• Journal of the Korean Applied Science and Technology
• /
• v.30 no.1
• /
• pp.146-151
• /
• 2013

This paper reveals the performance decrease and recovery of PEMFC when the contaminated fuel gas and air source with sulfur impurities such as hydrogen sulfide and sulfur dioxide were simultaneously introduced to anode and cathode, respectively. Three different GDLs were fabricated with different carbon black and activated carbon to prevent an introduction of sulfur compound impurities into MEA. components. The severity of $SO_2$ and $H_2S$ poisoning was depended on concentrations(3 ppm - 10 ppm) of sulfur impurities. Especially, cell performance degradation rate was rapid when MEA fabricated with CN-2 GDL because it had little porosity on GDL surface. Moreover, the cell performance can be recovered up to 90%-95% only with neat hydrogen and fresh air feeding.. Conclusively, MEA fabricated with porous CN-1 GDL showed the best cell performance and recovery efficiency during exposure to poisoning condition by simultaneous sulfur impurities.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.11a
• /
• pp.310-311
• /
• 2002

악취는 인간이 직접 후각으로 느끼는 환경오염의 지표로서 극히 낮은 농도에서도 피해를 유발하여 대기질 전반에 대한 불신을 초래하게 된다. 악취의 주요 발생원으로는 정유공장, 화학공장, 하수처리장, 분뇨 및 축산폐수처리장, 쓰레기 매립지 등으로 발생원이 매우 다양하고 여러 가지 복합된 화합물이 원인이 되어 악취를 유발시키는 것이 특징이다. 우리나라의 주거여건은 주변환경을 충분히 고려하지 못한 개발로 공업지역과 주거지역이 근접 또는 혼재하여 악취오염에 근본적으로 취약한 구조의 도시가 형성된 곳도 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 1999.10a
• /
• pp.338-345
• /
• 1999

동북아시아 지역은 최근의 급속한 경제성장으로 오염물질의 배출량도 급격한 증가추세에 있다. 중국의 배출량이 동북아지역 배출량의 대부분을 차지하고 있으며, 산출자료에 따라 다르기는 하지만, 그 중 아황산가스는 80％이상을 중국이 배출하고 있는 것으로 나타나고 있다(김용표, 1999). 강수나 에어로졸 생성에 중요한 역할을 하는 주도적인 물질인 황화합물은 대류권 하부에 주로 2일에서 1주일정도 체류하면서 보통 수백에서 수천 km까지 이동이 가능하다.(중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.04a
• /
• pp.89-90
• /
• 2000

건식 침적은 강수가 없는 경우에 대기중의 오염물질이 식생, 토양, 수면 등의 지표면으로 직접 이동되는 과정을 일컫는 것으로서, 다음 식 (1)과 같이 대기중 오염물질의 농도와 건식 침적속도의 곱으로서 건식 침적속을 구할 수 있다. F=$V_d$.C 이때, F는 건식 침적속 (g/$\textrm{m}^2$/sec), $V_d$는 건식 침적속도 (m/sec), C는 대기중의 오염물질 농도 (g/$\textrm{m}^3$)이다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2001.11a
• /
• pp.43-44
• /
• 2001

산업의 발달과 함께 화석연료의 소비가 증가하면서 산성강하물(Acid precipitation)에 대한 관심이 증가하여 왔다. 산성강하물은 주로 화석연료의 연소를 통해 대기로 배출된 질소와 황 산화물들로, 산화ㆍ환원, 산ㆍ염기 중화반응 등 다양한 변환과정을 거쳐 비나 눈과 같은 습성과정이나 가스나 입자상 물질과 같은 건성과정을 통해 다시 토양과 호수 등에 침적되어 이들을 산성화시키는 원인이 된다. 따라서 산성강하물에 대한 이해를 위해서는 강수의 화학조성과 아울러 가스와 입자상으로 존재하는 질소와 황화합물에 대한 관측이 필수적이다. (중략)

• 한국가스학회:학술대회논문집
• /
• 2003.05a
• /
• pp.91-98
• /
• 2003

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2001.05a
• /
• pp.222-223
• /
• 2001

Arylsulfatase (EC 3.1.6.1)는 arylsulfate의 황산 ester 결합을 비가역적으로 가수분해하는 효소이다. 이러한 효소는 토양에서 처음 발견된 이래 동식물 및 미생물에서 검출되어졌으며, 주로 토양 중 황화합물의 recycle에 관여하여 토양 환경에 영향을 미치는 요인으로 보고되었다 (Spei. and Ross, 1978). Arylsulfatase에 대한 연구는 주로 토양으로부터 분리된 세균에 국한된 실정이다. (중략)

• Microbiology and Biotechnology Letters
• /
• v.45 no.3
• /
• pp.257-264
• /
• 2017

Mixed substrate oil cakes are known to emit sulfides, ammonia, and amines. Microorganisms capable of removing odorous gases related to these sulfur compounds were isolated from colonies enriched in vials containing oil cakes and water. Activity tests for hydrogen sulfide and methyl mercaptan reduction were performed to measure the sulfide reduction ratio of the isolates. Control groups were prepared with 0.25 g oil cakes and 10 ml water in a 100-ml vial without inoculation. The experimental groups were prepared similarly, albeit with an inoculum. Hydrogen sulfide removal efficiency of >90% was observed for an isolate, which was identified as Brevundimonas diminuta by 16S rDNA sequence analysis. The sequence was deposited in the Korean Collection for Type Cultures under the accession number KCTC11724BP. B. diminuta could remove up to 200 ppmv standard hydrogen sulfide in 24 hours and demonstrated a maximum hydrogen sulfide and methyl mercaptan removal efficiency of 100% at 453 ppmv and 98 ppmv, respectively, in vial tests. Furthermore, B. diminuta cells in 20% (v/w) medium showed removal efficiency of >85% for sulfur compounds in an odor emission chamber for swine manure.

• Korean Journal of Food Science and Technology
• /
• v.32 no.3
• /
• pp.544-549
• /
• 2000

This study was performed to compare optimum analytical method for the contents of naturally occurring sulfur dioxide in foods and to investigate the contents of sulfur dioxide in foods in order to provide a fundamental data when distinguish between added and naturally occurring sulfur dioxide. The determination of the contents of sulfur dioxide in foods from the 20 kinds, 180 cases of samples has been analyzed by the optimized Monier-Williams method, modified Rankine method and Acid Distillation/Ion Chromatography. As a result of the study, the contents of naturally occurring sulfur dioxide in foods by the optimized Monier-Williams method showed from 1.02 to 43.87 ppm and highly content of 43.87, 15.37, 11.50, 11.21 and 10.60ppm were observed in garlic, platicodon, green onion, cabbage and onion, the others were less than 10.00ppm. The sulfur dioxide contents in green onion and garlic by modified Rankine method were showed to be 2.87 and 6.14ppm, respectively, the others were detected less than 2.50ppm. The contents of sulfur dioxide by Acid Distillation/Ion Chromatography showed 15.43, 9.82, 5.74, 5.37, 2.14 and 0.49ppm in garlic, cabbage, green onion, onion, potato and apple, respectively and the others were not detected. And the contents of sulfur dioxide in green onion, onion, cabbage and garlic showed higher levels of sulfur dioxide in these foods than the others because of the naturally occurring sulfur containing compounds. The optimized Monier-Williams method, which is the of official analytical method of Korean Food Code, was suitable for monitoring of sulfur dioxide of most foods. Acid Distillation/Ion Chromatography was thought to be adequate for sulfur containing foods such as green onion, onion and cabbage. In order to distinguish between added and naturally occurring sulfur dioxide, it is though to be need of the fundamental data for the contents of sulfur dioxide in sulfite-free foods and continue the investigation for it.

• Journal of Animal Science and Technology
• /
• v.50 no.3
• /
• pp.391-400
• /
• 2008

Odor management is significantly concerned with sustainable livestock production because odor nuisance is a primary cause for complaint to neighbors. This study was conducted to measure the concentration of odorous compounds, odor intensity, and odor offensiveness at unit process in animal waste treatment facility combined composting and methane fermentation process by an instrumental analysis and direct olfactory method. Ammonia, sulfur-containing compounds, and volatile fatty acid were analyzed at each process units and boundary area in summer and winter, respectively. Higher concentration of odorants occurred in the summer than in the winter due to high ambient temperature. The maximum concentration of odorants was detected in composting pile when mixed manure was being turned followed by inlet, curing, outlet, and screen & packing process. Highest concentration of detected odorous compounds was ammonia ranging from 3.4 to 224.7 ppm. Among the sulfur-containing compounds measured, hydrogen sulfide was a maximum level of 2.3 ppm and most of them exceeded reported odor detection thresholds. Acetic acid was the largest proportion of VFA generated, reaching a maximum of 51 to 89%, followed by propionic and butyric acid at 1.9 to 35% and 1.8 to 15%, respectively. Malodor assessment by a human panel appeared a similar tendency in instrumental analysis data. Odor quotient for predicting major odor-causing compounds was calculated by dividing concentrations measured in process units by odor detection thresholds. In the composting process, hydrogen sulfide, ammonia, dimethyl sulfide, and methyl mercaptan were deeply associated with odor-causing compounds, while the major malodor compounds in the inlet process were methyl mercaptan, hydrogen sulfide, and butyric acid.