial fabric, AC and Ag-AC. It was found that E. coli proliferated on the surface of the heat exchanger after 5 days, which dramatically increased bioaerosol counts in the effluent air stream. The fabric filter could not control the increased bioaerosol and most of the E. coli penetrated the filter. The bacterial removal efficiency was found to be approximately 45% in the AC filter, while the antibacterial efficiency increased to 70% using the Ag-AC filter. Consequently, the Ag-AC filter can be an effective method to control bioaerosol and improve indoor air quality.

• Carbon letters
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• v.4 no.3
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• pp.140-145
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• 2003

Antibacterial behaviors of PAN-based activated carbon fibers (ACFs) containing silver metal were investigated. The effects of surface and pore structures of the ACFs were studied by $N_2$/77 K adsorption and D-R plot as a function of silver loading content. The antibacterial activities were investigated by a dilution test against Staphylococcus aureus (S. aureus; gram positive) and Klebsiella pnemoniae (K. pnumoniae; gram negative). As experimental results, the ACFs showed some decreases in specific surface areas, micropore volumes, and total pore volume with an increase of silver content. However, the antibacterial activities of the ACFs were strongly increased against S. aureus as well as K. pnumoniae, which could be attributed to the presence of antibacterial metal in the ACFs system.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.807-813
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• 2014

The Ag-impregnated activated carbon was produced from bamboo activated carbon by soaking method of silver nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. Soaking conditions are the variation of silver nitrate solution concentration (0.002~0.1 mol/L) and soaking time (maximum 24 h). The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20{\sim}850^{\circ}C$) and NO gas partial pressure (0.1~1.8 kPa). As results, Ag amounts are saturated within 2h, Ag amounts increased 1.95 mg Ag/g (0.2%)~ 88.70 mg Ag/g (8.87%) with the concentration of silver nitrate solution in the range of 0.002~0.1 mol/L. The specific volume and surface area of bamboo activated carbon of impregnated with 0.2% silver were maximum, but decreased with increasing Ag amounts of activated carbon due to pore blocking. In NO reaction, the reaction rate of impregnated bamboo activated carbon was retarded as compare with that of bamboo activated carbon. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.69l[BA(Ag)] and 80.5 kJ/mol[BA], 66.4 kJ/mol[BA(Ag)], respectively.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.202-206
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• 2004

The objectives of this study are to investigate the relationship between the silver ion concentrations released from the point-of-use(POU) water purification devices installed silver impregnated activated carbon filters and the antibacterial activities against HPC bacteria. Total of 68 POU devices were tested. The concentrations of the eluted silver ion from the silver impregnated activated carbon filter showed the range from $4\;{\mu}g/L$ to $386\;{\mu}g/L$, and the HPC bacteria were found to diversely grow within the range 0-5,200 cfu/mL. The average silver concentrations released from UF units system and RO units system were $30\;{\mu}g/L$ and $73\;{\mu}g/L$, respectively. And the number of colonies were reduced significantly as the elution levels of silver exceeded $100\;{\mu}g/L$, however silver ions below the concentration of $100\;{\mu}g/L$ were not particularly effective for eradicating HPC bacteria from water.