• Proceedings of the KAIS Fall Conference
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• 2000.10a
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• pp.55-60
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• 2000

The adsorption isotherms can be assigned to typical Type I for Ag and Cu-treated ACFs and Type I and Type II for Ni-treated ACFs. From the DSC analysis, A $g_{0.9}$-ACF occurs only exothermic curve at the temperature of $203^{\circ}C$, and relatively stable composition curves were formed. But C $u_{0.3}$-ACF and C $u_{0.4}$-ACF occur endothermic curves at the temperature of 57.26, 107.02 and $215.87^{\circ}C$. N $i_{1.0}$-ACF occurs large endothermic curves at 59.26, 98.40 and $208.89^{\circ}C$ and N $i_{0.8}$-ACF are shown endothermic curves at 59.26 and $157.77^{\circ}C$. From the biological results, the percentages of the antibacterial effects were 96.5-100 for Ag-ACFs, 92.3-99.8 for Cu-ACFs and 95.5-100 for Ni-ACFs, respectivelylyvelylyly

• Environmental Engineering Research
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• v.25 no.4
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• pp.488-497
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• 2020

The present study investigates the feasibility of nitrogenous heterocyclic compounds (NHCs) (Pyridine-Quinoline) degradation by catalytic wet peroxidation (CWPO) in the presence of nanoscale zerovalent iron supported on granular activated carbon (nFe⁰/GAC) using statistical optimization technique. Response surface methodology (RSM) in combination with Box-Behnken design (BBD) was used to optimize the process parameters of CWPO process such as initial pH, catalyst dose, hydrogen peroxide dose, initial concentration of pyridine (Py) and quinolone (Qn) were chosen as the main variables, and total organic carbon (TOC) removal and total Fe leaching were selected as the investigated response. The optimization of process parameters by desirability function showed the ~85% of TOC removal with process condition of initial solution pH 3.5, catalyst dose of 0.55 g/L, hydrogen peroxide concentration of 0.34 mmol, initial concentration of Py 200 mg/L and initial concentration of Qn 200 mg/L. Further, for TOC removal the analysis of variance results of the RSM revealed that all parameter i.e. initial pH, catalyst dose, hydrogen peroxide dose, initial concentration of Py and initial concentration of Qn were highly significant according to the p values (p < 0.05). The quadratic model was found to be the best fit for experimental data. The present study revealed that BBD was reliable and effective for the determination of the optimum conditions for CWPO of NHCs (Py-Qn).

• Korean Journal of Materials Research
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• v.31 no.5
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• pp.264-271
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• 2021

Porous carbons have been widely used as electrode material for supercapacitors. However, commercial porous carbons, such as activated carbons, have low electrochemical performance. Nitrogen-doping is one of the most promising strategies to improve electrochemical performance of porous carbons. In this study, nitrogen self-doped porous carbon (NPC) is prepared from melamine foam by carbonization to improve the supercapacitive performance. The prepared NPC is characterized in terms of the chemical structures and elements, morphology, pore structures, and electrochemical performance. The results of the N₂ physisorption measurement, X-ray diffraction, and Raman analyses reveal that the prepared NPC has bimodal pore structures and pseudo-graphite structures with nitrogen functionality. The NPC-based electrode exhibits a gravimetric capacitance of 153 F g^-1 at 1 A g^-1, a rate capability of 73.2 % at 10 A g^-1, and an outstanding cycling ability of 97.85 % after 10,000 cycles at 10 A g^-1. Thus, the NPC prepared in this study can be applied as electrode material for high-performance supercapacitors.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.2
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• pp.1-9
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• 2016

This study aims to assess the effectiveness of activated carbon (AC) and crushed concrete (CC) as capping material to block the release of nitrogen, phosphorus, and organic substance from reservoir sediments. The efficiency of AC and CC as capping material was evaluated in a reactor in which a 1 or 3 cm thick layer of capping materials was placed on the sediments collected from Mansu reservoir in Anseong-city. Dissolved oxygen (DO) concentration, total nitrogen (T-N), total phosphorus (T-P), and chemical oxygen demand (COD) concentration in reservoir water above the uncapped sediments and capping material were monitored for 45 days. The release rate of T-N was in the following increasing order: AC 3 cm ($1.18mg/m^2{\cdot}d$) < CC 1 cm ($2.66mg/m^2{\cdot}d$) < AC 1 cm ($2.94mg/m^2{\cdot}d$) < CC 3 cm ($3.42mg/m^2{\cdot}d$) < uncapped ($4.59mg/m^2{\cdot}d$). The release rate of T-P was in the following increasing order: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($0.03mg/m^2{\cdot}d$) < AC 1 cm capped ($0.07mg/m^2{\cdot}d$) < uncapped ($0.24mg/m^2{\cdot}d$). The release of nitrogen and phosphorus were effectively blocked by AC capping of 3 cm thickness, and CC capping of 3 cm thickness effectively controlled the release of phosphorus. The order of increasing COD release rate was as follows: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($5.03mg/m^2{\cdot}d$) < AC 1 cm ($7.28mg/m^2{\cdot}d$) < uncapped ($10.05mg/m^2{\cdot}d$), indicating that AC and CC capping effectively interrupted the release of organic contaminants from the sediments. It was concluded that AC and CC could effectively block the release of T-N, T-P and COD release from contaminated reservoir sediments.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1052-1057
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• 2005

Recently, the ozone treatment of wasting activated sludge has become one of the effective and feasible process for the sludge reduction. The objective of this study is to investigate the availability of ozonized wasting sludge on external carbon sources 13r phosphorus release. Experiment results showed that the ozone treatment of activated sludge could produce a large amount of VFA such as acetic acid and isobutyric acid. For example, 50.24 mg/L acetic acid was produced with the ozone dose of 0.05 g $O_3/g$ SS, and 123.56 mg/L acetic acid with 0.5 g $O_3/g$ SS. The higher ozone dose was applied, the more VFA was produced from sludge reduction into a limited point. Finally, using ozonated sludge as only carbon source, the batch experiment, to measure phosphorus release rate in anaerobic condition were performed. The specific phosphorus release rates were investigated as 0.94, 1.37, 1.48, 1.68 mg P/g VSS/hr with ozone dose of 0.05, 0.1, 0.2, 0.5 g $O_3/g$ SS, respectively. Considering the degree of mineralization, VFA production, phosphorus release rate, and economical aspect, the optimal ozone dose for sludge reduction and using carbon sources ranged from 0.05 to 0.1 g $O_3/g$ SS.

• KSBB Journal
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• v.18 no.3
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• pp.211-216
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• 2003

The removal yield of dissolved organic matter in drinking water by biological activated carbon (BAC) process was investigated. The tested processes wer raw water-AC process (BAC1), raw water-ozonation-BAC process (BAC2), and raw water-ozonation-coagulation/sedimentation-BAC process (BAC3). The amounts of organic matter was measured as dissolved organic carbon (DOC), ulta-violet radiation at 254 nm wavelength ($UV_{254}$), total nitrogen (T-N), ammonia nitrogen (NH_3$-N), and total phosphate (T-P). As a results, 30.7% DOC was removed by BAC2 process, which showed higher removal efficiency than BAC1 or BAC3 processes. The removal yield of $UV_{254}$ in BAC1, BAC2, and BAC3 processes were observed as 45.3%, 44.6%, 58.4%, respectively. And the removal yield of ammonia nitrogen were 66%, 81%, 29% in each BAC processes. The optimal empty bed contact time (EBCT) of BAC processes was estimated as 10 minute. This study has shown that BAC process combined with ozone treatment was efficient for removing dissolved organic matter in water.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.1
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• pp.25-36
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• 2022

To identify the effect and mechanism of carbon monoxide (CO) on delayed rectifier K⁺ currents (I_K) of human cardiac fibroblasts (HCFs), we used the wholecell mode patch-clamp technique. Application of CO delivered by carbon monoxidereleasing molecule-3 (CORM3) increased the amplitude of outward K⁺ currents, and diphenyl phosphine oxide-1 (a specific I_K blocker) inhibited the currents. CORM3-induced augmentation was blocked by pretreatment with nitric oxide synthase blockers (L-NG-monomethyl arginine citrate and L-NG-nitro arginine methyl ester). Pretreatment with KT5823 (a protein kinas G blocker), 1H-[1,-2,-4] oxadiazolo-[4,-3-a] quinoxalin-1-on (ODQ, a soluble guanylate cyclase blocker), KT5720 (a protein kinase A blocker), and SQ22536 (an adenylate cyclase blocker) blocked the CORM3 stimulating effect on I_K. In addition, pretreatment with SB239063 (a p38 mitogen-activated protein kinase [MAPK] blocker) and PD98059 (a p44/42 MAPK blocker) also blocked the CORM3's effect on the currents. When testing the involvement of S-nitrosylation, pretreatment of N-ethylmaleimide (a thiol-alkylating reagent) blocked CO-induced I_K activation and DL-dithiothreitol (a reducing agent) reversed this effect. Pretreatment with 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)-21H,23H porphyrin manganese (III) pentachloride and manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (superoxide dismutase mimetics), diphenyleneiodonium chloride (an NADPH oxidase blocker), or allopurinol (a xanthine oxidase blocker) also inhibited CO-induced I_K activation. These results suggest that CO enhances I_K in HCFs through the nitric oxide, phosphorylation by protein kinase G, protein kinase A, and MAPK, S-nitrosylation and reduction/oxidation (redox) signaling pathways.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.569-575
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• 2002

Two bacterial strains capable of degrading trichloroethylene (TCE), isolated form soils contaminated with various chlorinated alkenes, were identified as Alcaligenes odorous N6 and Nocardia sp. Hl7. In addition, four KCTC strains, including three strains of Pseudomonas putida and one strain of Sphingomonas chlorophenolica, exhibited an ability to degrade toluene. A. odorans N6 and Nocardia sp. H17 degraded 84% of the initial amount of TCE in a basal salts medium (BSM), containing 0.2 mM TCE as the sole source of carbon and energy, in a day. The optimal pH for growth was within a range of 7.0-8.0. A mixed culture of the four toluene-degrading isolates degraded 95% of 0.2 mM TCE with 1.5 mM toluene as an inducer, whereas no TCE was degraded by the same mixture without an inducer. When a mixed culture of all 6 isolates was used, the degradation efficiency of 0.2 mM TCE was 72% without an inducer, in a day, and 82% with toluene as an inducer. In a continuous treatment, 1,000 mg/1 of TCE in an artificial wastewater was completely removed within 18 h when an activated sludge was used along with the microbial mixture, which was 27 h laster than when only an activated sludge was used. Accordingly, it would appear that such a microbial mixture could be effectively applied to the biological treatment of wastewater containing TCE with or without an inducer.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.357-365
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• 1993

This study was conducted for the efficient utilization of biomaterials such as starch residue, tangerine skin, and green tea residue, which are agricultral by-products discarded in Cheju Province annually, as adsorbents and biomaterials were examined for their removal ability of heavy metal ions in waste water by batch adsorption experiments. The removal efficiency of biomaterials for heavy metal ions was above 80-90% and almost similar to activated carbon and the adsorption ability of those treated with 포르말린 was improved in the green tea residue only for $Pb^{2+}$, $Cu^{2+}$, and $Zn^{2+}$. In the conditions of pH, the removal efficiency of heavy metal ions was high in the range of 5-7. In the solutions which heavy metal ions were mixed, the removal efficiency was similar at $Ag^+$, $Pb^{+2}$ and reduced to about 10% at the other ions, as compared with the solutions they were not mixed. Adsorption isotherm of biomaterials was generally obeyed to Freundlich formular than Langmuir formular and Freundlich constant, 1/n were obtained in the range of 0.1-0.5.

• Journal of Applied Biological Chemistry
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• v.51 no.1
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• pp.17-19
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• 2008

Isoflavanone has been synthesized from the reduction of isoflavone in nearly quantitative yield. Isoflavone with seven equivalents of ammonium formate in the presence of Pd/C in ethanol under $N_2$ atmosphere exclusively produced the two-electron reduced product in two hours. It was characterized by various spectroscopic methods, including UV-VIS, EI-MS, $^1H$-NMR, $^{13}C$-NMR and $^1H$, $^1H$-COSY. The racemic mixture was separated by Sumi-Chiral column chromatography and the absolute configurations of the enantiomers were characterized by circular dichroism spectroscopy.