• Asian Journal of Atmospheric Environment
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• v.11 no.1
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• pp.15-28
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• 2017

The adsorptive removal properties of synthetic A4 zeolite were investigated against a total of 16 offensive odors consisting of reduced sulfur compounds (RSCs), nitrogenous compounds (NCs), volatile fatty acids (VFAs), and phenols/indoles (PnI). Removal of these odors was measured using a laboratory-scale impinger-based adsorption setup containing 25 g of the zeolite bed (flow rate of $100mL\;min^{-1}$). The high est and lowest breakthrough (%) values were shown for PnIs and RSCs, respectively, and the maximum and minimum adsorption capacity (${\mu}g\;g^{-1}$) of the zeolite was observed for the RSCs (range of 0.77-3.4) and PnIs (0.06-0.104), respectively. As a result of sorptive removal by zeolite, a reduction in odor strength, measured as odor intensity (OI), was recorded from the minimum of approximately 0.7 OI units (indole [from 2.4 to 1.6]), skatole [2.2 to 1.4], and p-cresol [5.1 to 4.4]) to the maximum of approximately 4 OI units (methanethiol [11.4 to 7.5], n-valeric acid [10.4 to 6.5], i-butyric acid [7.9 to 4.4], and propionic acid [7.2 to 3.7]). Likewise, when removal was examined in terms of odor activity value (OAV), the extent of reduction was significant (i.e., 1000-fold) in the increasing order of amy acetate, i-butyric acid, phenol, propionic acid, and ammonia.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.404-408
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• 2009

The liquid desiccant air-conditioning system has been proposed as an alternative to the conventional vapor compression cooling systems to control air humidity. The complete system of liquid desiccant air-conditioning system is consisted two main components those are humidifier (regeneration) and dehumidifier. Humidifier part is connected to the load when summer season which is the air condition is hot and humid have to be turned into comfort condition on human. This paper purpose is performances study of air flow rate effect on a structured packed tower on cooling and dehumidifier system using liquid lithium chloride as the desiccant. Experimental apparatus used in this present study is consisted of three components those are load chamber, packed tower and chiller. Load chamber’s volume is $40m^3$, and packed tower dimension is cubic with length 0.4m occupied with packed column. Totally, 15 experimental has done using 5 times repeat on each variable of air velocity that varying on 2m/s, 3m/s and 4m/s with other conditions are controlled. Air inlet initial temperature and relative humidity are set respectively on $30^{\circ}C$ and 52%, desiccant flow rate is 0.63 kg/s, desiccant temperature is $10^{\circ}C$ and desiccant concentration is 0.4. The result of this study shows that averagely, the moisture removal rate and the heat transfer rate are influenced by the air velocity. Higher air velocity will increase the heat transfer and decreasing the moisture removal rate. At adiabatic condition the air velocity of 2 m/s respectively is having the higher moisture removal rate acceleration then the air velocity of 3m/s and 4 m/s until the steady state condition.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.373-380
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• 2000

A new type of photocatalyst plasma air purification filter for decomposition of some VOCs has been developed. The photocatalyst plasma air purification filter employs the pulsed discharge plasma as an energy source of TiO2. photocatalyst instead of UV light. In closed room(2m3) test removal efficiency of some VOCs was 80∼100% in 15∼24 hours. In the initial step of phptocatalyst plasma reaction. Acetone and Nitromethane etc were detected. But they were completely oxidized to CO2 and H2O.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.4
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• pp.45-51
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• 2018

The objective of this study is to evaluate the applicability of a manhole-filter odor eliminator that is installed on a manhole to remove hydrogen sulfide ($H_2S$) contained in the sewage of urban streets; $H_2S$ is the very cause of offensive odor from such sewage. An analysis of the capability of impregnated activated carbon, which is contained in the manhole filter, to adsorb hydrogen sulfide shows that some 99.8% of hydrogen sulfide can be removed. A performance evaluation of the manhole-filter odor eliminator, which was made on Manhole Section 4 known as the representative malodorous manhole section of Seoul, Korea, indicates that more than 97% of hydrogen sulfide ($H_2S$), one of typical malodor-generating substances, can be eliminated. The results and findings of the study as described above suggest that the applicability of the manhole-filter odor eliminator to eliminate offensive odor generated from sewer manholes is satisfactory.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.314-324
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• 2011

Algal biomass cultivated by wastewater is potentially useful resource for biodiesel production. However, little is known about algal nutrient metabolism and microbial interaction with bacteria under real municipal wastewater condition. In this work, we characterized nitrogen and phosphorus removals of municipal wastewater by a representative wastewater-growing algal population. Ankistrodesmus gracilis SAG 278-2, and analyzed its ecological interaction with wastewater bacterial communities. Compared to wastewater sludge itself, algal-bacterial co-culture improved nutrient removal. According to bacterial community analysis with 16S rRNA genes, a selective and dominant growth of a Unclassified Alcaligenaceae population resulted from algal growth in the algal-bacterial co-culture. The selectively stimulated bacterial population is phylogenetically close to Alcaligenes faecalis subsp. 5659-H, which is known to be co-present interact with algae in aquatic environment. These findings suggest that algal growth/metabolism may have effects on selection of a specific bacterial population in algal-bacterial co-cultures that can efficiently remove nutrients from municipal wastewater.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.61-68
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• 2009

The main objective of this study was to examine the removal of heavy metals from water by inflated vermiculites. The component of vermiculites was analyzed by XRF, and the concentration of metal ion was measured by ICP-AES. Serial batch kinetic tests and batch sorption tests were conducted to determine the removal characteristics for heavy metals in aqueous solutions. As a result, solution pH values of tests with the inflated vermiculites generally increased and then stabilized. Equilibrium pHs were generally established within 5 hrs. In addition, removal rates of inflated vermiculites were tested at the initial concentration of 3 mg/L. As a result, at equilibrium concentration, except for chromium (36.23%), Most of the heavy metals were effectively removed (96.08~98.54%). Finally, sorption data were correlated with both Langmuir and Freundlich isotherms. The Qmax obtained from Langmuir isotherm were determined to Pb $725.4mg\;kg^{-1}$, Cd $568.8mg\;kg^{-1}$, Zn $540.2mg\;kg^{-1}$, Cu $457.2mg\;kg^{-1}$ Cr $0.9mg\;kg^{-1}$ respectively. The results of the study indicate that inflated vermiculites can be properly used as an adsorbent for various heavy metals because of its outstanding removal rate.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.108-111
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• 2000

FeS/FeS$_2$ minerals have been known to be potentially useful reductant to the removal of common organic contaminants in groundwater and soil. This research is aimed at improving our understanding of factors affecting the pathways and rates of reductive transformation of Hexachloroethane by catalytical iron minerals in natural system. Hexachloroethane is reduced by FeS/FeS$_2$ minerals under anaerobic condition to tetrachloroethylene and trichloroethylene with pentachloroethyl radical as the intermediate products. The kinetics of reductive transformations of the Hexachloroethane have been investigated in aqueous solution containing FeS, FeS$_2$. The proposed reduction mechanism for the adsorbed nitrobenzene involves the electron donor-acceptor complex as a precursor to electron transfer. The adsorbed Hexachloroethane undergo a series of electron transfer, proton transfer and dehydration to achieve complete reduction. It can be concluded that the reductive transformation reaction takes place at surface of iron-bearing minerals and is dependent on surface area and pH. Nitrobenzene reduction kinetics is affected by reductant type, surface area, pH, the surface site density, and the surface charge. FeS/FeS$_2$-mediated reductive dechlorination may be an important transformation pathway in natural systems.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.737-741
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• 2005

In this study, the effect of copper content on the NO removal efficiency by Cu/MCM-41 has been investigated. MCM-41 was prepared by hydrothermal synthesis using a gel mixture of colloidal silica solution and cetyltrimethylammonium. Cu/MCM-41 was manufactured with copper content (5, 10, 20, and 40%) in Cu(II) acetylacetonate. The surface properties of MCM-41 were investigated by using pH, XRD, and FT-IR analyses. $N_2/77K$ adsorption isotherm characteristics, including the specific surface area and micropore volume were studied by BET's equation and Boer's t-plot methods. NO removal efficiency was confirmed by gas chromatography technique. From the experimental results, the MCM-41 was analyzed to have the surface functional groups of Si-OH and Si-O-Si and the characteristic diffraction lines (100), (110), (200), and (210) corresponding to a hexagonal arrangement structure. The copper content supported on MCM-41 appeared to increase the NO removal efficiency in spite of decreasing the specific surface areas or micropore volumes. Consequently, it was found that the copper content in Cu/MCM-41 played an important role in improving the NO removal efficiency, which was mainly attributed to the catalytic reactions.

• KSBB Journal
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• v.11 no.1
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• pp.15-21
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• 1996

Purification of hyaluronic acid produced by Streptococcus equi was carried out to obtain clinical grade hyaluronic acid. The removal method of the bacteria was selected as filtration because filtration was the most effective method in removing impurities such as protein and nucleic acid of the fermentation broth. The removal efficiencies of protein and nucleic acid of hyaluronic acid solution were increased to 75% and 67%, respectively, by filtration with adding 0.6% of activatied carbon and 1.0% colite. Hyaluronic acid solution was precipitated by mixing with 2 volumes of ethanol. Effects of pH and conductivity on ethanol preciptation of hyaluronic acid were investigated. Protein and nucleic acid of hyaluronic acid were remained almost constant regardless of pH and conductivity, and the recovery of hyaluronic acid was optimum as about 85% at pH 7 and l00mS of conductivity Protein of hyaluronic acid was completly removed by three serial filtration and ethanol precipitation, however, nucleic acid was not removed. Hyaluronic acid solution was passed through a column of Duolite A7 to remove its nucleic acid, where 65% of nucleic acid was removed at pH 7 and 40mS of conductivity. The residual nucleic acid of hyaluronic acid solution was completly removed by treatment of 0.2% hydroxyapatite and the clinical grade hylauronic acid could be obtained.

• Membrane and Water Treatment
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• v.9 no.1
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• pp.9-15
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• 2018

Coagulation process using aluminum sulfate ($Al_2(SO_4)_3$) and ferric chloride ($FeCl_3$) was employed as a treatment method for decolorization of a synthetic textile wastewater containing red dye in this paper. Factors such as initial pH, coagulant dosage, initial concentration, conductivity and mixing conditions that influence color removal efficiency were experimentally tested. It was found that $Al_2(SO_4)_3$ is more efficient than $FeCl_3$ as coagulant. When $40mgL^{-1}$ aluminum sulfate was used, results showed that color induced by the red dye was efficiently removed (> 90 %) and was obtained in a large range of initial pH from 4 to 8 with, and for a dye concentration lower than $235mg\;L^{-1}$. After addition of the coagulant, the medium had to be mixed for 30 min at 60 rpm, then allowed to settle for 40 min. The effects of water conductivity in the range $0.035-2.42mS\;cm^{-1}$ and dye concentration up to $380mg\;L^{-1}$ were also followed and discussed.