• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.79-86
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• 2010

Effects of operating parameters such as applied voltage, solution conductivity, ferrous ion concentration, electrode material on phenol degradation by pulsed corona discharges were investigated in laboratory scale experiments. The increase of applied voltage enhanced the phenol degradation by generating more energetic electrons. The solution conductivity inversely affected phenol removal rate in the tested ranges because the increase of conductivity decreased the electric field strength through the liquid phase. The addition of ferrous sulfate promoted the phenol degradation through the OH radical production by the Fentonlike reactions between ferrous ion and hydrogen peroxide generated by pulsed corona discharges. Catechol and hydroquinone were detected as primary intermediates of phenol degradation and the decrease of pH and the increase of conductivity were observed probably due to the generation of organic acids. Almost all of the initial phenol was disappeared and 29% of total organic corbon (TOC) was removed in the condition of 0.5 mM of ferrous sulfate after approximately 230 kJ of discharge energy transferred to the reactor.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.2
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• pp.66-79
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• 1998

This study purposes to elucidate the characteristics of local water quality and the evolutional process of the spring water have been studied with the samples from 55 selected springs, from the coast region to the Baegrogdam, a caldera lake of Halla mountain in Cheju Island. Results of hydrochemical analyses in the 55 spring water show that Gwaneumsa is pollued with high hydrogen concentration, and spring waters from Yusuarmchun, Jangsumul, Dukjisemmul, Sinch'onk'nmul, Youngchunsa, Woonyangchun, Harwontongmul, Dongheamul, Seakdalsengsu, Andukkyekok, Dotimul, Kinmul, Harkangmul and Jungkeummul are polluted by the pollution sources from the surface surrounding ground. Spring waters of Samyang3suwon, Meungbusa, Sernurungmul, Tosanmul, Jungkeummul, Kwakgimul, Aewolharmul, Konemul and Nokgomul are also polluted from the sea water intrusion. The electrical conductivity, pH and the concentration of nitrate nitrogen and bicarbonate increase when the precipitation increases, but the concentration of sodium, chloride and sulphate decrease when the precipitation increases. The concentrations of potassium, magnessium and calcium are nearly independent of the precipitaion. Quality characteristics of spring water show complicated group of spring water through piper's trilinear diagram. The high mountain region consists of groups of sodium or potassium type and bicarbonate type; the middle mountain region consists of groups of sodium or potassium type and no dominant type; the low mountain consists of groups of no dominant type and sulfate or nitrate type; the coast region consists of groups of sodium or potassium type and chloride type or no dominant type. These characteristics indicate that the spring waters are changed from bicarbonate type in the high and middle mountain regions into non-bicarbonate type in the coastal region, as the precipitated waters flow downslope.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.74-83
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• 2016

Bacillus subtilis SRCM 101269 having safety and amo gene isolated from Korean traditional fermented food and their investigated characterization to apply the cow manure such as cellulase and xylanase activities, 16S rRNA sequencing, and ability of removal of livestock manure odor. Cow manure application results for the removal of livestock manure odor, the ammonia gas was reduced more than two-folder compared to the control group after 6 days, and reduced to less than 10 ppm after 9 days. In the case of cow manure added fowl droppings and other wood-based mixture components, ammonia gas maintained constant after 3 days of fermentation. However, in the case of sample inoculated B. subtilis SRCM 101269, ammonia gas reduced in course of fermentation time, and concentration of hydrogen sulfide also reduced for 65 ppm. Changes of nitrite concentration according to fermentation time no showed different for cow manure, however nitrite concentration in mixed livestock manure increased when compared to control. And then sulfate concentration in cow manure decreased, and no showed different when compared to the initial fermentation. No apparent change of sulfate concentration in mixed livestock manure detected. Through the previously studies, B. subtilis SRCM 101269 has high potential in industrial application manufacturing the cow manure as removal of livestock manure odor.

• Journal of the Korean Chemical Society
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• v.53 no.2
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• pp.125-132
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• 2009

The magnetized water is known to have a unique pattern of hydrogen bond between water molecules, thereby producing different physicochemical properties from the ordinary water. We have examined the effect of magnetized water on the change of critical micelle concentrations (CMC) of some surfactants. The CMC changes of SDS (sodium dodecyl sulfate) and CTAB (cetyltrimethylammonium bromide) dissolved in the magnetized water have been determined by the conductivity measurement at $25\;{^{\circ}C}$ and that of SDS, CTAB and Pluronic F-68 have also been examined by the surface tension method at $25\;{^{\circ}C}$. The CMC variation of SDS was examined by ITC (Isothermal Titration Calorimeter) at $25\;{^{\circ}C}$. The CMC of SDS, CTAB, and Pluronic F-68 are more decreased in the magnetized water, SDS is about $2.7{\sim}6.5$25 %, CTAB is about $2.3{\sim}3.0$%, and Pluronic F-68 is about 24.2 %, than in the control water.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.86-91
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• 2008

Dicamba(3,6-dichloro-2-methoxybenzoic acid) is used to control for pre and post-emergence of annual and perennial broad-leaf weeds. It is very soluble in water and highly mobile, acidic herbicide. So it is easily moved and detected in groundwater. Zerovalent iron(ZVI) has been used for the reductive degradation of certain compounds through amination of nitro-substituted compounds and dechlorination of chloro-substituted compounds. In this study, we investigated the potential of ZVI for the oxidative degradation of dicamba in water. The degradation rate of dicamba by ZVI was more rapidly increased in pH 3.0 than pH 5.0 solution. The degradation percentage of dicamba was increased with increasing amount of ZVI from 0.05% to 1.0%(w/v) and reached above 90% within 3 hours of reaction. As a result of identification by GC-MS after derivatization with diazomethane, we obtained three degradation products of dicamba by ZVI. They were identified 4-hydroxy dicamba or 5-hydroxy dicamba, 4,5-dihydroxy dicamba and 3,6-dichloro-2-methoxyphenol. 4-Hydroxy dicamba or 5-hydroxy dicamba and 4,5-dihydroxy dicamba are hydroxylation products of dicamba. 3,6-dichloro-2-methoxyphenol is hydroxyl group substituted compound instead of carboxyl group in dicamba. We also confirmed the same degradation products of dicamba in the Fenton reaction which is one of oxidation processes using ferric sulfate and hydrogen peroxide. But we could not find out the dechlorinated degradation products of dicamba by ZVI.

• Journal of Environmental Health Sciences
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• v.20 no.1
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• pp.62-67
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• 1994

Introduction : Recently, water and environmental pollution becomes serious social problem and high technology makes this pollution accelerate. Hydrogen sulfide, the main subject of our research, is one of the most dangerous air pollutant like SO$_x$ and NO$_x$. The major contaminant in coal gasification is H$_2$S, which is very toxic, hazardous and extremely corrosive. Therefore, control of hydrogen sulfide to a safe level is essential. Although commercial desulfurization process called liquid scrubbing is effective for removal of H$_2$S, it has drawbacks, the loss of sensible heat of the gas and costly wastewater treatment. Many investigations are carried out about high-temperature removal ol H$_2$S in hot coal-derived gas using metal oxide or mixed metal qxide sorbents. It was reported that ZnO was very effective sorbent for H2S removal, but it has big flaw to vaporize elemental zinc above 600\ulcorner \ulcorner As alternative, metal oxides such as CaO, $Fe_2O_3$, TiO$_2$ and CuO were added to ZnO. Especially, different results are reported for $Fe_2O_3$ additive. Tamhankar et al. reported SiO$_2$ with 45 wt% $Fe_2O_3$ sorbent is favorable for removal of H$_2$S and regeneration.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.4
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• pp.390-396
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• 2012

In order to understand the nature of dendritic zinc growth, electrochemical zinc redox reaction on nickel plate was investigated in aqueous solutions containing different concentrations, 0.2, 0.1 and 0.02 $mol{\cdot}dm^{-3}$ (M), of zinc sulfate ($ZnSO_4$) or zinc chloride ($ZnCl_2$). Zinc ion was efficiently reduced and oxidized on nickel in the high-concentration (0.2 M) solution, whereas relatively poor efficiency was obtained from the other low-concentration solutions (0,1 and 0.02 M). Cyclic voltammetry (CV) analysis revealed that the 0.2 M electrolyte solution decomposes at more positive potentials than the 0.1 and the 0.02 M solutions. These results suggested that the concentration of electrolyte solution and anion would be an important factor that suppresses the reaction of the zinc dendrite formation. Scanning Electron Microscopy (SEM) data revealed that the shape of dendritic zinc and its growing behavior were also influenced by electrolyte concentration.

• Journal of Microbiology
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• v.35 no.4
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• pp.300-308
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• 1997

The catechol 2,3-dioxygenase (C23O) encoded by the Pseudomonas putida xylE gene was over-produced in Escherichia coli and purified to homogeneity. The activity of the C23O required the reduced form of the Fe(II) ion since the enzyme was highly susceptible to inactivation with hydrogen perocide but reactivated with the addition of ferrous sulfate in conjunction with ascorbic acid. The C23O activity was abolished by treatment with the chemical reagents, diethyl-pyrocarbonate (DEPC), tetranitromethane (TNM), and 1-cyclohexy1-3-(2-morpholinoethyl) car-bodiimidemetho-ρ-toluenesulfontate (CMC), which are modifying reagents of histidine, tyrosine and glutamic acid, respectively. These results suggest that histidine, tyrosine and glutamic acid residues may be good active sites for the enzyme activity. These amino acid residues are conserved residues may be good active sites for the enzyme activity. These amino acid residues are conserved residues among several extradion dioxygenases and have the chemical potential to serveas ligands for Fe(II) coordination. Analysis of random point mutants in the C23O gene derived by PCR technique revealed that the mutated positions of two mutants, T179S and S211R, were located near the conserved His165 amd Hos217 residues, respectively. This finding indicates that these two positions, along with the conserved histidine residues, are specially effective regions for the enzyme function.

• Macromolecular Research
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• v.17 no.5
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• pp.332-338
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• 2009

Rheological behavior of natural hydrogel produced from seeds of three Salvia spp. (S. miltiorrhiza (SM), S. sclarea (SS), S. viridis (SV)) was investigated by using a Rheometer equipped with a cone and plate geometry measuring system under never-dried condition. Different chemical contents of such hydrogels give significant effects on their rheological properties. Because of incomplete penetration of water inside the hydrogels after drying before-dried hydrogels were used for rheological analysis. To know molecular interactions which predominated in the gel formation, some constituents were externally added to the 1.0% (w/w) hydrogel. Addition of urea to disrupt hydrogen bonds reduced 3.4-67% viscosity of the untreated hydrogels and changed viscoelastic properties from gel to liquid-like behavior. Neutral salts added to the hydrogel solution at 0.1 M also lowered the viscosity in a manner related with increase in size of cations and temperature. Changing from gel state to liquid-like state was also easily confirmed by oscillation measurement (storage, G', and loss, G", modulii) typically observed in the cases of potassium sulfate and potassium thiocyanate. Influence of pH variation on the viscosity explained that weak alkaline condition (pH 8-9) creates a higher resistance to flow due to increasingly electrostatic repulsions between negative charges ($COO^-$) Importance of calcium bridges was also demonstrated by recovery of viscosity of the hydrogels by addition of calcium after acidification. The summarized results indicate that electrostatic repulsion is a major contributor for production of hydrogel structure.

• Journal of Plant Biotechnology
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• v.34 no.3
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• pp.173-180
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• 2007

The full-length cDNA of LeAPR1 encoded a protein of 461 amino acid residues, which contained homology with phosphoadenosine phosphosulphate reductase (PAPS reductase) in N-terminal and an adenylylsulfate reductase in N-term and C-terminal. Analysis of the deduced amino acid sequence of LeAPR1 revealed that it shares high sequence identity with potato StAPR (96% identity)(Gene bank accession no. CDC44841). We found that multiple copies of LeAPR1 gene are present in the tomato genome through southern blot using genomic DNA was digested with 3 different restriction enzymes. The expression of LeAPR1 was also examined in various organs and its expression was also detected at high levels in roots and stems. Only high amounts of LeAPR1 transcripts were detected at high transcripts in the leaves at time 0, and then reduced as the plant stressed by the NaCl and abscisic acid (ABA). After 24h treatment of NaCl and ABA were showed increasing patterns of LeAPR1 gene. Time course of LeAPR1 gene expression was examined under oxidative stresses from metyl viologen (MV) and hydrogen peroxide ($H_2O_2$). In the presence of 10 mM $H_2O_2$ and $50\;{\mu}M$ MV, the levels of LeAPR1 transcript in leaves decreased after 1 h, and then increased strongly, peaked at 24 h. Our results indicated that LeAPR1 may play a role function of circadian regulation involved in abiotic stresses signaling pathways.