• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.936-941
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• 2010

This study was conducted to investigate formaldehyde removals by silver nano-particles attached on the surface of granular activated carbon (Ag-AC) and to compare the results to those obtained with ordinary activated carbon (AC). The BET analysis showed that the overall surface area and the fraction of micropores (less than $20{\AA}$ diameter) of the Ag-AC were significantly decreased because the silver particles blocked the small pores on the surface of the Ag-AC. The formaldehyde removal capacity of the Ag-AC determined using the Freundlich isotherm was higher than that of AC. Despite the decreased BET surface area and micropore volume, the Ag-AC had the increased removal capacity for formaldehyde, presumably due to catalytic oxidation by silver nano-particles. In contrast, the adsorption intensity of the Ag-AC, estimated by 1/n in the Freundlich isotherm equation, was similar to that of the ordinary AC, indicating that the surface modification using silver nano-particles did not affect the adsorption characteristics of AC. In a column experiment, the Ag-AC also showed a longer breakthrough time than that of the AC. Simulation results using the homogeneous surface diffusion model (HSDM) were well fitted to the breakthrough curve of formaldehyde for the ordinary AC, but the predictions showed substantial deviations from the experimental data for the Ag-AC. The discrepancy was due to the catalytic oxidation of silver nano-particles that was not incorporated in the HSDM. Consequently, a new numerical model that takes the catalytic oxidation into accounts needs to be developed to predict the combined oxidation and adsorption process more accurately.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.178-182
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• 2006

The purpose of this research is to remove the bromate that is a disinfection by-poduct of water purification by ozone. I achieved a high rate of removal with iron, copper, or silver impregnated activated carbon by using both the adsorbing power of granular activated carbon and the oxidizing power of metal ions as deoxidizing agents. In the removal test of bromate with the quantity of activated carbon input I injected each activated carbon by 0.1, 0.3, 0.1, and 1.0 g and let them react for 240 minutes. I found the quantity of removed bromate was in proportion to the amount of input. The removal rate of bromate increased about 20% when I used acid treated activated carbon. The metal impregnated activated carbon had a higher removal rate of bromate than that of general activated carbon by about $30{\sim}50%$. Iron impregnated activated carbon showed a 92% removal rate of bromate. Iron, copper, or silver impregnated activated carbon removed about $0.9{\sim}1.5mg\;{BrO_3}^-/g$ while general activated carbon removed about $0.02{\sim}0.45mg\;{BrO_3}^-/g$. In the continuous column reaction, there were breakthrough phenomena at 96, 180, and 252 hours when I tested EBCT by 1, 2 and 3 minutes while I was changing the flux rate of bromate from 15.6 to 46.8 mL/min.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.65-72
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• 2003

Adsorption and desorption characteristics of methyl iodide at high temperature conditions up to 25$0^{\circ}C$ by TEDA-impregnated activated carbon and silver-ion exchanged zeolite(AgX-10), which are used for radioiodine retention in nuclear facility, were experimentally evaluated. In the range of temperature from 3$0^{\circ}C$ to 25$0^{\circ}C$, the adsorption capacity of base activated carbon decreased sharply with increasing temperature but that of TEDA-impregnated activated carbon showed higher value even at high temperature ranges. Especially, the residual amount of methyl iodide after desorption on TEDA-AC represented 30% lower value than that on AgX-10. However, it can be used as an adsorbent for the removal of methyl iodide up to 15$0^{\circ}C$ if it is preventing explosion by Ignition. The breakthrough curves of methyl iodide in the fixed bed packed with AgX-10 uP to 40$0^{\circ}C$ were compared upon the effects of bed temperatures, bed depth and input concentration of methyl iodide. Removal mechanism of methyl iodide on AgX-10 was proposed, based on the analysis of by-product gas generated from adsorption reaction.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.310-316
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• 2006

In this study, activated carbon in a powder form was used to remove dissolved ammonia which causes a fouling smell in water. Since the adsorption capacity of common powder activated carbon is not high enough, we prepared powder activated carbon deposited on an acid solution to enhance the adsorption capacity. The acid-impregnated activated carbon was applied on the surface of porous fibril support ($10{\sim}50{\mu}m$) by which adsorption and separation processes take place simultaneously by varying effective pressure. As the result, the ammonia removal efficiency is above 60% in the mixing process which is 10~15% higher than general powder activated carbon. From the result of an experiment on the pure permeable test of a dynamic membrane, its transmittance is 400~700 LMH (liter per hour), indicating that the prepared membrane works as a microfiltration membrane. Therefore, it is expected that the membrane prepared in this way would improve the efficiency of water treatment than conventional membranes.

• Environmental engineer
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• s.174
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• pp.79-82
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• 2001

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.62-67
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• 2016

In this study, a pellet-type adsorbent was prepared by using the water-treatment sludge as a raw material, and its physical and chemical properties were analyzed through $N_2$-adsorption, XRD, XRF, and $NH_3$-TPD measurements. Adsorption performance for gaseous ammonia and formaldehyde was compared between the pellet-type adsorbents prepared from water-treatment sludge and the impregnated activated carbon. Although the surface area and pore volume of the pellet-type adsorbent produced from water-treatment sludge were much smaller than those of the impregnated activated carbon, the pellet-type adsorbent produced from water-treatment sludge could adsorb ammonia gas even more than that of using the impregnated activated carbon. The pellet-type adsorbent prepared from water-treatment sludge showed a superior adsorption capacity for ammonia which can be explained by chemical adsorption ascribed to the higher amount of acid sites on the pellet-type adsorbent prepared from water-treatment sludge. In the case of formaldehyde adsorption, the impregnated activated carbon was far superior to the adsorbent made from the water-treatment sludge, which can be attributed to the increased surface area of the impregnated activated carbon.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2015.10a
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• pp.529-530
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• 2015

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.47-52
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• 2003

The adsorption characteristics of rert-butyl mercaptan(TBM) on base activated carbon and activated carbon impregnated with $CuCl_2$ or KI were studied. Adsorption of TBM on the surface of the KI or $CuCl_2$ impregnated activated carbon was detected by gas chromatograph equipped with a flame photometric detector. The amount of adsorption on those impregnated carbon found to be 7 or 8 times greater than on the non-impregnated activated carbon and varied according to the concentration of impregnated metal. FT-IR measurement showed that major reaction occuring on the surface of the catalytic adsorbent was dimerization of TBM into di-tert-butyl disulfide which had no stench.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.552-553
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• 2007

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.147-148
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• 2009