• Journal of Environmental Health Sciences
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• v.8 no.2
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• pp.33-46
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• 1982

This experiment was carried out for the purpose of reducing alkaloid in reconstituted tobacco sheet and effluent of reconstituted tobacco sheet manufacturing company by treating oxidizing agents such as ozone, sodium hypochlorite, perchloric acid and hydrogen peroxide to tobacco extract created from the manufacturing process of reconstituted tobacco sheet. The effect of alkaloid reduction in tobacco extract by the volume added, time of treatment and pH of oxidizing agents were as follows: 1. When the solid rate of tobacco extract stood at 10 percent, the content of alkaloid, total sugar, total nitrogen and chlorine was 1,600mg/l, 11,000mg/l, 3,200mg/l and 4,000mg/l, respectively. 2. The effect of alkaloid reduction through ozone treatment was in proportion to time of ozone treatment. Alkaloid showed a 31.2 percent reduction under 8 hours' ozone treatment and 0.23g ozone consumed to remove lmg alkaloid. 3. Alkaloid reduction through sodium hypochlorite treatment was influenced by quantity of chlorine in sodium hypochlorite solution. To remove lmg alkaloid, 36.3mg chlorine was used. Reduction of alkaloid was not affected by time of sodium hypochlorite treatment, while showed the best reaction under pH 5-7. 4. The effect of alkaloid reduction by perchloric acid was under the control of the volume added and time of treatment of perchloric acid. The volume of perchloric acid required to remove alkaloid was on the decrease as time of treatment was getting longer. lmg alkaloid was removed by 0.15g perchloric acid under 8 hours' perchloric acid treatment. 5. Alkaloid reduction reacted slowly to the volume added and time of treatment of hydrogen peroxide. Under 8 hours' hydrogen peroxide treatment, it showed maximum removal, registering 10 percent alkaloid reduction.

• Polymer(Korea)
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• v.24 no.6
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• pp.869-876
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• 2000

In order to improve the cell-compatability of poly(L-lactide-co-glycolide) (75 : 25 by mole ratio of lactide to glycolide, PLGA) surfaces, the physicochemical treatments have been demonstrated. Chemical treatments were 70% perchloric acid. 50% sulfuric acid and 0.5 N sodium hydroxide solution and physical methods were corona and plasma treatment. The water contact angle of surface treated PLGA decreased from 73$^{\circ}$ to 50~60$^{\circ}$, i.e., increased hydrophilicity, due to the introduction of oxygen-containing functional group onto PLGA backbone by the measurement of an electron spectroscopy for chemical analysis. It could be observed that the adhesion and growth of fibroblast cell on physicochemically treated PLGA surfaces, especially perchloric acid treated PLGA surface, were more active than on the controt. In conclusion, it seems that surface wettability as hydrophilicity of PLGA plays an important role in cell adhesion, spreading and growth.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.127-133
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• 1979

A simple and rapid colorimetric method for determination of panaxadiol and , panaxadiol was developed. 1. After heating with 60% perchloric acid, panaxadiol and panaxadiol yielded red.purple color with absorption maximum at 540 nm and 538 nm, respectively. 2. The maximum colors of the Panaxadiol and panaxadiol were reached when the algycones were treated at 6$0^{\circ}C$, 5 minutes or 7$0^{\circ}C$ 3 minutes. 3. The absorbance varied linearly with the amount of aglycone in the reaction mixture. And the colorimetric method was sensitive to about 10$\mu\textrm{g}$ of aglycone in 5.5ml of the reaction mixture. 4. The color was stable for about a week at 4$^{\circ}C$. 5. $\beta$-Sitosterol, oleanolic acid and cholesterol were not yielded red color by treatment with 60% perchloric acid under the conditions described.

• Korean Journal of Food Science and Technology
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• v.3 no.2
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• pp.105-109
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• 1971

Effects of perchloric acid (PCA) and trichloroacetic acid (TCA) on the color generation by orcinol reaction were systematically investigated. When the concentration of PCA on hot acid treatment was varied from 1 through 5 to 10%, and then the concentration of PCA on orcinol reaction was adjusted to 5% of reaction volume, no difference in the color generation was observed between 5 and 10% of PCA, but clearly observed between 1 and 5% PCA. When RNA was treated in 5% hot PCA and then PCA concentrations on orcinol reaction were adjusted to 5% and 10%, respectively, remarkable differences in color generation were observed. When RNA was treated in 10% hot PCA and then PCA concentration on orcinol reaction was adjusted to 5% no difference in color generation between 5% and 10% hot acid treatment was observed. The results show that PCA concentration must be adjusted prior to orcinol reaction.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.465-469
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• 2006

Pre-treatment methods to determine various heavy metal contents in packaging papers were investigated by ICP-ES (Inductively Coupled Plasma Emission Spectrometry) analysis. Pre-treatment methods utilized in this study include dry ashing and decomposition methods ($HNO_{3-}HClO_{4-}HF,\;HNO_{3},\;and\;H_{2}SO_{4-}HNO_{3}$). They were compared with the conventional extraction (water) and migration (3% acetic acid) methods. The five representative heavy metals (Cd, As, Pb, Cr and Hg) were analyzed. For Cd, Hg, and As, the results were below detection limit of the instrument. In case of Cr and Pb, the migration test is considered to be a better method compared to the extraction test, but all pretreated methods showed much higher detection efficiency than the extraction or migration test. However, the detection ratio between the migration test and decomposition methods was different. Among all decomposition methods, the nitric acid - perchloric acid - hydrofluoric acid treatment brought a slightly higher detection value than others, but there was no significant difference among them except sulfuric acid - nitric acid method. Concerning Pb, the sulfuric acid - nitric acid method showed a low detection efficiency compared to other decomposition methods. The sulfuric acid - nitric acid method is, thus, not considered to be a suitable analysis method for Pb in packaging papers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.45-51
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• 2007

This study was carried out to investigate various heavy metal contents in packaging papers by pre-treatments for ICP-ES (Inductively Coupled Plasma Emission Spectrometry) analysis. Pre-treatment methods of heavy metals in this study include extraction, migration and decomposition methods (dry ashing, $HNO_3-HClO_4-HF,\;HNO_3,\;and\;H_2SO_4-HNO_3$). Test results were compared with conventional extraction (water) and migration (3% acetic acid) methods. The five representative heavy metals (Cd, As, Pb, Cr and Hg) were analyzed. For Cd, Hg, and As, the results were below detection limit of the instrumental technique. It was considered that the migration test was a better method compared to extraction test, but all the decomposition methods showed much higher detection values than the extraction or migration test. In case of recycled corrugated containers, 3% acetic acid solution extracted about 25% of chromium and 30% of lead compared to the content by decomposition methods. Among all decomposition methods, the nitric acid - perchloric acid - hydrofluoric acid treatment brought a slightly higher detection value than others, but there was no significant difference among them except sulfuric acid - nitric acid method.

• Polymer(Korea)
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• v.24 no.6
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• pp.877-885
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• 2000

PLA, PGA and PLGA films were treated with chloric acid mixture solution [70% perchloric acid (HClO$_4$)/potassium chlorate (KClO$_3$) aq. saturated solution, 3 : 2] to increase surface wettability and thus cell compatibility. The surface-treated PLA, PGA, and PLGA films were characterized by the measurement of water contact angle, electron spectroscopy for chemical analysis, and scanning electron microscopy. Surface wettability of chloric acid-treated PLA, PGA, and PLGA film surfaces was gradually increased with increase of treatment time. Unlike EtOH pre-treatment, chloric acid-treated polymer films maintain hydrophilic surface after drying. In cell adhesion test, fibroblasts were cultured on the chloric acid-treated film surfaces for 1 and 2 days. As the surface wettability increased, the cell adhesion on the surface were increased. In conclusion, this study demonstrated that the surface wettability of polymer plays an important role for cell adhesion and proliferation behavior.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.340-344
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• 1985

In this study, an effective method for purifying of crude agar was attempted, and at the same time, the effect of crude protein and ash contained in impurified agar on the gel strength of the agar were investigated. In order to reduce the content of protein of crude agar, the agar extract was treated with a protein precipitant such as tricholoroacetic acid(TCA) or perchloric acid(PCA), whereas washing with deionized water was applied to decrease the ash content of agar extract. Among the protein precipitants used in the experiment PCA reduced the crude proteins of crude agar most efficiently; addition of 0.01% PCA resulted in the reduction of crude protein content by 3%, and the gel strength of agar thereby increased from 220g/$cm^{2}$ to 402g/$cm^{2}$. High ash content of crude agar was removed by means of washing treatment and it decreased from 8.1% to 2.7%, leading to the gel strength of 530g/$cm^{2}4$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.149-149
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• 2017

Aluminum alloys have poor corrosion resistance compared to the pure aluminum due to the additive elements. Thus, anodizing technology artificially generating thick oxide films are widely applied nowadays in order to improve corrosion resistance. Anodizing is one of the surface modification techniques, which is commercially applicable to a large surface at a low price. However, most studies up to now have focused on its commercialization with hardly any research on the assessment and improvement of the physical characteristics of the anodized films. Therefore, this study aims to select the optimum temperature of sulfuric electrolyte to perform excellent corrosion resistance in the harsh marine environment through electrochemical experiment in the seawater upon generating porous films by variating the temperatures of sulfuric electrolyte. To fabricate uniform porous film of 5083 aluminum alloy, we conducted electro-polishing under the 25 V at $5^{\circ}C$ condition for three minutes using mixed solution of ethanol (95 %) and perchloric (70 %) acid with volume ratio of 4:1. Afterward, the first step surface modification was performed using sulfuric acid as an electrolyte where the electrolyte concentration was maintained at 10 vol.% by using a jacketed beaker. For anode, 5083 aluminum alloy with thickness of 5 mm and size of $2cm{\times}2cm$ was used, while platinum electrode was used for cathode. The distance between the two was maintained at 3 cm. Anodic polarization test was performed at scan rate of 2 mV/s up to +3.0 V vs open circuit potential in natural seawater. Surface morphology was compared using 3D analysis microscope to observe the damage behavior. As a result, the case of surface modification showed a significantly lower corrosion current density than that without modification, indicating excellent corrosion resistance.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.67-67
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• 2018

The 5xxx series aluminum alloys are recently used in not only marine system but also automotive area because of a low density material, good mechanical properties and better resistance to corrosion. However, Aluminum alloys are less resistant than the purest aluminum such as 1xxx aluminum alloy. Electrochemical anodization technique has attracted in the area of surface treatment because of a simple procedure, a low-cost efficiency than other techniques such as lithography and a large volume of productivity, and so on. Here, The relationship between the corrosion behavior and the thickness of aluminum anodic oxide have been studied. Prior to anodization, The 5052 aluminum sheets ($30{\times}20{\times}1mm$) were degreased by ultra-sonication in acetone and ethanol for 10 minutes and eletropolished in a mixture of perchloric acid and ethanol (1:4, volume ratio) under an applied potential of 20V for 60 seconds to obtain a regular surface. During anodization process, Aluminum alloy was used as a working electrode and a platinum was used as a counter electrode. The two electrodes were separated at a distance of 5cm. The applied voltage of anodization is conducted at 40V in a 0.3M oxalic acid solution at $0^{\circ}C$ with appropriate magnetic stirring. The surface morphology and the thickness of AAO films was observed with a Scanning Electron Microscopy (SEM). The corrosion behavior of all samples was evaluated by an open-circuit potential and potentio-dynamic polarization test in 3.5wt% NaCl solution. Thus, The corrosion resistance of 5052 aluminum alloy is improved by the formation of an anodized oxide film as function of increase anodization time which artificially develops on the metal surface. The detailed electrochemical behavior of aluminum 5052 alloy will be discussed in view of the surface structures modified by anodization conditions such as applied voltages, concentration of electrolyte, and temperature of electrolyte.