• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.372-377
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• 2007

In order to assess its capability as biofilter bed material under variable conditions of two parameters (inlet gas concentration and inlet gas flow rate), reticulated polyurethan was applied to remove hydrogen sulfide via a biological process. We detected a maximal elimination capacity (critical loading rate) of $488.3(330.1)g-H_2S/m^3{\cdot}hr$, when reticulated polyurethane was employed as supporting material of biofilter. This study show that the application of reticulated polyurethane carrier might be a favorable choice as a packing material in biofilter for the biological removal of hydrogen sulfide.

• Korean Journal of Veterinary Research
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• v.55 no.3
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• pp.191-197
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• 2015

Escherichia (E.) coli is commensal bacteria found in the intestine; however, some pathogenic strains cause diseases in animals and humans. Although E. coli does not typically produce hydrogen sulfide ($H_2S$), $H_2S$-producing strains of E. coli have been identified worldwide. The relationship between virulence and $H_2S$ production has not yet been determined. Therefore, characteristics of $H_2S$-producing isolates obtained from swine feces were evaluated including antibiotic resistance patterns, virulence gene expression, and genetic relatedness. Rates of antibiotic resistance of the $H_2S$-producing E. coli varied according to antibiotic. Only the EAST1 gene was detected as a virulence gene in five $H_2S$-producing E. coli strains. Genes conferring $H_2S$ production were not transmissible although the sseA gene encoding 3-mercaptopyruvate sulfurtransferase was detected in all $H_2S$-producing E. coli strains. Sequences of the sseA gene motif CGSVTA around Cys238 were also identical in all $H_2S$- producing E. coli strains. Diverse genetic relatedness among the isolates was observed by pulsed-field gel electrophoresis analysis. These results suggested that $H_2S$-producing E. coli strains were not derived from a specific clone and $H_2S$ production in E. coli is not associated with virulence genes.

• Journal of the Korean Applied Science and Technology
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• v.28 no.1
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• pp.57-63
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• 2011

Polymer electrolyte membrane fuel cell (PEMFC) performance degrades when hydrogen sulfide ($H_2S$) is present in the fuel hydrogen gas; this is referred to as $H_2S$ poisoning. This paper reveals $H_2S$ poisoning on PEMFC by measuring electrical performance of single cell FC under various operating conditions. The severity of $H_2S$ poisoning depended on $H_2S$ concentration under best operating conditions($65^{\circ}C$ of cell temperature and 100% of anode humidification). $H_2S$ adsorption occured on the surface of catalyst layer on MEA, but not on the gas diffusion layer(GDL) by analyzing SEM/EDX data. In addition, MEA poisoning by $H_2S$ was cumulative but reversible. After poisoning for less than 150 min, performance of PEMFC was recovered up to 80% by just inert nitrogen gas purging.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.820-825
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• 2007

Earthworm casting was the natural fertilizer that contained high concentrations of nutrients such as nitrogen, phosphate and potassium and of over $10^8$ CFU/ml of microorganisms. Greater than 80% of feed was excreted through the fermentation by the intestinal enzyme, after worm had eaten feeds such as fallen leaves and rotten roots under the ground. Also, the soil structure of casting was known to be very efficient in the aspects of the porosity, the water permeability, and deodorizing activities. In this research, the biofilter packed with a biomedia made of casting and waste polyurethane foam, a binder, which helped to improve the durability and perpetuity of casting, was investigated to degrade malodorous hydrogen sulfide gas. The biomedia had no need of extra supply of nutrients and of microbial inoculations. On the beginning of the operations, it showed 100% removal of hydrogen sulfide gas without lag phase. At SV of 50 $h^{-1}$, hydrogen sulfide gas from the outlet of the biofilter was not detected, when inlet concentration increased to 450 ppmv. After that, removal efficiency decreased as increasing inlet hydrogen sulfide concentration. Hydrogen sulfide removal was maintained at almost 93% until inlet concentration was increased up to 950 ppmv, at which the elimination capacity of $H_2S$ was 61.2 g $S{\cdot}m^{-3}{\cdot}h^{-1}$. Maximum elimination capacity guaranteing 90% removal was 61.2, 65.9, 84.7, 89.4 g $S{\cdot}m^{-3}{\cdot}h^{-1}$ at SV ranging from 50 $h^{-1}$ to 300 $h^{-1}$, but was 59.3 g $S{\cdot}m^{-3}{\cdot}h^{-1}$ at SV of 400 $h^{-1}$. The results calculated from Michaelis-Menten equation revealed that $V_m$ increased from 66.04, 88.96, 117.35, 224.15, to 227.54 g $S{\cdot}m^{-3}{\cdot}h^{-1}$ with increasing space velocity in the range of 50 $h^{-1}$ to 400 $h^{-1}$. However, saturation constant$(K_s)$ decreased from 79.97 ppmv to 64.95 and 65.37 ppmv, and then increased to 127.72 and 157.43 ppmv.

• Journal of Environmental Health Sciences
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• v.46 no.2
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• pp.170-183
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• 2020

Objectives: This study was conducted to estimate a technology to reduce hydrogen sulfide (H₂S) in sewage odor using microbial deodorant. Methods: After injecting five commercially available microbial deodorants into fresh sewage, the concentration of hydrogen sulfide over time was measured using the headspace method. H₂S concentration in odor samples was measured using gas chromatograph/FPD. Calculated odor concentration and calculated odor intensity by H₂S concentration remaining after treatment with microbial deodorant were evaluated theoretically. Results: The rate of H₂S abatement by microbial deodorant differed depending on the experimental conditions and the type of deodorant, but it was found to range from 63 to 82%. Especially, two deodorants showed high H₂S reduction rates of over 80% on average. However, based on the best deodorant, the theoretically calculated odor concentration by H₂S after microbial deodorant treatment was 4,400 OU_k, and the theoretical odor intensity was also rated at 4 degrees or higher. Conclusions: In conclusion, microbial deodorant is considered to have a relatively high effect on reducing H₂S in sewage odor. However, even after treatment with microbial deodorant, calculated odor concentration and calculated odor intensity were relatively high. This is thought to be caused by other odorous substances besides H₂S.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.171-176
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• 2016

Sour gas is natural gas or any other gas containing significant amounts of hydrogen sulfide ($H_2S$). Natural gas is usually considered sour gas if there are more than 5.7 milligrams of $H_2S$ per cubic meter of natural gas, which is equivalent to approximately 4 ppm by volume under standard temperature and pressure We have surveyed on the treatment and removal technology of sour gas, sour gas include a lot of hydrogen sulfide($H_2S$), Carbon dioxide($CO_2$), utane($C_4H_{10}$) and mercaptan($C_nH_{4n-1}SH$) etc. We need high technology for development for these kinds of raw gases and we should specially take care of treating and removal of theses raw gases. Therefor we are going to describe about these kinds of raw gases and about methods how to treat these kinds of gases.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.4
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• pp.379-386
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• 2011

Catalyst-assisted plasma system with a DBD (Dielectric Barrier Discharge) reactor was used to remove hydrogen sulfide, which is one of the odorous species in this study. The ${\gamma}-Al_2O_3$ and ${\beta}$-Zeolite catalysts impregnated by Ag, Cu and Mn species were employed as catalysts and their $H_2S$ removal characteristics under plasma irradiation were investigated. From the experimental study, we found that the $H_2S$ removal efficiency increases with decreasing space velocity in the system and increasing specific input energy. Furthermore, ${\beta}$-Zeolite catalysts are efficient to remove $H_2S$ than ${\gamma}-Al_2O_3$ catalysts. Especially, the catalysts impregnated by Ag have higher removal efficiency than other catalysts (Cu, Mn).

• KSBB Journal
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• v.16 no.3
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• pp.286-289
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• 2001

A beterotrophic Pseudomonas putida B2 was used to treat of hydrogen sulfide containing gas. The experimental approach involved operating two indentical bench-scale biofilters with media consisting of a mixture of peatmoss, perlite and granular activated carbon(GAC). One column was seeded with Pseudomonas putida B2 and the other was left unseeded. The biofilter was operated for 16 days under EBRT for 20-40 sec, at a temperature of 25-30$^{\circ}C$ and a hydrogen sulfide concentration of 40-190 ppm. The biofilter inocculated with P.putida B2 exhibited high hydrogen sulfide removal efficiency, average of 95%, at a gydrogen sulfide concentration of 40-190 ppm (flow rate 3.6 L/min). However, at a shock loading of 190 ppm the biofiter showed a removal efficiency of 78.9% and the control only showed a removal efficiency of 31.6%. The critical load of this biofilter was 14.83 g/㎥hr, and the critical load of the control column was 4.93 g/㎥hr. These results suggest that P. putida B2 has the potential to be used as a $H_2S$ removal agent in a biofilter.

• Analytical Science and Technology
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• v.7 no.3
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• pp.261-269
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• 1994

The iodide formed stoichiometrically for sulfide by its oxidation with iodate was extracted as an ion-pair with methylene green into 1,2-dichloroethane and the extract was measured spectrophotometrically at 656nm for the determination of sulfide. Hydrogen sulfide separated from the sample matrix was introduced into a solution containing pH 3.5 acetate buffer and iodate, in which the hydrogen sulfide was completely converted into iodide. A linear calibration graph was obtained over the range $3{\times}10^{-7}{\sim}1.2{\times}10^{-5}M$ sulfide($0.0096{\sim}0.384{\mu}g$ of $S^{2-}/ml$) and the detection limit was $0.0032{\mu}g/ml$. The apparent molar absorptivity and a correlation coefficient(r) were $6.7{\times}10^4L\;mole^{-1}\;cm^{-1}$ and 0.999, respectively. When applied to the stream water samples, the proposed method gave a relative standard deviation of 1.59% at $5{\times}10^{-6}M$ sulfide level.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.1
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• pp.1-8
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• 2023

Hypothyroidism alone can lead to myocardial fibrosis and result in heart failure, but traditional hormone replacement therapy does not improve the fibrotic situation. Hydrogen sulfide (H₂S), a new gas signaling molecule, possesses anti-inflammatory, antioxidant, and anti-fibrotic capabilities. Whether H₂S could improve hypothyroidism-induced myocardial fibrosis are not yet studied. In our study, H₂S could decrease collagen deposition in the myocardial tissue of rats caused by hypothyroidism. Furthermore, in hypothyroidism-induced rats, we found that H₂S could enhance cystathionine-gamma-lyase (CSE), not cystathionine β-synthase (CBS), protein expressions. Finally, we noticed that H₂S could elevate autophagy levels and inhibit the transforming growth factor-β1 (TGF-β1) signal transduction pathway. In conclusion, our experiments not only suggest that H₂S could alleviate hypothyroidism-induced myocardial fibrosis by activating autophagy and suppressing TGF-β1/SMAD family member 2 (Smad 2) signal transduction pathway, but also show that it can be used as a complementary treatment to conventional hormone therapy.