• KEPCO Journal on Electric Power and Energy
• /
• v.4 no.1
• /
• pp.39-45
• /
• 2018

Ammonia Adsorbed Fly Ash (AAFA) samples produced from coal fired plants equipped with SNCR (Selective Non-Catalytic Reduction) of nitrogen oxides with urea have been chemically analyzed, and their physical and dissolution properties have been investigated. XRD results for the ammonia component in AAFA ascertained that ABS (ammonium bisulfate) and AS (ammonium sulfate) were deposited on fly ash as $SO_3$ reacted with unreacted ammonia at SNCR. SEM and EDS images showed that fine ashes on large fly ash surface of sphere type were agglomerated, due to adhesive role of ammonium salts attached fly ashes. Dissolution test results of ammonium salts absorbed on AAFA in distilled water or sea water showed that the proportion of un-ionized $NH_3$ to $NH_4{^+}$ were primarily a function of pH and temperature. Increasing pH and temperature causes an increase in the fraction of un-ionized $NH_3$. At pHs of 9.6 and 10.7, un-ionized $NH_3$ and $NH_4{^+}$ ions are present in equal amounts at distilled water and sea water, respectively.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.6
• /
• pp.843-853
• /
• 2009

The sediment samples were collected from Seonakdong River and were analyzed for sulfide species such Acid Volatile Sulfide(AVS) and Elemental Sulfur(ES) and Chromium Reducible Sulfide(CRS). Then characteristics of the formation of sulfide species were investigated for six selected samples. Finally the relationship between environmental factors and sulfate reducing rate(SRR) was investigated using two selected samples. Concentrations of AVS and CRS were relatively high, which suggests that organics input to the sediments has been continued until recently and that potential of heavy metals leaching from the sediments is low. SRR in the sediments was closely related to fraction of fine particles(silt+clay) and also to dissolved organic carbon content of the sediment(DOCsed). The dependences of environmental factors such as organic content, temperature, sulfate concentration on the SRR was relatively strong in the selected experiments conducted with the samples from Noksan gate and Daejeo gate samples. The environmental factor dependencies were stronger in the Noksan gate samples than in the Daejeo gate samples, which is probably due to higher surface area of the Noksan gate sediments.

• Natural Product Sciences
• /
• v.15 no.4
• /
• pp.185-191
• /
• 2009

Intestinal epithelial cells (IEC) play an important role in the mucosal immune system. IEC-derived mediators of inflammatory cascades play a principal role in the development of colon inflammation. The aim of this study was to investigate the inhibitory effect of aqueous extracts of Schizandra chinensis fruits (SC-Ex) on the production of inflammatory mediators by the human colonic epithelial cells. HT-29 cells were stimulated with dextran sulfate sodium in the presence or absence of SC-Ex to examine the cytoprotection and production of IL-8 and reactive oxygen species (ROS). It was shown that dextran sulfate sodium (DSS) caused the reduction of cell viability and production of IL-8 and ROS in DSS-treated HT-29 cells. We observed that the treatment of SC-Ex protected significantly cell proliferation from DSS-induced damage in dose-dependent manner. SC-Ex (10 and 100 ${\mu}g$/ml) also suppressed DSS-induced production of IL-8 mRNA and protein. Moreover, DSS-induced ROS production was inhibited markedly by the treatment of 100 ${\mu}g$/ml SC-Ex. These results suggest that SC-Ex has the protective effects on DSS-induced cell damage and the release of inflammatory mediators in the intestinal epithelial cells.

• Corrosion Science and Technology
• /
• v.3 no.5
• /
• pp.187-193
• /
• 2004

We have investigated the differences between the general corrosion and microbiologically influenced corrosion (MIC) of steels in terms of electrochemical behavior and surface phenomena. Corrosion potential of steels in the absence of SRB (sulfate-reducing bacteria) shifted to a low level and was maintained throughout the experimental period (40 days). The potential in the presence of SRB, however, shifted to a noble level after 20 days' incubation, indicating the growth of SRB biofilms on the test metal specimens and a formation of corrosion products. In addition, the color of medium inoculated with SRB changed from gray to black. The color change appeared to be caused by the formation of pyrites (FeS) as a corrosion product while no significant color change was observed in the medium without SRB inoculation. Moreover, corrosion rates of various steels tested for MIC were higher than those in the absence of SRB. This is probably because SRB were associated with the increasing corrosion rates through increasing cathodic reactions which caused reduction of sulfate to sulfide as well as formation of an oxygen concentration cell. The pitting corrosions were also observed in the SRB-inoculated medium.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.2
• /
• pp.313-321
• /
• 2000

This research is to remove heavy metals from AMD(Acid Mine Drainage) using AFMR(Anaerobic Floating Media Reactor) process. Two AFMR were operated at HRT(hydraulic retention time) of 3 days. COD/sulfate ratio from 0.3 to 0.8, temperature from $30^{\circ}C$ to $35^{\circ}C$, and alkalinity of 1.000mg/l(as $CaCO_3$). At COD/sulfate($SO{_4}^{2-}$) ratio of 0.5 and temperature of $35^{\circ}C$, the ratio of reduced sulfate($SO{_4}^{2-}$)/removed COD(mg/mg) kept about 1 and the reactor achieved 99.99% of Cr, Pb anee Fe, 98% of Cd, and 90% of Mn removal efficiencies, respectively. Decreasing temperature to $30^{\circ}C$ increased the ratio of reduced sulfate($SO{_4}^{2-}$)/removed COD(mg/mg) to 1.37. Amount of sulfate reduction maximized at the temperature of $30^{\circ}C$ and the COD/sulfate ratio of 0.4 in the influent and then removal efficiencies of heavy metals were 99.99% of Fe, 99.99% of Pb, 99,99% of Cr, 97.3% of Mn, 99.9% of Zn, 99.9% of Cd and 99.9% of Cu.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.2
• /
• pp.151-157
• /
• 2005

A one-dimensional numerical model was developed to simulate vertical profiles of electron acceptors and their reduced species in benthic sediments. The model accounted for microbial degradation of organic matter and subsequent chemical reactions of interest using stoichiometric relationships. Depending on the dominant electron acceptors utilized by microorganisms, the benthic sediments were assumed to be vertically subdivided into six zones: (1) aerobic respiration, (2) denitrification, (3) manganese reduction, (4) iron reduction, (5) sulfate reduction, and (6) methanogenesis. The utilizations of electron acceptors in the biologically mediated oxidation of organic matter were represented by Monod-type expression. The mass balance equations formulated for the reactive transport of organic matter, electron acceptors, and their corresponding reduced species in the sediments were solved utilizing an iterative multistep numerical method. The ability of model to simulate a freshwater sediments system was tested by comparing simulation results against published data obtained from lake sediments. The simulation results reasonably agreed with field measurements for most species, except for ammonia. This result showed that the C/N ratio (106/16) in the sediments is lower than what the Redfield formula prescribes. Since accurate estimates of vertical profiles of electron acceptors and their reduced species are important to determine the mobility and bioavailability of trace metals in the sediments, the model has potential application to assess the stability of selected trace metals in the sediments.

• The Korea Journal of Herbology
• /
• v.29 no.4
• /
• pp.45-52
• /
• 2014

Objectives : The purpose of this study was to evaluate the efficacy of HT008 on pain relief and functional improvement in participants with mild knee osteoarthritis (OA) in comparison with that of glucosamine sulfate. Methods : This randomized double-blind trial was conducted at Kyung Hee University Medical Center in Seoul where participants with knee pain for more than 6 months and degenerative osteoarthritis were enrolled. The 100 participants were received either HT008 or glucosamine sulfate 750 mg twice daily for 8 weeks and evaluated at baseline, 4 and 8 weeks after the treatment. We primarily evaluated the differences between two groups with respect to changes in the visual analogue score (VAS) for pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score from baseline to week 8. Secondarily the difference between and within two groups with respect to changes in WOMAC stiffness and physical function score, and Lequesne Functional Severity Index (LFI) were also evaluated. Results : At week 8, treatment with HT008 resulted in a significant reduction of the VAS for pain and WOMAC pain scores compared to the glucosamine sulfate (both p=0.003). Patients receiving HT008 experienced statistically significantly greater improvements in WOMAC physical function scores and LFI (p = 0.014 and p=0.016, respectively) than glucosamine sulfate-treated group. The within-group change in WOMAC physical function and stiffness, and LFI during the 8-week intervention revealed significant improvements in HT008-treated group. Conclusions : HT008 treatment allows significant pain reduction and functional improvement compared with glucosamine sulfate. These data confirm HT008 as an effective and safe symptomatic drug for knee OA.

• Journal of Powder Materials
• /
• v.4 no.2
• /
• pp.106-112
• /
• 1997

$Cu-Al_20_3 $ composite powders were prepared by hydrogen reduction of $Cu^{2+}$ from ammoniacal copper sulfate solution on alumina core using autoclave. The copper reduction rate and the properties of copper layer were investigated using Scanning Electron Microscope(SEM), X-ray diffractometer, size and chemical analyzers. The reduction rate of $Cu^{2+}$ showed the maximum value when the molar ratio of [$NH_3$]/[$Cu^{2+}$] was 2. In order to prevent the agglomeration of Cu powder and ethane reduction rate, $Fe^{2+}$ and anthraquinone which act as catalysis were added in the solution. Catalysis was effectively chanced with the addition of two elemerts at a time. Optimum conditions obtained in this study were hydrogen reduction temperature of 205$^{\cire}C$, stirring speed of 500 rpm and hydrogen partial pressure of 300 psi. Obtained $Cu-Al_20_3 $ composite Powders were found to have the uniform and continuous copper coating layer of nodule shape with 3~5 $\mu$m thickness.

• Journal of Powder Materials
• /
• v.22 no.4
• /
• pp.260-265
• /
• 2015

Spherical fine cobalt powders were fabricated by new liquid reduction method. Commercial cobalt sufate heptahydrate was used as raw material. Also ethylene glycol was used as solvent and hydrazine-sodium hypophosphite mixture was used as reduction agent for the new liquid reduction method. A plate shaped cobalt powders with an approximately 300 nm were prepared by a traditional wet ruduction method using distilled water as solvent and hydrazine. Spherical fine cobalt powders with an average size of $1-3{\mu}m$ were synthesized by a new liquid reduction method in 0.3M cobalt sulfate and 1.5M hydrazine-0.6M sodium hypophosphite mixture at 333K.

• Journal of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.186-194
• /
• 1988

The electrochemical reduction of O,O-dimethyl-O-(3-methyl-4-nitrophenyl)-phosphorothioate (Fenitrothion) has been studied in acetonitrile solution containing surfactant micelle by direct current (DC)-differential pulse (DP) polarography, cyclic voltammetry (CV) and controlled potential coulometry (CPC). The partially reversible electron transfer-chemical reaction(EC, EC mechanism) of fenitrothion reduction proceeded by four electron transfer to form O,O-dimethyl-O-(3-methyl-4-hydroxyaminophenyl)-phosphorothioate which undergoes single bond of the phosphorus atom and phenoxy group cleaves to give p-amino-m-cresol and dimethyl thiophosphinic acid as major product by two electron transfer-protonation at higher negative potential. The polarograpic reduction waves shown to suppressed due to inhibitory effect of sodium lauryl sulfate micelle solution and split up on selectivity of anionic micelle effect in two step at the first reduction peak.