• 제목/요약/키워드: $SO_4^{2-}$

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Seasonal color change of the oxyhydrous precipitates in the Taebaek coal mine drainage, south Korea, and implications for mineralogical and geochemical controls

  • Kim, J. J.;C. O. Choo;Kim, S. J.;K. Tazaki
    • 한국광물학회:학술대회논문집
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    • 한국광물학회.한국암석학회 2001년도 공동학술발표회 논문집
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    • pp.38-39
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    • 2001
  • The seasonal changes in pH, Fe, Al and SO$_4$$\^$2-/ contents of acid drainage released from coal mine dumps play a major role in precipitation of metal hydroxides in the Taebaek coal field area, southeastern Korea. Precipitates in the creeks underwent a cycle of the color change showing white, reddish brown and brownish yellow, which depends on geochemical factors of the creek waters. White precipitates consist of Al-sulfate (basaluminite and hydrobasaluminite) and reddish brown ones are composed of ferrihydrite and brownish yellow ones are of schwertmannite. Goethite coprecipitates with ferrihydrite and schwertmannite. Ferrihydrite formed at higher values than pH 5.3 and schwertmannite precipitated below pH 4.3, and goethite formed at the intermediate pH range between the two minerals. With the pH being increased from acid to intermediate regions, Fe is present both as schwertmannite and goethite. From the present observation, the most favorable pH that basauluminte can precipitate is in the range of pH 4.45-5.95. SEM examination of precipitates at stream bottom shows that they basically consist of agglomerates of spheroid and rod-shape bacteria. Bacteria species are remarkably different among bottom precipitates and, to a less extent, there are slightly different chemical compositions even within the same bacteria. The speciation and calculation of the mineral saturation index were made using MINTEQA2. In waters associated with yellowish brown precipitates mainly composed of schwertmannite, So$_4$ species is mostly free So$_4$$\^$2-/ ion with less AlSo$_4$$\^$+/, CaSo$\sub$(aq)/, and MgSo$\sub$4(aq)/. Ferrous iron is present mostly as free Fe$\^$2+/, and FeSo$\sub$4(aq)/ and ferric iron exists predominantly as Fe(OH)$_2$$\^$+/, with less FeSo$\sub$4(aq)/, Fe(OH)$_2$$\^$-/, FeSo$_4$$\^$-/ and Fe$\^$3+/, respectively Al exists as free Al$\^$3+/, AlOH$_2$$\^$-/, (AlSo$_4$)$\^$+/, and Al(So$_4$)$\^$2-/. Fe is generally saturated with respect to hematite, magnetite, and goethite, with nearly saturation with lepidocrocite. Aluminum and sulfate are supersaturated with respect to predominant alunite and less jubanite, and they approach a saturation state with respect to diaspore, gibbsite, boehmite and gypsum. In the case of waters associated with whitish precipitates mainly composed of basaluminite, Al is present as predominant Al$\^$3+/ and Al(SO$_4$)$\^$+/, with less Al(OH)$\^$2+/, Al(OH)$_2$$\^$+/ and Al(SO$_4$)$\^$2-/. According to calculation for the mineral saturation, aluminum and sulfate are greatly supersaturated with respect to basaluminite and alunite. Diaspore is flirty well supersaturated while jubanite, gibbsite, and boehmite are already supersaturated, and gypsum approaches its saturation state. The observation that the only mineral phase we can easily detect in the whitish precipitate is basaluminite suggests that growth rate of alunite is much slower than that of basaluminite. Neutralization of acid mine drainage due to the dilution caused by the dilution effect due to mixing of unpolluted waters prevails over the buffering effect by the dissolution of carbonate or aluminosilicates. The main factors to affect color change are variations in aqueous geochemistry, which are controlled by dilution effect due to rainfall, water mixng from adjacent creeks, and the extent to which water-rock interaction takes place with seasons. pH, Fe, Al and SO$_4$ contents of the creek water are the most important factors leading to color changes in the precipitates. A geochemical cycle showing color variations in the precipitates provides the potential control on acid mine drainage and can be applied as a reclamation tool in a temperate region with four seasons.

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1,2-Propanediol로부터 Lactic acid의 생성 (Production of Lactic Acid from 1,2-Propanediol by Yeast)

  • Chae, Ki-Soo;Seu, Jung-Hwn
    • 한국미생물·생명공학회지
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    • 제9권2호
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    • pp.51-57
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    • 1981
  • 토양과 sludge 에서 1,2-propanediol을 자화할 수 있는 미생물을 분리하여 이들 중 가장 많은 젖산을 생성 하는 호모 한 균주(Y-1-4)를 선정하였다. 배양액에 생성된 산은 paper chromatography와 IR spectrum에 의해서 젖산으로 확인되었다. 이 효모는 탄소원으로서 ethanol, glycerin, glucose 및 1,2-propanediol 등을 자화할 수 있었는데 1,2-propanediol 으로부터만 젖산을 생성했다. 1,2-propanediol 에서부터 젖산생성의 최적 배지 및 최적 배양조건을 검토해서 1,2-propanediol 2.0%, NH$_4$Cl 0.5%, KH$_2$PO$_4$ 0.1%, MgSO$_4$.7$H_2O$ 0.05%, FeSO$_4$.7$H_2O$ 0.025%, yeast extract 0.04%와 CaCO$_3$ 0.3%를 함유하는 배지를 3$0^{\circ}C$에서 4일간 진탕 배양한 결과 젖산 생성량은 liter당 12.1gram 이었다.

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황-요오드 열화학 수소체조 공정에서 2 액상 정체 특성 (2 Liquid Phase Purification Characteristics for Sulfur-Iodine Thermochemical Hydrogen Production)

  • 이광진;차광서;강영한;박주식;배기광;김영호
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 춘계학술대회
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    • pp.69-72
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    • 2007
  • The objective of this work was to study the properties of purification of two liquid phase for exclusion of impurities in each phase. The experiments for process variables were carried out in the temperature range($H_{2}SO_{4}$ phase: $413{\sim}513$ K, $HI_{x}$ phase: $353{\sim}453$ K) and in the $N_{2}$ flow rate range($H_{2}SO_{4}$, $HI_{x}$ phase: $50{\sim}200$ mL/min). As the results, it is appeared that the principles of $H_{2}SO_{4}$ phase purification was due to stripping, evaporation and reverse bunsen reaction and $HI_{x}$ phase purification was due to stripping and reverse bunsen reaction. In purification of $H_{2}SO_{4}$ phase, the concentration rate of $H_{2}SO_{4}$ phase was controled by temperature but the temperature had few effects on yield of $H_{2}SO_{4}$. In purification of $HI_{x}$ phase, we observed products of side reactions($H_{2}S$, S) over 433 K. The purity of $HI_{x}$ phase was increased with increasing $N_{2}$ flow rate because impurites were decreased with increasing conversion of reverse reaction.

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Effects of Sulfuric Acid Concentration and Alloying Elements on the Corrosion Resistance of Cu-bearing low Alloy Steels

  • Kim, Ki Tae;Kim, Young Sik
    • Corrosion Science and Technology
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    • 제17권4호
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    • pp.154-165
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    • 2018
  • During the process of sulfur dioxide removal, flue gas desulfurization equipment provides a serious internal corrosion environment in creating sulfuric acid dew point corrosion. Therefore, the utilities must use the excellent corrosion resistance of steel desulfurization facilities in the atmosphere. Until now, the trend in developing anti-sulfuric acid steels was essentially the addition of Cu, in order to improve the corrosion resistance. The experimental alloy used in this study is Fe-0.03C-1.0Mn-0.3Si-0.15Ni-0.31Cu alloys to which Ru, Zn and Ta were added. In order to investigate the effect of $H_2SO_4$ concentration and the alloying elements, chemical and electrochemical corrosion tests were performed. In a low concentration of $H_2SO_4$ solution, the major factor affecting the corrosion rate of low alloy steels was the exchange current density for $H^+/H_2$ reaction, while in a high concentration of $H_2SO_4$ solution, the major factors were the thin and dense passive film and resulting passivation behavior. The alloying elements reducing the exchange current density in low concentration of $H_2SO_4$, and the alloying elements decreasing the passive current density in high concentration of $H_2SO_4$, together play an important role in determining the corrosion rate of Cu-bearing low alloy steels in a wide range of $H_2SO_4$ solution.

탈황슬러지 및 생슬러지를 이용한 혐기성 병합소화 특성평가 (Characteristic evaluation of anaerobic co-digestion using desulfurization sludge and primary sludge)

  • 구슬기;정우진;장순웅;박명수
    • 유기물자원화
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    • 제31권4호
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    • pp.51-58
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    • 2023
  • 본 연구에서는 혐기성소화에서 황화합물의 영향을 평가하기 위하여 탈황 슬러지 및 하수슬러지(생슬러지)를 이용한 병합소화를 진행하였다. 실험은 500 mL duran bottle을 이용한 batch test의 형태로 수행되었으며, 원료의 혼합 비율은 COD/SO4의 비율을 기준으로 선정하였다. 실험 결과, COD/SO4 20 이하의 혼합 비율에서 바이오가스 발생량 및 수율의 감소가 확인되었다. 특히 COD/SO4 10 이하에서는 식종슬러지에서 자체적으로 발생하는 바이오가스를 보정하기 위해 원료를 투입하지 않은 seed (283.5 mL)보다 낮은 수치를 나타내었다. 메탄 수율의 경우 COD/SO4 50의 0.396 m3 CH4/kg VS에 비해 COD/SO4 20에서 0.135 m3 CH4/kg VS로 급격하게 감소하는 경향을 보였다. 반면, 황화수소의 수율은 COD/SO4 50의 0.0097 m3 H2S/kg VS에 비해 COD/SO4 20의 비율에서 0.0223 m3 H2S/kg VS로 급격하게 증가하였으며, 특히 COD/SO4 10에서 0.0855 m3 H2S/kg VS로 가장 높은 결과를 나타내었다. 이러한 결과를 바탕으로, 혐기성소화에 있어 황화물의 영향은 COD/SO4 비율이 20 이하로 감소할 경우, 악영향을 줄 수 있는 것으로 판단된다.

Pseudomonas aeruginosa EL-KM에 의한 환경친화적 항균물질의 생산과 특성 (Production and Characteristics of Environment-Friendly Antimicrobial Substance by Pseudomonas aeruginosa EL-KM)

  • 이상준;이경민;이오미;차미선;박은희;박근태;손홍주
    • 한국환경과학회지
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    • 제11권1호
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    • pp.33-40
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    • 2002
  • An antimicrobial substance-producing microorganism was isolated from soil samples. Based of the taxonomic characteristics of its morphological, cultural, physiological properties and 16s rRNA sequence alignment, this microorganism was identified as Pseudomonas aeruginosa, and we named Pseudomonas aeruginosa EL-KM. The optimal culture condition for production of antimicrobial substance was 1% mannitol, 0.4% yeast extract, 0.5% Nacl, 0.2% $K_2SO_4$, 100$\mu$M $MgSO_4$.$7H_2O$, 10$\mu$M $CaCl_2$.$2H_2O$, 1$\mu$M $FeSO_4$.$7H_2O$, 1$\mu$M $MnSO_4$.$4-5H_2O$, initial pH 7 and 200 rpm at 3$0^{\circ}C$. The purification of the antimicrbial substance was performed by silica gel column chromatographys, and fraction with TLC $R_f$ 0.77 value represented good antimicrobial activity. The crude antimicrbial substance was stable within a pH range of 3-10 and temperature range of 4$^{\circ}C$-121$^{\circ}C$ autoclaving. This crude antibacterial substance acted as bacteriolytic agent against Vibrio cholerae non-Ol ATCC 25872, and also exhibited excellent properties, when the substance was demonstrated against many other gram-positive, gram-negative bacteria, yeast and fungi.

Fresh-cut사과 전처리에 따른 물성학적 품질 특성

  • 박연주;최소영;김인호;문광덕
    • 한국식품저장유통학회:학술대회논문집
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    • 한국식품저장유통학회 2003년도 춘계총회 및 제22차 학술발표회
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    • pp.118-118
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    • 2003
  • 편의와 fresh-like quality를 선호하는 소비 경향에 맞추어 가공한 fresh-cut사과의 선도 연장을 위한 저해제를 탐색하였다. 실험에 사용된 사과는 박피하여 속심을 제거한 사과를 8조각으로 절단하여 저해제에 3분간 침지한 후 물기를 제거하고 각각 LDPE 포장지에 포장하여 실온에서 저장하면서 colorimeter와 rheometer를 이용하여 색도와 물성을 측정하였다. 저해제로는 1% ascorbic acid, citric acid, NaCl, MgCl$_2$, CaCl$_2$, KCl, CaSO$_4$, MgSO$_4$, $Na_2$SO$_4$, oxalic acid, calcium lactate, calcium citrate를 사용하였으며 천연저해제로는 건칡, 맥문동, 목향, Rhubarb, 당귀, 오약, 시체, 지각, 천문동, 청피, 계피, 구기자, 당귀, 진피, 감초, 녹차, 후추 등을 열수추출하여 사용하였다. 물리적인 변화는 시간이 경과함에 따라 감소하는 추세를 보였으며 일부 건조로 인해 texture의 증가를 나타내기도 했다. 처리에 따른 물리적인 변화로는 CaCl$_2$, NaSO$_4$, Cl, 시금치를 처리하였을 때 그 변화가 가장 작았으나 시금치의 경우 시금치로 인한 사과의 색변화로 관능적으로 좋지 않았다. 한약재는 목향, 당귀, 지각, 계피를 처리하였을 때 물리적인 변화가 가장 작았으나 시금치와 마찬가지로 처리 초기에 한약재 자체의 향과 색으로 인하여 관능적으로 좋지 못한 결과를 나타냈다. 갈변 정도를 나타내는 ΔE의 변화는 KCl과 CaCl$_2$, CaSO$_4$를 처리한 구에서 변화가 가장 작았으며 한약재를 처리하였을 경우 당귀, 천문동을 처리한 구에서 효과를 보였다. oxalic acid는 갈변저해에는 효과적이었으나 시간이 경과함에 따라 수분의 용출이 증가하였으며 물성의 변화도 컸다. 또한 ZnCl$_2$를 처리한 구에서는 이취 발생과 수분 용출이 컸으며 색의 변화도 컸다.

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

  • 전병일
    • 한국환경과학회지
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    • 제11권7호
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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.

SI 열화학싸이클 황산분해공정의 Bench-scale 상압 실험 (Bench-scale Test of Sulfuric Acid Decomposition Process in SI Thermochemical Cycle at Ambient Pressure)

  • 전동근;이기용;김홍곤;김창수
    • 한국수소및신에너지학회논문집
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    • 제22권2호
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    • pp.139-151
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    • 2011
  • The sulfur-iodine (SI) thermochemical water splitting cycle is one of promising hydrogen production methods from water using high-temperature heat generated from a high temperature gas-cooled nuclear reactor (HTGR). The SI cycle consists of three main units, such as Bunsen reaction, HI decomposition, and $H_2SO_4$ decomposition. The feasibility of continuous operation of a series of subunits for $H_2SO_4$ decomposition was investigated with a bench-scale facility working at ambient pressure. It showed stable and reproducible $H_2SO_4$ decomposition by steadily producing $SO_2$ and $O_2$ corresponding to a capacity of 1 mol/h $H_2$ for 24 hrs.

새만금 유역에서 논 최적관리기법의 수질개선 효과와 정책고려사항 (Effect of Paddy BMPs on Water Quality and Policy Consideration in Saemangeum Watershed)

  • 김종건;이수인;신재영;임정하;나영광;주소희;신민환;최중대
    • 한국습지학회지
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    • 제20권4호
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    • pp.304-313
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    • 2018
  • 새만금 간척지의 농지 간척 사업은 대부분 2020 년까지 완공 될 예정이며, 그 시기 토지의 관개용수 활용에 대한 대비가 필요한 실정이다. 그러나 관개수의 수질은 드물게 목표 농도를 충족하고 있다. 이에 본 연구에서는 논에서의 최적관리기법(BMPs)인 토양검정시비(SO#1), SO#1과 SO#3의 복합처리(SO#2), 배수물꼬(SO#3), 완효성 비료시비 (SO#4) 방법을 관행재배(CT: Control)와 비교하여 논 비점오염원 저감효과 및 정책개발 시의 고려사항을 기술하였다. 논에서의 유출 저감은 SO#3(25%)와 SO#1(27%)에서 관행재배와 비교하였을 때 상대적으로 높았으나, SO#4(9%)와 SO#2(7%)에서 낮게 나타났다. 논 유출량의 NPS 오염물질 농도와 부하는 변화의 폭이 높게 나타났으며 BMPs 중에 유의한 차이는 나타나지 않았다. 또한 농민들의 인식조사 결과, 농민들은 실제 BMP 구현의 한계로 기존 관행적인 영농활동을 유지하고 있는 것으로 나타났다. 따라서 NPS 오염물질 관리와 관개수 절약을 위해서 농민 교육 및 지원과 함께 관개물꼬 및 논의 담수심을 자동 조절할 수 있는 관리방안이 필요할 것으로 판단된다.