• 상하수도학회지
• /
• 제13권2호
• /
• pp.47-54
• /
• 1999

SRB(Sulfate Reducing Bacteria) converts sulfate into sulfide using an organic carbon source as the electron donor. The sulfide formed precipitates the various metals present in the AMD (Acid Mine Drainage). This study is the fundamental research on heavy metal removal from AMD using SRB. Two completely mixed anaerobic reactors were operated for cultivation of SRB at the temperature of $30^{\circ}C$ and anaerobic batch reactors were used to evaluate the effects of carbon source, COD/sulfate($SO_4^=$) ratio and alkalinity on sulfate reduction rate and heavy metal removal efficiency. AMD used in this study was characterized by low pH 3.0 and 1000mg/l of sulfate and dissolved high concentration of heavy metals such as iron, cadmium, copper, zinc and lead. It was found that glucose was an organic carbon source better than acetate as the electron donor of SRB for sulfate reduction in AMD. Amount of sulfate reduction maximized at the COD(glucose)/sulfate ratio of 0.5 in the influent and then removal efficiencies of heavy metals were 97.5% of Cu, 100% of Pb, 100% of Cr, 49% of Mn, 98% of Zn, 100% Cd and 92.4% of Fe. Although sulfate reduction results in an increase in the alkalinity of the reactor, alkalinity of 1000mg/1 (as $CaCo_3$) should be should be added continuously to the anaerobic reactor in order to remove heavy metals from AMD.

• 한국버섯학회지
• /
• 제11권4호
• /
• pp.181-186
• /
• 2013

${\gamma}$-Aminobutyric acid(GABA) is a four carbon non-protein amino acid that has several well-known physiological functions, such as a postsynaptic inhibitory neurotransmitter in the brain and induction of hypotensive and tranquilizer effects. A lactic acid bacterium was isolated from button mushroom bed, which is showing high GABA productivity by TLC or HPLC analysis. The strain was identified as Lactobacillus hilgardii by analysis of 16S rDNA gene sequence. When the maximum production of GABA by L. hilgardii was investigated with various concentration of monosodium glutamate, the yield of GABA reached to be 53.65 mM at 1% mono sodium glutamate (MSG) in flask cultivation. A Glutamate decarboxylase (GAD) enzyme, which was known to convert MSG to GABA, was purified from a cell-free extract of L. hilgardii and the molecular weights of purified GAD was estimated to 60,000 by SDS-PAGE. The optimum pH and temperature of GAD were at pH4.6 and at $37^{\circ}C$, respectively. The GAD activity was increased by the addition of sulfate ions such as ammonium sulfate, sodium sulfate and magnesium sulfate, indicating that the increase of hydrophobic interaction causes the increase of GAD activity.

• KSBB Journal
• /
• 제18권3호
• /
• pp.180-185
• /
• 2003

GAGs의 추출 방법 중 효소의 사용으로 추출 효율의 상승과 원료수급의 문제점을 해결할 수 있었다. 그러나 효소 사용에 따른 생산단가의 상승과 단백질 함량의 증가에 따른 화장품 규격을 만족시킬 수 없음으로, 1/60 M sodium phosphate buffer로 105$^{\circ}C$로 열수 추출하는 것이 화장품 규격을 만족시키는 방법으로 나타났다. 이렇게 추출한 GAGs의 SO$_4$ 함량은 31.2%이고 회분의 함량이 22.2%로 GAGs 추출 향상을 위해 사용되어지는 sodium phosphate의 사용으로 회분 함량이 높아졌음을 알 수 있고 무기질 분석에서 Na의 함량이 3.0 mg%로 총 무기질의 47.6%를 차지하고 있었다. 시료를 HPLC로 분석하였을 때 chondroitin sulfate A, C와 동일한 분석시간을 나타내어 chondroitin sulfate의 함유 가능성을 나타내고, glucosamine과 galactose가 78.0% 존재하는 것을 당조성 분석을 통해 확인하였다. 일반 성분, HPLC분석, 당 조성분석과 아미노산 분석결과로 glucosamine과 galacturonic acid가 주가 되어 threonine으로 연결된 구조를 하는 GAGs라는 것을 알 수 있다. 화장품 원료 기준에 맞추기 위해서는 sulfate 함량이 35.0~45.0%, 단백질 함량은 14.0~22.0%로 유지해야하므로 제단백결과 5.0%, 10.0%, 20.0% TCA (w/v) 처리, 10.0%, 20.0%, 40.0% HCI (v/v) 처리, UF(ultra filtration)를 포함한 10.0% TCA (w/v), 20.0% SSA (w/v), 25.0% HCI (v/v) 처리 결과 5.0% TCA (w/v) 및 10.0% HCI (v/v)이 화장품 기준에 적합하며 경제적이며 효율적이라는 것을 알 수 있었다.

• 농약과학회지
• /
• 제7권1호
• /
• pp.12-17
• /
• 2003

감자 생산에 치명적인 흑각병을 유발하는 흑각병원균 (Erwinia carotovora subsp. atroseptica) 을 방제할 수 있는 화학적 방제제를 선발하기 위하여 7 종의 항생제와 oxolinic acid, 그리고 4 종의 구리제를 대상으로 병원균에 대한 억제효과와 저항성을 in vitro에서 조사하였다. Streptomycin, streptomycin sulfate, oxolinic acid는 0.02 mM 처리 24 시간 후, 그리고 구리제인 copper hydroxide, copper oxide, copper sulfate 는 3 mM 처리 24 시간 후 완전히 억제되었다. 약제들에 대한 병원균의 저항성을 조사하고자 최소 억제농도의 1.3 배를 처리하고 72 시간 후에 생존율을 조사한 결과, 항생제 및 oxolinic acid 처리구에서는 저항성균이 관찰되었으나, 구리제 처리구에서는 관찰되지 않았다. 저농도 처리로 병원균을 방제할 수 있는 2 종의 항생제 및 oxolinic acid 와 저항성균 유발 가능성이 낮은 구리제 3 종을 혼합처리였을 경우, streptomycin + copper oxide(0.016 + 1.2 mM, 9.3 + 171.6 ppm), streptomycin + copper hydroxide(0.016 + 1.5 mM, 9.3 + 146.3 ppm), streptomycin sulfate+copper oxide(0.005 + 1.2 mM, 7.0 + 171.6 ppm), streptomycin sulfate+copper hydroxide(0.005 + 1.5 mM, 7.0+146.3 ppm) 처리 24 시간 후 병원균의 생장은 완전 억제되었고, 72 시간 후 저항성균이 전혀 관찰되지 않았다. 그러나 oxolinic acid+구리제 혼합처리의 경우와 2 종의 항생제 및 oxolinic acid + copper sulfate 혼합처리의 경우 공히 균생장 억제효과가 나타나지 않았다. 본 실험의 결과는 효과적인 감자흑각병의 방제를 위하여 약제의 단일 사용보다는 혼합 사용하는 경우 더 높은 방제효과와 낮은 저항성균 유발효과가 있다는 것 을 보여주고 있다.

• 한국농공학회논문집
• /
• 제54권5호
• /
• pp.25-34
• /
• 2012

It has been well known that concrete structures exposed to acid and sulfate environments such as sewer etc. show significant decrease in their durability due to chemical attack. Such deleterious acid and sulfate attacks lead to expansion and cracking in concrete, and thus, eventually result in damage to cement mortar by forming expansive hydration products due to the reaction between cement hydration products and acid and sulfate ions. In this study, the effect of fly ash and blast furnace slag on the bond performances of structural synthetic fiber in latex modified cement mortar under sulfate environments. Fly ash and blast furnace slag contents ranging from 0 % to 20 % are used in the mix proportions. The latex modified cement mortar specimens were immersed in fresh water, 8 % sodium sulfate ($Na_2SO_4$) solutions for 28 and 50 days, respectively. Pullout tests are conducted to measure the bond performance of structural synthetic fiber from latex modified cement mortar after sulfate environments exposure. Test results are found that the incorporation of fly ash and blast furnace slag can effectively enhance the PVA fiber-latex modified cement mortar interfacial bond properties (bond behavior, bond strength and interface toughness) after sulfate environments exposure. The microstructural observation confirms the findings on the interface bond mechanism drawn from the fiber pullout test results under sulfate environments.

• Journal of Pharmaceutical Investigation
• /
• 제22권4호
• /
• pp.307-315
• /
• 1992

Dissolution rate of practically insoluble mefenamic acid was improved by roll mixing with sodium lauryl sulfate (SLS) or polyvinylpyrrolidone (PVP). The dissolution rate of the drug roll mixtures with SLS was superior to that of roll mixtures with PVP. The maximal dissolution rate was found in the roll mixtures system with SLS content of 60%. The dissolution rate of mefenamic acid roll mixtures with SLS content of 60% reached to the maximum value after 10 min of roll mixing. The transport of roll mixtures with SLS across rat jejunum was studied by the perfusion method using everted rat jejunum in vitro. The absorption rate of roll mixtures was superior to that of mefanamic acid.

• 한국대기환경학회지
• /
• 제2권2호
• /
• pp.66-74
• /
• 1986

Rain samples were collected at 10 sites in the Seoul area during the period of August through November, 1985. THe concentrations of the major cations $(H^+, Ca^{++}, MG^{++}, Na^+, K^+, NH_4^+)$ and the major anions $(SO_4^=, NO_3^-, Cl^-)$ were measured to characterize the main sources of chemical ions in rainwater. Correlating concentrations of ions to pH, calculated coefficients ranged from 0.1485 to 0/4296. Sulfate shows the largest coefficient indicating that sulfate is more closely associated with hydrogen ion than other ions. This may suggest that sulfuric acid contributes more to the acidity of rainwater in Seoul. It appears that the major chemicals measured in rainwater are from the anthropogenic sources of air pollution. Predominant chemicals are acidic at the Guro-, the Sinseol-, the Yangnam-, and the Ssangmun-dong with sulfate being the most predominant. IT also indicates that alkaline substances resulting from soil and dust have a significant effect on pH values of rainwater by neutralizing actions. According to Granat-model analysis, it is estimated that the relative contributions to the rainwater acidity in Seoul are 84% from sulfuric acid, 8% from nitric acid and 8% from hydrochloric acid.

• 환경위생공학
• /
• 제12권1호
• /
• pp.15-23
• /
• 1997

The anionic exchange resins with the Dowex-1 and Amberlite CG-400 form were transformed into resin of sulfate and acetate acid form, respectively. The uranyl complex ions with SO$_{4}$$^{2-}$ and CH$_{3}$COO$^{-}$ were adsorbed on the anion exchange resion mentioned above, and these complex ions were eluted as mixture eluents of 0.7M HNO$_{3}$ - 0.5M NH$_{4}$NO$_{3}$ by anion exchange chromatography. The optimum adsorption conditions of uranyl anion complex ions adsorbed on the upper of the resin colmun were 1.5-2.0 ml/min of flow rates at pH 2.0 and adsorptive power of uranyl complex ion of sulfuric acid type were nearly consistent with the Caussion normal distribution curve, whereas the elution state of UO$_{2}$(Ac)$_{2}$$^{4-}$ with acetic acid type was departed. The weighing form obtained from resin of sulfuric acid and aceric acid type was U$_{3}$O$_{8}$ whose recovery was 91.7%. The possibility of recovering uranium from the monazite sulfate solution using a strong base anion resin, Amberlite CG-400(sulfate form), was successfully recovered more than 90%.

• 한국세라믹학회지
• /
• 제24권5호
• /
• pp.437-446
• /
• 1987

In this study the attempts were made to investigate the possibilities of using domestic clay minerals and zeolite, which are available in almost unlimitted quantities, for preparation of aluminum sulfate, white carbon and silica gel. Aluminum sulfate was obtained by the method of sulfuric acid treatment. White carbon and silica gel were prepared by utilizing crystalline silica which was obtained as a by product during preparing the aluminum sulfate. White carbon was obtained by reacting 5.0 weight percent sulfuric acid solution with water glass which was a reaction product of crystalline silica and soldium hydroxide in a autoclave, while silica gel was obtained by reaction 10.0 weight percent acetic acid solution with water glass.

• 한국세라믹학회지
• /
• 제25권3호
• /
• pp.300-306
• /
• 1988

The catalytic effect of salts on formation of ${\alpha}$-calcium sulfate hemihydrate under water vapor at atmospheric pressure was studied and the formation of q-calcium sulfate hemilydrate from by-product gypsum of phosphoric acid process was investigated. The order of catalytic effect of salts are as follow: Ammonium chloride>Sodium succinate>Calcium chloride>Sodium tartrate>Magnesium chloride The prismatic crystals was formed when ammonium chloride, calcium chloride and magnesium chloride was added, whereas the needle crystals was formed when sodium tartrate was added. Ammonium chlorideis most successful in catalytic effects in formation of ${\alpha}$-calcium sulfate hermihydrate for the by-product gypsum of phosphoric acid process.