• 한국지하수토양환경학회지:지하수토양환경
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• 제20권6호
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• pp.117-126
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• 2015

Reductive degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by nanoscale zero-valent iron (nZVI) was investigated to evaluate the feasibility of using it for in-situ groundwater remediation. Batch experiments were conducted to quantify the kinetics and efficiency of RDX removal by nZVI, and to determine the effects of pH, dissolved oxygen (DO), and ionic strength on this process. Experimental results showed that the reduction of RDX by nZVI followed pseudo-first order kinetics with the observed rate constant (k_obs) in the range of 0.0056-0.0192 min⁻¹. Column tests were conducted to quantify the removal of RDX by nZVI under real groundwater conditions and evaluate the potential efficacy of nZVI for this purpose in real conditions. In column experiment, RDX removal capacity of nZVI was determined to be 82,500 mg/kg nZVI. pH, oxidation-reduction potential (ORP), and DO concentration varied significantly during the column experiments; the occurrence of these changes suggests that monitoring these quantities may be useful in evaluation of the reactivity of nZVI, because the most critical mechanisms for RDX removal are based on the chemical reduction reactions. These results revealed that nZVI can significantly degrade RDX and that use of nZVI could be an effective method for in-situ remediation of RDX-contaminated groundwater.

• 한국광물학회지
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• 제24권4호
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• pp.279-287
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• 2011

토양 하부 및 지하수에 생존하고 있는 미생물들이 지하수의 산화/환원전위 변화에 관여하는 사실을 알아보기 위해 미생물들을 주입한 수용액의 시간별 Eh 변화량을 측정하였다. 황산염환원 미생물이 주입된 경우 수용액의 Eh값이 5일 만에 -120 mV에서 -500 mV까지 떨어졌으며, 실험 결과 디설프리칸스 세균이 불가리스 세균보다 수용액을 환원하는 능력이 상대적으로 좋았다. 철환원 미생물인 스와넬라 세균의 경우 Eh값이 황산염환원 세균보다 조금 높은 -400 mV를 보여 주었다. 금속환원미생물에 의해 수용액의 Eh값이 떨어지는 동안 용존 황산염 혹은 산화철이 환원되고 맥키나와이트(FeS)라는 황화광물이 형성되기 시작하였다. 이러한 실험 결과를 바탕으로 일반 지하수의 산화/환원전위는 그 지하수에 생존하고 있는 지하미생물들의 대사 활동에 많은 영향을 받고 있다는 사실과 극환원된 지하수 및 생기원 황화광물들이 풍부한 지하 환경은 산화 핵종들이 환원된 형태로 침전되어 핵종 이동이 억제될 가능성이 높은 곳으로 판단된다.

• 한국염색가공학회지
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• 제33권4호
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• pp.191-201
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• 2021

In this study, an eco-friendly indigo reduction system(scale up reduction, use of buffer solution, and pH control) using baker's yeast(Saccharomyces cerevisiae) was applied for natural indigo(Polygonum tinctorium) dyeing of Hanji fabric and Hanji-mixture fabric(Hanji/Cotton, Hanji/Silk). The effect of concentration of baker's yeast, repeat dyeing, and bath reuse was investigated in terms of dye uptake indicating reduction power. And the oxidation-reduction potential(ORP) was monitored. We also evaluated color properties and colorfastness according to the color strength. The yeast concentration did not significantly affect the maximum reduction power. However, the highest yeast concentration was effective in improving the initial dye uptake, and its the reduction retention power was the most excellent. Even on the last reduction day, the effect of increasing the dye uptake by repeat dyeing was observed. And it was confirmed that the reduction bath could be reused for up to 30 days by supplementing yeast at the end of reduction. For all the fabrics used, deeper and darker PB color were obtained by repeat dyeing. As dyeing was repeated, purplish tint got stronger on the Hanji/Silk fabric compared to other fabrics. Regardless of the composition of Hanji fabrics and color strength, washing and dry cleaning fastness were relatively good with above rating 4-5, and fastness to rubbing and light were acceptable with a rating 3-4 ~ 4-5. The eco-friendly natural indigo dyeing process using niram and baker's yeast would offer global marketability and diversity of Hanji product as a sustainable high value-added material.

• Journal of Ecology and Environment
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• 제41권9호
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• pp.235-245
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• 2017

Background: Loading of excess nutrient via bioremediation of polluted sediment to overlying water could trigger anoxia and eutrophication in coastal area. The aim of this research was to understand the changes of overlying water features such as dissolved oxygen (DO); pH; oxidation reduction potential (ORP); $chlorophyll-{\alpha}$ ($Chl-{\alpha}$); and nitrogen nutrients ammonia ($N-NH_4{^+}$), nitrate ($N-NO_3{^-}$), and nitrite ($N-NO_2^-$) when the sediment was not treated (control) and treated by calcium peroxide for 5 weeks. Methods: The water samples were analyzed for measuring physical and chemical properties along with the sediment analyzed by polymerase chain reaction (PCR) including denaturing gradient gel electrophoresis (DGGE) for identifying the phylogenetic affiliation of microbial communities. Results: Results showed that due to the addition of calcium peroxide in sediment, the overlying water exposed the rise of dissolve oxygen, pH, and ORP than control. Among the nitrogen nutrients, ammonia inhibition was higher in calcium peroxide treatment than control but in case of nitrate inhibition, it was reversed than control. $Chlorophyll-{\alpha}$ was declined in treatment column water by 30% where it was 20% in control column water. Actibacter and Salegentibacter group were detectable in the calcium-peroxide-treated sediment; in contrary, no detectable community ware found in control sediment. Both phylogenetic groups are closely related to marine microflora. Conclusions: This study emphasizes the importance of calcium peroxide as an oxygen release material. Interaction with peroxide proved to be enhancing the formation of microbial community that are beneficial for biodegradation and spontaneity of nutrient attenuation into overlying water.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 추계학술대회
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• pp.99-102
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• 2004

Display process has adopted RCA clean, being applied to large area and coped with environmental issue for last ten years. However, the approaching concept of ozonized, hydrogenised, or electrolyzed water cleaning technologies is within RCA clean paradigm. In this work, only electrolyzed anode water was applied to clean particles and organics as well as metals based on Pourbaix concept, and as a test vehicle, MgO particles were introduced to prove the new concept. The electrolyzed anode water is very oxidative with high oxidation reduction potential(ORP) and low in pH of more than 900mV and 3.1, respectively. MgO particles were immerged in the anode water and its weight losses due to dissolution were measured with time. Weight losses were in the ranges of 100 to 500 micrograms in 250m1 anode waters depending on their ORP and pH. Therefore it was concluded that the cleaning radicals in the anode water was at least in the range of 1 to 5E20 ea per 250 ml anode water equivalent to IE18 ea/cm3. Hence it can be assumed that the anode water be applied to display cleaning since 1E10 to IE15 ea/cm3 ranges of contaminants are being treated. In addition, it was observed that anode water does not develop micro-roughness on hydrophobic surface while it does on the native silicon oxide.

• 대한환경공학회지
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• 제32권4호
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• pp.379-392
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• 2010

최근 국내에서 인공습지는 하 폐수처리장 방류수의 후처리, 비점오염원 관리, 생태하천 복원 등 다양한 용도로 적용되고 있다. 그러나 인공습지가 설치되는 지역의 기후, 유입수의 특성, 지역적 특성 등에 따라 매우 영향을 많이 받기 때문에 인공습지 내에서의 오염물질의 제거기작은 확실하게 이해되고 있지는 않다. 그러므로, 이 연구에서는 인공습지 내에서 질소, 인을 중심으로 한 오염물질의 제거기작을 중심으로 살펴보았다. 그 결과, 질소 제거의 주된 기작은 인공습지 내의 근권(rhizosphere)에서의 질산화/탈질에 의한 것으로 판단되며, 인 제거의 주된 기 작은 인공습지내 여재 등의 기층(substrate)에서의 흡착에 의한 것으로 판단된다. 그러나, 인공습지내의 인의 거동은 산화/환원 전위(ORP), 흡착/탈착, 미생물의 작용 등에 따라 다양한 형태를 가질 수 있는 것으로 판단된다.

• 상하수도학회지
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• 제12권4호
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• pp.86-96
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• 1998

In this study, an intermittently aerated activated sludge process, modified process from conventional activated sludge process, was developed to treat high strength swine wastewater, which has been blamed as major pollutant for stream pollution. Therefore, the optimum cycle for oxic and anoxic period, SRT, and OLR were studied as design parameters. The effects of different time interval for oxic and anoxic period on nitrification and denitrification were examined by operating two reactors with 60/60min and 60/90min as oxic/anoxic period. Although the reactor with 60/60min showed complete denitrification of $NO_x-N$ generated during oxic period, the reactor with 60/90min showed incomplete nitrification due to the inactivity of nitrifier by accumulated $NH_3-N$ toxicity during anoxic period. Therefore, it is recommended to operate same interval for oxic and anoxic period. In order to determine the optimum cycle for oxic/anoxic period, four different reactors with 30/30, 60/60, 90/90 and 120/120min were examined. The reactor operation with 90/90min was optimum to get the most stable results in this study. However, the optimum cycle for oxic and anoxic period should be changed with characteristics of influent wastewater and operating conditions. According to lie operation results of three reactors with SRT of 15, 20 and 30days. The reactor with 2Odays SRT showed best removal efficiency of T-N. The optimum OLR would be $2.5Kg\;COD/m^3/day$ which showed the most stable nitrification and denitrification. Since characteristics of influent wastewater in the real system has a severe fluctuation, so it is very difficult to determine each interval for oxic and anoxic period. Therefore, ORP curves, describing the change of oxidation/reduction potential in reactor, can be used as a control parameter for automatic control of oxic and anoxic period. In other words, bending point (Nitrate Knee) of ORP curve during anoxic period could be used as a starting point of oxic period.

• 한국산학기술학회논문지
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• 제13권7호
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• pp.3285-3294
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• 2012

현장 갯벌에서의 미생물제제와 $CaO_2$처리를 통한 효율성을 관찰하고자 유용미생물 및 미생물과 $CaO_2$를 혼합하여 특수 처리한 제제를 $100m^2$ 크기의 각 처리구에 3.6kg씩 살포하여 6주간 모니터링 결과, 두 처리구로부터 pH 및 ORP는 평균 pH 7이하, ORP는 초기 값(-178 mV ~ -188 mV)에 비해 .121.06 mV ~ -142.06 mV로 다소 상승하였다. 강열감량과 COD의 경우, 큰 변화가 없었으며 질소와 인 계열은 다소 효과가 있었는데 암모니아는 시간이 경과함에 따라 대조구와 더불어 낮아지는 경향을 보였으며 질산성질소의 경우, $CaO_2$와 미생물제제의 혼합처리(11.3%)가 미생물제제 처리(7.3%)보다 질산염농도가 감소한 이유는 산소발생에 의한 어느 정도의 호기화된 조건에서 질산화반응에 의해 퇴적토의 질산염이 수층으로 용출된 결과로 생각되며 이에 따라 총 질소의 농도도 혼합처리에 의한 감소(6.1%)로 이어진 결과라 판단된다. 마찬가지로 인의 경우에도 초기 농도가 다소 높은 수치(T-P는 0.761 mg/g, $PO_4-P$는 0.529 mg/g)를 보였으나 혼합 처리구에서 T-P는 29%, $PO_4-P$는 31.8%의 감소율로 미생물제제보다 인의 용출을 억제시킨 결과로 나타났다.

• 한국식품과학회지
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• 제39권2호
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• pp.152-157
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• 2007

해조성분 강화 기능성소금 3종(Hizikia mineral salt, fucoidan salt, laver salt)을 제조하여 일반적 품질특성 및 무기성분 조성, 용해도, 관능특성 및 ACE 저해활성과 bile acid 결합력을 알아보았다. 수분함량은 Hizikia mineral salt의 경우 대조시료와 유의한 차이가 없었으나 fucoidan salt와 laver salt는 상대적으로 높은 수분함량을 나타내었다. 염도는 해조성분 강화 기능성소금 3종 모두 대조시료 보다는 약간 낮은 값을 나타내었고 pH는 Hizikia mineral salt의 경우 11.34로 다소 높은 값을, fucoidan salt와 laver salt은 6.88과 6.53으로 중성에 가까운 값을 나타내었으며, ORP는 -229 mV에서 38 mV로 월등히 낮은 값을 나타내었다. 기능성 소금의 L, a, b 값은 모두 정제염 보다는 약간 어두운색을 나타내었다. 무기물 함량은 Hizikia mineral salt에서 혈압 저하에 효과가 있는 무기성분인 $K^{+}$ 함량이 다량 함유되어 있었으며 용해도는 Hizikia mineral salt가 다소 떨어지는 경향을 나타내었으나 큰 차이는 나타나지 않았다. 관능특성을 알아본 결과 $Na^{+}$ 이외의 미네랄 성분을 다량 함유하고 있는 Hizikia mineral salt를 제외한 나머지 fucoidan salt, laver salt에서는 색을 제외한 모든 항목에서 높은 점수를 받아 조미기능성 염으로서도 사용가치가 기대되었다. 또한, laver salt는 54.8% 수준의 ACE 저해 활성값을 나타내었으며, fucoidan salt는 54.1-80.7% 수준의 높은 bile acid 결합특성을 각각 나타냄으로서 콜레스테롤 대사 및 혈압조절 기능성을 갖고 있는 것으로 사료되었다.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1010-1015
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• 2008

The effects of heat treatment on the physicochemical properties and mineral composition of sun-dried salt were investigated. The salts parched at high temperature were appeared the higher alkalinity and the lower oxidation-reduction potential (ORP) than the samples without heat treatment. The commercial salts (bamboo salt and yellow loess salt) and the sun-dried salt parched at high temperature had relatively higher sodium ion content (418-450 ppm) compared to that (418.0 ppm) of refined salt. The increase of calcium ion occurred in the salts parched at high temperature compared to the sun-dried salt without heat treatment, but the magnesium ion was vice versa. The commercial salt, yellow loess salt had highest turbidity (0.973) whereas sun-dried salt showed lowest level (0.097) among the tested samples. Turbidity of heat treatment samples decreased as solubility increased. The maximum concentration of dialyzed salt was reached after 4 hr regardless of various processed salts, but those had no difference significantly among the tested samples. The X-ray diffraction patterns of the parched sun-dried salts showed different peak intensity with common salts, and they were similar to the patterns of oxide salts, especially MgO. The maximum value (2.56%) of MgO appeared in the sun-dried salt parched at $1,400^{\circ}C$.