• The Journal of Engineering Geology
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• v.20 no.3
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• pp.271-279
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• 2010

Time-dependent behavior similar to secondary deformation related to mineral dissolution is easily observed when performing a laboratory pressure experiment. In this research, to observe the dissolution of quartz found in bentonite used as buffer material for the geological disposal of high-level waste (HLW) under conditions of high pH, we calculated the diffusion of $OH^-$ ions and the behavior of quartz dissolution using the homogenization analysis method. The results reveal that the rate of quartz dissolution is proportional to the temperature and interlayer water thickness. In particular, in a high-pH environment, the reacted area (and therefore the dissolution rate) increases with decreasing interlayer water thickness.

• Resources Recycling
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• v.18 no.2
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• pp.56-61
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• 2009

The dissolution of domestic aluminum hydroxide of 99.7% purity has been performed with mineral and organic acid prior to the synthesis of aluminum compounds from aluminum solution. Mean particle size of aluminum hydroxide used in the work was $14.4{\mu}m$, $22.9{\mu}m$ and $62.3{\mu}m$, respectively and the effect of reaction temperature, concentration of acid and reaction time on the dissolution of aluminum hydroxide has been examined. As a result, the dissolution of aluminum hydroxide was increased with the concentration of HCl and more than 70% dissolution was obtained with 5 mole/l HCl at $70^{\circ}C$ for reaction time of 4 hr. As far as the dissolution of aluminum hydroxide with sulfuric acid was concerned, it was found that the optimum concentration of sulfuric acid was about 6 mole/l for the effective dissolution of aluminum hydroxide. When oxalic acid was used for the dissolution of aluminum hydroxide, nearly complete dissolution could be obtained by the dissolution for 16 hr with 1.0 mole/l oxalic acid at $90^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.2 no.2
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• pp.111-117
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• 1974

Studies were carried out on the practical use of Naringinase and some chracteristics of Naringin solublizing enzme which might hydrolyae naringin to purunin. Obtained results were as follows. 1. Selected strain for Naringinase producing was identified to be Aspergillus niger S-1 and its naringinase was applied to chinese citron processing to remove the bitter taste. 2. Of the naringinase, naringin solubilizing enzyme was purified on a DEAE-Sephadex A-50 column and crystalized from acetone and ammonium sulfate. 3. Hydrolized naringin which has higher solubility rather than naringin or naringenin were identified by thin layer chromatography. 4. Hydrolyzed naringin and naringin were separatly determinated by ethylacetate extraction and this result was compared with sensory test.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.436-439
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• 2012

본 연구는 오존수 제조장치에 인젝터를 이용한 오존 주입방식을 도입하여 소형화, 저전력화를 실현하고자 하였다. 오존발생기, 물-오존 혼합기(인젝터), 오존용해조, 배오존 처리기로 구성된 시스템을 제작하여 인젝터 주입방식에 의한 오존수 제조장치의 오존 용해특성과 그 적용성을 검토하였다. 오존 용해 특성으로 물-공기량에 따른 인젝터 성능, 용해조에서의 오존 용해능 등을 검토하였다. 인젝터 방식은 기존의 가압용해방식에 비하여 저농도 용해능을 보였으나, 인젝터 내부의 물-오존 접촉효율이 높아 평형농도에 도달되는 시간이 단축됨을 확인하였다. 제조된 오존수의 적용 효용성은 용존오존의 잔류시간과 미생물 살균능 검사를 통하여 실시하였다. 횡형식 인젝터 시스템에 의해 용해된 용존오존의 잔류시간이 기존의 가압용해방식에 비하여 다소 짧았으나 미생물의 살균능에는 크게 차이가 나지 않았다.

• Analytical Science and Technology
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• v.23 no.6
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• pp.511-517
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• 2010

Dissolution procedure of vanadium pentoxide, which is widely used as a catalyst for production of sulfuric acid or an oxide reaction of the numerous organic compounds, was investigated. Reagent of vanadium pentoxide was completely dissolved in aqua regia-$H_2O_2$-HF solution, but plate type of vanadium pentoxide sample was not clearly dissolved with mixed acids. Thus, in order to establish the dissolution procedure for plate type of vanadium pentoxide, the solubility of vanadium pentoxide was investigated through comparison of acid treatment-fusion and microwave digestion methods. The optimized acid for dissolution of vanadium compound was found to be mixing acids of aqua regia, $H_2O_2$ and HF. Acid-fusion and microwave digestion methods have a similar property in the solubility of vanadium compound, but the latter was more quick and convenient procedure. The content of vanadium pentoxide was found to be $97.9{\pm}0.9%$ using an inductively coupled plasma atomic emission spectrometer after dissolution of a sample with the microwave digestion system.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.43-47
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• 2003

산화환경에 노출된 폐광석에 포함되어 있는 황화광물은 산소와 물과의 화학반응을 통한 산화작용을 받게 되고 주변 환경에 유해한 금속원소의 용출이 발생될 것으로 예상된다. 그러나 용해된 금속이온은 침전(precipitation), 공침(coprecipitation), 흡착(adsorption)반응에 의해 수용액으로부터 제거되어 자연적으로 고정화될 수 있다. 이번 연구는 서보광산의 폐광석 내 용해된 중금속원소들의 이동을 제한하는 요인으로서 2차 산화광물의 침전 및 용해된 중금속 원소들의 흡착 가능성을 광물학적으로 연구하였다. (중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.116-121
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• 2005

Immobilization technique by PVA encapsulation is an effective alternative for wastewater treatment. However little information is available about the effect of PVA characteristics on physical properties as an encapsulation media. This study aims at investigating the effect of the preparation methods of PVA and filler addition to media on the solubility of PVA. The solubility decreased as the freezing temperature decreased and the vacuum-drying was applied. Addition of the PAC (Powered Activated Carbon) and organoclay decreased the solubility of the PVA gels. Organoclay was more effective for lowering the solubility about 25% than the PAC. Nitrification with the PVA-coating media was less sufficient than with the polyurethane media due to the mass transfer restriction for oxygen and nutrients.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.798-806
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• 1993

In this study we developed the synthesis of high purity tungsten oxide from tungsten chlorides obtained by the chlorination of scheelite in a fluidized bed reactor. Within a minute of dissolution time, tungsten chlorides were almost dissolved in $H_2O_2$ solution. The proper dissolution conditions for the tungsten chlorides were as follows : $H_2O_2$ concentration 0.5%, dissolution temperature $15^{\circ}C$ and $H_2O_2$ amount to 0.5g tungsten chlorides 30ml. Under above conditions, the tungsten oxide prepared from dissolved product was identified as $WO_3$ and the purity of $WO_3$ was 99.53%.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.712-716
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• 2010

Salting-out technique was adopted to crystallize dye crystals from dye solution. Solubility of dye solution and crystallization kinetics of Reactive Red 218 was investigated. Solubility of dye solution is decreased by higher KCl concentration. The empirical expressions of salting-out crystallization kinetics for Reactive Red 218 in continuous MSMPR crystallizer was $G=6.864{\times}10^{-5}{\Delta}C^{1.207}$ and $B^0=4.8{\times}10^{22}{\Delta}C[1.1{\times}10^{-13}+{({\Delta}C)}^{0.7}{M_T}^2]$.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.94-102
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• 1993

The effects of temperature and of $Na_2O$ and $SiO_2$ contents on the crystallization of zeolite A were studied, by examining crystallization curves and particle size distributions of final products at various crystallization conditions. Crystallization process could be simulated adopting the assumptions of constant linear growth rate and equilibrium between amorphous solid phase and soluble species. Rate constants were determined by comparing the simulated crystallization curves with experimental data. Rate constant for linear growth increased with temperature and crystallization rate at different mole ratio of $Na_2O/H_2O$ correlated reasonably well with increase of soluble species. The rate constant of crystallization did not increase with increase in mole ratio of $Na_2O/H_2O$, but the rate of nuclei formation and the fraction of soluble species were enhanced. The rate constants for linear growth of zeolite A were determined as $0.07{\sim}0.24{\mu}m{\cdot}min^{-1}$ at these experimental conditions Apparent activation energy was estimated as $49kJ{\cdot}mol^{-1}$.