• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.372-379
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• 2007

The converter slag can be used to remove phosphate ion into the form of solid state from the wastewater. This research aims to evaluate the change of pH, alkalinity, leaching of positive ion in the wastewater and the removal of phosphate from the initial condition of wastewater. The change of pH was abruptly increased upto pH 11 for the initial condition of pH from 7.0 to 8.5 fer 0.5 unit of pH. The alkalinity was steadily increased from 10 hours of reaction time not same as pH increase. The removal of phosphate was very effective till 10 hours of reaction then it was slow after that time. The positive ion, magnesium ion was leached from the concentration of 2.0 mg/L to 4.3mg/L at the reaction time of 27 hours and 36 hours. Therefore, converter slag can be used to remove the phosphate in the form of Struvite from the wastewater.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.372-378
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• 2019

Traditional ceramic glazes formulated with copper oxide (CuO) exhibited antibacterial properties on Staphylococcus aureus (Gram Positive) and Escherichia coli (Gram Negative). All the ceramic glazes containing CuO showed antibacterial behavior when fired in reducing atmosphere. However, some of copper glazes presented antibacterial behavior and had no antibacterial properties at all when sintered in an oxidizing atmosphere. To elucidate the antibacterial mechanism, ceramic glazes were studied for phase and microstructure analysis, dissolution behavior and surface zeta potential. Metallic copper was precipitated in the glaze layer when sintered in reducing atmosphere. Less than 0.05 ppm of Cu ion was dissolved from glazes. Ca ion was most dissolved among all the samples. Glaze surface was highly negatively charged when CuO was added over 3 wt.% regardless of the sintering atmosphere. The antibacterial behavior of ceramic glazes seemed to be directly related to the dissolution behavior of cations, but the antibacterial behavior of oxidized specimens was not explained by the dissolution behavior. Surface potential of ceramic glazes appeared to play an auxiliary role in antibacterial properties.

• Journal of the Korean Chemical Society
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• v.15 no.1
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• pp.5-9
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• 1971

A separation scheme using cation exchange procedure is designed specifically for the rapid determination of thorium in monazite samples. All the coexisting ions in monazite, including rare earth ions, are eluted with 3N hydrochloric acid. The remaining thorium is eluted from the resin column with 5N sulfuric acid prior to spectrophotometric determination with thorin reagent. The radioactive tracers and spectrophotometric methods were used to confirm the quantitative elution of thorium and also the chemical purity of the eluted thorium from the column.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.62-65
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• 2001

담수와 해수가 혼합되는 환경에서 퇴적 저니로부터의 오염 물질 용출률을 조사하였다. 축산폐수와 산업폐수의 영향을 받은 두 지점의 퇴적저니 시료에 대해 해수와 담수로 장기(약4주) 용출 시험을 행한 결과, 해수보다는 담수에서의 오염물질(영양염류 및 중금속) 용출률이 높은 것으로 조사되었는데, 이는 담수에서의 이온강도(ionic strength)가 상대적으로 낮아 오염성분의 포화농도가 높기 때문인 것으로 판단된다. 또한, 용존산소의 농도를 달리하여 시험한 결과 무산소 상태에서의 용출률이 호기성 상태에서 보다 높은 것으로 나타났으며, 그 원인이 생물학적인 것인지 화학적인 것인지는 밝혀지지 않았다. 시험결과를 종합해 볼 때 무산소 상태의 담수에서 오염물질의 용출이 극대화되며, 따라서 강어귀 등과 같이 유속이 작아져 오염물질의 침강은 잘되는 반면 오염물질의 해수에 의한 희석 효과는 적은 경우가 저니로 인한 수질 환경영향이 가장 클 것으로 예측된다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.213-215
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• 2006

반응용액의 pH와 반응시간에 따른 용출실험 결과를 PHREEQC를 이용하여 용출된 중금속이 어떠한 화학적 형태가 우세한지 알아보고자 하였다. 용출용액에 용해된 Zn, Cd, Cu, Mn 및 Fe의 주요 존재형태는 free ion 및 sulfate complexes($metal-SO_4$)인 것으로 계산되었다. pH 5와 pH 3의 조건에서 각 원소의 화학적 존재형태는 서로 유사하고, 반응시간이 증가할수록 free ion 상태로 존재하는 비율은 감소하고 sulfate complexes로 존재하는 비율은 증가하는 경향을 보였다. pH 1에서 용출된 용액에 존재하는 각 원소의 화학적 존재형태는 sulfate의 농도가 크게 증가됨에도 불구하고 free ion 상태로 존재하는 금속이온의 함량의 증가비율보다 sulfate complexes로 존재하는 함량의 증가비율이 더 큰 것으로 예측되었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.179-186
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• 1998

We have been investigated the effects of the initial pH of the aquous solution, reaction temperature and time for the flaking of the soda-lime glass container. Flaking of glass occuurred in the cases of the $121^{\circ}C$, above pH 11 of solution with no $Mg^{2+}$ ions in solution. The pH of the solution approached to pH 10 under the conditions of below pH 9 of start solution. The flaking mechanism of the glass seem to be composed of formation of leached layer of $Ca^{2+}$ and $Na^{2+}$ ion and separation of these layers during the cooling by the difference of thermal expansion between leached layer and glass surface. The leaching of alkali ions in glass depends on the pH condition of the start solution and the temperature. In the case of $Mg^{2+}$ ions are added, $Mg^{2+}$ ions accelerate the flaking of the sodalime glasses and forms the magnesium silicate compound which result in the decrease of the pH of the solution.

• Korean Journal of Food Science and Technology
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• v.14 no.2
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• pp.141-145
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• 1982

Busuge is conventional snack food in Korea which is made from steeped glutinous rice. The effect of the steeping time on total acidity, viscosity, canons, phosphorus and raising power of glutinous rice was investigated. Total acidity was increased from 0.3 to 1.02% by steeping for 20 days at $10^{\circ}C$. Viscosity was increased from 25.5 to 32.4 cP after 14 days steeping and thereafter decreased to 23.5 cP. K, Na, Ca, Mg and P were leached 68, 67, 85 and 16% on 20 days steeping, respectively. K, Na and P were leached in the initial period, and Ca, Mg in the middle period of steeping. Raising power was increased according to the acidity increase and leaching of Ca, Mg and inorganic phosphorus during steeping. However, influence of the former on raising power was greater than the after.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.596-601
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• 2010

Serious problems in reclaimed land for agriculture are high soil salinity and very poor vertical drainage. However, desalinization in these soils is very difficult. To identify the change of soil permeability by the gypsum incorporation in soils we observed elution patterns and salt distribution of the soil using soil columns packed with reclaimed saline soil with various rates of gypsum amendment. Saturated hydraulic conductivity ($K_{sat}$) of the top soil of reclaimed saline soils without gypsum incorporation was close 0 cm $hr^{-1}$ while $K_{sat}$ increased up to 0.3 cm $hr^{-1}$ with increasing amount of gypsum for 0.4% or more gypsum. Also $K_{sat}$ of the reclaimed saline soils for top soil was drastically increased to 1.0 cm $hr^{-1}$ or slightly greater after 141 hour's elution experiment. The cumulative amount of cation recovered in the effluent also increased in the order of gypsum incorporation rate 0.8% > 0.6% > 0.4 > 0.2%. Soil EC in soil columns decreased from initial 33.9 dS $m^{-1}$ to less than 0.4 dS $m^{-1}$ and exchangeable Ca 2+ increased by 32~140% according to gypsum incorporation rate.

• Journal of the Korean Chemical Society
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• v.33 no.2
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• pp.232-237
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• 1989

The elution mechanism of rare earth elements in cation exchange resin which was substituted with $NH_4^+,\;Zn^{2+}\;or\;Al^{3+}$ as a retaining ion had been investigated. Rare earths or rare earths-EDTA complex solution was loaded on the top of resin bed and eluted with 0.0269M EDTA solution. When the rare earth-EDTA complex was adsorbed on the $Zn^{2+}\;or\;Al^{3+}$ resin form, retaining ion was complexed with EDTA and liberated rare earths was adsorbed in the resin again. Adsorbed rare earths in resin phase could be eluted by the complexation reaction with EDTA eluent. On $NH_4^+$ resin form, the rare earth-EDTA complex which had negative charge could not adsorbed on the cation exchange resin because the complexation reaction between $NH_4^+$ and EDTA was impossible. So the elution time was much shorter than in $Zn^{2+}\;or\;Al^{3+}$ resin form. When the rare earths solution was loaded on the $Zn^{2+},\;Al^{3+}$ resin form bed, rare earths was adsorbed in the resin and the retaining ion was liberated. Adsorbed rare earths in resin bed was exchanged by EDTA eluent forming rare earths-EDTA complex, and eluted through these processes. On $NH_4^+$ resin form, rare earths loaded was adsorbed by exchange reaction with $NH_4^+$. As the EDTA eluent was added, rare earths was liberated from resin forming negatively charged rare earth-EDTA complex and eluted without any exchange reaction. So the elution time was greatly shortened and there was no metallic ion except rare earths in effluent. When the $Zn^{2+}\;and\;Al^{3+}$ was used as retaining ion, the pH of efflent was decreased seriousely because the $H^+$ liberated from EDTA molecule.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.141-144
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• 2003

청양 및 서보광산에서 채취한 광미 및 오염된 토양에 대한 산성비를 고려한 용출실험 결과, 아연, 카드뮴 및 망간 pH 6.2-5.8, 철 pH 5.2-3.2, 코발트 pH 4.4-3.2, 구리 pH 3.2-3.0, 납과비소 pH3.0-3.5의 용출조건에서 최초로 각 원소의 용출이 발생하였다. 반응용액의 최종 pH5.0-1.5사이에서 용출되는 중금속은 이온교환형태 및 탄산염광물형태와 수반된 것이 용해된 것이다. 반응용액의 최종 pH1.5이하에서 용출되는 중금속은 철과 밀접하게 수반된 것으로 해석되었다. 청양광산과 서보광산의 광미가 pH2.0이하로 유지되는 경우가 발생한다면, 청양광산은 비소(최대 6,006$\mu\textrm{g}$/g), 아연(최대 2,503$\mu\textrm{g}$/g) 및 납(최대 29,638$\mu\textrm{g}$/g), 서보광산은 납(최대 2,258$\mu\textrm{g}$/g)과 111소(최대 874$\mu\textrm{g}$/g)의 오염확산이 크게 우려되며, 이 결과는 광미에 대한 환경복원이 필요한 것을 지시한다. 서보광산의 오염된 토양은 pH3.0까지의 산성비와 반응하는 경우에는 중금속의 오염확산이 거의 우려되지 않으며, pH3.0이하의 강산 용액과 반응한다면 아연의 오염확산이 우려된다.