• 한국염색가공학회지
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• 제14권6호
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• pp.305-312
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• 2002

In order to give a silk-like touch to PET fabrics, the PET fabrics were treated with NaOH alkaline solution in various conditions. In alkaline treatment, the liquor flow type pilot weight reduction apparatus with magnetostrictive ultrasonic transducer was used for the study. The effects of ultrasonic application, treatment time and temperature at NaOH 4% and 6"A solution on the decomposition rate of PET fabrics. From the results of the decomposition rate of PET fabrics, the qualitative and quantitative analysis of oligomer after decomposition of PET fabrics carried out by the HPLC. On the other hand, the surface pore characteristics of decomposition PET fabrics measured by porosimetery. The pore characteristics on the surface of treated PET fiber depended on the decomposition rate and did not depend on the ultrasonic cavitation. The pore diameter of alkaline untreated PET fiber were 15A and those of treated PET fibers were 5~6$\AA$ at the maximum pore volume. The average pore sizes of fiber before and after treatment were 141 h and 160h, respectively. Total amount of oligomer of the untreated PET fibers were 1.70wt% and 67.7% of total oligomer occupied with PET cyclic trimer and PET cyclic tetramer. Total amount of oligomer of fiber with 26.9% and 48.0% of weight loss without ultrasonic application were 1.78wt% and 1.79wt%, respectively. Also total amount oligomer of fibers which were reduced 27.7% and 48.2% of weight loss with ultrasonic application were 1.74wt%. This result showed that the removal rate of oligomer in the process of alkaline hydrolysis with ultrasonic higher than that of without ultrasonic application.tion.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2006년도 춘계학술발표회 논문집
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• pp.180-181
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• 2006

The hydrolysis of some vinylsulfonyl (VS) typed reactive dyes were investigated at the pH, temperature and other experimental conditions. The hydrolytic behaviour, especially, stability in various pH value, of the water soluble reactive dyes are examined. In neutral and acid condition, mother dyes are a quite stable. Other hand, it was found that dimerization and decomposition for these dyes were estimated in an aqueous alkaline medium. These alkaline hydrolysis behaviour was monitored by the high performance liquid chromatography.

• 한국염색가공학회지
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• 제14권4호
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• pp.214-222
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• 2002

In order to give a silk-like touch to PET fabrics, the PET fabrics were treated with NaOH alkaline solution in various conditions. In alkaline treatment, the liquor flow type pilot weight reduction apparatus with magnetostrictive ultrasonic transducer was used for the study. The weight loss of PET fabrics hydrolyzed in 4% and 6% NaOH solution, at $95^\circ{C}$ and $99^\circ{C}$ for 60min. with ultrasonic application showed 3.7~4.6% higher than that of treated fabric without ultrasonic application. From the difference of specific weight loss, the treatment condition of the maximum of hydrolyzation effect appeared at $95^\circ{C}$ in $4^\circ{C}$ and at $90^\circ{C}$ in 6% NaOH solution, respectively. During the alkali hydrolysis of PET fabrics, the decomposition rate constant(k) increased exponentially with the treatment temperature and were not related with ultrasonic cavitation. The activation energy$(E_a)$ in decomposition of PET fabrics were 21.06kcal/mol with ultrasonic application and 21.10kcal/mol without ultrasonic application. The ultrasonic application gave a little higher value of the activation entropy$(\Delta{S}^\neq)$ and a little lower value of Gibbs free energy$(\Delta{S}^\neq)$ compared with not used ultrasonic apparatus.

• 기술사
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• 제14권1호
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• pp.22-29
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• 1981

This study concernes the decomposition of cyanide ion in electroplating plant wastewater and COD variation of photodeveloping wastewater under various conditions. Determinations of CN- concentration were carried out by AgNO$_3$ titration method. The sample solutions were pretreated by passing ozone and decompositions were checked as a function of time for ozone treatment. Analysis of film developing wastewater was carried out by KMnO$_4$ method. Electroplating plant wastewater was also examined at various pH; decomposition rate of cyanide ion was found to increase at higher pH. Time required for the decomposition could be shortened by removing the heavy metal ions under alkaline condition. The effect of temperature on decomposition was studied at 40$^{\circ}$ and 60$^{\circ}C$. The result was better at 40$^{\circ}C$ although time for decomposition was almost same at both temperatures. Analysis of film developing wastewater revealed that COD decrease was faster during the first 1 to 2 hours. However, further decrease could not be effected. The existence of unknown special organics resistant to the decomposition was believed to be the reason.

• Ocean and Polar Research
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• 제25권1호
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• pp.53-62
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• 2003

Inductively coupled plasma mass spectrometry (ICP-MS) is useful instrument for determining abundance of rare earth elements, due to very low detection limits and rapid data acquisition. In this article, two methods are used for decomposition of alkaline rocks; close vessel acid digestion and $Na_2Co_3$ fusion. The two analytical results show good agreements. Considering total dissolved solids and detection limits, the most adequate dilution factor is 5,000 times. Polyatomic ion interferences during analysis can give rise to Inaccuracies. After correction from oxide and hydroxide interference, the analytical result show 20-30% decrease for Gd and Tm, 10-20% decrease for Tb and Er. In comparing the analytical results from KORDI with other institutes, most rare earth elements abundance show good agreements except Lu.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.231-234
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• 2002

According to recent investigations regarding Fenton-like reaction, it was reported that there was a key factor to decompose organic materials by not only the hydoroxyl radical but also several reductants which were superoxide anion and hydroperoxide anion. This research was focused on an investigation of the decomposition of carbon tetrachloride(CT) by reductants which were generated by pyrolusite with hydrogen peroxide. Generally, CT decomposition rate increased with raising pH values. Especially,, CT was decomposed over 60 percent by 10,000 ppm of hydrogen peroxide within 10 minutes in neutral condition. In addition, the decomposition of chlorinated compounds would be accelerated in alkaline condition, even with low concentration of hydrogen peroxide.

• Journal of Pharmaceutical Investigation
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• 제18권3호
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• pp.125-131
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• 1988

This study was undertaken to investigate the proteolytic enzyme from Neungee mushroom [Sarcodon aspratus (Berk) S. Ito]. The proteolytic activity of Neungee was higher than other several edible mushrooms under various pHs. The potency of proteolytic enzyme of Neungee was same as the digestive drugs containing protease. So the proteolytic activity of the enzyme was increased in neutral or weak alkaline pH, whose characteristics would be alkaline protease. The specific activity of the purified enzyme obtained by using Tris acryl CM-cellulose ion exchange increased 20 times as compared with that of the crude extract. The proteolytic enzyme was stable at room temperature, but decomposition was fast when incubated at higher temperature more than $40^{\circ}C$. The half life of the enzyme was longest in neutral pH and rate constant was increased in acidic or alkaline solution.

• 자원리싸이클링
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• 제29권1호
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• pp.17-24
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• 2020

침철석을 주요 맥석광물로 하는 난용성 자원으로부터 희토류를 회수하기 위해 화학적 분해-산 침출의 2단계 방법을 이용한 맥석광물 분해 및 희토류 침출율 향상 연구를 수행하였다. 화학적 분해에는 알칼리인 NaOH를 사용하였으며 NaOH 용액 농도 20-50 wt%, 광액 농도 10% (w/w), 온도는 각 농도에서 NaOH 용액이 끓지 않는 최대 온도로 하여 분해 반응을 진행하였다. NaOH 농도가 높아질수록 경희토류 (Ce, La, Nd) 와 철은 고체상의 분해 산물 내에 농축되는 경향을 나타냈으며, 알루미늄과 인은 용액상으로 제거되어 50 wt% NaOH로 분해 시 고체상에 각각 0.96%, 0.17% 만이 잔류하는 것으로 나타났다. 또한, 주요 맥석광물인 침철석의 결정성이 분해 과정 후 감소하는 것으로 분석되었다. 50 wt% NaOH 분해 산물을 3.0 M 염산, 80 ℃ 조건에서 3시간 동안 침출했을 때, 94% 이상의 희토류 침출율을 달성하였으며 (Ce 80%), 불순물 중 알루미늄 침출율이 12%, 인 침출율이 0%로 감소하여 본 광석에 대한 최적 분해 및 침출 조건으로 선정하였다. 본 실험 결과로부터 희토류와 철의 침출율 간에 양의 상관관계가 있는 것으로 분석되었으며, 따라서 침철석의 결정성 감소가 희토류 침출율 향상에 기여한다고 할 수 있다.

• Archives of Pharmacal Research
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• 제20권6호
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• pp.643-646
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• 1997

Thermal stability of a red pigment, carthamin, frm Carthamus tinctorius was investigated to explore possible applications as natural color additives for foods, cosmetics, and nutraceuticals. Degree of degradation reactions of carthamin at acidic, neutral and alkaline conditions were determined with UV/V is spectral measurements. Decomposition half lives of carthamin at 25.deg. C were 4.0 h, 5.1 h, and 12.5 h at pH 5.0, pH 7.0, and pH 12.0, respectively, indicating that carthamin is much more stable at alkaline pH than acidic or neutral conditions. The activation energies of carthamin at pH 5.0, pH 7.0, and pH 12.0 were 15.6, 15.7 and 16.8 kcal/mol, respectively.

• 한국세라믹학회지
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• 제46권3호
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• pp.271-274
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• 2009

Redox investigation of Sn and S ion was attempted in alkaline earth borosilicate glass melts with only 1 mol% $Na_2O$ by means of Square Wave Voltammetry (SWV). According to voltammograms, there was only one peak due to $Sn^{4+}/Sn^{2+}$ in melt doped with $SnO_2$. The calculated standard enthalpy and entropy of the reduction of $Sn^{4+}$ to $Sn^{2+}$ were 116kJ/mole and 62 J/mol K, respectively. The determined redox ratio, [$Sn^{2+}$] / [$Sn^{4+}$] in the temperature range of $1300{\sim}1600^{\circ}C$ was in $0.4{\sim}2.1$. On the contrary, in the voltammogram of melt doped with $BaSO_4$ there was no peak due to $S^{4+}/S^o$ but shoulder that might be attributed to the adsorption of sulfur at the electrode. The absence of the peak related with $S^{4+}/S^o$ was discussed from the view-point of the thermal decomposition behavior of $BaSO_4$ in the glass batch.