• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.263-270
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• 2016

Recent Engineered nanoparticles were increasingly exposed to environmental system with the wide application and production of nanomaterials, concerns are increasing about their environmental risk to soil and groundwater system. In order to assess the transport behavior of silver nanoparticles (AgNPs), a saturated packed column experiments were examined. Inductively coupled plasma-mass spectrometry and a DLS detector was used for concentration and size measurement of AgNPs. The column experiment results showed that solution chemistry had a considerable temporal deposition of AgNPs on the porous media of solid glass beads. In column experiment, comparable mobility improvement of AgNPs were observed by changing solution chemistry conditions from salts (in both NaCl and $CaCl_2$ solutions) to DI conditions, but in much lower ionic strength (IS) with $CaCl_2$. Additionally, the fitted parameters with two-site kinetic attachment model form the experimental breakthrough curves (BTCs) were associated that the retention rates of the AgNPs aggregates were enhanced with increasing IS under both NaCl and $CaCl_2$ solutions.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.140-144
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• 1996

Trickle bed를 이용하여 고분가 촉매에 의한 용존산소 제거반응을 수행하였다. 고분자 촉매는 폴리스티렌-디비닐 벤젠의 공중합체로 이루어진 담체를 제조하여 백금 용액을 함침시킨 후 수소로 환원하여 제조하였다. trickle bed는 수소 및 산소로 포화되어 있는 물을 향류식으로 접촉할 수 있도록 설계하였다. 이 경우는 액상 실험 장치와 달리 포화기가 없기 때문에 장치는 비교적 단순하였으나 컬럼내에 축적되는 액상의 축적이 중요한 운전변수로 나타났다. trickle bed에서의 용존산소 제거 거동을 semi-empirical relation으로 나타내어 실험치와 비교한 결과 예측된 모델과 매우 잘 일치하는 것으로 나타났다.

• Journal of Soil and Groundwater Environment
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• v.6 no.2
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• pp.3-13
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• 2001

It has been known that nonlinear characteristics of sorption affect the transport behavior of water soluble pollutants in soils. However detailed experimental studies have not been performed to verify the effect of non-linearity of adsorption isotherm on transport of chemicals in porous media. In this research, the distortion of breakthrough curves of a cationic surfactant (cetylpyridinium chloride, CPC) in a engineered stainless steel column packed with glass beads were investigated. Glass beads with about 110 $\mu\textrm{m}$diameter coated with a thin n-decane film were used as the media providing the sorption surface for CPC. The CPC adsorption isotherm on the surface of n-decane from aqueous solution was a typical Langmuir type. The breakthrough curve of CPC using step Input showed a late breakthrough on the front side and early breakthrough on the back side accordance to the shape of the isotherm. The retardation factor of CPC was found to be a strong function of the input concentration, which also a manifestation of the non-linearity of the isotherm. The retardation factors for the CPC with step input agreed with those of pulse input that the maximum concentrations are controlled to be the same as the step input concentrations. This results support the validity of the unproven field practices of using hydrogeotracers with non-linear adsorption isotherms to determine the hydrogeological parameters, e.g., NAPL saturation, air-water or NAPL-water interfacial areas.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.189-195
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• 2004

Rapid and simple method was developed for simultaneous determination of vitamins A and E contents in infant formula. Vitamins A and E were extracted by PDA-HPLC with reversed phase column using organic solvent, and their contents in Certified Reference Material (CRM) and infant formula were determined and compared with results of Food Standards Codex and AOAC method for evaluation of developed method, Vitamins A and E contents in CRM determined by developed method were within certified range of standard values. Developed method has great advantages of simple and rapid sample preparation and simultaneous determination of vitamins A and E by PDA-HPLC using reversed phase column.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.63-69
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• 2004

Hematite-coated sand was examined for the application of the PRB (permeable reactive barrier) to the arsenic-contaminated subsurface in the metal mining areas. The removal efficiency of As in a batch and a flow system was investigated through the adsorption isotherm, removal kinetics and column experiments. Hematite-coated sand followed a linear adsorption isotherm with high adsorption capacity at low level concentrations of As (＜1.0 mg/L). In the column experiments, high content of hematite-coated sand enhanced the removal efficiency, but the amount of the As removal decreased due to the higher affinity of As (V) than As (III) and reduced adsorption kinetics in the flow system. Therefore. the amount of hematite-coated sand, the adsorption affinity of As species and removal kinetics determined the removal efficiency of As in a flow system.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.35-43
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• 2011

Permeable Reactive Barriers (PRB) method is an economical method that does not require any other methods to be operated once it is installed as it controls of groundwater flow in the barrier, which is inserted a reactive material on the way of pollutant. The major dominant element of PRB is a reactive material in the reactive wall, and such factors as purification efficiency and used time based on the chemical and physical features in between the reactant and pollutant. High purification efficiency can be expected when a rational design that is synthetically considered in features of packing density, operation period, and adsorption reactant of pollutant. A column test was conducted for an application test using CFW as its adsorption reactant in order to remove copper($Cu^{2+}$) in the PRB system. The CFW was used for the reactant and selected inflow speed, density and thickness of PRB as its necessary factors for design of PRB. As a result of the experiment, the removal efficiency decreased as operating time of PRB increased and the efficiency linearly increased upon the length. Therefore, it is confirmed that the thickness of reactive materials in PRB system can be designed using the proposed formula considering purification time and density of CFW.

• Journal of the Korean Geotechnical Society
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• v.27 no.10
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• pp.5-12
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• 2011

This study was focused on the reactivity of furnace slag against cadmium to design the vertical drain method with reactive column for improving contaminated sea shore sediment. The kinetic sorption test was performed by changing the initial concentration and pH. Using pseudo-second-order model, the reactivity of furnace slag was quantitatively analyzed. Equilibrium removal amount ($q_e$) of furnace slag increased and rate constant ($k_2$) decreased with the increase of initial cadmium concentration. With the increase of pH, the equilibrium removal amount ($q_e$) and rate constant ($k_2$) increased in the same initial concentration. Required retention time was related to the inverse of the product of the equilibrium removal amount ($q_e$) multiplied by rate constant ($k_2$). The required retention time could be used to design the length of reactive column.

• Journal of the Korean Chemical Society
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• v.39 no.8
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• pp.635-642
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• 1995

Improved sample introduction system has been investigated for the determination of volatile organic compounds in water using a purge & trap preconcentration apparatus and a capillary gas chromatography/mass spectrometry. The present limitations associated with the moisture control module and cryorefocusing system suggested by EPA were discussed. To solve the problems such as improper separation of peaks due to the adsorption of water and contamination of purge & trap system, a more efficient connection system between the purge & trap apparatus and the gas chromatograph was introduced and the optimum operational conditions were suggested. A carbopack B/carboxen 1000 and 1001 trap was used for the purge & trap procedure and a custom made crosslinked dimethyldiphenylpolysiloxane capillary column was used for the separation of compounds. Accuracy and precision of the method suggested in this report were examined and the method detection limit of each compound was proposed for the simultaneous determination of 54 volatile organic compounds in water.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.1
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• pp.149-158
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• 2007

To investigate the characteristics of the nitrogen mineralization of oil cakes according to changes in temperature(10, 20, $30^{\circ}C$) moisture(40, 50, 60, 70% of field capacity in loam and 50, 60, 70, 80% of field capacity in sandy loam), mineral nitrogen was measured in soil after incubation for 30 days. In addition, the mineralization in sandy loam and loam which had different soil texture were compared. According to incubating the castor seed, soybean, and rice bran cakes with soil, the higher the temperature and moisture content were, the higher the content of mineral nitrogen was observed. The content of mineral nitrogen was higher in sandy loam than loam. The content of mineral nitrogen was decreased with soil depth increasing and was also higher in sandy loam than loam.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.157-162
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• 1985

The cell cultures and crude extracts of Bacillus sphaericus 1593 K-5 and its mutant Spo-Dl216 were respectively bioassayed against Culex pipiens var. pollens mosquito larvae. The B. sphaeriucs 1593 K-5 showed toxic activity against the larvae. LC$_{50}$ values (cells/$m\ell$) was 2.6$\times$10$^2$. Also the LC$_{50}$ ($\mu\textrm{g}$ Protein/$m\ell$) of the crude extract was 10.26. However, B. sphaericus Spo-Dl216 didn't show toxic activity against the larvae. The soluble cytoplasmic toxin in broken B. sphaeriucs 1593k-5 cells was partially purified by gel permeation chromatography and ion exchange chromatography. Among the fractions of the gel permeation chromatography only a single fraction was found to be toxic. LC$_{50}$ values ($\mu\textrm{g}$ protein/$m\ell$) of the active fraction was 0.182. The active fraction of the gel permeation was subjected to ion exchange chromatography. Only a single fraction showed toxic activity and its LC$_{50}$ values ($\mu\textrm{g}$ protein/$m\ell$) was 0.02..02.