Methyl tert-Butyl Ether(MTBE)의 in-situ Remediation을 위한 Modified Fenton Process에 관한 연구

정영욱,서승원,김민경,이종열,공성호,Chung, Young-Wook,Seo, Seung-Won,Kim, Min-Kyoung,Lee, Jong-Yeol,Kong, Sung-Ho 한국지하수토양환경학회 2007 지하수토양환경 Vol.12 No.2

기존의 연구를 통해 Fenton's reagent(FR)를 이용하여 MTBE의 제거가 가능하며, 그러나 중성 pH영역에서는 철이온이 수산화물로 침전되어 반응성이 낮아지므로 FR만을 이용한 처리는 높은 수소이온 농도조건(pH $3{\sim}4$)이라는 제약으로 인해 직접적인 토양 및 지하수의 MTBE 오염처리에 있어 여러 가지 어려움이 있다. 이에 본 연구에서는 효과적인 처리를 위하여 NTA, oxalate, acetate 등의 chelating agent가 철이온과 반응하여 생성된 착화합물을 이용하는 modified Fenton reaction을 도입하여 중성 pH영역에서도 철이온이 안정화되어 높은 분해효율을 나타낼 수 있도록 하였다. MTBE의 분해경향은 chelating agent의 종류와 농도, 철이온 농도 그리고 pH 변화에 따라 크게 영향을 받는 것으로 나타났다. 가장 적합한 착화합물을 선택하기 위하여 총 6개의 chelating agent(citrate, oxalate, succinate, acetate, NTA, EDTA)를 실험한 결과, 처리효율과 chelating agent의 생분해도, 독성 등을 고려하여 최종 3가지 종(oxalate, acetate, NTA)이 선정되어 이후의 실험에서는 위의 3종만을 chelating agent로 이용하였다. 동일한 실험조건($H_2O_2$ : 5%, chelating agent : 6 mM, $Fe^{3+}$ : 2 mM, pH 7)하에서의 적용성 평가한 결과, Fe-NTA가 반응시작 30분만에 99.9%의 가장 높은 제거효율을 나타내었다. Oxalate의 경우, NTA보다는 그 분해효율이 낮으나 다른 chelating agent보다 상대적으로 높은 효율(24시간 후 최대효율 : 91.3%)을 보여주며, acetate를 이용한 경우도 본 실험에서 좋은 결과(24시간 후 최대효율 : 75.8%)를 나타내었다. 또한, 적정 철이온의 농도는 oxalate가 chelating agent로 이용되면 철이온 농도가 3 mM일때 가장 큰 분해효율을 보이며, acetate의 경우는 5 mM까지 농도가 증가함에 따라 그 효율도 조금씩 증가하는 것으로 나타났다. 이와같이 MTBE의 in-situ remediation을 위한 modified Fenton 공정은 철이온을 중성 pH영역에서 안정화시켜 실제 토양에 적용하였을 때, 높은 분해효율을 얻을 수 있으며, 경제적인 자체 생분해도가 높은 저분자 유기산을 이용하였으므로 생물학적 처리와 연계를 가능하게 해주는 장점을 나타낸다. 또한 토양 내 존재하는 철광석을 촉매로 이용할 경우, 주입되는 철이온 없이도 $H_2O_2$에서의 hydroxyl radical 생성을 증가 시킬 수 있으므로 보다 경제적이고 친환경적인 처리기법을 도출해 낼 수 있다. A recent study showed that MTBE can be degraded by Fenton's Reagent (FR). The treatment of MTBE with FR, however, has a definite limitation of extremely low pH requirement (optimum pH $3{\sim}4$) that makes the process impracticable under neutral pH condition on which the ferrous ion precipitate forming salt with hydroxyl anion, which result in the diminishment of the Fenton reaction and incompatible with biological treatment. Consequently, this process using only FR is not suitable for in-situ remediation of MTBE. In order to overcome this limitation, modified Fenton process using NTA, oxalate, and acetate as chelating reagents was introduced into this study. Modified Fenton reaction, available at near neutral pH, has been researched for the purpose of obtaining high performance of oxidation efficiency with stabilized ferrous or ferric ion by chelating agent. In the MTBE degradation experiment with modified Fenton reaction, it was observed that this reaction was influenced by some factors such as concentrations of ferric ion, hydrogen peroxide, and each chelating agent and pH. Six potential chelators including oxalate, succinate, acetate, citrate, NTA, and EDTA were tested to identify an appropriate chelator. Among them, oxalate, acetate, and NTA were selected based on their remediation efficiency and biodegradability of each chelator. Using NTA, the best result was obtained, showing more than 99.9% of MTBE degradation after 30 min at pH 7; the initial concentration of hydrogen peroxide, NTA, and ferric ion were 1470 mM, 6 mM, and 2 mM, respectively. Under the same experimental condition, the removal of MTBE using oxalate and acetate were 91.3% and 75.8%, respectively. Optimum concentration of iron ion were 3 mM using oxalate which showed the greatest removal efficiency. In case of acetate, $[MTBE]_0$ decreased gradually when concentration of iron ion increased above 5 mM. In this research, it was showed that modified Fenton reaction is proper for in-situ remediation of MTBE with great efficiency and the application of chelatimg agents, such as NTA, was able to make the ferric ion stable even at near neutral pH. In consequence, the outcomes of this study clearly showed that the modified Fenton process successfully coped with the limitation of the low pH requirement. Furthermore, the introduction of low molecular weight organic acids makes the process more available since these compounds have distinguishable biodegradability and it may be able to use natural iron mineral as catalyst for in situ remediation, so as to produce hydroxyl radical without the additional injection of ferric ion.

APID공정 내 공정진단을 위한 dynamic $\bar{x}$-R 관리도의 적용

안상우,곽성근,정영욱,정무근,박재우,An, Sang-Woo,Kwak, Sung-Keun,Jung, Young-Wook,Chung, Mu-Keun,Park, Jae-Woo 한국물환경학회 2009 한국물환경학회지 Vol.25 No.5

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to evaluate and monitor the effluent water quality ($BOD_5$, SS, T-N, and T-P) and operating conditions (Influent, SVI, SRT, and HRT) as process capable and stable parameters for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 7.7, 5.6, 10.8, and 1.6 mg/L. Trend analysis of influent $BOD_5$, SS, T-N, and T-P in APID process were illustrated that APID process need for more strong APID process management on the winter session, such as developing new intermediated aeration mode, operating methods, and managements strategy. At the application of control chart, the signal of uncommon effects at APID process was determined much higher existing control chart tntr conventional control chart in this study. These results indicate that conventional control chart has been collected and determined cleary signal at only stable situation. Therefore, newly developed APID process of dynamic control chart can be one of the useful tool for monitoring and management process.

PAFS를 이용한 SBO 사고완화 해석연구

이동영(Dong-Young Lee),박영재(YoungJae Park),전성수(Seong-Su Jeon),정영욱(Young Wook Chung),황도현(Do Hyun Hwang) 한국유체기계학회 2023 한국유체기계학회 학술대회 논문집 Vol.2023 No.7

피동보조급수계통을 이용한 SBLOCA-LOHPI 사고완화에 대한 계통코드 해석연구

전성수(Seong-su Jeon),박영재(Youngjae Park),이동영(Dong-young Lee),정영욱(Young Wook Chung),황도현(Do Hyun Hwang) 한국유체기계학회 2023 한국유체기계학회 학술대회 논문집 Vol.2023 No.7

APID공정 내 공정진단을 위한 dynamic x(-)-R 관리도의 적용

안상우 ( Sang Woo An ),곽성근 ( Sung Keun Kwak ),정영욱 ( Young Wook Jung ),정무근 ( Mu Keun Chung ),박재우 ( Jae Woo Park ) 한국물환경학회 2009 한국물환경학회지 Vol.25 No.5

흰쥐 시상에서 Epidermal growth factor receptor면역반응 신경세포의 생후 발달에 관한 연구

박영란,정윤영,김종중,문정석,오재욱,정영욱,김주수 조선대학교 2003 The Medical Journal of Chosun University Vol.28 No.1

Background and Objectives : Epidermal growth factor receptor (EGFR), a 170-kDa transmembrane glycoprotein, appears to mediate epidermal growth factor (EGF) activity. Transforming growth factor-α and EGF produce their biological effects in numerous systems by stimulating the EGFR In this study, we examine the postnatal development of EGFR immunoreactivity in the different regions of the thalamus of the rat Materials and Methods : The present study is based on 28 postnatal cases of rat thalamus ranging from the day of birth, postnatal day 0 (P0) to 30 days (P3, P5, P10, P15, P20, P30), and these cases were compared with adult rat thalamus. Cryostat sections were processed free-floating with monoclonal antibody by immunohistochemistry Results : EGFR immunoreactivity in the thalamus of the rat showed very different patterns according to postnatal ages and thalamic areas. EGFR-immunoreactive cells appeared in the first two postnatal weeks, except the ventral posterior thalamic nuclei. In the early postnatal days, EGFR-immunoreactive cells appeared thalamic midline structures, increased progressively in the first two postnatal weeks, and followed mediolateral gradient. The mature patterns of EGFR-immunoreactive cells were achieved at P20 Conclusion : These data indicate that the maturation of EGFR-immunoreactive cells requires a relatively prolonged period of time to achieve an adult configuration. Many growth factors probably play protective or neurotrophic roles at EGFR-immunoreactive neurons of thalamus both young and adult rats In addition to difference in time of appearance in thalamic nuclei and developing pattern with mediolateral gradient suggest that EGFR-immunoreactivities are correlated with the appearance of the related functional.

척수를 손상시킨 후 꼬리정맥에 주입한 사람탯줄혈액세포가 뇌줄기에 미치는 영향

김종중,정윤영,박영란,문영민,현영식,정영욱,문정석 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.1

Background and Objectives: Stem cells are a valuable resource for treatment of many disease, but limited access to stem cells in some organs such as brain restricts their utility. Many approaches have been attempted to restore the function following brain stem injury (BSI) and spinal cord injury (SCI). The use of the human umbilical cord blood cells (hUCB) - a rich source of nonembryonic or adult stem cells - has recently been reported to ameliorate the behavioral consequences of stroke. Mateiials and Methods: Forty rats were divided into 8 groups: (1) SCI l+hUCB (infused 1 day post injury); (2) SCI 2+hUCB (infused 2 days post injury); (3) SCI 3+hUCB (infused 3 days post injury); (4) SCI 4+hUCB (infused 4 days post injury); (5) SCI 5+hUCB (mfusedt 5 days post injury); (6) SCI 6+hUCB (infused 6 days post injury); (7) LO+hUCB (laminectomy+hUCB); and (8) LO (laminectomy only). SCI was produced by compressing the spinal cord for one minute with an aneurysm clip calibrated to a closing pressure of 50 g. We report here that immunhistotochemical identification of fluorescent hUCB positive cells in the brain stem after compressed spinal cord injury using mouse anti-human mitochondria monoclonal antibody (MAB1273). Results: All SCI+hUCB (1-8) groups contained fluorescent hUCB positive cells in the all area of the brain stem. But especially a large number of fluorescent hUCB positive cells were observed in the whole area of the brain stem of the experimental 5 (SCI 5+hUCB) and 6 (SCI 6+hUCB)groups. No hUCB positive cells were found in the brain stem of group with non-injured spinal cord of these animals and group with laminectomy only. Conclusion: These results suggest that hUCB are potentially useful as a vector for treating a variety of the central nervous system disorders, and we are sure that continuous of stem cell study will give an best opportunity to treat the uncurable disorders in the future.