• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.695-700
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• 1994

Hydrogenolysis reactions of CFC-113a catalyzed by various heterogeneous catalysts $(Rh/Al_2O_3,\;Pd/C,\;Ni,\;Al_2O_3,\;Active\;carbon)$ were investigated in the liquid and gas phases. In the liquid phase reaction, different catalysts showed different activities, but all catalysts used gave high selectivities toward HCFC-123 over 95%. It was noticeable that the neutral $Al_2O_3$ showed both a high activity and a selectivity in the liquid phase reaction. In the gas phase reaction, transition metals on carbon(Pd/C, Pt/C) were so active for hydrogenolysis of CFC-113a that they even catalyzed the production reaction of overhydrogenated compounds such as $HCFC-133a(CF_3CH_2Cl)\;and\;HFC-143a(CF_3CH_3)$. $Al_2O_3$, which showed the high activity in the liquid phase reaction, did not show a remarkable activity. When $Al_2O_3$ was used in the liquid phase reaction, the hydrogenolysis of CFC-113a proceeded without any side products in THF. However, the same reaction in MeOH produced side products, such as $CH_3OCH_3\;and\;CH_3CH_2OCH_3$ from solvent. Based on this result, including heterogeneous catalysts, it was concluded that the solvent played an important role in the liquid phase reaction.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.117-124
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• 2022

The International Maritime Organization (IMO) is tightening environmental regulations in the shipping sector to reduce air pollutants such as greenhouse gases emitted from ships. Meanwhile, the paradigm of the shipbuilding and shipping industries is shifting toward eco-friendly and high-efficiency ships worldwide. The Republic of Korea is also promoting a policy to expand the supply of eco-friendly ships from 2020 to disseminate them. In this article, a survey was conducted with 12 experts on the government's eco-friendly ship supply policy, and the priority of the policy was evaluated using the analytic hierarchy process (AHP). As a result of the comprehensive evaluation of the priorities for six priority tasks, "Securing the world's leading technology for future eco-friendly ships" for the development of carbon-free and low carbon ships was the highest. This study, which analyzed the importance of eco-friendly ship policies through AHP analysis, can be used as data to preemptively respond to international marine environmental regulations and to improve policy execution efficiency such as budget allocation and policy development regarding protecting national shipping and shipbuilding industries.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.331-346
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• 2023

Recently, green processes that can be directly used in an energy-efficient and electrified society to achieve carbon neutrality are attracting attention. Existing heat and pressure-based desalination technologies that consume tremendous amounts of energy are no exception, and the growth of next-generation electrochemical-based desalination technologies is remarkable. One of the most representative electrochemical desalination technologies is electrochemical ion separation (EIONS) technology, which includes capacitive desalination (CDI) and battery desalination (BD) technology. In the research field of EIONS, various system applications have been developed to improve system performance, such as capacity and cyclability. However, it is very difficult to understand the meaning and novelty of these applications immediately because there are only a few papers that summarize the research background for domestic readers. Therefore, in this review paper, we aim to describe the technological advances and individual characteristics of each system in clear and specific detail about the latest EIONS research. The driving principle, research background, and strengths and weaknesses of each EIONS system are explained in order. In addition, this paper concluded by suggesting the future development and research direction of EIONS. Researchers who are just beginning out in EIONS research can also benefit from this study because it will help them understand the research trend.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.177-185
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• 2022

In this study, the economic feasibility of a local energy facility that uses forest biomass as an energy source was assessed. We analyzed profitability using data from the Forest Energy Self-sufficient Village Project financed by the Korea Forest Service. The energy facility has a cogeneration generator and wood chip boiler. Wood chip, which has lower heat value and is cheaper than wood pellets, is used as fuel. Revenue comes from the sale of electricity, heat, and renewable energy certificates. Additionally, we considered the sale of carbon credits as substitutes for fossil fuels. The expenditure consists of fuel costs and fixed costs, and the initial investment is treated as a sunk cost. Under the condition of a 55% operation rate and wood chip price of 95,000 KRW per ton, the annual net revenue is positive. Crucial factors for managing the facility sustainably are operation rate and fuel cost. A simulation in which two factors were changed showed that the annual net revenue is negative with a 50% operation rate and 100,000 KRW per ton of wood chip price. To improve net revenue, an increase in the operation rate or a decrease in the wood chip price is required. Additionally, selling carbon credits will make the operation of the facility more profitable. Furthermore, the payment required to procure wood chips could contribute to the rural economy. To foster the use of forest biomass for energy, the price for heat supplied from renewable energy sources should be subsidized.

• Korean Journal of Remote Sensing
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• v.39 no.2
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• pp.169-181
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• 2023

Recently, in order to reduce carbon dioxide (CO₂) emissions, which is the main cause of global warming, Korea has declared carbon emission reduction targets and carbon neutral. Accurate assessment of regional emissions and atmospheric CO₂ concentrations is becoming important as a result. In this study, we identified the spatiotemporal differences between satellite-based atmospheric CO₂ concentration and CO₂ emissions for the Korean Peninsula region using column-averaged CO₂ dry-air mole fraction from the Orbiting Carbon Observatory-2 and emission inventory. And we explained these differences using solar-induced fluorescence (SIF), a photosynthetic reaction index according to vegetation growth. The Greenhouse Gas Inventory and Research Center (GIR) and Emissions Database for Global Atmospheric Research (EDGAR) emissions continued to increase in Korea from 2014 to 2018, but the satellite-based atmospheric CO₂ concentration decreased in 2018, respectively. Regionally, GIR and EDGAR emissions increased in 2018 in Gyeonggi-do and Chungcheongbuk-do, but satellite-based CO₂ concentrations decreased for the corresponding years. In addition, the correlation analysis between emissions and satellite-based CO₂ concentration showed a low correlation of 0.22 (GIR) and 0.16 (EDGAR) in Seoul and Gangwon-do. Atmospheric CO₂ concentrations showed a different correlation with SIF by region. In the CO₂-SIF correlation analysis for the growing season (May to September), Seoul and Gyeonggi-do showed a negative correlation coefficient of -0.26, Chungcheongbuk-do and Gangwon-do showed a positive correlation coefficient of 0.46. Therefore, it can be suggested that consideration of the CO₂ absorption process is necessary for analyzing the relationship between the atmospheric CO₂ concentration and emission inventory.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.554-568
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• 2021

Forests are the largest carbon (C) sinks in terrestrial ecosystems. Recently, as enhancing forest C sequestration capacity has been proposed as a basic direction of the Republic of Korea's "2050 Carbon Neutral Strategy," accurate estimation of forest C sequestration has been emphasized. According to the Intergovernmental Panel on Climate Change guidelines, sequestration quantity is calculated from changes in C stocks in forest C pools, such as biomass, deadwood, litter and soil layer, and harvested wood products. However, in Korea, only the overstory biomass increase is now considered the amount of sequestration quantity, so there can be a significant difference from the actual forest C sequestration. In this study, we quantified forest C exchange through C flux measurement using an eddy covariance system and an automated soil chamber system in a 57-year-old Korean pine plantation located in Mt. Taehwa, Gwangju-si, Gyeonggi-do. Then, the net amount of C sequestration was compared with the amount of the overstory biomass increase. We estimated the annual C stock change in the remaining C pools by comparing the net sequestration amount from the C flux measurement with the overstory biomass increase and C stock change in the litter layer. Therefore, the net C sequestration of the Korean pine plantation estimated from the flux measurement was 5.96 MgC ha^-1, which was about 2.2 times greater than 2.77 MgC ha^-1 of the overstory biomass increase. The annual C stock increase in the litter layer was estimated to be 0.75 MgC ha^-1, resulting in a total annual C stock increase of 2.45 MgC ha^-1 in the remaining C pools. Our results indicate that the domestic forest is a larger C sink than the current methods, implying that more accurate calculations of the C sequestration capacity are necessary to quantify C stock changes in C pools along with the C flux measurement.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.191-195
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• 1999

An integrated wastewater treatment pond system is developed for treatment and recycling of excreta from dairy cattle. It is composed of three ponds in series. A pit with a capacity of $10m^3$, 2-day hydraulic residence time, and overflow velocity of $1.5m^3m^{-2}day^{-1}$ is located internally in primary pond. It is designed for efficient sludge sedimentation and effective methane fermentation. It receives $5m^3/day$ of diluted cattle excreta by the water used for clearing stalls. A submerged gays collector for the recovery of methane is installed on the top of the pit. The average BOD_5 concentration of influent is 398.7mg/l. That of the effluent from primary pond is 49.2mg/l. About 88% of BOD_5 are removed in primary pond. It is assumed that about 60% of the influent BOD_5 is removed in the pit and that almost all of the carbon of the removed BOD_5 in the pit is converted to methane and carbon dioxide. Methane fermentation of the pit is well established at $16^{\circ}C$. This phenomena results from temperature stability, complete anaerobic condition, and neutral pH of the pit. Gas from the collector is almost 90% methane, less than 9% nitrogen, and less than 1% carbon dioxide. Thus a purified methane is produced, which can be used as energy source.

• The Korean Journal of Mycology
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• v.23 no.4 s.75
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• pp.325-331
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• 1995

The effect of cultural conditions on mycelial growth, polysaccharide production in Phellinus linteus and its monosaccharide composition was studied. P. linteus showed the highest growth (0.9 g/100 ml) on glucose but the polysaccharide production was the highest (13.7%) on mannose. The fungus grew very well at neutral pH (0.9 g/100 ml) but the growth was reduced to 0.47 g per 100 ml at alkaline pH. For the different pH, the yield of polysaccharide was in the range of $5{\sim}8%$. The highest yield of 7.94% was obtained at pH 5. Also a variation in monosaccharide composition was observed for different carbon sources and pH. The composition ranges of glucose, mannose, and galactose of polysaccharide were $80{\sim}95%,\;3{\sim}12%,\;and\;2{\sim}10%$ depending on carbon sources, respectively. In contrast, the variation of composition range of three monosaccharides was narrower for different pH than that for carbon sources. These results suggested the possibility of the improvement of production and the physiological modification of the polysaccharide.

• Analytical Science and Technology
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• v.10 no.3
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• pp.161-167
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• 1997

This is on hydrogen ion-selective memebrane electrodes which were made of tetrabenzylmethylenediamine (TBMDA), tetrabenzylethylenediamine (TBEDA), tetrabenzylpropylenediamine(TBPDA) and tetrabenzylhexylenediamine(TBHDA) as neutral carriers. Their response potentials to carbon number between amino groups showed linear selectivities to hydrogen ion in the range of pH 1~pH 9, pH 2~pH 9, pH 3~pH 9 and pH 4~pH 9 and slopes were 48mV/pH, 52mV/pH, 64mV/pH, 59mV/pH respectively. The interferences effect on the cations were measured to alkali metal ions($Li^+$, $Na^+$, $K^+$), alkaline earth metal ions ($Mg^{2+}$, $Ca^{2+}$, $Sr^{2+}$, $Ba^{2+}$), transition metals ions($Cu^{2+}$, $Ni^{2+}$, $Co^{2+}$) and anions($I^-$, $Br^-$, ${NO_3}^-$, $SCN^-$), and selectivity coefficients were measured by separate-solution method. The membrane electrode made of TBMDA among the electrodes showed the best selectivity in acidic solution.

• Journal of Climate Change Research
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• v.2 no.4
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• pp.283-295
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• 2011

Many actions against climate change have been taken to reduce greenhouse gases (GHGs) emissions at home and abroad. As of 2007, the GHGs emitted from buildings accounted for about 23 % of Korea's total GHGs emission, which is the second largest GHG reduction potential following industry. In this study, we introduced Carbon Zero Building (CZB), which was constructed by the National Institute of Environmental Research to cut down GHGs from buildings in Korea, and evaluated the main applied technologies, the amount of energy load and reduced energy, and economic values for CZB to provide data that could be a basis in the future construction of this kind of carbon-neutral buildings. A total of 66 technologies were applied for this building in order to achieve carbon zero emissions. Applied technologies include 30 energy consumption reduction technologies, 18 energy efficiency technologies, and 5 eco-friendly technologies. Out of total annual energy load ($123.8kWh/m^2$), about 40% of energy load ($49kWh/m^2$) was reduced by using passive technologies such as super insulation and use of high efficiency equipments and the other 60% ($74.8kWh/m^2$) was reduced by using active technologies such as solar voltaic, solar thermal, and geothermal energy. The construction cost of CZB was 1.4 times higher than ordinary buildings. However, if active technologies are excluded, the construction cost is similar to that of ordinary buildings. It was estimated that we could save annually about 102 million won directly from energy saving and about 2.2 million won indirectly from additional saving by the reduction in GHGs and atmospheric pollutants. In terms of carbon, we could reduce 100 ton of $CO_2$ emissions per year. In our Life Cycle Cost (LCC) analysis, the Break Even Point (BEP) for the additional construction cost was estimated to be around 20.6 years.