• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.153-159
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• 2004

This study was focused on evaluating physical properties and SO$_{x}$ removal capability of porous lime filters prepared by a foaming and a gelcasting method. Porosities of lime filters ranged from 55% to 85%, and their mean pore sizes were about 95 ${\mu}{\textrm}{m}$. It was observed that porous lime filters had the continuous pore structure that most pores were inter-connected by many windows. Before SO$_{x}$ removal reaction a surface of porous lime filters was made up of calcium oxide, but after reaction calcium sulfate became a main component. The SO$_{x}$ removal efficiency and the conversion ratio of calcium oxide to calcium sulfate increased according to reaction temperature and porosity. At 100$0^{\circ}C$, SO$_{x}$ removal efficiency of filters was always over 98% regardless of the porosity. In case of the filter with the porosity of 85%, the conversion ratios of calcium oxide increased according to the reaction temperature, and they were in the range 30% to 60%. to 60%.

• Journal of Soil and Groundwater Environment
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• v.18 no.7
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• pp.18-24
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• 2013

The influences of various operating parameters on physico-chemical techniques were evaluated to remediate petroleum-contaminated sandy soil including S/L ratio, kinetic, and effect of soil particle size. The simple extraction using tap water removed only 20.6% of total petroleum hydrocarbon (TPH), and addition of NaOH enhanced the removal of TPH to approximately 30%. To meet the regulation levels, a surfactant, sodium dodecyl sulfate, was added, and the removal of TPH increased to 4 times. Probably, the carbonate minerals affected chemical aging and soprtion of petroleum, which inhibited the extraction of TPH. The soil with smaller particle size contained more TPH, and the removal of TPH was obstructed with smaller particle size. However, NaOH addition increased the removal of TPH in the smaller particles. The physico-chemical properties of soil influenced greatly the removal of petroleum even in sandy soil.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.2
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• pp.111-116
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• 2000

Transboundary air pollution has recently become an area of increasing scientific interest and political concern as countries are receiving air pollutants from their neighbors. In order to gain a better understanding of the long-range transport processes of air pollutants and the source-receptor relationships among neighboring countries, an atmospheric transport model coupled with a RAMS(Regional Atmospheric Modeling System) model was applied to the East Asia region during the entire month of January 1993. The scalar transport option of the RAMS model was used to calculate special atmospheric constituents such as trace gases or aerosols. The sulfate production in clouds and rainwater and its removal processes by dry and wet deposition were considered. The sulfate budget from source regions to receptor regions was estimated by analysing the source-receptor relationships. When a specific receptor site revealed a sulfate value higher than the sulfate concentration based on its own source origin, this was taken to indicate long-range transport from another source region. The contribution ratio from various source region was calculated. The contribution ratio of dry and wet deposition was higher on the main continent of the East region. Furthermore, the high deposition amounts were identified on the west coast of Korea and the East China Sea.

• Journal of the Korean GEO-environmental Society
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• v.18 no.12
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• pp.25-36
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• 2017

This research was conducted to investigate the removal characteristics of heavy metals and sulfate ion from acid mine drainage (AMD) by multi-functional zeolite-slag ceramics (ZS ceramics), in which natural zeolite and converter slag were mixed and calcined at high temperature. The batch test showed that the removal efficiency of heavy metals by pellet-type ZS ceramics increased as the mixing weight ratio of converter slag to natural zeolite increased. The optimal mixing ratio of natural zeolite to converter slag for the removal of heavy metals and sulfate ion from AMD was observed to be 1:2~1:3. The adequate calcination temperature and time of ZS ceramics for the treatment of AMD were found to be $600{\sim}800^{\circ}C$ and 2 hours, respectively. The removal test of heavy metals and sulfate ion from AMD by the ZS ceramics prepared in optimal condition exhibited very high removal efficiencies close to 100% for all heavy metals (Al, As, Cd, Cu, Fe, Mn, Pb, Zn) and 77.1% for sulfate ion. The experimental results in this study revealed that the ZS ceramics could function as an effective agent for the treatment of AMD.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.672-678
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• 1998

Chitin was extracted from crab shell of Portuns triberculatus and deacethylated to yield chitosan with various molecular weights. The absorption and the fluorescence spectra of Rhodamine 6G(Rh 6G)-sodium dodecyl sulfate(SDS) and Rh 6G-chitosan systems were obtained. From the spectra, we observed that the absorption and the fluorescence intensity of Rh 6G-SDS system decreased when S/D(the concentration of SDS to that of Rh 6G ratio) was below or at 32, while they increased when S/D was above 32. From the suspended solid(SS) removal rate and the transmittance of Rh 6G-SDS-chitosan system, we found that when S/D ratio was 32 its flocculating behaviour was much stronger than Rh 6G-SDS system. As the concentration and the molecular weight of chitosan increased, we also found that S/D range was extended from 32 to 100. With increasing the molecular weight of chitosan, the SS removal rate increased around pH 2~9 but decreased remarkably at pH>12.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.7-14
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• 2012

Batch tests were carried out to evaluate the thermal treatment of low volatile organic compounds in low-permeability soil. The chemical oxidation by sodium persulfate catalyzed by heat and Fe (II) was evaluated. Enhanced persulfate oxidation of n-decane (C-10), n-dodecane (C-12), n-tetradecane (C-14), n-hexadecane (C-16), and phenanthrene was observed with thermal catalyst, indicating increased sulfate radical production. Slight enhancement of the pollutants oxidation was observed when initial sodium persulfate concentration increased from 5 to 50 g/L. However, the removal efficiency greatly decreased as soil/water ratio increased. It indicates that mass transfer of the pollutants as well as the contact between the pollutants and sulfate radical were inhibited in the presence of solids. In addition, more pollutants can be adsorbed on soil particles and soil oxidant demand increased when soil/water ratio becomes higher. The oxidation of the pollutants was significantly improved when catalyzed by Fe(II). The sodium persulfate consumption increased at the same time because the residual Fe(II) acts as the sulfate radical scavenger.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.3
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• pp.75-82
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• 2008

Two UASB reactors were operated to investigate the effect of high concentration of sulfate on anaerobic digestion of propionate using an upflow anaerobic sludge blanket (UASB) reactor. An organic loading rate of $1.2kg\;COD/m^3{\cdot}d$ and a hydraulic retention time of 1.6 d were maintained during this study. In the absence of sulfate, the UASB reactor achieved about 95% removal of chemical oxygen demand whereas in the presence of $2,000\;SO_4^{2-}mg/L$, the COD removal rate decreased to 83% due probably to the inhibition of dissolved sulfide inhibition. Interactions between the methane producing bacteria (MPB) and sulfate reducing bacteria (SRB) were measured to investigate the competition between MPB and SRB. The MPB consumed average 58% of the available electron donors at $COD/SO_4^{2-}$ ratio of 1. Propionate was consumed mainly by SRB, converting sulfate into sulfide and suppressing the methane production. The specific methanogenic activity (SMA) using acetate and propionate increased as microorganism acclimated to the substrate.

• Textile Coloration and Finishing
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• v.17 no.2 s.81
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• pp.31-39
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• 2005

This study was conducted to remove the dyes in dye wastewater by the chemical precipitation or biological treatment which are one of the main pollutants in dye wastewater. In order to remove the disperse dyes effectively in aqueous solution by chemical precipitation process, coagulation and flocculation tests were carried out using several coagulants on various reaction conditions. It was found that the Ferrous sulfate was the most effective coagulant for the removal of disperse dye(DB79), and we could get the best result for the removal of disperse dye(DB56) in the aspects of TOC removal efficiency and sludge yield. When the Ferrous sulfate dosage was 800mg/l, the sludge settling velocity was very fast$(SV_{30}=4\%)$, and the color was effectively removed in the disperse dye(DB79) solution. Although the color removal was ineffective when the Alum was used as a coagulant, the sludge yield decreased in comparison with the Ferrous sulfate or the Ferric sulfate being used in the disperse dye(DB56) solution. In order to decolorize disperse dye(DR17) by using biological treatment process, a strain which has potential ability to degrade disperse dyes was isolated from natural system. The optimal culture conditions of temperature and pH were found to be $40^{\circ}C\;and\;8.5\~9$, respectively. When yeast extract was mixed with polypeptone at the mixing ratio of 1:1 as a nitrogen source, decolorization efficiency was highest$(93\%)$ among the nitrogen sources. The strain screened was excellent to adjust to pH, and it seems to have ability to control pH needed to growth. The optimal culture conditions in concentration of $MgSO_{4.}\cdot7H_2O\;and\;KH_2PO_4$ were $0.1\%(w/v)\;and\;0.2\%(w/v)$, respectively. Strains degrading and decolorizing reactive dyes, RB198 and RR141 which were isolated from water system, are named RBK1 and RRK. And the cell growth characteristics of RBK1 and RRK were investigated. The optimal culture conditions of temperature and pH were found to be 30t' and 7.0, respectively. Optimum nitrogen source was peptone, and it was found that decolorization efficiencies by strains RBK1 and RRK, were $85\%\;and\;62\%$, respectively, with introduction of 4,000mg/l of peptone. In the case of RBK1, color removal efficiencies were very high below 400mg/l. Decolorization efficiency was over $90\%$ at 20hours of culture time. The Color degradation ability of RRK was lower than that of RBK1.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.446-450
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• 2006

In order to treat the wastewater containing organic compound, pre-treatment system connected with MSP(molecular separation process) was investigated. With the aim of selecting an optimum process of Fenton's oxidation, removal efficiency of each process in the optimum reaction condition was recommended. The $Fe/H_{2}O_{2}$(ferric sulfate to hydrogen peroxide)reagent is referred to as the Fenton's regent, which produces hydroxyl radicals by the interaction of Fe with $H_{2}O_{2}$. The powerful oxidizing ability and extreme kinetic reactively of the hydroxyl radical was well established. Increasing dosage of $Fe/H_{2}O_{2}$ increased removal efficiency as molar ratio of $Fe/H_{2}O_{2}$ between 0.2 and 2.5. Optimum dosage of molar ratio was 1. The removal efficiency for reaction condition was increased as pH decreased when the molar ratio of $Fe/H_{2}O_{2}$ was 1.7. Fenton's oxidation was most efficient in the reaction time 35 min for complex wastewater. Also, coagulation aid experiments using kaolin resulted in 3% of kaolin dosage.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.418-421
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• 2006

Fatty acid methyl esters, also referred to as biodiesel, have been determined to have a great deal of potential as substitutes for petro-diesel. In order to enhance productivity in the biodiesel production process, feedstocks were previously recommended to be anhydrous, with a free fatty acid content of less than 0.5%. In this study, the effects of several catalysts, methanol molar ratio, catalyst amount, and reaction time on the reduction of free fatty acid level were studied with a simulated feedstock consisting of 20% oleic acid in rapeseed oil. Ferric sulfate was selected as the best catalyst. Increasing the catalyst amount and methanol molar ratio is very effective in decreasing the acid value of the simulated mixture. Our results may provide useful information with regard to the development of more economic and efficient free fatty acid removal system.