• 한국재료학회지
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• 제31권2호
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• pp.101-107
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• 2021

Pores produced by carbonization in bulk graphite process degrade the mechanical and electrical properties of bulk graphite. Therefore, the pores of bulk graphite must be reduced and an impregnation process needs to be performed for this reason. In this study, bulk graphite is impregnated by varying the viscosity of the impregnant. The pore volume and pore size distribution, according to the viscosity of the impregnant, are analyzed using a porosimeter. The total pore volume of bulk graphite is analyzed from the cumulative amount of mercury penetrated. The volume for a specific pore size is interpreted as the amount of mercury penetrating into that pore size. This decreases the cumulative amount of mercury penetrating into the recarbonized bulk graphite after impregnation because the viscosity of the impregnant is lower. The cumulative amount of mercury penetrating into bulk graphite before impregnation and after three times of impregnation with 5.1cP are 0.144 mL/g and 0.125 mL/gm, respectively. Therefore, it is confirmed that the impregnant filled the pores of the bulk graphite well. In this study, the impregnant with 5.1 cP, which is the lowest viscosity, shows the best effect for reducing the total pore volume. In addition, it is confirmed by Raman analysis that the impregnant is filled inside the pores. It is confirmed that phenolic resin, the impregnant, exists inside the pores through micro-Raman analysis from the inside of the pore to the outside.

• 약학회지
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• 제29권4호
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• pp.176-182
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• 1985

As a part of the studies on adsorptive properties of Korean halloysite clays, Hadong white clays of premium grade were examined for geometric pore structured by mercury porosimetry and for specific surface areas by nitrogen adsorption according to the BET procedure. Three size fractions of the native clay sample were derived from passage BS #100, #200 and #325 meshes, respectively. Several parameters lhus observed in relation to the pore structures are shown below: 1. The size fraction of BS #100, #200 and #325 show internal pore volumes of 25.3, 30.2 and $35.0m^2g^{-1}$, respectively. 2. In the distribution curves of the cumulative pore volume against pore diameter, it has been shown that the larticle sizes, the steeper the distribution over the larger ranges of pore diameters. The converse is true the smaller particles. 3. Internal pore areas increase with decrease in pore sizes. It follows that the pores having diameters of $\leq$0.1$\mu\textrm{m}$ are responsible for more than 90% of the total pore area. 4. The behaviour of nitrogen adsorption can be best described by BET type IV isotherm. Further, the hysteresis loops of the adsorptiondesorption curves become narrower with decresing particle sizes. 5. The specific surface areas observed for the fractions of BS #100, BS #200 and BS #325 are 34.6, 35.4 and 43.2m $^2g^{-1}$, respectively. and the calcined clay of BS #325 has a specific surface area near $30.4m^2g^{-1}$.

• 대한화학회지
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• 제33권4호
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• pp.350-356
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• 1989

타르, 니코틴 등 몇 가지 연초 에어로솔 성분의 흡착거동을 해석한 결과 비교적 저비점 피흡착질의 흡착률은 축적 동공부피의 증가와 더불어 증가하였다. 반면 비교적 고비점 피흡착질의 흡착률은 보다 작은 반경의 동공부피가 증가할수록 감소하였다. 여기에 사용된 흡착제는 활성탄, 실리카겔, 알루미나 및 활성백토이었다. 비표면적이 큰 흡착제가 보다 큰 흡착률을 가진다는 일반적인 경향은 고비점 피흡착질에 대해서는 성립되지 않았다. 이상의 결과는 위의 흡착거동을 탈착등온식을 기초로 하여 동공부피분포와 관련시켜 검토하므로써 얻어진 것이다.

• 한국환경농학회지
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• 제25권4호
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• pp.316-322
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• 2006

본 연구는 도곡 광산의 광미 중 Cd, Cu, Pb, Zn의 용출 특성을 탐색하기 위해 수행하였으며, 환경에 영향을 미칠 수 있는 수용성과 0.1 M HCl 용출물을 대상으로 Batch 시험과 Column 시험을 실시하였다. Batch 시험에서 수용성 중금속은 Cd 2.31 mg/kg, Cu 129.38 mg/kg, Pb 17.17 mg/kg, Zn 287.53 mg/kg이었으며, 0.1H HCl 추출물은 Cd mg/kg, Cu mg/kg, Pb mg/kg, Zn mg/kg이었다. 수용성 중금속의 초기 용출농도는 Zn > Cu > Pb > Cd의 순이었으며, 수용성 중금속의 용출속도상수는 Pb > Cu > Cd > Zn의 순이었다. 0.1M HCl 추출물의 초기 용출농도는 Zn > Cu > Pb > Cd의 순이었으며, 용출속도상수는 Pb > Cd > Zn > Cu의 순이었다. 중금속의 용출속도는 주로 추출액과 광미의 물리적 화학적 특성에 따라 달라질 수 있으며, 이러한 결정 요소에 의하여 본 시험에서는 Pb의 용출속도가 가장 높은 것으로 조사되었다. Column시험에서 수용성 중금속은 Cd과 Cu, Zn의 경우 2 pore volume에서 의사평형에 도달하였으나, Pb의 경우 10 pore volume에서 의사 평형에 도달하였다. 0.1 M HCl을 column에 통과시켰을 때 Cd, Cu, Zn은 1 pore volume에서 용출농도의 최대점을 나타냈으나, Pb은 5 pore volume에서 최대점을 나타내었으며, 이동속도는 Cd > Zn > Cu > Pb의 순으로 조사되었다.

• Geomechanics and Engineering
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• 제21권5호
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• pp.423-432
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• 2020

Hydraulic conductivity is one of the engineering properties of soil. This study focusses on the influence of cement content on the hydraulic conductivity of cemented sand, which is investigated based on the results from numerical analysis and laboratory testing. For numerical analysis the cemented samples were scanned using X-ray Computed Tomography (CT) while laboratory testing was carried out using a triaxial setup. Numerical analysis enables us to simulate flow through the sample and provides insight to the microstructure. It quantifies the pore volume, proportion of interconnected voids and pore size distribution in both cemented and uncemented samples, which could be computed only through empirical equations in case of laboratory testing. With reduction in global voids, the interconnecting voids within the samples also reduce with cement content. Gamma cumulative distribution function is used to predict the percentage of voids lesser than a given pore volume. Finally, the results obtained from both numerical analysis and laboratory testing are compared.

• 한국환경농학회지
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• 제21권4호
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• pp.291-296
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• 2002

In this investigation we tried to investigate the effect of oxalic acid on the fate of native sulfate in Bt soil that contained a high kaolinitic clay by observing the distribution of two anions using soil column under the given competitive adsorption between displaced and displacing anions. To do this, the soil columns uniformly packed to a bulk density of 1.25 $g/cm^3$ with Cecil Bt soil were disected and analyzed the amounts of sulfate and oxalic acid both in solution and solid phases after flowing the designated pore volumes of oxalic acid The results showed that two sets of curves-nonlinear (> $10^3M$) and linear (> $10^3M$) curves where the solution of oxalic acid was not adiustet while the approaches to the plateau were slow when pH of oxalic acid was adjusted to 5. The cumulative amount of sulfate desorbed by successive addition of oxalic acid was nonlinearly approached to the plateau at the concentration of $10^3M$ or greater, indicating that the number of addition of oxalic acid increased with decreasing order of oxalic acid. However, the plateau did not obtain where the concentration of oxalic acid were less than $10^4M$, showing a linear increase. Therefore, we may conclude that the rate-limited desorption was involved as the concentration of oxalic acid decreased.

• Korean Membrane Journal
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• 제8권1호
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• pp.67-73
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• 2006

Transparent materials are well known but preparation of transparent poly 2-hydroxyethyl methacrylate {poly (HEMA)} material by varying solvent is a new one and economically reliable. This material is prepared from hydroxyl based monomer HEMA by radical polymerization using benzoyl peroxide (BPO) as initiator and isobutanol, 2-butanol, 1-butanol, hexane and toluene as a solvent. The reaction temperature, time and stirring speed were set at $70^{\circ}C$, 4 hrs and 150 rpm, respectively. The polymer was characterized for functional group by IR spectroscopy. It was observed that the intensity of band at $1637 cm^{-1}$ a characteristic band of C=C stretching disappeared indicating that it was completely consumed after polymerization. It was observed that swelling percentage increases with increase as time passes but after a certain time a constant swelling percentage is achieved. SEM pictures reveals that poly (HEMA) prepared by different solvent shows pore with a distinguishable void up to several micrometers. The BET surface area, cumulative pore volume and average pore diameter is greater in poly (HEMA) prepared by hexane as a solvent compared to other solvents. Poly (HEMA) prepared by 1-butanol as a solvent shows higher glass transition temperature compared to other solvents. Poly (HEMA) prepared by different solvents shows $90{\sim}94%$ light transmission property from light transmission measurement and looks transparent.

• Membrane and Water Treatment
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• 제13권3호
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• pp.129-137
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• 2022

In this study, the removal of Ciprofloxacin (CPX) from aqueous solutions was investigated by a new activated carbon adsorbent prepared from orange peel (ACOP) with chemical activation using ZnCl₂. The physicochemical properties of orange peel activated carbon were characterized by proximate and ultimate analysis, scanning electron microscopy, BET surface area determination and Fourier transformation infrared spectroscopic studies. According to Brunauer-Emmett-Teller isotherm and non-local-density functional theory, the cumulative surface area, pore volume and pore size of ACOP were determined as 1193 m² g^-1, 0.83 cc g^-1 and 12.7 Å, respectively. The effects of contact time, pH, temperature and ACOP dose on the batch adsorption of CPX were studied. Adsorption equilibrium data of CPX with ACOP were found to be compatible with both the Langmuir and Freundlich isotherms. CPX adsorption capacity of ACOP was calculated as 181.8 mg g^-1 using Langmuir isotherm. The CPX adsorption kinetics were found to be harmonious with the pseudo-second-order kinetic model. Conclusively, ACOP can be assessable as an effective adsorbent for the removal of ciprofloxacin (CPX) from aqueous solutions.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.101-102
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• 2019

The use of high fluidity concrete has been added in recent construction work. In this study, we analyzed segregation resistance due to admixture substitution of the system high fluidity concrete that was hardened. The research results show that the resistance to segregation at the time of admixture replacement is improved. The best results were shown with a ternary system mixed like FA and BS.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.133-134
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• 2021

Limestone-calcined clay-Cement (LC3) concrete provides a solution for sustainability, durability, and profitability of concrete industry. This study shows experimental studies of the macro properties (residual compressive strength), the meso properties (mesoscopic images), and micro properties (thermogravimetric (TG) analysis, X-ray powder diffraction (XRD), FTIR spectra, Raman spectra, Mercury intrusion porosimetry, and SEM) of LC3 paste with various mixtures and at high elevated temperatures (20 ℃, 300 ℃, 550 ℃ and 900 ℃). We find (1) Regarding to macro properties, LC3 cementitious materials are at a disadvantage in compressive strength when the temperature is higher than 300 ℃. (2) Regarding to meso properties, when the temperature reached 550 ℃, all samples generated more meso cracks. (3) Regarding to micro properties, first, as the substitution amount increases, its CH content decreases significantly; second, at 900 ℃, for samples with calcined clay, a large amount of gehlenite crystalline phase was found; third, at elevated temperatures (20 ℃, 300 ℃, 550 ℃ and 900 ℃), there is a linear relationship between the residual compressive strength and the cumulative pore volume; fourth, at 900 ℃, a large amount of dicalcium silicate was generated, and damage cracks were more pronounced. The experimental results of this study are valuable of material design of fire resistance of LC3 concrete.