• KSBB Journal
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• 제29권2호
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• pp.118-123
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• 2014

It was confirmed that malodor connected with an air-conditioner in an automobile is caused by microbial volatile organic compounds (MVOCs) produced by microorganisms getting into an air-conditioner when it is operating. Chemicals such as hydrogen sulfide, dimethyl sulfide, nbutyric acid, n-valeric acid, iso-valeric acid, n-octanol and toluene were detected above the odor threshold inside the automobile. The characteristics of a funky odor in the air blown into the automobile were due to detected sulfur compounds (hydrogen sulfide and dimethyl sulfide). Dimethyl sulfide was produced by microorganisms such as Aspergillus versicolor, Methylobacterium aquaticum, Herbaspirillum sp. and Acidovorax sp. In addition, the characteristics of a sour odor in the air blown into the automobile were due to detected organic acids (n-butyric acid, n-valeric acid and iso-valeric acid). N-valeric acid and iso-valeric acid were generated from Aspergillus versicolor, while iso-valeric acid was produced by Methylobacterium aquaticum. In addition, the odor intensity of the air blown into the automobile was affected by the concentration of detected sulfur compounds and organic acids. On the other hand, it is estimated that chemicals such as hydrogen sulfide, n-octanol and n-butyric acid detected in the air blown into the automobile were produced by non-identified species of microorganisms.

• 분석과학
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• 제7권3호
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• pp.261-269
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• 1994

요오드산 이온의 황이온의 산화에 의해 화학양론적으로 형성되는 요오드이온과 methylene green과의 이온쌍을 1,2-dichloroethane으로 추출하여 656nm에서 분광광도법에 의해 황이온의 정량법을 확립하였다. 시료기질로부터 분리되어지는 황화수소는 pH 3.5 초산 완충용액과 요오드산 이온이 포함된 용액에 도입되어 완전히 전환되었다. 황이온의 정량범위는 $3{\times}10^{-7}{\sim}1.2{\times}10^{-5}M$ ($0.0096{\sim}0.384{\mu}g/ml$) 였으며, 검출한계는 $0.0032{\mu}g/ml$였고, 몰흡광계수는 $6.7{\times}10^4L\;mole^{-1}\;cm^{-1}$였다. 본 정량법을 하천수 중에 응용하였을 때 $5{\times}10^{-6}M$ 농도에서 상대표준편차는 1.59%로 미량에서 공존이온의 영향을 거의 받지 않고 재현성 있는 결과를 나타내므로 실시료 중에 효과적으로 응용할 수 있으리라 생각된다.

• Corrosion Science and Technology
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• 제18권3호
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• pp.102-109
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• 2019

The hydrogen diffusion and trapping model with a numerical finite difference method (FDM) was modified and extended to accommodate $H_2S$ corrosion and scale forming processes of high-strength steel under tensile stress condition. The newly proposed diffusion model makes it possible to clearly understand combined effect of tensile stress and $H_2S$ corrosion process on hydrogen diffusion behaviors. The core concept of this theoretical approach is that overall diffusion behavior is separated into diffusion process through two respective layers: an outer sulfide scale and an inner steel matrix. Diffusion coefficient values determined by curve-fitting permeation data reported previously with the newly proposed diffusion model indicate that the application of tensile stress can contribute to continual increase in the diffusivity in the sulfide scale with a high density of defect. This suggests that the scale with a lower stability under the stress condition can be a key parameter to enhance hydrogen influx in the steel matrix. Consequently, resistance to hydrogen assisted cracking of the steel under tensile stress can be decreased significantly.

• 청정기술
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• 제23권1호
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• pp.113-117
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• 2017

본 연구에서는 섬유활성탄에 탄산나트륨을 첨착제로 이용하여 탄산나트륨 첨착섬유활성탄을 제조하고 동일조건에서 제조한 탄산나트륨 첨착입상활성탄과 황화수소 제거 성능을 비교한 후 그 활용가능성을 검토하고자 하였다. 첨착용액의 농도와 첨착시간을 변수로 하여 탄산나트륨 첨착섬유활성탄과 탄산나트륨 첨착입상활성탄의 흡착능을 구하였는데 먼저 두 경우 모두 첨착용액의 농도에 비례하여 탄산나트륨의 첨착되는 양도 증가하나 3 wt%이상에서는 기공충전(pore filling) 현상으로 첨착양에 변화가 없었다. 따라서 황화수소 제거를 위한 탄산나트륨 첨착섬유활성탄과 탄산나트륨 첨착입상활성탄의 제조시 최적의 탄산나트륨 용액 농도는 3 wt%인 것으로 판단되었다. 또한 탄산나트륨 첨착섬유활성탄의 경우 탄산나트륨 첨착을 위한 담지시간이 탄산나트륨 첨착입상활성탄에 비하여 2배 가까이 빠른 것으로 나타났다. 황화수소 제거효율은 탄산나트륨 첨착섬유활성탄이 탄산나트륨 첨착입상활성탄에 비하여 30% 이상 증가하였고 이는 비표면적의 측정결과로 설명되었다. 결과적으로 향상된 비표면적을 가진 섬유활성탄에 황화수소와 화학적으로 반응하는 탄산나트륨을 첨착하여 제조상 시간적 이점과 향상된 황화수소 흡착능을 확인할 수 있었다.

• 유기물자원화
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• 제16권4호
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• pp.43-49
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• 2008

본 연구의 목적은 석유화학에너지를 대체하기 위해 바이오가스 생산을 위한 돈분 및 음식물쓰레기 혼용 혐기소화 시 황화수소가스 농도 및 발생비율을 모니터링 한 것이었다. 바이오가스 생산을 위한 혼합혐기 소화는 휘발성 고형물 2%기준 다양한 돈분 및 음식물쓰레기 혼합비율하에서 시럼병을 이용하여 수행하였다. 황화수소가스 발생비율은 처리별 소화기간에 따라 다양하다 할지라도, 수급원료를 돈분만을 이용한 경우는 음식물 쓰레기와 비교할 때 황화수소 발생량은 2.4배 낮게 나타난 것으로 관측되었다. 돈분과 음식물쓰레기 혼합비율에 따른 황화수소가스 농도에 미치는 영향에 대해서는 음식물쓰레기 혼합비율이 높으면 높을수록 황화수소 농도가 높게 나타났다. 황화수소가스 평균 농도는 돈분처리, 0.1452% 에서부터 음식물쓰레기 처리, 0.3420% 까지 다양 하였다. 돈분 및 음식물쓰레기 혼용 혐기발효 시 바이오가스 조성비율은 메탄가스가 53.2%, 이산화탄소 23.9%, 황화수소 0.3% 및 수분을 포함한 기타 22.7%로 이루어져 있는 것으로 나타났다.

• 환경위생공학
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• 제24권4호
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• pp.80-89
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• 2009

In the organic waste, food waste is the most difficult controls. In the study, food waste was treatmented to removal only the dockage. To decrease the hydrogen sulfide($H_2S$) in the produced biogas, iron chloride put in the anaerobic digester. Respectively treatment quantity of the food waste, content of the methane($CH_4S$) gas in the biogas, produced gases quantity, put in the quantity of the Iron chloride, pH, TS, Alkalinity, VFA, Ammonia. The results obtained from the experiment are as follows: 1. The produced biogases quantity/the treatment quantity of the food waste was $83.82{\sim}129.41m^3/ton$. 2. The content of the hydrogen sulfide($H_2S$) in the produced biogas is below of the 500ppm. The iron chloride put in the anaerobic digester. 200~300kg of the iron chloride put in the anaerobic digester at the steady-state. 400~850kg of the iron chloride put in the anaerobic digester at the unsteady-state. 3. Factor of the operator was the pH: 7.7~8.4, content of mathane: 55~65%. 4. TS(total solid) of the digestor sludge was 17~20%, Alkalinity was 38,500~41,750ppm, VFA(Volatile Fatty Acids) was 2,800~2,420ppm, Ammonia was 4,300~3,650ppm.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.20-25
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• 2008

Sulfide stress corrosion cracking (SSCC) of materials exposed to oilfield environment containing hydrogen sulfide ($H_2S$) has been recognized as a materials failure problem. Laboratory data and field experience have demonstrated that extremely low concentration of $H_2S$ may be sufficient to lead to SSC failure of susceptible materials. In some cases, $H_2S$ can act synergistically with chlorides to produce corrosion and cracking failures. SSC is a form of hydrogen embrittlement that occurs in high strength steels and in localized hard zones in weldment of susceptible materials. In the heat-affected zones adjacent to welds, there are often very narrow hard zones combined with regions of high residual stress that may become embrittled to such an extent by dissolved atomic hydrogen. On the base of understanding on sulfide stress cracking and its mechanism, SSC resistance for the several materials, those are ASTM A106 Gr B using in the oil industries, are evaluated.

• 한국환경과학회지
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• 제16권6호
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• pp.763-769
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• 2007

This study compared the performance of a bioscrubber, a biofilter, and a combined system of bioscrubber and biofilter employed being operated at the laboratory-scale. for the removal of hydrogen sulfide. The bioscrubber maintained 100% removal of hydrogen sulfide up to inlet load of $56\;g-S/m^3{\cdot}hr$, while the removal efficiency was decreased with the increase of inlet load. The biofilter showed 100% removal efficiency up to inlet load of $126\;g-S/m^3{\cdot}h$ and the maximum elimination capacity of $126\;g\;S/m^3{\cdot}h$ for the inlet load of $224\;g-S/m^3{\cdot}h$. On the other hand, the combined system of bioscrubber and biofilter showed 100% removal for an inlet hydrogen sulfide load of up to $85\;g-S/m^3{\cdot}h$ and the maximum elimination capacity of $153\;g-S/m^3{\cdot}h$ for inlet loads of $224\;g-S/m^3{\cdot}h$.

• 한국습지학회지
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• 제23권1호
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• pp.54-59
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• 2021

폐수처리장에서 발생하는 바이오가스 중의 황화수소를 처리하기 위하여 습식스크러빙 장치가 적용되었다. 유입 H2S의 농도가 5,000mg/L이상에서 DIWS 장치에 물만을 사용할 경우 25%의 제거율을 나타내어 후속으로 소각처리 공정이 도입되어야만 98% 이상의 제거율을 나타냈다. 유입 H2S의 농도가 5,000mg/L일 때 CH4과 CO2는 각각 8.7%와 28.6% 감소하여 배출되었다. DIWS 장치에 중화약품으로 Na2CO3와 NaOH를 사용하였을 때 pH가 11.2~11.5를 유지하면서 H2S는 97.2% 제거되었다.

• 한국치위생학회지
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• 제11권2호
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• pp.263-275
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• 2011

Objectives : This study was performed analysis of Halitosis components following by subjective cognition of halitosis and Oral State in order to provide basic data for halitosis prevention and establish a device to efficiently eliminate halitosis and analyze the factors that affect the halitosis. Methods : 80 adults were participated who visited at the Dental Clinic in Kyoung-gi do, on the period of the March to September in 2010. The obtained results, through the oral examination, halitosis check and interview, Individually, were as followings. Results : According to the ammonia level was a high relationship between sex, CPI, Tongue plaque, DMFT index which were statistically significant (p<0.05). Total oral gas level was a relationship between VAS, tongue plaque, DMFT index(p<0.05). The Correlation coefficient between the Hydrogen sulfide level and Methyl mercaptan was estimated as r=0.534(p<0.01). As for the multiple regression analysis result, there have been selected dimethyl sulfide and Tongue plaque, Gingival index as factors affecting Bridge, Methyl mercaptan level is as factors affecting Hydrogen sulfide level. Conclusions : There was relationship between the periodontal disease and Ammonia gas component, hydrogen sulfide, dimethyl sulfide, methyl mercaptan. Which were statistically significant total oral gas level and oral variables. Such dental caries as the prevention or early treatment of periodontal disease.