• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.227-234
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• 2018

In this work, we have prepared the reactive media with the pyrophyllite based using ceramic extrusion process. The characteristics of pyrophyllite were analyzed using XRD, XRF, DSC-TGA and Zeta-potential analysis. The study of pyrophyllite based ceramic reactive media were conducted under various roasting temperature (500 to $1,300^{\circ}C$) conditions. With increasing the roasting temperature, strength was increased but BET surface area was decreased. Thermally treated pyrophyllite were analyzed by means of weight loss and structural changes as detected by using XRD, DSC-TGA and SEM analysis. Pyrophyllite primarily transforms to pyrophyllite dehydroxylate after roasting at $1,000^{\circ}C$. Pyrophyllite dehydroxylate transforms to mullite and cristobalite at $1,300^{\circ}C$. This study demonstrates that pyrophyllite could be used as a reactive media for ceramic support layers from Permeable Reactive Barriers.

• Journal of the Korean Chemical Society
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• v.52 no.3
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• pp.217-222
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• 2008

We investigate the kinetics of diffusion-influenced catalytic reactions occurring in small reaction volume. From a simple exact model study, we find that the reaction rate coefficient decreases with the size of reaction volume. The explicit expression for the average reaction rate constant is presented, which can be regarded as a generalization of well-known Collins-Kimball rate constant into the reactions occurring in a small reaction volume. It turns out that the traditional diffusion influenced reaction dynamics is followed by a single exponential relaxation phase with a rate constant dependent on the reaction volume for the catalytic reactions occurring in small reaction volumes.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.199-204
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• 1998

고에너지 전자가 매질 내에서 수송될 때, 매질 내에서 Photoneutron 생성률과 생성된 중성자 에너지 분포를 EGS4 코드를 사용하여 계산하였다. EGS4 코드는 광자-전자 연계 수송코드로 Photoneutron 반응단면적을 제공하지 않기 때문에, Photoneutron 반응단면적 계산루틴과 생성된 중성자 에너지분포 계산루틴을 작성하여 Ta와 Pb의 표적 매질에 100 MeV의 전자가 입사하였을 때 표적의 두께변화에 따른 Photoneutron 생성률과 생성된 중성자 에너지분포를 계산하였다.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.237-245
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• 2005

The batch tests were performed to evaluate the applicability of the permeable reactive barrier (PRB) to in-situ treatment of groundwater with high concentration of heavy metals. The lead\chates used in this study were collected from waste rock dump of the Imgy mine, and have a low pH and high metal concentration. The acidity loading was 65kg as $CaCO_3/day$, metal loading of Fe+Al+Mn was 11.6kg/day. This type of water could be treated with biological-mediated sulfate reduction using the organic carbon mixture as a reactive media. The batch tests were carried out with five mixtures that were composed with different mixing ratios of mushroom compost, pine-tree bark, and limestone cheep. Results indicated that the PRB could reduce the acidity loading $CaCO_3/day$ to 12.3kg and reduce the metal loading to 3.3kg/day. Considering about the low pH and high metal loading, the contaminated water may be ameliorated by passing it through the buffering PRB composed with inorganic carbonate materials and then through the PRB composed with the organic carbon mixture which can induce sulfate reduction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.207-217
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• 1992

In this study, isolated and cultured nitrogen fixed microbes were seeded in the three-phase fluidized bed in which gas, solid and liquid were contacted directly. Input velocity was varied from 8.12 cm/hr to 16.32 cm/hr. And upflow gas pressure was fixed to 80 psi. Return ratios were from 0.2 to 0.6 with the each experimental condition. According to these condition, movement of media, growth of biofilm and removal efficiency were measured. As the results, in case of briquette ash, biofilm was developed to $170{\mu}m$ when velocity was 8.12 cm/hr and return ratio was 0.6. In this condition, COD removal efficiency was 97% and $NH_4$-N removal efficiency was 83%. At the same condition, biofilm thickness of glass bead was $17.59{\mu}m$ and its COD and $NH_4$-N removal efficiency was 83% and 72%. Nitrogen fixed microbes have following characters: it formed dark-brownish sludge, excellent adhesive force, easy solid-liquid separation and low oxygen uptake ratio, but sensitive to DO concentration. Not only it endured shock loading, but required short time to steady state.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.984-991
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• 2008

This paper reports experimental results, demonstrating the feasibility of horseradish peroxidase(HRP) and H$_2$O$_2$ to reduce phenol transport in saturated porous media. A laboratory-scale packed column reactor(ID: 4.1 cm, sand-bed height 12 cm) column was utilized to simulate injection of HRP and H$_2$O$_2$ into an aquifer contaminated with phenol. Effluent concentrations of phenol and polymerization products were monitored before and after enzyme addition under various experimental conditions(enzyme dose: 0$\sim$2 AU/mL, [ionic strength]: 5$\sim$100 mM, pH: 5$\sim$9). The concentration of phenol in the column effluent was found to decrease by nearly 90% in the presence of HRP(2 AU/mL) and H$_2$O$_2$ in the continuous flow system at pH 7 and ionic strength 20 mM. The influent phenol was converted in the system to insoluble precipitate, which deposited in pore spaces. The remains were discharged as soluble oligomers. About 8% of total pore volume in column system was decreased by deposition of polymer produced.

• Journal of the Korean Chemical Society
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• v.17 no.4
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• pp.262-268
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• 1973

p-Phenylenediamine was tetrazotized with sodium nitrite in an excess amount of concentrated hydrochloric acid media at -10$^{\circ}$C. It was also tetrazotized almost completely in 45% perchloric acid media. The two diazo groups in the tetrazonium salt were substituted by halogen, and the degree of tetrazotization reaction was observed by dihalobenzene yielded. The result of the tetrazotization was dependent upon the stability of the tetrazonium salt, and the stability was determined by concentration and quantity of the acid media. In dilute acid media the tetrazonium salt was unstable and completely decomposed. In concentrated acid media, though the tetrazonium salt was stable, tetrazotization reaction was retarded. To harmonize the two opposing tendencies it was advisable to find the optimum acidity of media at which the salt was fairly stable. About $40{\sim}45$% of the acid media was suitable. The fact that the $H^+$ ion behaved as a negative catalyst supported the assumption that the diazotization reaction is primarily a reaction between the free amine and a nitroso group. The reaction of tetrazotization is expressed with respect to the kinetics and mechanism of diazotization.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.185-193
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• 2004

A physical model experiment was conducted using a sand and gravel-filled tank model, to investigate the influence on the GPR response of LNAPL vapor phase effects in the unsaturated zone and of residual phase of LNAPL trapped in the saturated zone. Background measurements of GPR were made with only water in the tank using a fluctuating water table model. Gasoline was, then, injected into the bottom of the model tank to simulate a subsurface discharge from a leaking pipe or tank at depth, obtaining GPR data with rising and lowering of water table. Results from the experiment show the GPR sensitivity to the changes in the moisture content in the vadose zone and its effectiveness for monitoring minor fluctuation of the water table. The results also demonstrate a potential of GPR for monitoring possible vapor phase effects of volatile hydrocarbons in the vadose zone as a function of time, and for detecting the effects of residual phase of hydrocarbons in the water saturated system. In addition, the results provide the basis for a strategy that has the potential to successfully detect and delineate residual LNAPL contamination in the water-saturated system at field sites where the conditions are similar to those simulated in the physcial models described herein.

• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.19-28
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• 2009

The acid mine drainage (AMD) and landfill leachates released into the subsurface environment can result in serious environmental problems like soil and groundwater contamination. The AMD and the leachates of landfill were known to contain many heavy metals. In this study, the author assessed the reactivity and ability of the FeS coated-ALC for the removal of contaminants (As, Cd, Cu, Pb, Ni, Zn, Al) in AMD and leachates in landfill. The synthetic nano-FeS and Autoclaved Lightweight Concrete (ALC) were used as reactive materials in the permeable reactive barriers(PRBs). The result of batch test indicated that synthetic nano-FeS can remove 99% of heavy metals for the 1hr of reaction time except for As and Ni(about 90%). However, the 80% of As and Ni was removed in column 1(FeS coated-ALC). The column 2(Ore FeS) removed more than 99% of heavy metals. The pH of the column 1 was increased from 3.51 to 6.39~6.50, and the pH with column 2 was increased from 3.51 to 9.20. As the result of this study, the author can surmise that the synthetic nano-FeS coated ALC will use as a very good reactive material of the PRBs to treat the contaminated groundwater with AMD and leachate of landfill.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.36-41
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• 2005

복소유전율상수인 실수부(Real part)와 허수부(Imaginary part)를 측정하기 위하여 Frequency Domain Reflectometry with Vector Network Analyzer(FDR-V) 측정 장비로 $1{\sim}18GHz$ 범위 내에서 매질의 기본 구성단위인 공기, 물, 흙입자에 대한 기본적인 유전율 특성을 파악하고, 이들로부터 다공질 매질내 유류 오염물질의 함유 특성을 측정할 수 있다. 또한 제작된 시료에 대한 포화도와 1GHz 범위에 분포하는 실수부 유전율상수와의 관계로부터 매질의 공극내 함유된 물질의 유전율상수 특성에 매우 민감한 반응을 보이므로, 이들로부터 매질의 공극률 내지 유효공극률의 측정이 가능할 것으로 사료된다.