• Carbon letters
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• v.8 no.4
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• pp.280-284
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• 2007

Samples of active carbon of $1150\;m^2/g$ surface area were impregnated with ammoniacal salts of copper, chromium and silver, with and without triethylenediamine. The samples of impregnated carbon were aged at $50^{\circ}C$, with and without 90% RH (relative humidity), for a little more than one year and chemically evaluated periodically. Initially copper (II) and chromium (VI) reduced very fast in the samples in humid atmosphere to the extent of 30% and 60% respectively in four months. These values were found to be unaffected by the presence of triethylenediamine (TEDA) indicating that the chemical did not retard the reduction process of chromium (VI) and copper (II). However, in the absence of humidity the reduction of the impregnants was significantly less (10-12%, w/w) in four months. It was quite evident; therefore, that the moisture was mainly responsible for the reduction of chromium (VI) and copper (II) species in impregnated carbons. The prolonged ageing of the samples with and without triethylenediamme after four months with and without humid atmosphere showed that the extent of reduction of chromium (VI) was very low, i.e. 5-10% and of copper (II) was 2-25%. Silver is not reduced due to carbon, as it remained unchanged in concentration on storage. The impregnated carbon samples (100 g) without triethylenediamine, which were aged at room temperature for 5 years in absence of humidity and unaged when evaluated against cyanogen chloride (CNCl) at a concentration of 4 mg/L and airflow rate of 30 lpm showed a high degree of protection (80- 110 minutes).

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.207-214
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• 2003

Removal efficiency of methyl iodide at high temperature process by TEDA-impregnated activated carbon used for radioiodine retention in nuclear facility was experimentally compared with that of silver ion-exchanged synthetic zeolite(AgX), In temperature ranges of$30^{\circ}C$ to $400^{\circ}C$, adsorption capacity of un-impregnated carbon was sharply decreased, but TEDA-impregnated carbon showed similar values of adsorption capacity of AgX even around $100^{\circ}C$. Especially, loading amount of methyl iodide on TEDA carbon up to$250^{\circ}C$ represented higher values compared to un-impregnated carbon. Breakthrough curves of methyl iodide in fixed bed packed with AgX and TEDA-impregnated carbon at high temperature was compared. Removal mechanism of methyl iodide on AgX was proposed, based on analysis of by-product gas generated from adsorption reaction.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.549-554
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• 2005

Porous ceramic beads that had skeleton structure were impregnated with Ag from silver nitrate solution. Ag-impregnated porous ceramic beads were performed to evaluate the antibacterial properties on Escherichia coli and Staphylococcus aureus, also, compared with commercial silver-activated carbon on antibacterial activity. As concentration of silver nitrate solution increased, deposited-Ag contents of outer and inner surface of beads were increased. The size of silver particles supported on porous ceramic bead were range of $0.5{\sim}2.0\;{\mu}m$. The observed effects of the prepared Ag-impregnated beads on antibacterial activity are as follows : i) Antibacterial activity should be directly proportional to silver nitrate solution and reaction time. ii) The antibacterial activity against Escherichia coli was better than that against Staphylococcus aureus.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.475-483
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• 2019

Special chemical warfare agents are lethal gases that attack the human respiratory system. One of such gases are blood agents that react with the irons present in the electron transfer system of the human body. This reaction stops internal respiration and eventually causes death. The molecular sizes of these agents are smaller than the pores of an activated carbon, making chemical adsorption the only alternative method for removing them. In this study, we carried out a Computational Fluid Dynamics simulation by passing a blood agent: cyanogen chloride gas through an SG-1 gas mask canister developed by SG Safety Corporation. The adsorption bed consisted of a Silver-Zinc-Molybdenum-Triethylenediamine activated carbon impregnated with copper, silver, zinc and molybdenum ions. The kinetic analysis of the chemical adsorption was performed in accordance with the test procedure for the gas mask canister and was validated by the kinetic data obtained from experimental results. We predicted the dynamic behaviors of the main variables such as the pressure drop inside the canister and the amount of gas adsorbed by chemisorption. By using a granular packed bed instead of the Ergun equation that is used to model porous materials in Computational Fluid Dynamics, applicable results of the activated carbon were obtained. Dynamic simulations and flow analyses of the chemical adsorption with varying gas flow rates were also executed.

• Carbon letters
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• v.13 no.2
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• pp.109-114
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• 2012

A nuclear, biological, chemical (NBC) canister was indigenously developed using active carbon impregnated with ammoniacal salts of copper (II), chromium (VI) and silver (I), and high efficiency particulate aerosol filter media. The NBC canister was evaluated against carbon tetra chloride ($CCl_4$) vapours, which were used as a simulant for persistent chemical warfare agents under dynamic conditions for testing breakthrough times of canisters of gas masks in the National Approval Test of Respirators. The effects of $CCl_4$ concentration, test flow rate, temperature, and relative humidity (RH) on the breakthrough time of the NBC canister against $CCl_4$ vapour were also studied. The impregnated carbon that filled the NBC canister was characterized for surface area and pore volume by $N_2$ adsorption-desorption isotherm at liquid nitrogen temperature. The study clearly indicated that the NBC canister provides adequate protection against $CCl_4$ vapours. The breakthrough time decreased with the increase of the $CCl_4$ concentration and flow rate. The variation in temperature and RH did not significantly affect the breakthrough behaviour of the NBC canister at high vapour concentration of $CCl_4$, whereas the breakthrough time of the NBC canister was reduced by an increase of RH at low $CCl_4$ vapour concentration.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.120-125
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• 2001

Generally, hydroxyapatite(HAp), zeolite, carbon molecular sieve , activated carbon and alumina are used as heavy metal ions adsorption materials. Among those adsorption materials, HAp which has good positive ion-exchange ability with metal ion, and zeolite are utilized in wastewater treatment. Most of water pollutions are caused by hazardous heavy metals ions as well as bacteria in waste water. In this study, a adsorption materials (HAP and zeolite) are ion-exchanged with a well known antimicrobial metal ions, such as $Ag^+,\;Cu^{2+},\;and\;Zn^{2+}$, in order to give a adsorption of heavy metal ions and a killing effects of bacteria. The antimicrobial effects of adsorption materials are observed using by E. Coli. The results show that there is a complete antimicrobial effect in the adsorption materials with $Ag^+$ at the concentration of $1{\times}10^{-4}$cell/$m\ell$ of E. Coli until 24 hours. However, there is not good antimicrobial effects in the adsorption materials with $Cu^{2+},\;and\;Zn^{2+}$ substitution. Feng et. al. showed the denaturation effects of silver ions which induces the condensed DNA molecules and losing their replication abilities.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.144-152
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• 1993

A bacterium which degrades efficiently synthetic detergents was isolated from the polluted waters, activated sludge of wastewater treatment plants or polluted soil. This bacterium showed considerably higher growth rate in the agar plate containing $2,000{\mu}g/ml$ of synthetic detergents than any other isolated strains, was identified as a Pseudomonas fluorescens or strains similar to it. The strain was named as a Pseudomonas fluorescens S1. Optimum pH and temperature for the growth of the Pseudomonas fluorescens S1 were pH 7.0 and $30^{\circ}C$, respectively. The strain was resistant to streptomycin and gentamycin, but sensitive to kanamycin. The strain was greatly resistant to zinc chloride, lead nitrate and copper sulfate, but unable to grow in the presence of relatively low concentrations of mercury chloride and silver nitrate. This strain utilized benzene, catechol, cyclohexane and xylene as a sole carbon source. The strain was well grown in the medium containing ABS 10,000${\mu}g$/ml. Degradation of ABS was 55% and 60% at 20${\mu}g$/ml and 100${\mu}g$/ml of ABS, respectively. Benzene ring was degraded 45% in 100${\mu}g$/ml of ABS. During the incubation of the strain in the medium containing ABS 100${\mu}g$/ml and COD 10,000${\mu}g$/ml for 4 days, degradation of ABS and COD were reduced to 40${\mu}g$/ml and 3,200${\mu}g$/ml, respectively. Total amino acid content of the Pseudomonas fluorescens S1 grown with 1,000${\mu}g$/ml of ABS was 115mg/g cell, whereas its content was decreased in the bacterium grown without synthetic detergent by 9.4%.