• 한국환경보건학회지
• /
• 제38권3호
• /
• pp.251-260
• /
• 2012

Objectives: The purpose of this study was evaluating the applicability of the circulation dielectric barrier plasma process (DBD) for efficiently treating non-biodegradable wastewater, such as phenol. Methods: The DBD plasma reactor system in this study consisted of a plasma reactor (discharge, ground electrode and quartz dielectric tube, external tube), high voltage source, air supply and reservoir. Effects of the operating parameters on the degradation of phenol and $UV_{254}$ absorbance such as first voltage (60-180 V), oxygen supply rate (0.5-3 l/min), liquid circulation rate (1.5-7 l/min), pH (3.02-11.06) and initial phenol concentration (12.5-100 mg/l) were investigated. Results: Experimental results showed that optimum first voltage, oxygen supply rate, and liquid circulation rate on phenol degradation were 160 V, 1 l/min, and 4.5 l/min, respectively. The removal efficiency of phenol increased with the increase in the initial pH of the phenol solution. To obtain a removal efficiency of phenol and COD of phenol of over 97% (initial phenol concentration, 50.0 mg/l), 15 min and 180 minutes was needed, respectively. Conclusions: It was considered that the absorbance of $UV_{254}$ for phenol degradation can be used as an indirect indicator of change in non-biodegradable organic compounds. Mineralization of the phenol solution may take a relatively longer time than that required for phenol degradation.

• 대한화학회지
• /
• 제52권2호
• /
• pp.133-139
• /
• 2008

고상추출 매질로 bis-(2-ethylhexyl)phthalate를 포함하는 polyvinyl chloride막을 사용하여 카드뮴의 잔유양 을 측정하기 위한 새로운 민감하고 선택적인 분광광도법을 연구하였다. Bis-(2-ethylhexyl)phthalate는 가소제로 사용되 었다. 수용액에서 Cd(II)은 색을 가진 Cd(II) - I- - MG 착체(여기서 MG는 malachite green이다). 형으로 있는 막에 의해 트랩되었고, 카드뮴 착체는 막에 농축되었다. 그린색의 막의 흡수는 분광광도법을 사용하여 629 nm에서 측정되었 다. 카드뮴 농도는 Cd(II) 농도와 25분 동안 착색후 막의 흡수 사이에 관계로 나타내는 검정곡선으로부터 계산하였다. 검정곡선은 시험용액에서 10-760 μgL-1 cadmium 범위에서 선형이었다. 3Sbl criterion의 검출한계는 1.8199 μgL-1 상 대 표준편차(RSD)는 4% (n=5).보다 적다. 제안된 방법은 Tadjan강(Sari-Iran), 에 있는 카드뮴의 잔량을 성공적으로 측 정하였다. 28.7 μgL-1의 평균 값을 얻었다.

• 한국염색가공학회지
• /
• 제28권1호
• /
• pp.1-13
• /
• 2016

Natural colorant extracts were obtained by extraction from tumeric root, gardenia seeds, mugwort and green tea using water, methanol, ethanol and acetone as extractants at room temperature for 3 hours under shaking condition(180rpm) with liquor ratio(solid:solvent; 1:100). The main pigment components of tumeric root, gardenia seeds, mugwort and green tea are known to be curcumin, crocin, chlorophyll b and epigallocatechin gallate, respectively. The effects of the kind of extractant and pH on the color characteristics of natural colorant extracts were investigated. The solubility parameters of pigment components were determined to find adequate extractant. The solubility parameters of curcumin, crocin, chlorophyll b and epigallocatechin gallate were found to be 27.85, 29.40, 19.48 and $37.97(J/cm^3)^{1/2}$. As expected, solvents that have a solubility parameter similar to that of pigment component were generally found to be effective to obtain pigment extracts having high visible absorbance(A). The extract(pigment/solvent) with high visible absorbance was generally found to have low $L^*$(lightness) and high Chroma($C^*$, purity).

• 공업화학
• /
• 제16권3호
• /
• pp.366-371
• /
• 2005

본 연구에서는 methylene blue의 오존 산화하는 동안 BOD, COD, TOC, 흡광도 그리고 탈색 비율을 분석하였으며, 오존산화반응은 methylene blue가 충진되어 있는 원형모양의 반응기에서 수행한 결과 다음과 같은 결론을 얻었다. 탈색도는 최대파장(${\lambda}_{max}$, 660 nm)에서 흡광도를 측정하였다. 오존농도는 $50{\pm}10mg/L$를 사용하였으며 40 min 후 거의 오존산화반응이 끝났다. 그 결과로 $30^{\circ}C$에서 오존산화 반응 후 $TOC/TOC_0$ 비율은 83.8%로 나타났고, COD는 초기값보다 44.0% 감소하였다. 그리고 $BOD_5/COD$ 비율은 64.2%에서 90.8%로 오존산화 반응 후 생분해도가 증가하는 것으로 나타났다. 반응속도상수는 $3.30{\times}10^{-2}min^{-1}$로 나타났으며, 활성화 에너지는 $3.01kcal{\cdot}mol^{-1}$로 나타났다.

• Bulletin of the Korean Chemical Society
• /
• 제35권11호
• /
• pp.3275-3279
• /
• 2014

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

• 한국식품영양과학회지
• /
• 제23권2호
• /
• pp.287-292
• /
• 1994

This paper was investigated to elucidate the nitrite-scavenging action as one of biological actions of green tea extracts. Green tea extracts exhibited remarkable nitrite-scavenging action. Among the green tea extracts, steamed green tea showed higher nitrite-scavenging action than roasted green tea. Nitrite-savenging actions of gren tea extracts were hardly influenced until three times extraction with hot water. Furthermore , the nitirte-scavenging action of green tea extracts showed ph dependent , highest at pH 1.2 and lowest at pH 6.0. The nitrite -scavenging rate in sample extracts /amine /nitrite systems exhibited faster than that in amine/nitrite systems. In order to screen the nitirte-scavenging factors, samples extracts were fractionated with methanol. in both samples, methanol-soluble fractions possessed greater nitrite-scavenging action than methanol-insoluble fractions .The nitrite-scavenging action of methanol-soluble fractions increased with proportion to absorbance at 420nm and at 280nm, while that of green tea extracts increased with the contents of total phenols and absorbance at 280nm.

• 한국응용과학기술학회지
• /
• 제38권1호
• /
• pp.9-18
• /
• 2021

본 연구는 인디고 염료로 모발에 도포하여 염색효과와 모질 특성 변화를 알아보고자 하였다. 연구방법은 인디고 염료를 중탕하여 사용하였다. 염료를 건강모와 탈색한 시료 모발에 도포 후 열처리와 자연방치 시간을 다르게 하였다. 측정은 시료별로 도포 전과 후를 측정하여 비교 분석하였다. 염색효과를 알기 위해 색차계를 이용하여 L⁎, a⁎, b⁎값과 물 빠짐을 측정하였다. 모질 변화를 알기 위해 인장강도, 메틸렌블루를 이용한 흡광도, 광택을 측정하였다. 결과는 염색효과 측정 결과 모든 시료에서 L⁎값, a⁎값, b⁎ 값의 도포 전과 후의 통계분석 결과는 유의미한 결과로 염색 효과가 있었다. 물 빠짐 측정결과는 1일차에는 가장 많이 빠졌고, 3일차부터는 더 이상의 물 빠짐이 없었다. 인장강도 측정결과는 모든 시료의 평균값은 증가하였다. 그러나 통계분석 결과 유의미하지 않은 결과로 모질의 특성 변화는 없었다. 메틸렌블루를 이용한 흡광도 분석결과 건강7L(3)을 제외 한 시료에서 통계분석 결과 모질의 특성 변화는 없었다. 광택측정결과는 통계분석 결과 광택에 변화를 주는 것을 알 수 있었다. 결론은 인디고 염료에 의한 모발 염색효과가 있었고, 모질의 특성 변화는 광택은 있고, 인장강도와 흡광도 변화는 없었다. 차후 다양한 염색 처리방법 연구와 신뢰성과 객관적 결과를 위한 측정 연구가 필요하다.

• 전기학회논문지
• /
• 제63권9호
• /
• pp.1239-1244
• /
• 2014

In this study, two fiber-optic sensors were fabricated to measure water level and temperature using optical fibers, a coupler, a Lophine and an OTDR (optical time-domain reflectometer). First, using Fresnel's reflection generated at the distal-ends of each optical fiber, which was installed at different depth, we measured the water level according to the variation of water level. Next, we also measured the temperature of water using a temperature sensing probe based on the Lophine, whose absorbance changes with the temperature. The measurable temperature range of the fiber-optic sensor is from $5^{\circ}C$ to $65^{\circ}C$ because the maximum operation temperature of the optical fiber without a physical deterioration is up to $80^{\circ}C$.

• Toxicological Research
• /
• 제24권3호
• /
• pp.207-212
• /
• 2008

Pesticide residues play several key roles as environmental and food pollutants and it is crucial to develop a method for the rapid determination of pesticide residues in environments. In this study, a simple, effective, and sensitive method has been developed for the quantitative analysis of methoxyfenozide in water and soil when kept under laboratory conditions. The content of methoxyfenozide in water and soil was analyzed by first purifying the compound through liquid-liquid extraction and partitioning followed by florisil gel filtration. Upon the completion of the purification step the residual levels were monitored through high performance liquid chromatography(HPLC) using a UV absorbance detector. The average recoveries of methoxyfenozide from three replicates spiked at two different concentrations and were ranged from 83.5% to 110.3% and from 98.1% to 102.8% in water and soil, respectively. The limits of detection(LODs) and limits of quantitation(LOQs) were 0.004 vs. 0.012 ppm and 0.008 vs. 0.024 ppm, respectively. The method was successfully applied to evaluate the behavioral fate of a 21% wettable powder(WP) methoxyfenozide throughout the course of 14 days. A first-order model was found to accurately fit the dissipation of methoxyfenozide in water with and a $DT_{50}$ value of 3.03 days was calculated from the fit. This result indicates that methoxyfenozide dissipates rapidly and does not accumulate in water.

• Composites Research
• /
• 제35권1호
• /
• pp.18-22
• /
• 2022

복합재료의 제조에 있어서 분산은 매우 중요한 요소 중 하나이다. 복합재료의 제조 시 matrix 용재에 강화재를 보다 잘 분산하기 위하여 용매를 사용하는데 용매에 따라 분산도가 달라지기 때문에 어떠한 용매가 분산에 용이할지에 대한 연구가 필요하다. 본 연구에서는 다양한 솔벤트 용매(DMF, NMP, Ethylene glycol, Acetone, DI water)에 대해 나노 필러인 산화 그래핀(Graphene oxide)의 용매에 따른 GO의 분산거동과 용해도 분석을 통해 분산에 유리한 용매를 파악하고자 하였다. 그 결과 UV-Vis spectroscopy 흡광도 측정을 통해 DMF와 Ethylene glycol이 가장 좋은 분산성을 가짐을 알 수 있는 반면 DI water는 가장 낮은 분산성을 보임을 알 수 있었다. 또한 표면장력과 시간에 따른 분산 육안 관측을 통해 DI water, Ethylene glycol, NMP, DMF, Acetone 순으로 분산성이 우수한 것을 알 수 있었는데 이는 Hansen solubility parameter 값과 일치하는 경향임을 확인할 수 있었다.