• 한국염색가공학회지
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• 제25권3호
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• pp.215-222
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• 2013

The purpose of this study is to minimize fading fabrics of surgical gown by repeated severe laundering and sterilization condition. The study showed that the best conditions were reduction cleaning using sulphinic acid derivatives or glucose organic chemicals at $98^{\circ}C$ alkaline solutions. In these conditions, color difference values(dE) were below 1.0 that means unrecognizable color change by repeated laundering and sterilization. If it treated with only laundering, reduction cleaning conditions may adjust over $80^{\circ}C$ alkaline solution. In conclusion, it is needed to select the high-washing fastness dye and reduction cleaning using sulphinic acid derivatives or glucose organic chemicals at $98^{\circ}C$ alkaline solutions for removal unfixed dyes.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1145-1152
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• 2013

The rate constant of alkaline fading of methyl green ($ME^{2+}$) was measured in the presence of non ionic (TX-100), cationic (DTAB) and anionic (SDS) surfactants. $ME^{2+}$ hydrolyses and fades in neutral water and in this work we search the effects of surfactants on its fading rate. The rate of reaction showed remarkable dependence on the electrical charge of the used surfactants. It was observed that the reaction rate constant decreased in the presence of DTAB and SDS and increased in the presence of TX-100. Binding constants of $ME^{2+}$ to TX-100, DTAB and SDS and the related thermodynamic parameters were obtained by classical (or stoichiometric) model. The results show that binding of $ME^{2+}$ to TX-100 and DTAB are two-region and that of SDS is three-region. Also, the binding constants of $ME^{2+}$ to surfactant molecules in DTAB/TX-100 and SDS/TX-100 mixed solutions and their stoichiometric ratios were obtained.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2051-2056
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• 2009

The rate constants of alkaline fading of malachite green ($MG^+$) was measured in the presence of nonionic (TX-100), cationic (DTAB) and anionic (SDS) surfactants. This reaction was studied under pseudo-first-order conditions at 283∼303 K. The rate of fading reaction showed noticeable dependence on the electrical charge of the used surfactants. It was observed that the reaction rate constants were increased in the presence of TX-100 and DTAB and decreased in the presence of SDS. According to Hughs-Ingold rules for nucleophilic substitution reactions, the electric charge of MG/surfactant compound along with decrease in dielectric constant of $MG^+$ micro-environment in this compound varies the rate of fading reaction. Binding constants of surfactant molecules to $MG^+$ were calculated using cooperativity, pseudo-phase ion exchange and classical models and the related thermodynamic parameters were obtained by classical model. The results show that the binding of $MG^+$ to TX-100 is exothermic and binding of $MG^+$ to DTAB and SDS in some concentration ranges of the used surfactants is endothermic and in the other ones is exothermic.

• KSBB Journal
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• 제26권5호
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• pp.471-476
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• 2011

Nowadays biodiesel (fatty acid methyl ester, FAME) has been becoming an important issue as a desired alternative of energy products because of non-toxic, biodegradable properties, and lower exhaust emissions. During esterification of fatty acids or transesterification of oils and fats with short chain alcohols by the alkali-catalyzed methanolysis, FAME and unrefined glycerol are generated. Quantification of glycerol as a by-product is important because of a determinant of biodiesel quality. However, the glycerol analysis by gas chromatography (GC) method has laborious works with sample preparation, long time and cost of sample analysis. Thus, there is a need to analyze glycerol more simply. Herein we demonstrate that the colorimetric assay for glycerol analysis conducted by UV-vis spectrophotometer at the wavelength 617 nm whose peak is maximum intensity of malachite green, resulting in the red-shift occurred proportionally as a function of glycerol amount. Thus, it is considered the solvent media for malachite green fading for biodiesel production: (1) water, (2) MeOH, and (3) EtOH. The resulting findings show that the peak intensity at 617 nm in glycerol-malachite green mixture had a relationship between glycerol concentration and degree of peak shift as increase in pure glycerol concentration approximately at pH 7.0. However, when it was measured the unrefined glycerol concentration by diluting and adjusting with water to buffer (pH 7.0), it was not observed the absorption peak at 617 nm because of impurities and OH ions. In case of glycerol from biodiesel production factories, glycerol concentration could be successfully measured.

• 한국수소및신에너지학회논문집
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• 제32권1호
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• pp.41-52
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• 2021

NiO and Co3O4-doped porous La(CoNi)O3 perovskite oxides were prepared from excess Ni addition by a hydrothermal method using porous silica template, and characterized as bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for Zn-air rechargeable batteries in alkaline solution. Excess Ni induced to form NiO and Co3O4 in La(CoNi)O3 particles. The NiO and Co3O4-doped porous La(CoNi)O3 showed high specific surface area, up to nine times of conventionally synthesized perovskite oxide, and abundant pore volume with similar structure. Extra added Ni was partially substituted for Co as B site of ABO3 perovskite structure and formed to NiO and Co3O4 which was highly dispersed in particles. Excess Ni in La(CoNi)O3 catalysts increased OER performance (259 mA/㎠ at 2.4 V) in alkaline solution, although the activities (211 mA/㎠ at 0.5 V) for ORR were not changed with the content of excess Ni. La(CoNi)O3 with excess Ni showed very stable cyclability and low capacity fading rate (0.38 & 0.07 ㎶/hour for ORR & OER) until 300 hours (~70 cycles) but more excess content of Ni in La(CoNi)O3 gave negative effect to cyclability.

• 대한화학회지
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• 제38권12호
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• pp.880-884
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• 1994

알칼리성 $100\circC$ 과망간산칼륨에 의한 화학적 산소 요구량 절차에서 과망간산의 진한 분홍색의 탈색 정도가 COD의 양에 의존하는 사실에 착안하여 간단하게 COD를 정량할 수 있는 간접 분광광도법의 기초 조건들을 조사하였다. 여러 농도의 COD(0∼5 ppm) 표준시료(시료량 5ml)와 과량의 과망간산을 함유한 용액 10ml를 일정 시간 동안 환류한 후 535nm에서 측정한 흡광도-농도 곡선이 가장 좋은 직선성을 갖는 조건을 찾았다. 과망간산칼륨 농도 0.15 mM, NaOH 0.2%, 가열 온도 $100\circC$, 그리고 가열 시간 10분일 때가 가장 좋았다. 총 소요 시간은 15분이며, t-검정 결과 공정시험법과 큰 차이가 없었다.

• 한국의류학회지
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• 제32권12호
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• pp.1963-1970
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• 2008

전통적인 니남쪽염료 제조법을 기준으로 굴껍질가루 대신 칼슘하이드록사이드를 사용하여 천연인디고분말염료를 만들었다. 제조한 인디고분말염료에 대한 텐셀의 염색성을 몇 가지 실험조건에서 조사하였으며 염색견뢰도를 측정하였다. 제조한 인디고분말염료는 약 15.5%의 인디고 성분과 0.757%의 인디루빈 성분을 함유하는 것으로 분석되었다. 환원과 염색을 자동염색기로 one-step으로 하였으며 환원제로 소디움하이드로설파이트를 사용하였다. 최대염착량은 $60^{\circ}C$에서 얻었으며 초기 20분 동안에 염착이 거의 이루어졌다. 본 연구의 실험조건 범위에서는 염료농도 4g/L까지는 2g/L의 환원제 농도에서, 염료농도 8g/L에서는 3g/L의 환원제 농도에서 최대염착량을 보였다. 텐셀은 염욕에 가성 소다를 넣지 않고 pH 5.75에서 염색할 때 훨씬 높은 염착량을 나타냈다. 염색견뢰도는 4/5-5등급으로 대체로 우수하였으며, 염착량이 낮을수록 더 높은 광퇴색을 보였다.