• 상하수도학회지
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• 제25권4호
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• pp.555-564
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• 2011

The photocatalytic degradation of trichloroethylene (TCE) in $TiO_2$ aqueous suspension has been studied. $TiO_2$ photocatalysts are prepared by a sol-gel method. The dominant anatase-structure on $TiO_2$ particles is observed after calcining the $TiO_2$ get at $500^{\circ}C$ for 1hr. The Langmuir-Hinshelwood model is applicable to describe the photodegradation, which indicates that adsorptionof the solute on the surface of $TiO_2$ particles plays an important role in photodegradation. Photocatalysts with various transition metals (Nd, Pd and Pt) loading are tested to evaluate the effect of transition metal impurities on photodegradation. The photodegradation efficiencies with $TiO_2$ including Pt, Pd and Nd are lower than pure $TiO_2$ powder. The effect of pH is investigated and the maximum photodegradation efficiency is obtained at pH 7. In addition, the intermediates such as dichloromethane, chloroform, and trichloroethane are detected during the photodegradation of TCE.

• KSBB Journal
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• 제16권5호
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• pp.511-515
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• 2001

TCE및 TCE 분해산물의 높은 독성으로 인하여 TCE 분해 효소 및 세포 불활성화가 일어나서 장기간 안정되게 반응기 운전이 어렵다는 단점을 극복하고, TCE와 성장기질사이의 경쟁적 저해관계로 인한 처리효율 감소도 막기 위하여 TCE분해단계와 세포 및 효소 재활성화 단계를 구분시킨 2단계 CSTR/TBF 시스템을 개발하였다. B. ceapcia G4를 분해 미생물로 사용하였으며, 탄소원인 phenol과 공기 및 배지가연속적으로 공급되는 CSTR에서 효소 및 세포 재활성를 도모하고, TBF에서는 폐가스에 포함된 기사의 TCE를 공기와 함께 공급하여 B. cepcia G4 미생물막에의한 TCE가 분해되도록 구성하였다. 2단계 CSTR/TBF 시스템은 유입 TCE 농도가 15pp $m_{v}$까지도 100% 수준의 처리 효율을 보여주었으며, 고농도의 TCE를 안정적으로 장기간 처리할 수 있었다.다.

• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.61-66
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• 1998

A microorganism which degrades phenol and co-metabolizes trichloroethylene (TCE) was isolated from Yangsan stream after enrichment in a medium containing phenol as the sole carbon source. The isolate EL-43P was identified as the genus Rhodococcus by its morphological, cultural and physiological characteristics. Phenol-induced cells of Rhodococcus sp. EL-43P degraded TCE. Toluene and nutrient broth could not replace the phenol requirement. The optimal conditions of initial pH and temperature of media for growth were 7.0~9.0 and $30~50^{\circ}C$, respectively. Rhodococcus sp. EL-43P could grow with phenol up to 1,000 ppm. Growth was inhibited by phenol at a concentration above 1,500 ppm. It was observed that Rhodococcus sp. EL-43P was able to degrade 90% of phenol (1,000 ppm) after 40 h in a culture. Phenol-induced cells of Rhodococcus sp. EL-43P degraded 95% of $5{\mu}M$ TCE in 6 h. Rhodococcus sp. EL-43P hardly degraded TCE above $100{\mu}M$.

• KSBB Journal
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• 제13권5호
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• pp.483-490
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• 1998

Two unidentified methanotrophic strains (MM-white and MM-red) secreting soluble methane monooxygenase (sMMO) involved in thrichloroethylene biodegradation have been isolated from mixed methanotrophic consortium (MM) around Taejon area. Subsequently four methanotrophic strains were isolated from MM and named according to their color; white (MS-white), yellow (MS-yellow), pink (MS-pink) and reddish brown (MS-rbrown). All strains except MS-yellow which can take glucose as well as methane, metabolized methane as a sole carbon source. They all showed symbiotic behavior when methane was used as the sole carbon source. Optimum conditions of cell growth for MM were pH of 6.8 - 7.2, temperature of 29 - 32$^{\circ}C$, and gas flow rate of 6 (for methane), 40 (for air), and 4 ml/min (for carbon dioxide). The sMMO activity was expressed as naphthalene oxidation rate (${\mu}$mol/ mg protein/ hr). The sMMO activity for MM grown in flask culture with 1 ${\mu}$M of CuSO4 was 36, while it was 61 without copper. The activity for MM grown in the fermentor without CuSO4 was 1077, but is was 197 after reaction with 5 ppm of TCE. The methanotrophs showed significantly high sMMO activity despite the presence of 1 ${\mu}$M of CuSO4, although most of other strains already known could not express sMMO activity under this condition.

• 상하수도학회지
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• 제29권1호
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• pp.39-46
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• 2015

The degradation characteristics of perchloroethylene by ferrate(VI) oxidation have been studied. The degradation efficiency of perchloroethylene in aqueous solution was investigated at various values of ferrate(VI) dosage, pH, initial concentration of perchloroethylene and aqueous solution temperature. GC-ECD has been used to analyze the changes of perchloroethylene concentration. The optimum conditions of perchloroethylene degradation were obtained at pH 7.0 and $25^{\circ}C$ of aqueous solution temperature. Also, the experimental results showed that perchloroethylene removal efficiency increased with the decrease of initial concentration of perchloroethylene. Lastly intermediate products were identified by GC-MS techniques. Trichloroethylene and chloroform were identified as reaction intermediates.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.512-515
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• 2000

A parallel reactor system which is consisted of two trickle bed reactors (TBR) was developed for the biodegradation of trichloroethylene (TCE) in waste gas stream. The reactor were packed with porous ceramic materials and Burkholderia cepacia G4 was inoculated to form biofilms. Each reactor was operated alternatively in TCE degradation or reactivation mode, and the effect of switching time on TBR performance was investigated. The MO (monooxygenase) activity during the TCE transformation decreased below 10 % within 24 hr, but could be recovered to the initial high level within 10 hr after supplying the reactivation medium supplemented with phenol as a carbon source. This shows that the parallel TBR system has a great potential for the long-term stable treatment of TCE.

• 대한환경공학회지
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• 제22권5호
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• pp.971-980
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• 2000

가용성 메탄산화효소를 분비하는 혼합 메탄자화균총을 celite R-635에 고정화시켜 TCE 분해를 위한 새로운 형식의 가압 산기식 혼합 메탄자화균총 고정층 생물막 반응기를 설계하였다. Celite R-635에서 용출되는 용액의 pH는 약 4시간 후부터 안정화되어서 중성 영역에 도달하므로 더 이상 중화할 필요가 없었다. 혼합 메탄자화균 생물막을 완전히 형성하기 위해서는 130일이 걸렸으며, 처음에 흰색을 띠고 있었던 celite는 점차 붉게 변해 갔었다. 생물막이 형성된 후에는 메탄과 산소를 각각 2.5~4, 8~10 ppm씩 공급할 때 하루 동안 체류한 후 0.5~1, 1~2 ppm 정도로 농도가 낮아졌다. 초기에 2 ppm의 TCE를 메탄자화균 고정층 생물막 반응기에서 10시간 동안 체류시켰을 때 79.9%의 분해 효율을 보였다.

• 생명과학회지
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• 제13권6호
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• pp.970-975
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• 2003

생촉매 및 생물막 반응기를 이용한 TCE 생분해는 TCE를 무해한 최종산물로 처리할 수 있는 환경친화적 방법이며, 초기 시설비와 운영비도 낮아 경제성도 우수한 기술로 평가할 수 있다. 그러나, TCE 및 독성 분해산물로 인하여 생촉매 불활성화가 일어나서 장기간 안정된 반응기 운전이 어렵고, TCE와 성장기질사이의 경쟁적 저해로 인하여 처리효율이 저하된다는 단점이 있다. 이러한 문제점을 극복하기 위하여 TCE 처리 단계와 생촉매 재활성화 단계를 구분시킨 2단계 CSTR/TBF 시스템에 대하여 TCE 연속처리용 시스템으로써의 실규모 적용 가능성을 평가해 보았다. B. cepacia 및 M. trichosporium을 생촉매로 사용한 2단계 CSTR/TBF 시스템은 고농도 유입 TCE와 다양한 운전조건에서도 28∼525mg TCE/1$.$day수준의 높은 TCE 처리효율을 안정되게 유지할 수 있어 산업폐가스 처리를 위한 실규모 처리 시스템으로 적용 가능성이 높다고 평가할 수 있었다.

• 대한환경공학회지
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• 제22권6호
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• pp.991-1000
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• 2000

메탄올 주요 탄소원으로 사용하며 가용성 메탄산화효소 (soluble methane monooxygenase, sMMO)를 분비하는 혼합 메탄차화균을 celite R-635에 고정화시켜 TCE를 함유한 폐수를 연속적으로 처리하였다. 2 ppm의 TCE를 공급했을 때 각각 6. 20시간의 체류시간에서 약 80.4, 84.5%의 처리 효율을 얻었으며, 체류시간이 증가함에 따라서 제거율도 서서히 증가하였다. 5 ppm의 TCE를 공급하고 10시간 동안 체류시켰을 때, '초기에는 TCE의 제거능이 낮았으나 점차 81%까지 증가하였다. 또한 산소를 공급하면서 메탄을 주기적으로 공급할 때 5 ppm의 TCE가 체류시간 10. 15시간에서 각각 88.5, 96.5%까지 제거되었다. 반응기 내에 산소가 고갈된 상태에서 메탈을 고농도로 공급하면 MMO에 흡착된 메탄의 산화반응이 쉽게 진행되지 않아 TCE 분해능이 떨어졌다. 파일롯트 플랜트 규모의 생물막 반응기에서의 TCE 분해 실험 결과, 실제 크기 규모의 공장에도 충분히 적용 가능할 것으로 사료되었다.

• Journal of Korean Society for Atmospheric Environment
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• 제17권E2호
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• pp.35-42
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• 2001

Recent development of photocatalytic degradation method that is mediated by TiO$_2$ is of interest in the treatment of volatile organic compounds(VOCs). In this study, trichloroethylene(TCE) and acetone were closely examined in a batch scale of photo-reactor as a function of water vapor, oxygen, and temperature. Water vapor inhibited the photocatalytic degradation of acetone, while there was an optimum concentration in TCE. A lower efficiency was found in nitrogen atmosphere than air, and the effect of oxygen on photocatalytic degradation of acetone was greater than on that of TCE. The optimum reaction temperature on photocatalytic degradation was about 45$^{\circ}C$ for both compounds. NO organic byproducts were detected for both compounds under the present experimental conditions. It was ascertained that the photocatalytic reaction in a batch scale of photo-reactor was very effective in removing VOCs such as TCE and acetone in the gaseous phase.