• Title/Summary/Keyword: $SO_2$ concentration

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Continuous ion-exchange membrane electrodialysis of mother liquid discharged from a salt-manufacturing plant and transport of Cl- ions and SO42- ions

  • Tanaka, Yoshinobu;Uchino, Hazime;Murakami, Masayoshi
    • Membrane and Water Treatment
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    • v.3 no.1
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    • pp.63-76
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    • 2012
  • Mother liquid discharged from a salt-manufacturing plant was electrodialyzed at 25 and $40^{\circ}C$ in a continuous process integrated with $SO_4{^{2-}}$ ion low-permeable anion-exchange membranes to remove $Na_2SO_4$ and recover NaCl in the mother liquid. Performance of electrodialysis was evaluated by measuring ion concentration in a concentrated solution, permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions, current efficiency, cell voltage, energy consumption to obtain one ton of NaCl and membrane pair characteristics. The permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions was low enough particularly at $40^{\circ}C$ and $SO_4{^{2-}}$ transport across anion-exchange membranes was prevented successfully. Applying the overall mass transport equation, $Cl^-$ ion and $SO_4{^{2-}}$ ion transport across anion-exchange membranes is evaluated. $SO_4{^{2-}}$ ion transport number is decreased due to the decrease of electro-migration of $SO_4{^{2-}}$ ions across the anion-exchange membranes. $SO_4{^{2-}}$ ion concentration in desalting cells becomes higher than that in concentration cells and $SO_4{^{2-}}$ ion diffusion is accelerated across the anion-exchange membranes from desalting cells toward concentrating cells.

Concentration of $NO_2$ and $SO_2$ of Underground Shopping Center in Chonan City (천안시내 지하상가의 이산화질소 및 이산화황 농도)

  • 손부순;장봉기
    • Journal of environmental and Sanitary engineering
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    • v.15 no.1
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    • pp.102-108
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    • 2000
  • Seasonal variation of $NO_2$ and $SO_2$ concentration was investigated at the underground shopping center in Chonan from October 1997 to August 1998. $NO_2$ and $SO_2$ was collected by personal air sampler at $0.4{\ell}/min$ and $0.5{\ell}/min$ respectively and analyzed using UV spectrophotometer at 550nm and 548nm individually. The results were as follows. 1. The concentration of $NO_2$ was 0.070 ppm in spring, 0.068 ppm in summer, 0.074 ppm in autumn and 0.085 ppm in winter. There was no significant difference. 2. The concentration of $SO_2$ was 0.0233 ppm in spring, 0.0216 ppm in summer, 0.0188 ppm in autumn and 0.0621 ppm in winter. There was significant difference (p<0.01). 3. The higher concentration of $NO_2$ and $SO_2$ gases were shown near the cafeteria (p<0.001, p<0.05). 4. The higher concentration of $NO_2$ was observed at indoor than the underground passage. There was significant difference between two values (p<0.01).

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Concentration of Sulfur dioxide ($SO_2$) of Subway Stations in Seoul (서울지역 지하철역 구내의 아황산가스 농도)

  • 손부순;장봉기
    • Journal of environmental and Sanitary engineering
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    • v.14 no.1
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    • pp.17-23
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    • 1999
  • This study was performed to survey the $SO_2$ level at several underground spaces connected to 5 subway stations (City Hall, Nam, Seoul stations, Hye Hwa and Ulchiro 1 Ga) in Seoul. The period of survey was from July to November, 1997.The results of the study were as follows; 1. The mean concentration of $SO_2$ was $0.057{\pm}0.015ppm$ in all subway stations. The highest $SO_2$ level among the five stations was $0.067{\pm}0.011 ppm$ at City Hall (P<0.01), and the highest with $0.071{\pm}0.013ppm$ at November (P<0.01).2. In underground shopping centers, the mean concentration of $SO_2$ was $0.112{\pm}0.059ppm$. 3. The mean concentration of $SO_2$ at evening with 0.057 pp and morning with 0.053 ppm were significantly higher than at noon with 0.043 ppm(P<0.05). 4. The $SO_2$ level of floor at Kang Nam station with 0.044 ppm was significantly higher than that of platform with 0.37 ppm(P<0.01). 5. For the City Hall stations, the line #1 and line #2 subway spaces show significantly different level of $SO_2$, 0.042ppm and 0.033 ppm respectively (P<0.05).

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Effects of Multiple-Cycle Operation and SO2 Concentration on CO2 Capture Capacity of Three Limestones in a Fluidized Bed Reactor (유동층 반응기에서 세 가지 석회석의 CO2 흡수능력에 미치는 반복횟수와 SO2 농도의 영향)

  • Ryu, Ho-Jung
    • Applied Chemistry for Engineering
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    • v.17 no.1
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    • pp.44-51
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    • 2006
  • Effects of multiple-cycle operation and $SO_2$ concentration on $CO_2$ capture characteristics of three limestones were investigated in a fluidized bed reactor. For each of these sorbents, the measured $CO_2$ capture capacity decreased as the number of cycles increased and as the $SO_2$ concentration increased. On the other hand, the $SO_2$ capture increased with the increased number of cycles and the $SO_2$ concentration. The total calcium utilization decreased as the number of cycles increased, but the effect of $SO_2$ concentrations on the total calcium utilization depended on the type of limestone. For Strassburg limestone, the total calcium utillization decreased with increasing $SO_2$ concentration. However, for Luscar and Danyang limestones, the total calcium utilization was almost independent of $SO_2$ concentration for the range investigated. The results showed that $SO_2$ in flue gas reduced the $CO_2$ capture capacity of limestone and that the sulfation pattern affected the $CO_2$ capture capacity.

The Variation of $SO_2$ Concentration According to Wind Speed in Urban Area (도심지역에서의 풍속에 따른 $SO_2$ 농도변화)

  • 羅振均
    • Journal of Korean Society for Atmospheric Environment
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    • v.5 no.2
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    • pp.97-105
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    • 1989
  • Recently, many studies on air quality prediction models have been performed to develope new ones. The purpose of the study is to obtain a method to predict $SO_2$ concentration simply in urban area using hour-to-hour meteorological data such as the wind speed, the incoming solar radiation, and the cloud coverages. The relationships between with speed and $SO_2$ concentrations are plotted in flgures. Predicted concentration curves are obtained for equation C=b/(1+au).

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A Stochastic Model for Air Pollutant Concentration (大氣汚染濃度에 관한 確率모델)

  • 김해경
    • Journal of Korean Society for Atmospheric Environment
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    • v.7 no.2
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    • pp.127-136
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    • 1991
  • This paper is concerned with the development and application of a stochastic model for daily sulphur dioxide $(SO_2)$ concentrations in urban area (Seoul). For this, the characteristics of the regression trend, periodicity and dependence of the daily $SO_2$ concentration are investigated by a statistisical analysis of the daily average $SO_2$ values measured in Seoul area during 1989 $\sim$ 1990. Based on these, nonlinear regression time series model for the prediction of daily $SO_2$ concentrations is derived. A statistical procedure for using the model to predict the concentration level is also proposed.

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A Study on the Characteristics of Concentrations of Atmospheric Aerosols in Pusan (부산지역의 입자상 대기오염물질의 농도특성에 관한 연구)

  • 최금찬;유수영;전보경
    • Journal of Environmental Health Sciences
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    • v.26 no.2
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    • pp.41-48
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    • 2000
  • This study has been carried out to determine the seasonal characteristics of concentration of various ionic (CI-, NO3-, SO42-, Na+, NH+, K+, Ca2+) and heavy metallic (Pb, Mn, Cu, Ni) species in Pusan from August 1997 to April 1998. The concentrations of CI-, Na+, K+ were higher during summer with 2.98 ${\mu}{\textrm}{m}$/㎥. Seasonal variation of total concentration of but the concentration of NH4+ was higher during winter with 2.46${\mu}{\textrm}{m}$/㎥. Seasonal variation of total concentration of heavy metals(Pb, Cu, Mn, Ni) were 186.0 ng/㎥ in summer, 222.6 ng/㎥ in autumn, and 135.83 ng/㎥ in winter. Over the seasons inspected, the concentration of Mn was higher in coarse particles than fine particles and concentration of Ni was higher in fine particles than coarse particles. during yellow sand period, the concentration of TSP was increased about two times than that of other period. SO42-, Ca2+ concentrations were higher than other ionic components because of soil particles. The concentration of Ni showed 94.62ng/㎥ was increased about 4~5 times than other period. Principal component of the yellow sand, SO42-, Ca2+ could be discreased by rainfall and washout effect of atmospheric aerosol was higher in coarse particles than fine particles. Results from PCA(principal component analysis) showed that major pollutant was NaCl by seasalt particulate and (NH4)2SO4.

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A Dynamic-Stochastic Model for Air Pollutant Concentration (大氣汚染濃度에 관한 動的確率모델)

  • 김해경
    • Journal of Korean Society for Atmospheric Environment
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    • v.7 no.3
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    • pp.156-168
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    • 1991
  • The purpose of this paper is to develop a stochastic model for daily sulphur dioxide $(SO_2)$ concentrations prediction in urban area (Seoul). For this, the influence of the meteorological parameters on the $SO_2$ concentrations is investigated by a statistical analysis of the 24-hr averaged $SO_2$ levels of Seoul area during 1989 $\sim$ 1990. The annual fluctuations of the regression trend, periodicity and dependence of the daily concentration are also analyzed. Based on these, a nonlinear regression transfer function model for the prediction of daily $SO_2$ concentrations is derived. A statistical procedure for using the model to predict the concentration level is also proposed.

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Survey on the Concentration of Sulphur Dioxide Gas in the Plastic Film House Cultivation (시설(施設) 하우스내 아황산(亞黃酸)(SO2)가스 발생현황(發生現況) 조사(調査))

  • Kim, Bok-Young;Lee, Jong-Sik;Jung, Goo-Bok
    • Korean Journal of Soil Science and Fertilizer
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    • v.30 no.4
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    • pp.357-360
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    • 1997
  • To fine out the concentration of $SO_2$ gas in plastic film house, the survey was conducted at 343 sites throughout the nation. The $SO_2$ concentration in plastic film house were similar both heating and non-heating, but $SO_2$ cocentration higher than 0.8ppm was detected at those with heating. The $SO_2$ concentration in plastic film house cultivated red-pepper higher than those of cucumber or tomato cultivation, and it was produced higher amounts at day time than night due to the higher temperature. In plastic film house with heating, $SO_2$ was leaked at brocken parts of heater and joint of stove pipe, sometimes, $SO_2$ discharged from smokestack was resucked with air. $SO_2$ concentration in the plastic film house with and without ventilation were 0.2 and 0.6ppm, respectively.

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Role of Transport on Aerosol Concentration at Crater Lake, Oregon USA (미국 오레곤주 Crater Lake의 에어로졸 농도에 미치는 수송의 역할)

  • 전병일
    • Journal of Environmental Science International
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    • v.11 no.7
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    • pp.669-677
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    • 2002
  • This study was conducted to investigate the characteristics of role of transport on aerosol concentration at Crate Lake, Oregon USA for 1988.3~1999. 5. The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of representatives from USA federal and regional-state organizations. Also IMPROVE sampler is designed to obtain a complete signature of the composition of the airborne particles affecting visibility. According to 10-day backward isentropic trajectory analysis, the frequency of local, marine and Asian trajectory showed 33.1%(335 cases), 47%(478 cases), 5.2%(53 cases) respectively. The monthly variation of nss $SO_4^{2-}$, nss S, $NO_3^-$, K and C showed the double peak pattern, high in April~May and August~september and showed the lowest concentration in Winter. The other constituents concentration except for Cl$^{[-10]}$ , Na, Mg was high in local trajectory than marine trajectory. A ratio nss $SO_4^{2-}$ to $SO_4^{2-}$ was 90.5% in marine trajectory and 98% in local trajectory. It suggest that the aerosol in Crater Lake was effected by salt. The annual mean concentration of nss $SO_4^{2-}$ and nss S decreased but the springtime concentration increased.