촉매를 이용한 이산화탄소 고정화 및 고리형 카보네이트 합성반응에 대한 계산화학적 해석

안혜영(Hye Young An),김민경(Min-Kyung Kim),정희철(Hui Cheol Jeong),엄기헌(Ki Heon Eom),원용선(Yong Sun Won) 한국청정기술학회 2016 청정기술 Vol.22 No.1

본 연구에서는 이론화학 또는 분자모델링이라 불리는 계산화학을 기존에 연구된 촉매반응 실험결과를 해석하는 데 접목시켜 보았다. 온실효과의 주범인 이산화탄소를 에폭사이드와 반응을 통해 고정화하고 카보네이트를 생성하는 반응을 선택하였는데 이 반응은 활성화 에너지(55~59 kcal/mol)가 높아 촉매의 사용이 불가피하다. 많은 기존 연구들 중에 ZIF-90/ionic liquid immobilized ZIF-90 (IL-ZIF-90), polystyrene-supported quaternized ammonium salt, KI/KI-glycine, dimethylethanolamine (DMEA)를 촉매로 사용한 경우에 대해 반응의 각 단계를 계산하여 반응의 경로를 예측하고 단계별로 구한 에너지를 바탕으로 에너지도를 구성함으로써 실험결과를 열역학적으로 해석하였다. ZIF-90/IL-ZIF-90과 KI/KI-glycine의 경우는 실험적으로 후자들이 상대적으로 높은 수율을 얻었는데 계산 결과 활성화에너지가 낮아진 이유가 아니라 전자들의 경우 반응 중간체가 높은 에너지를 가져 반응물로 되돌아가는 역반응에 의해 정반응의 진행이 방해를 받은 것으로 밝혀졌다. DMEA를 촉매로 사용하였을 경우는 활성화 에너지를 ~42 kcal/mol로 낮춰줌으로써 금속이나 할로겐염 없이도 촉매의 활성이 잘 일어남을 증명하였다. 폴리스티렌(polystyrene)으로 지지된 quaternized 암모늄염 촉매의 경우 클러스터 가정을 사용하여 계산을 진행하였으며 암모늄염의 -NH기와 에폭사이드의 O 원자 사이의 상호작용의 가능성을 확인할 수 있는 반응경로를 제시하였다. In this study, a computational chemistry methodology called as molecular modeling was been applied to explain several experiment results mechanistically. The reaction chosen for this study was to remove carbon dioxide, known as a primary greenhouse gas, by an epoxide via the carbon dioxide fixation to produce carbonates. This reaction inherently needs the use of catalysts because it has a significantly high activation barrier (55~59 kcal/mol). Among various types of catalysts, we studied in zeolitic imidazolate framework 90 (ZIF-90)/ionic liquid immobilized ZIF-90 (IL-ZIF-90), polystyrene-supported quaternized ammonium salt, KI/KI-glycine, and dimethylethanolamine (DMEA). First, probable reaction pathways were proposed based on calculated energetics by computational chemistry. The energetics was then used for the thermodynamic interpretation on the activity of catalysts. In the case of ZIF-90/IL-ZIF-90 and KI/KI-glycine, IL-ZIF-90 and KI-glycine showed better yields compared to their counterparts. The calculation proposed interesting results that it is not from the lowering of activation energy but from the unstable intermediates of ZIF-90 and KI-glycine. For DMEA, the calculated activation energy was ~42 kcal/mol, much lower than that of the non-catalytic reaction. A possible reaction pathway was located to confirm the interaction between -NH group from ammonium and oxygen from epoxide for polystyrene-supported quaternized ammonium salt.

동진강 유역내 하천의 특성별 영향평가

윤순강,김원일,김진호,김선종,고문환,엄기철 한국환경농학회 2002 한국환경농학회지 Vol.21 No.4

본 연구는 동진강 유역의 수질 보전을 위한 기초자료를 얻기 위하여 동진강 본류와 이에 유입되는 정읍천을 대상으로 2001년 5월부터 11월까지 수질 모니터링을 실시하였다. 동진강 본류의 수질은 BOD기준으로 상수원 Ⅱ~Ⅳ등급(2.84~6.45 ㎎/L)으로 지점별로는 DJ6(정읍천 합류후)이 4.07㎎/L로 높게 나타나 Ⅲ급수의 수질을 유지하였다. COD는 지점별로 11.20~32.96 ㎎/L의 범위로 정읍천 합류후의 농도가 32.96 ㎎/L로 가장 높게 나타나 정읍천을 통한 본류의 오염물질량의 증가를 알 수 있었다. T-N의 경우 4.16~5.84 ㎎/L의 범위로 유역 전반에 걸쳐 오염이 이루어지고 있는 것으로 나타났고, T-P의 경우 BOD, COD와 마찬가지로 정읍천 합류후가 0.19 ㎎/L로 타 지점에 비하여 놀게 조사되었다. 본류의 COD의 경우 장마후 갈수기에 높은 농도를 나타냈고, T-P의 경우는 하천의 유량이 증가하는 홍수기보다 장마전 갈수기의 오염정도가 높고 이후 장마후 갈수기로 갈수록 수질이 악화되는 것으로 조사되었다. 동진강 수질의 오염은 주로 하류로 갈수록 그 정도가 심하게 나타나는데, 이것은 정읍천을 통해 유입되는 도시 생활하수와 인근 공장단지의 산업폐수가 그 주 요인으로 오염물질(BOD, COD T-N 및 T-P)의 농도가 상승하는 주원인이 되고 있다. 따라서, 동진강 수계의 수질관리를 위해 주 오염원이 되고 있는 정읍천의 도시생활하수와 공장단지에서 방류되는 산업폐수의 제어에 대한 대책이 먼저 이루어져야 할 것으로 판단된다. Irrigation water quality along Donjin river watershed was monitored to find a possible pollutants, for maintaining water quality to achieve food safety through water quality preservation of river. As a pollution indicators, such as Biological Oxygen Demand(BOD), Chemical Oxygen Demand(COD), Total Nitrogen(T-N), and Total Phosphate(T-P) in Dongjin river were examined from May to November in 2001. The results were as follows : The BOD level of Dongji n river ranged from 2.84 to 6.45 mg/L, which would be in a Ⅱ~Ⅳ grade of the potable water criteria by Ministry of Environment. Averaged BOD level of downstream DJ6(After Jeongupcheon confluence) was 4.07 mg/L. The average COD level of Dongjin river ranged from 11.20 to 32.96 mg/L. COD level of DJ6 rapidly increased rapidly after the junction of Dongjin river and Jungupcheon because it showed the latter had relatively high pollution level. T-N content were significantly high in all sites of Dongjin river ranged through 4.16 to 5.84 mg/L. T-P examined high concentration than another thing point by 0.19 mg/L after Jeongupcheon confluence as BOD and COD. COD of main stream was expressed high concentration to dry season after rainy season. In case of T-P, pollution degree of dry season before rainy season appeared and examined that quality of water was worsened go by dry season after rainy season. The water quality of Dongjin river was deteriorated with inflow of Jungupcheon polluted by municipal and industrial sites near Jungup city.

만경강 유역내 하천의 특성별 영향 평가

윤순강,이종식,정구복,김민경,김선종,고문환,엄기철 한국환경농학회 2002 한국환경농학회지 Vol.21 No.4

본 연구는 만경강 유역의 수질 보전을 위한 기초자료를 얻기 위하여 만경강 본류와 이에 유입되는 지천을 선정하여 2001년 5월부터 11월까지 매월 수질 모니터링을 실시하였다. 만경강 유역내 본류 및 지천의 유기물과 영양염류 함량을 조사한 결과, 본류의 T-N은 3.78~12.68 ㎎/L였으며, 지천중 축산폐수가 유입되는 익산천의 농도가 가장 높았다. 본류의 T-P의 BOD는 각각 0.043~0.864 ㎎/L와 2.59~13.29 ㎎/L였으며, 지천중 익산천이 가장 높았다. 본류의 COD는 12.9~119.5 mg/L였으며, 지천중 도시생활하수가 유입되는 추천이 가장 높았다. 만경강 유역 수질저하의 주 원인은 축산폐수였으며, 도시생활하수가 그 다음으로 중요한 원인으로 평가되었다. 만경강 본류의 T-N과 T-P는 하천의 유량이 증가하는 홍수기인 7~8월보다 장마선 갈수기인 5~6월에 높았고, COD는 장마전 갈수기보다 홍수기에 높았으며 장마가 완전히 끝난 영농후 갈수기인 9~11월에도 수질저하가 지속되었다. 만경강에 유입되는 지천중 전반적으로 수질오염이 심각한 익산천과 추천은 영농후 갈수기에 수질이 가장 저하되었고 상대적으로 홍수기에는 양호하였다. A survey on four tributaries along with Mankyeong River was carried out to get the information for the water quality improvement and control. Typical paddy farming were major agricultural practices in Kosancheon and Soyangcheon. Iksancheon was livestock raising watershed. Chucheon was urban watershed. Water quality in six sites of main stream and four sites of tributaries in Mankyeong River were investigated from May to August in 2001. The concentration of nutrients in main stream of Mankyeong River were in the range of 3.78~12.68 mg/L for total nitrogen, 0.043~0.864 mg/L for total phosphorus, 2.59~13.29 mg/L for BOD and 12.9~119.5 mg/L for COD, respectively. Water quality of Mankyeong River mostly exceeded the standard water quality criteria of Korea. Major causes of water pollution were evaluated as sewage of swine and urban area. Among the four tributaries, water quality in agricultural practices, Kosancheon and Soyangcheon was relatively less polluted. While, the highest level of water pollution measured in Iksancheon was due to livestock The water quality of Iksancheon and Chucheon was generally more polluted in the dry period than in rainy period.

시비방법별 벼 재배에 따른 전과정평가 방법을 적용한 환경영향 평가

신중두,임동규,김건엽,박문희,고문환,엄기철 한국환경농학회 2003 한국환경농학회지 Vol.22 No.1

Consoli가 설명한 것처럼 전과정평가의 개념 및 일반적인 정의에 따르면, 전과정평가는농업생산에 관련된 환경영향을 평가하는데 부합하는 방법이라고 생각되며, 특별히 전과정 평가방법인 Eco-indicator 95는 농업 체재에 대한 환경영향을 분석하는데 적절한 기법인 것으로 입정되었다. Eco-indicator 95 method를 이용하여 지구온난화 및 수계 부영양화와 관련된 시비체계에 따른 벼 재배에 대해 비교할만한 분석체계를 이루었다. 그렇지만 본 연구에서 전화정평가 항목에 기록된 모든 관련 정보가 환경 영향에 고려되지 않았기 때문에 Eco-indicator 95 method를 농업생산 체계에 적용할 때 몇 가지 난제에 부닥친다. Eco-indicator 95 method에 토양 및 자원의 이용과 같은 몇 몇 중요한 환경적인 문제가 포함되지 않았으며, 이 방법의 다른 문제는 환경 평가를 위하여 현장 정밀연구가 수행되지 않았다는 것이다. 그렇지만 본 연구에서 얻어진 생태지표 지수를 이용하여 벼 재배에 따른 시비방법 간의 차이점을 나타내기에 충분하다고 여겨지며, 가장 높은 생태지표 지수를 나타낸 화학비료를 시용한 구에서 가장 큰 환경영향이 관측되었고, 이러한 차이점은 주로 화학비료 투입에 의한 토양중의 높은 인산 함량의 축적 때문인 것으로 여겨진다. 분석한 시비체재는 특별히 지구온난화 보다는 수계의 부영양화의 환경적인 문제에 기여되는 것으로 나타났으므로 질소 시용비율 및 시용기술 이외에 액비 시용에 따른 양분 용탈이 수계 환경에 명확히 영향을 미치는 것으로 나타났다. The suitability of the Life Cycle Assessment (LCA) methodology to analyze'the environmental impact of rice cultivation with different fertilizing systems is investigated. The first part of an LCA is an inventory of parameters used and emissions released due to the system under investigation. In the following step, the Life Cycle Impact Assessment, the inventory data were analyzed and aggregated in order to finally get one index representing the total environmental burden. For the Life Cycle Impact Assessment (LCIA) the Eco-indicator 95 method has been chosen because this is well documented and regularly applied impact assessment method. The resulting index is called Ec -Indicator value. The higher the Eco-indicator value the stronger is the total environmental impact of an analyzed few system. The rice field experiment conducted in middle parts of korea was chosen as an example for the life cycle impact analysis. In this experiment the treatments were consisted of none fertilizer plot (NF), standard fertilizer plot (SF) applied chemical fertilizers based on soil chemical analysis before rice transplan ing, and efflux fertilized plot (EF) applied with pig wastes fermented as the same rates of SF plot as basis on total nitrogen content. The obtained Eco-indicator values were clearly different among the treatments in the rice trial. The total Eco-Indicator values for SF and EF have been observed 58 and 38% relative to the NF, respectively. For all the treatments the environmental effects of eutrophication contributed most to the total Eco-indicator value. The results appeared that the LCA methodology is basically suitable to assess the environmental impact associated with different fertilizer applications for rice cultivation. A comparative analysis of the fertilizing system's contribution to global warming and eutrophication is possible.

논토양중 카드뮴 유효도와 수도의 흡수이행에 미치는 석회 및 Humic acid 사용효과

김민경,김원일,정구복,박광래,윤순강,엄기철 한국환경농학회 2004 한국환경농학회지 Vol.23 No.1

토양중 중금속이 식물에 흡수 및 이행되는 것을 경감시켜 여기에서 생산된 농산물의 안전성 향상을 위한 기초자료를 확보하고 논토양의 카드뮴 유효도와 흡수이행에 미치는 석회와 humic acid 처리 효과를 구명하기 위하여 실내경험과 포트실험을 수행하였다. 실내실험에서 공시토양에 2.5와 5.0 ton/ha의 석회와 1%와 2% humic acid를 처리한 후 토양중 가용성 카드뮴 함량 변화를 조사한 결과, 두 처리 모두 14일까지는 담수상태에서 처리효과로 인하여 가용성 카드뮴 함량이 감소하다가 그 이후에는 토양의 완충능에 의해 다시 증가하는 경향이었다. 이때, 토양의 가용성 카드뮴 함량은 토양 pH 및 양이온치환용량과 부의 상관이 있었다. 2.5 ton/ha의 석회와 1% 의 humic acid를 처리한 후 담수시켜 안정화된 다음 벼를 재배하여 조사한 결과, 석회와 humic acid 처리에 비해 분얼기와 수확기의 치화태 및 수용태 카드뮴 함량이 낮아졌으나, 분얼기에 비해 수확기에 토양중 이동이 어려운 산화물 및 탄산염태와 황화물 및 잔류태의 함량이 증가하였다. 식물에 흡수가 용이한 형태로 알려진 치환태와 수용태는 모두 토양 pH와 고도의 부의 상관이 있었다. 수확기의 줄기, 잎 및 현미 건물중은 석회 및 humic acide 처리구에서 대조구에 비해 모두 높았고, 특히 석회 처리구의 건물중이 현저하게 높았다. 석회 처리구에서 줄기와 잎의 카드뮴 함량은 각각 1.01과 0.37㎎/㎏으로 대조구와 비슷하였으나, 뿌리나 현미의 카드뮴 ?량은 각각 2.11과 0.09㎎/㎏으로 대조구에 비해 낮았다. 지상부와 뿌리의 카드뮴 함량은 humic acid 처리에 의해 현저히 낮아졌으며, 특히 현미로의 카드뮴 이행도 월등히 낮게 나타난다. This study was conducted to know the effect of lime and humic acid on cadmium availability and its uptake by plant grown in contaminated paddy soils with heavy metal. The treatment levels of lime were 2.5 and 5.0 ton/ha and that of humic acid were 1 and 2%. The contents of 0.1 N HCl extractable Cd were reduced with lime and humic acid and were negatively correlated with CEC as well as soil pH. The sequential extraction procedure was used to fractionate the heavy metals in soil into the designated from exchangeable (0.5 M KNO₃), water soluble (H₂O), organically bound (0.5 M NaOH), carbonate (0.05 M Na₂-EDTA) and sulfide/residual (4 M HNO₃). In soil amended with 2.5 ton/ha lime and 1% humic acid, chemical forms of Cd at tillering stage were predominant exchangeable+water soluble extractable Cd, whereas that at harvesting stage were predominant carbonate+sulfide/residual extractable Cd. The exchangeable forms of Cd in soil with lime and humic acid were negatively correlated with soil pH during the harvesting period. Total absorbed Cd of paddy rice tended to occur in the order of root > stem > leaf > brown rice. Cd con- tents of brown rice with lime and humic acid treatment were 0.09 and 0.08 mg/kg, respectively. That were lower than control, 0.20 ㎎/㎏. It could be that treatment of lime and humic acid in polluted soil by heavy metals would reduce the uptake of heavy metals by plants and be a temporary method of reclamation at the highly heavy metal contaminated soils.

Relative Sensitivity Analysis of the Soil Water Characteristics Curve

Eom, Ki-Cheol 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.6

This study was conducted to develop the SWCC estimation equation using scaling technique, and to investigate relative sensitivity of the SWCC according to the soil water tension, for the four kinds of soil texture such as Sand [S], Sandy Loam [SL], Loam [L] and Clay Loam [CL]. The SWCC estimation equation of scale factor [${\Theta}sc$] (Eq. 1) was developed based on the log function (Eq. 2) and exponential function (Eq. 3). ${\Theta}sc=[({\Theta}-{\Theta}r)/({\Theta}s-{\Theta}r)]$ (Eq. 1) ${\Theta}sc=-0.196ln(H)+0.4888$ (Eq. 2) ${\Theta}sc=0.3804(H)^{(-0.448)}$ (Eq. 3) where, ${\Theta}$: water content (g/g %), ${\Theta}s$: water content at 0.1bar, ${\Theta}r$: water content at 15bar, H: soil water tension (matric potential) (bar) Relative sensitivity of soil water content was decreased as increase soil water tension, those according to soil water tension were 0.952~0.620 compared to 0.1bar case. Relative sensitivity of scale factor was also decreased as increase soil water tension, those according to soil water tension were 0.890~0.577 compared to 0.2bar case.

Species Diversity Analysis of the Aquatic Insect in Paddy Soil

Ki-Cheol Eom,Min-Soo Han,Byung-Kook Lee,Ho-Yong Eom 한국토양비료학회 2013 한국토양비료학회지 Vol.46 No.3

The aquatic insect collected at six areas (each 2 for mountain area, plain field, and urban area) from 2009 to 2011 were classified to analyze the distribution and diversity of species. Frequency (number of aquatic insect: N), number of species (S), similarity index (C), richness index (R1, R2), variety index (V1, V2), evenness index (E1, E2, E3, E4, E5), and dominance index (D1) were investigated. Total N and S were 143 and 84, respectively. C matrix of 153 combinations was constructed with the average of 0.542. The average C of 3 years (0.659) was 9.9% P , more higher than the average C of 6 areas (0.560). The average values of the index of 18 plots were 2.28, 0.17, 1.24, 1.08, 0.07, 0.06, 0.01, 0.87, 0.31, 0.93 for R1, R2, V1, V2, E1, E2, E3, E4, E5, D1, respectively. The order in the coefficient of variation (CV) of the indicator for 18 plots was N (70.0%) > E3 (54.9%) > E1 (49.6%) > R2 (40.5%) > S (35.3%) > R1 (33.7%) > E2 (28.4%) > E5 (15.9%) > V1 (11.1%) > E4 (6.3%) > V2 (5.1%) > D1 (4.8%). The correlation matrix with 66 combinations between the indexes was constructed with statistical significance for 33 combinations. However, R1, V1, E2 and D1 were the proper indexes to represent species diversity of aquatic insect based on the correlation matrix and the theory of statistical independence. The richness index was highest in mountain, variety index in urban area, and evenness index in plain field. However, the dominance index was lowest in urban area.

Yield Response of Soybean to Drought Stress under Different Fertilizer Level

Eom, Ki-Cheol,Jung, Pil-Kyun,Koh, Mun-Hwan,Kim, Young-Sook,Lee, Kyung-Eun 한국토양비료학회 2013 한국토양비료학회지 Vol.46 No.4

This study was conducted to investigate the yield response of soybean to drought stress in 1984 and 1986 at the experiment field of the National Academy of Agricultural Science using experiment plots with different soil water tension and fertilizer levels. The average yield response factor (YRF) of soybean to evapotranspiration (ET) calculated as [(Ya/Ym)/(ETa/ETm)], where Ya, average yield; Ym, maximum yield; ETa, average ET; and ETm, maximum ET, was 0.91 with the range from 0.74 to 1.16. Relationship between yield index (YI=[Ya/Ym]) and evapotranspiration index (ETI=[ETa/PET]) was $YI=0.87{\cdot}(ETI)+0.09$. Relationship between YI and the maximum soil water tension (Hmax) was $YI=1.23-0.23{\cdot}{\log}$ (Hmax). Relationship between YI and the days of drought stressed (Dr) was $YI=0.877{\cdot}{\exp}$ ($-0.01{\cdot}Dr$). The relation between YI and fertilizer level (F) was $YI=-0.21{\cdot}F2+0.36{\cdot}F+0.33$, under very serious drought condition as the maximum soil water tension was 0.3 MPa.

Daily Changes in Red-Pepper Leaf Surface Temperature with Air and Soil Surface Temperatures

Eom, Ki-Cheol,Lee, Byung-Kook,Kim, Young-Sook,Eom, Ho-Yong 한국토양비료학회 2014 한국토양비료학회지 Vol.47 No.5

This study was conducted to investigate the changes in daily surface temperature of red pepper leaf compared to air and soil surface temperature. The maximum, minimum and average daily temperatures of red pepper leaf were 27.80, 11.40 and $19.01^{\circ}C$, respectively, which were lower by 0.10, 7.60 and $3.86^{\circ}C$ than air temperature, respectively, and lower by 15.00, 0.0 and $4.38^{\circ}C$ than soil surface temperature, respectively. Mean deviations of the difference between measured and estimated temperature by the E&E Model (Eom & Eom, 2013) for the air and surface temperature of red pepper leaf and soil were 0.64, 1.82 and $4.77^{\circ}C$, respectively. The relationships between measured and estimated scaled factor of the air and surface temperature of red pepper leaf and soil were very close to the 1:1 line. Difference between air and surface temperature of red pepper leaf showed a linear decreasing function with the surface temperature of red pepper leaf. Difference between soil surface temperature and air and surface temperature of red pepper leaf linearly increased with the soil surface temperature.

Species Diversity Analysis of the Aquatic Insect in Paddy Soil

Eom, Ki-Cheol,Han, Min-Soo,Lee, Byung-Kook,Eom, Ho-Yong 한국토양비료학회 2013 한국토양비료학회지 Vol.46 No.3

The aquatic insect collected at six areas (each 2 for mountain area, plain field, and urban area) from 2009 to 2011 were classified to analyze the distribution and diversity of species. Frequency (number of aquatic insect: N), number of species (S), similarity index (C), richness index (R1, R2), variety index (V1, V2), evenness index (E1, E2, E3, E4, E5), and dominance index (D1) were investigated. Total N and S were 143 and 84, respectively. C matrix of 153 combinations was constructed with the average of 0.542. The average C of 3 years (0.659) was 9.9% P, more higher than the average C of 6 areas (0.560). The average values of the index of 18 plots were 2.28, 0.17, 1.24, 1.08, 0.07, 0.06, 0.01, 0.87, 0.31, 0.93 for R1, R2, V1, V2, E1, E2, E3, E4, E5, D1, respectively. The order in the coefficient of variation (CV) of the indicator for 18 plots was N (70.0%) > E3 (54.9%) > E1 (49.6%) > R2 (40.5%) > S (35.3%) > R1 (33.7%) > E2 (28.4%) > E5 (15.9%) > V1 (11.1%) > E4 (6.3%) > V2 (5.1%) > D1 (4.8%). The correlation matrix with 66 combinations between the indexes was constructed with statistical significance for 33 combinations. However, R1, V1, E2 and D1 were the proper indexes to represent species diversity of aquatic insect based on the correlation matrix and the theory of statistical independence. The richness index was highest in mountain, variety index in urban area, and evenness index in plain field. However, the dominance index was lowest in urban area.