• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.398-402
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• 2012

The catalytic performance of some metal oxides in the vapor phase selective oxidation of $H_2S$ in the stream containing ammonia and water was investigated. Among the catalysts tested $Fe_2O_3/SiO_2$ was the most promising catalyst for practical application. It showed higher than 90% $H_2S$ conversion and very small amount of $SO_2$ emission over a temperature range of $240{\sim}280^{\circ}C$. The effects of reaction temperature, $O_2/H_2S$ ratio, amount of ammonia and water vapor on the catalytic activity of $Fe_2O_3/SiO_2$ were discussed to better understand the reaction mechanism. The $H_2S$ conversion showed a maximum at $260^{\circ}C$ and it decreased with increasing temperature over $280^{\circ}C$. With an increase of $O_2/H_2S$ ratio from 0.5 to 4, the conversion was slightly increased, but the selectivity to elemental sulfur was remarkably decreased. The increase of ammonia amount favored the conversion and the selectivity to elemental sulfur with a decrease in $SO_2$ production. The presence of water vapor decreased both the activity and the selectivity to sulfur, but increased the ATS selectivity.

• Journal of Bio-Environment Control
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• v.7 no.3
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• pp.246-252
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• 1998

This study was carried out to investigate the quality of ground water for hydroponics in Kyeongnam area in 1995. Water samples were collected and analyzed from 77 wells in green houses throughout Kyeongnam area. The values of several components in well water were as follows ; 7.4 in pH, 0.46dS/m in EC, 0.3mg/L in N $H_{4}$-N, 25.4mg/L in $Ca^{2＋}$, 42.6mg/L in C $l^{[-10]}$ and 72.5mg/L in S $O_{4}$$^{2-}$. The pH value showed high positive significance of correlationships with $Ca^{2＋}$ and EC. Also, the EC value showed high positive significance with N $a^{＋}$, $Ca^{2＋}$, S $O_{4}$$^{2-}$, $Mg^{2＋}$ and C $l^{[-10]}$ .

• Korean Journal of Metals and Materials
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• v.50 no.2
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• pp.183-190
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• 2012

Hydrogen was generated by the reaction of metal hydride with water. The variation of hydrogen generation with the kind of powders (milled $MgH_2$, and $MgH_2$ milled with various contents of MgO, $MgCl_2$ or $Ni+Nb_2O_5$) was investigated. $MgH_2$ powder with a hydrogen content of 6.05 wt% from Aldrich Company was used. Hydrogen is generated by the reaction of Mg as well as $MgH_2$ with water, resulting in the formation of byproduct $Mg(OH)_2$. For about 5 min of reaction time, milled $95%MgH_2+5%MgO$ has the highest hydrogen generation rate among milled $MgH_2+x%MgO$ (x=0, 5, 10, 15 and 20) samples. Milled $90%MgH_2+10%MgCl_2$ has the highest hydrogen generation rate among all the samples.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.3
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• pp.754-758
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• 2004

To test the cytoprotective effect of sophorae radix (SR) against hydrogen peroxide (H₂O₂)-induced cytotoxicity, we investigated the cell viability using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay in the presence of methylene chloride, n-butanol, ethyl acetate and water soluble fraction of SR water extracts in H9c2 cells. These results were obtained as followed; H₂O₂ decreased the cell viability of H9c2 cells in a dose dependent manner. Cells pretreated with SR water extracts were protected the H₂O₂-induced decrease of viability in H9c2 cells. Among organic solvents fractions of SR water extracts, ethyl acetate soluble fractions of SR protected the decrease of viability induced by H₂O₂ in H9c2 cells. These results suggest that ethyl acetate soluble fractions of SR water extracts is effective in the prevention of H₂O₂-induced cytotoxicity.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.123-130
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• 2007

The effects of hydrogen peroxide treatment on the reduction of waterworks sludge were investigated in this study. Sludge treated by peroxidation $H_2O_2$ oxidation) was dewatered using a pressure filter at 3atm. It was observed that $H_2O_2$ treatment at the acidic condition significantly reduce both cake water content and specific resistance to filtration (SRF), indicating the enhancement of dewaterability and filterability. The filterability by hydrogen peroxide treatment at pH 3.5 was better than acidic treatment and became comparable with polymer conditioning. The sludge filterability evaluated by SRF was optimal at a dose 2ml $H_2O_2$/sludge($0.02g\;H_2O_2/gTS$) after adjusting of pH to 3.5. The $H_2O_2$ oxidation at pH 3.5 also produced even more dewatered cake when compared with polymer conditioning. The reduction rate of sludge mass at an optimal condition showed 34% compared with untreated sludge. The effects of peroxidation on sludge properties including zeta potential, bound water and particle size were also evaluated. Peroxidation at the acidic condition reduced both bound water and zeta potential. By $H_2O_2$ combined with sulfuric acid leached iron caused Fenton's reaction, which showed a potential to significantly reduce the amount of solids mass and to produce more compact cake with higher filterability.

• Journal of Hydrogen and New Energy
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• v.34 no.4
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• pp.327-333
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• 2023

The water gas shift reaction was carried out using the commercial catalyst pellet and the simulated gases expected to occur from waste plastic gasification. In the water gas shift reaction, the high temperature shift reaction and the low temperature shift reaction were continuously performed with CO:H₂O ratio of 1:2, 1:2.5, and 1:3, and the CO conversion and H₂ increase rate were evaluated. The H₂ increase rate increased in order to CO:H₂O ratio of 1:3 > CO:H₂O ratio of 1:2.5 > CO:H₂O ratio of 1:2. The CO conversion showed a high value of more than 97% at each CO:H₂O ratio. The water gas shift reaction at a CO:H₂O ratio of 1:3 showed the highest H2 increase rate and CO conversion.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.481-491
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• 2015

The aim of this study was to evaluate the chemical quenching system for residual ozone and to determine the operating condition for the quenching system. Hydrogen peroxide ($H_2O_2$) and sodium thiosulfate ($Na_2S_2O_3$) were investigated as quenching reagents for ozone removal, and the tendency of each chemical was notably different. In the case of $H_2O_2$, the degradation rate of ozone was increased as the concentration of $H_2O_2$ increase, and temperature and pH value have a significant effect on the degradation rate of ozone. On the other hand, the degradation rate of ozone was not affected by the concentration of $Na_2S_2O_3$, temperature and pH value, due to the high reactivity between the ${S_2O_3}^{2-}$ and ozone. This study evaluates the decomposition mechanism of ozone by $H_2O_2$ and $Na_2S_2O_3$ with consideration for the water quality and reaction time. Furthermore, the removal test for the quenching reagents, which can be remained after reaction with ozone, was conducted by GAC process.

• Analytical Science and Technology
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• v.20 no.4
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• pp.355-360
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• 2007

The title complex, $(C_3H_{12}N_2)[\{Cd(H_2O)(C_6H_5O_7)\}_2]{\cdot}6H_2O$, I, has been prepared and its structure characterized by FT-IR, EDS, elemental analysis, ICP-AES, and X-ray single crystallography. It is triclinic system, $P{\bar{1}}$ space group with a = 10.236(2), b = 11.318(2), c = $13.198(2){\AA}$, ${\alpha}=77.95(1)^{\circ}$, ${\beta}=68.10(1)^{\circ}$, ${\gamma}=78.12(1)^{\circ}$, V = $1373.5(3){\AA}^3$, Z = 2. Complex I has constituted by protonated 1,3-diaminopropane cations, citrate coordinated cadmium(II) anions, and free water molecules. The central cadmium atoms have a capped trigonal prism geometry by seven coordination with six oxygen atoms of three different citrate ligands and one water molecule. Citrate ligands are bridged to three different cadmium atoms. Each cadmium atom is linked by carboxylate and hydroxyl groups of citrate ligand to construct an one-dimensional ladder-type assembly structure. The polymeric crystal structure is stabilized by three-dimensional networks of the intermolecular O-H${\cdots}$O and N-H${\cdots}$O hydrogen-bonding interaction.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1047-1053
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• 2009

The future use of hydrogen as an energy source is expected to increase on account of its environmentally friendliness. In order to enhance the production of hydrogen, Pd ions (0.01, 0.05, 0.1, and 0.5 mol%) were incorporated $TiO_2$ (Pd-$TiO_2$) and used as a photocatalyst. The UV-visible absorbance decreased with increasing level of palladium incorporation without a wavelength shift. Although all the absorption plots showed excitation characteristics, there was an asymmetric tail observed towards a higher wavelength caused by scattering. However, the intensity of the photoluminescence (PL) curves of Pd-$TiO_2$ was smaller, with the smallest case being observed at 0.1 and 0.5 mol% Pd-$TiO_2$, which was attributedto recombination between the excited electrons and holes. Based on these optical characteristics, the evolution of $H_2$ from methanol/water (1:1) photo-splitting over Pd-$TiO_2$ in the liquid system was enhanced, compared with that over pure $TiO_2$. In particular, 2.4 mL of $H_2$ gas was produced after 8 h when 0.5 g of a 1.0 mol% Pd-$TiO_2$ catalyst was used. $H_2$ was stably evolved even after 28 h without catalytic deactivation, and the amount of $H_2$ produced reached 14.5 mL after 28 h. This is in contrast to the case of the Pd 0.1 mol% impregnated $TiO_2$ of $H_2$ evolution of 17.5 mL due to the more decreasedelectron-hole recombination.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.77.2-77.2
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• 2013

We present the interim results of simultaneous time monitoring observations of $^{28}SiO$ v = 1, 2, J = 1-0, $^{29}SiO$ v = 0, J = 1-0 and $H_2O$ $6_{16}-5_{23}$ maser lines toward 10 known water fountain sources at a post-AGB stage. The observations have been carried out from 2009 June to 2013 September using the 21m single dish radio telescopes of the Korean VLBI Network. From six sources, we detected well separated red- and blue-shifted $H_2O$ maser features with large velocity ranges more than 100 km $s^{-1}$. From four sources, we detected red- and/or blue-shifted $H_2O$ maser features depended on observational epochs. However, we could not detected SiO maser emission from any sources and any epochs. For a representative water fountain source W43A, we obtained $H_2O$ maser spectra at 17 epochs which show a clear bipolar and discontinuous mass ejections. They also showed a periodic change between red-shifted and blue-shifted peaks. However, we need a more regular and short-time interval monitoring observations in order to fix the period and peak intensity variation interval.