• KSBB Journal
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• v.8 no.2
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• pp.156-163
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• 1993

Strains degrading ethylene glycol(EG) and terephthalic acid(TPA) were isolated from water systems, and identified as Pseudomonas sp. They were named as Pseudomonas sp. EAW for EG and as Pseudomonas sp. TS2 for TPA. The optimal culture conditions of temperature, pH and nitrogen source were found to be $35^{\circ}C$, 7.5 and ammonium sulfate, respectively. The growth of strains and removal efficiency was slightly promoted by trace elements such as niacin and biotin in case of EG, and by trace elements such as $Na_2MoO_4{\cdot}2H_2O$ and thiamin i case of TPA. With increasing inoculation sloe for batch culture, the removal efficiency of EG by the strain EAW was conspicuously increased, while the removal efficiency of TPA by the strain TS2 was not changed as much as that of EG. The growth rate of the strain EAW was much more decreased than that of the strain TS2 in the enrichment medium, as the frequency of repeated-batch culture in the rich-medium increased. in case of real wastewater, growth rate and removal efficiencies of EG and TPA were lower than those in the enrichment medium. $COD_{Mn}\;and\;COD_{Cr}$ removal efficiencies after 48 hrs batch culture in real wastewater were 89% and 93%, respectively. The specific growth rate was inhibited when the initial concentration of EG or TPA was more than 25g/L.

• Elastomers and Composites
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• v.57 no.4
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• pp.181-187
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• 2022

CdSe-Mn nanocomposites were synthesized using a microwave method with sodium sulfite (Na₂SO₃), selenium (Se), cadmium sulfate octahydrate (3CdSO₄·8H₂O), ammonia solution (NH₃·H₂O), and manganese (II) sulfate monohydrate (MnSO₄·H₂O). We obtained CdSe-Mn-C₆₀ nanocomposites by calcining CdSe-Mn nanocomposites and fullerene (C₆₀) in an electric furnace at 700 ℃ for 2 h. X-ray diffraction, Raman spectroscopy, and scanning electron microscopy were used to characterize the crystal structures, lattice vibrations, and surface morphologies of the products, respectively. The photocatalytic activities of the CdSe-Mn-C₆₀ nanocomposites were investigated based on the photocatalytic degradations of organic dyes such as BG, MB, MO, and RhB under ultraviolet (UV) irradiation at 254 nm. UV-visible spectrophotometry was used to confirm the degradation process.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.49-53
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• 2000

For decompose carbon dioxide, manganese oxide was synthesized with $0.25M-MnSO_{4}{\cdot}nH_{2}O$ and 0.5M-NaOH by coprecipitation. We made magnetite deoxidized manganese oxide by hydrogen reduction for 1hour at $330^{\circ}C$. We investigated characteristics of catalyst, hydrogen reduction degree and decomposition rate of carbon dioxide. The structure of the hausmannite certified spinel type. The specific surface area of synthesized hausmannite and deoxidized hausmannite were $22.36m^{2}/g$, $33.56m^{2}/g$ respectively. The decomposition rate of $CO_{2}$ of deoxidized hausmannite was 57%.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.137-140
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• 2000

Marine microorganism strain 96CJ10356 produced exopolysaccharides, designated as EPS-R. To optimize culture conditions for the production of EPS-R, carbon, nitrogen, mineral salt, temperature, and pH were examined. STN medium was suggested as follow; sucrose 20, tryptone 10, NaCl 10, $MgSO_4$ 5, $CaCl_2$ 1, $KH_2PO_4$ 0.0076, $K_2HPO_4$ 0.0083, $FeCl_2$ 0.005, $MnCl_2$ 0.001, $NaMoO_4$ 0.001, $ZnCl_2$ 0.001 (g/1) and pH 7.0 About 9.23 g/l of EPS-R was obtained from the STN medium after cultivation for 120 h at $25^{\circ}C$ in 5-liter jar fermentor with an aeration rate of 0.17 vvm. Apparent viscosity and flocculation activity of the culture broth were increased with the production of the EPS-R and the maximal values were reached to 415 cp and 1400 units/ml against 0.5 % activated carbon, respectively.

• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.161-164
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• 1979

The effect of acidity and the metal surface area of the Pd loaded zeolite catalysts; prepared from $Ca^{2+}-,\;La^{3+}-,\;NH_4^+-$exchanged Y and dealuminated HY was studied for the reaction of n-butane. The amount of strong acid site determined by the temperature programmed desorption of ammonia increased in the order NaY < CaY < LaY. Total amount of acid site decreased with increasing degree of dealumination, but the portion of strong acid site increased with increasing $SiO_2/Al_2O_3$ ratio. The effective metal surface area determined by the CO adsorption technique was large for those zeolite catalysts having strong acidity. It was found that conversion of n-butane was strongly dependent on the acidity and the effective metal surface area of the catalysts. The fact that the conversion of n-butane was proportional to the effective metal surface area suggests that the dehydrogenation by metallic component is the primary step in the reaction of n-butane.

• Economic and Environmental Geology
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• v.18 no.3
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• pp.225-237
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• 1985

Mineralization of Daehwa and Donsan W-Mo deposits can be devided into three distinct depositional stages on the basis of mineral paragenesis and flnid inclusion studies; stage I, deposition of oxides and silicates ; stage II, deposition of base-metal sulfides and sulfosalts with carbonates; stage III, deposition of barren calcite and fluorite. Tungsten, molybdenum and tin mineralization occurred in stage I. Fluid inclusion studies reveal that ore fluid of stage I were homogeneous $H_2O-CO_2$ fluids containing 3.5~14.6 mol % $CO_2$. Minimum temperature and pressure of stage I ore fluids were $240^{\circ}C$ and 500 bars respectively. Salinities of aqueous type I inclusions in minerals of stage I range from 3.7 to 7.6 wt. % equi. NaCl. whereas those of $CO_2$-containing type III inclusions range from 0.3 to 4.4 wt. %. Temperatures of stage II ore fluids range from 200 to $305^{\circ}C$ on the whole and salinities were in the range of 3.2~7.2 wt. %. Homogenization temperatures of fluid inclusions in calcite and fluorite of stage III range from 114 to $186^{\circ}C$ and salinities were in the range of 0.9~4.3 wt. %. Sulfur fugacities during stage II deduced from mineral assemblages and tamperature data from fluid inclusions declined from earlier to later in the range of $10^{-11}{\sim}10^{-18}atm$. Fluid inclusion evidences suggest that the dominance of $CO_2$ in ore fluid during W-Mo mineralization is the characteristic features of Cretaceous W-Mo deposits of central district of Korea compared to those of Kyeongsang basin district.

• Elastomers and Composites
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• v.55 no.4
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• pp.321-328
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• 2020

Zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and sodium hydroxide (NaOH) were dissolved in distilled water and stirred for 30 min. The resulting solution was sonicated by an ultrasonic wave for 45 min. This solution was washed with distilled water and ethanol after centrifugation; next, it was placed in an electric furnace at 200℃ for 1 h under the flow of Ar gas to obtain zinc oxide nanoparticle. A zinc oxide nanoparticle-(C60) fullerene nanowhisker composite was synthesized using the zinc oxide nanoparticle solution, C60-saturated toluene, and isopropyl alcohol via the liquid-liquid interfacial precipitation method. The zinc oxide nanoparticle and zinc oxide nanoparticle-(C60) fullerene nanowhisker composite were characterized using X-ray diffraction, scanning electron microscopy, and Raman spectroscopy, and they were used for the catalytic degradation of methyl orange (MO) under ultraviolet (at 254 and 365 nm) and ultrasonic irradiation. In addition, the catalytic degradation of MO over the zinc oxide nanoparticle and zinc oxide nanoparticle-(C60) fullerene nanowhisker composite was evaluated using ultraviolet-visible spectroscopy.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.239-246
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• 2008

Yeongweol sericite deposit of Gangwon Province is regarded as one of the sericite deposits derived from granitic rocks due to post-magmatic alkali metasomatism, and the other sericite deposit of the same origin is the Daehyun mine of Gyungbug Province. Sericite ores were originated from leucocratic granitic stocks of Cambrian-Triassic age which intruded the pegmatitic migmatite of the unknown age and granite of the Pre-cambrian age, respectivcly. Jangsan quartzite of the lowermost formations of the Paleozoic era, which played as the capping rock protected from the leakage of the hydrothermal solution. It is well known that those sericite deposits arc formed during formation of the geosyncline, and they are also situated in the margins of the Hambaeg Syncline. Leucocratic granites commonly contain pegmatites with tourmaline crystals, and are rich in potassium feldspars, and sodium plagioclase as well. Sericitized ores are mainly found as we go up to the higher elevations or to the margins of the stocks. And some of the Highest grade sericite ores show the monominerallic character composed of nearly pure sericite probably doc to the ultra greisenization. Chemical analysis shows higher $Na_{2}O$ and $K_{2}O$ contents $(2.00\sim7.03wt%)$ as the sericitizations arc preceded and they represent obvious greisenization. But low CaO contents $(0.05\sim4.51wt%)$ indicate that albitizations are so weak. Pyrophyllite of the Youngweol area is often accompanied by the sericite, indicating rather stronger thermal effect than the Daehyun mine. It is known that there are several Sn deposits originated from greisenization in the Taebaegsan region. And greisens are inclined to contain W, Mo and several REE's such as Be, Nb and Li, and so Taebaegsan region interbedded with lots of carbonate formations are still worthwhile to survey for those metallic deposits.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.721-730
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• 1993

Various catalysts of $Cu_xH_3-{_{2x}}PMo_{12}O_{40}{\cdot}_nH_2O$ with different x-values have been prepared and characterized by thermal analysis, X-ray powder diffraction, infrared spectroscopy, BET surface-area measurement, electron microscopy, and temperature programmed desorption of ammonia. The properties of these catalysts in acrolein oxidation have been investigated in a continuous-flow fixed-bed reactor. The catalysts lost their water of crystallization at about $200^{\circ}C$ and their constitutional water between 300 and $400^{\circ}C$. The Keggin structure of the catalysts was identified by infrared spectroscopy. The decomposition of Keggin anion, $(PMo_{12}O_{40})^{3-}$, was increased with the increase of substituted copper content and identifiable $MoO_3$ and $P_2O_5$ as decomposition products were observed. The conversion of acrolein decreased with the increase of x probably due to the decrease of specific surface area and of total amount of acid sites. But specific reaction rate and selectivity to acrylic acid were maximized at x=1.0, and it showed specific acid site distributions.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.666-670
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• 2015

Competition among anion species in solution for same sorption sites and soil surface can be of major significance in determining the effective mobility of any potentially adsorbing species. Major soil anion species include $OH^-$, $F^-$, $Cl^-$, $HCO_3{^-}$, $CO_3{^-}$, $NO_3{^-}$, $SO_4{^{2-}}$, and $PO_4{^{3-}}$. And some micro nutrients such as boron and molybdenum exist as $H_2BO_3{^-}$ and $MoO_4{^{2-}}$, as do some heavy metals such as chrome and arsenic as $CrO_4{^{2-}}$ and $HAsO_4{^{2-}}$. Pesticides such as 2,4,5-T and 2,4-D also exist as anions. Many anion species are retained by more complex mechanisms than the simple electrostatic attractions involved in most cation adsorption reactions. In binary system composed of two anions, the adsorption of one anion is influenced by the other anion due to the competition for the available and limited binding sites in soil constituents. The specifically adsorbed anions may compete more effectively for sorption sites than that of nonspecifically adsorbed anion. In this study, we aim to evaluate the mathematical models to determine the magnitude of concentration variations in adsorption due to competitive interactions between anions introduced to a system in binary mixtures.