• 유기물자원화
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• 제29권4호
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• pp.55-65
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• 2021

본 연구는 독일 유기물분해율 표준시험법인 VDI4630 시험을 통해 메탄 생성 및 유기물의 분해율을 조사하였으며 시험을 위해 농업 분야의 11개의 폐기물 바이오매스를 공시재료로 선택하여 시험하였다. 본 연구의 목적은 초기에 빠르게 분해되는 생분해성 유기물과 이후 천천히 지속적으로 분해되는 유기물의 비율을 계산하기 위해 Double first-order kinetics 모델을 이용하여 유기물의 분포를 추정하고자 하였다. 그 결과로 본 연구에 적용된 모든 바이오매스는 초기 단계에서 빠른 분해를 보이다가 이후 분해 속도가 일정 시간 느려지기 시작하여 초기 분해 속도보다 10배 이상 느려지는 결과를 보였다. 이러한 분해율 변화 경향은 바이오매스 분해의 전형적인 형태이며 쉽게 분해되는 인자(k₁)는 채소 작물에서 0.097~0.152 day^-1 범위였고, 분해에 저항성을 가지는 인자(k₂)는 0.002~0.024 day^-1 사이에 위치하였다. 유기물 분해율이 높을수록 k₁ 상수 값이 더 크게 나타났으나 (0.152, 0.144day^-1) 오이와 파프리카 열매와 같이 표면에 왁스층이 존재하는 부산물은 k₁ 값이 오히려 줄기보다 낮았고 (0.002, 0.005day^-1), 무와 귤껍질도 k₁ 각각 0.097과 0.094 day^-1로 낮은 분해율과 k₁ 값을 보여 유기물의 분해율은 이분해성 유기물 분해 상수인 k₁ 값에 크게 영향을 미치는 것으로 분석되었다.

• 한국안전학회지
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• 제14권3호
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• pp.93-100
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• 1999

Decomposition efficiency, power consumption, and applied voltage of CFC(Chlorofluorocatbon) were investigated by SPCP(surface induced discharge plasma chemical processing) reactor to obtain optimum process variables and maximum decomposition efficiencies. Decomposition efficiency of CFC-12 with various electric frequencies(5~50kHz). flow rates (100~1,000mL/min), initial concentrations(100~1,000ppm), electrode materials(W, Cu, Al). electrode thickness(1, 2, 3mm) and reference gases($N_2$, $O_2$, air) were measured and the products were analyzed with FT-IR. Experimental results showed that at the frequency of 10kHz, the highest decomposition efficiency of 92.7% for CFC-12 were observed at the power consumptions of 29.6W. respectively, and that decomposition efficiency decreased with increasing frequency above 20kHz and decomposition efficiency per unit power were 3.13%/W for CFC-12. Decomposition efficiency was increased with increasing residence times and with decreasing initial concentration of pollutants. Decomposition efficiency was increased with increasing thickness of discharge electrode and the highest decomposition efficiency was obtained for the electrode diameter of 3m. As the electrode material, decomposition efficiency was in order that tungsten(W), copper(Cu), aluminum (Al). Decomposition of CFC-12 in the reference gas of $N_2$ showed the highest efficiency among three reference gases, and then the effect of reference gas on the decomposition efficiency decreased in order of air and $O_2$. The optimum power for the maximum decomposition efficiency was 25.3W for CFC.

• The Korean Journal of Ecology
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• 제10권3호
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• pp.109-118
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• 1987

The production and decomposition rates of litters were studied in three mountains, Mt. Halla, Mt. So-back and Mt. Tae-back. The amounts of N, P, K, Ca and Na in the soils were measured and the relationships between the mineral nutrients and decay rates were reserched, The annual litter production was the most as $1, 077.3g/m^2$ and the least as $248.0g/m^2$ in a stand of Quercus acutissima at 820m of the Mt. So-back and at 1, 350m of the Mt. So-back among the study sites, respectively. The decay rates of litter was the highest as k=0.448 and the lowest as k=0.082 in a stand of Q. acutissima at 820m of the Mt. So-back and at 1, 450m of the Mt. Tae-back at 1, 450m of the Mt. Tae-back among the study sites. The higher altitude was, the slower the decay rates were. The annual contents of mineral nutrient and their amounts inputted into the forest soil were proportional to the decay rate of organic metters.

• Journal of Ecology and Environment
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• 제29권1호
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• pp.23-27
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• 2006

This study was conducted to evaluate forest carbon cycling and soil $CO_2$ efflux rates in a 42-year-old pine (Pinus densiflora) stand located in Hamyang-gun, Korea. Aboveground and soil organic carbon storage, litterfall, litter decomposition, and soil $CO_2$ efflux rates were measured for one year. Estimated aboveground biomass carbon storage and increment in this stand were $3,250gC/m^2\;and\;156gC\;m^{-2}yr^{-1}$, respectively. Soil organic carbon storage at the depth of 30 cm was $10,260gC/m^2$ Mean organic carbon inputs by needle and total litterfall were $176gC\;m^{-2}yr^{-1}\;and\;235gC\;m^{-2}yr^{-1}$, respectively. Litter decomposition rates were faster in nne roots less than 2 mm diameter size ($<220\;g\;kg^{-1}yr^{-1}$) than in needle litter ($<120\;g\;kg^{-1}yr^{-1}$). Annual mean and total soil respiration rates were $0.37g\;CO_2m^{-2}h^{-1}$ and $2,732g\;CO_2m^{-2}yr^{-1}$ during the study period. A strong positive relationship existed between soil $CO_2$ efflux and soil temperature (r=0.8149), while soil $CO_2$ efflux responded negatively to soil pH (r=-0.3582).

• Journal of Forest and Environmental Science
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• 제29권1호
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• pp.38-48
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• 2013

Decomposition of plant material is an important component in the study of forest ecosystem because of its critical role in nutrient cycling. Different tree species has different nutrient release patterns, which are related to leaf litter quantitative traits and seasonal environmental factors. The quantitative traits of leaf litter are important predictors of decomposition and decomposition rates increase with greater nutrient availability in the forest ecosystems. At the ecosystem level, litter quantitative traits are most often related to the physical and chemical characteristics of the litter, for example, leaf toughness and leaf mass per unit area, and lignin content tannin and total phenolics. Thus, the analysis of litter quantitative traits and decomposition are highly important for the understanding of nutrient cycling in forest ecosystems. By studying the role of litter quantitative traits on decomposition and nutrient cycling in forest ecosystems will provide a valuable insight to how quantitative traits influence ecosystem nutrient dynamics. Such knowledge will contribute to future forest management and conservation practices.

• 한국안전학회지
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• 제14권1호
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• pp.73-77
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• 1999

In this study, $SO_2$ and $NO_2$ reduction have been investigated by using coil type plasma reactor. The experiments have been carried out changing discharge power, gas flow rate frequency and electrode style to obtain the decomposition rate. Decomposition rates of $SO_2$ and $NO_2$ were obtained 20~98% at gas flow rate 100ml/min~1,000ml/min and discharge power 5~25w respectively. The energy efficiency is very good at the high frequency power. The decomposition rate of $SO_2$ for 5kHz power supply is only 90%, but for 10kHz power supply is very high, more than 98% for 15w. The decomposition rate is increasing according to the residence time or the power consumption of the discharge. About 15W discharge power for 17$cm^2$ reactor is necessary to obtain the decomposition rate of $SO_2$ and $NO_2$ of more than 85% or 98%. From these experiments, the consumption power of the decomposition rate of 98% in 300ppm $NO_2$ gas in nitrogen gas proved to be 18W and 300ppm $SO_2$ gas to be 15w.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.344-352
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• 2010

Magnetite and inorganic sludge were mainly composed of $Fe_2O_4$ and $Fe_2O_3$, respectively. Initial specific surface areas of magnetite and inorganic sludge were 130 $m^2$/g and 31.7 $m^2$/g. $CO_2$ decomposition rate for inorganic sludge was increased with temperature. Maximum $CO_2$ decomposition rates were shown 89% for magnetite at $350^{\circ}C$ and 84% for inorganic sludge at $500^{\circ}C$. Specific surface area for magnetite was not varied significantly after $CO_2$ decomposition. However, specific surface area for inorganic sludge was greatly decreased from initial 130 $m^2$/g to approximately 50~60 $m^2$/g after reaction. Therefore, it was estimated that magnetite could be used for $CO_2$decomposition for a long time and inorganic sludge should be wasted after $CO_2$ decomposition reaction.

• 한국수소및신에너지학회논문집
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• 제22권1호
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• pp.21-28
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• 2011

Fe, Ni and Co, typical active components, were dispersed on $Al_2O_3$ and $TiO_2$ for $SO_3$ decomposition. $SO_3$ decomposition was conducted at the temperature ranges from $750^{\circ}C$ to $950^{\circ}C$ using the prepared catalysts. Alumina based catalysts showed the surface areas higher than Titania based catalysts, which resulted from spinel structure formation of alumina based catalysts. Catalytic $SO_3$ decomposition reaction rates were in the order of Fe>Co${\gg}$Ni. The metal sulfate decomposition temperature were in the order of Ni>Co>Fe from TGA/DTA analysis of metal sulfate. During $SO_3$ decomposition, metal sulfate can form on the catalysts. $SO_2$ and $O_2$ can be produced from the decomposition of metal sulfate. In that point of view, the less is the metal sulfate deomposition temperature, the higher can be the $SO_3$ decomposition activity of the metal component. Therefore, it can be concluded that metal component with the low metal sulfate decomposition temperature is the pre-requisite condition of the catalysts for $SO_3$ decomposition reaction.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1996년도 제7회 학술강연회논문집
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• pp.137-144
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• 1996

내열 복합 재료에 사용되는 경화된 페놀 수지(DURITE SC-1008)의 열분해 상수를 알아보기 위하여 Henderson and Freidman 분석법을 이용하여 반응 속도 상수를 구하였다. 가열 속도는 5,10, $20^{\circ}C$/min으로 변화 시켰으며 각각의 중량 감소 곡선으로부터 속도 상수 값을 구하였다. 열분해 반응은 크게 두 구간으로 나누어 진행되었으며 이러한 반응을 모사하기 위하여 반응 구간에 따른 속도 상수 값을 구하였다. 또한 실험 상수 값의 정확성을 확인하기 위하여 이론 열중량 곡선식을 직접 유도하여 상수 값을 대입한 결과 그 차이는 상관 계수가 1.19로써 실제 실험 값과 이론식에서 얻어진 값이 거의 일치되었다 그러므로 열분해 반응을 모사하기 위해서는 변화된 가열 속도에 따라서 중량 감소량을 구한 후 열분해 반응 구간을 분리하여 반응 상수론 구하는 것이 필요하다.

• 생태와환경
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• 제38권spc호
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• pp.31-38
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• 2005

Diel change in urea decomposition activity of epiphytic algae on Phragmites stems and phytoplankton in a shallow littoral reed zone in the south basin of Lake Biwa was investigated with an in situ technique using $^{14}C$-labelled urea. The daily rates of urea decomposition (sum of urea carbon incorporation rate and $CO_2$ liberation rate) by epiphytic and planktonic algae were calculated as 180 ${\mu}$ mole urea surface shoot area $m^{-2}\;day^{-1}$ and 210 ${\mu}$ mole urea $m^{-3}\;day^{-1}$. The chlorophyll a specific urea decomposition rates of epiphytic and planktonic algae were 4.7 to 6.4 and 4.4 to 6.2 ${\mu}$ mole urea mg chl. $a^{-1}$ incubation $time^{-1}$ in daytime and 4.2 to 5.7 and 2.4 to 3.5 ${\mu}$ mole urea mg chl. $a^{-1}\;time^{-1}$ in nighttime, respectively. High values were obtained during 12:00 ${\sim}$ 18:00 and low values during 00:00 ${\sim}$ 06:00 for both epiphytic and planktonic algal communities. A clear diel periodicity in the urea decomposing activity of the planktonic algae was observed. The activity of the epiphytic algae, on the other hand, showed no destinctive variation during a day. The present results indicate that epiphytic algae are one of the significant urea decomposers in a reed zone, and that the diel patterns are quite difference between both algal communities.