• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2000년도 추계학술발표논문집
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• pp.15-21
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• 2000

In chlorine dioxide delignification and bleaching the formation of chlorate is undesirable because it does not react with lignin and is harmful to the environment. Chlorate is mainly formed from the in-situ generated hypochlorus acid which is also the main reason for AOX formation. In previous literature scavengers of hypochlorous acid such as sulfamic aicd, DMSO, and hydrogen peroxide have been added to bleaching stages to reduce AOX formation but less attention has been paid to chlorate reduction. This paper thus focuses on the reduction of chlorate content caused by the following additives, sulfamic acid, DMSO, hydrogen peroxide, and oxalic acid. The results show that only sulfamic acid and DMSO reduce chlorate formation under our chlorine dioxide prebleaching conditions. Results by UV spectroscopy and pH adjustment show that scavengers react with hypochlorous acid much faster than with chlorine. Hydrogen peroxide and oxalic acid react with HClO/$Cl_2$much slower than DMSO and sulfamic acid do. The reason for the ineffectiveness of hydrogen peroxide and oxalic acid is ascribed to their slow reaction rates with HClO compared to that of chlorate formation. The fact that only 30-35% of the chlorate can be reduced by sulfamic acid and DMSO when charged in same mole ratio to chlorine dioxide, suggested that the reaction rate of DMSO and sulfamic acid with hypochlorous aicd are of the same magnitude as that of chlorate formation.

• Restorative Dentistry and Endodontics
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• 제43권2호
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• pp.14.1-14.16
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• 2018

Objectives: The aim of this systematic review was to critically analyze previously published studies of the effects of dentin surface pretreatment with deproteinizing agents on the bonding of self-etch (SE) adhesives to dentin. Additionally, a meta-analysis was conducted to quantify the effects of the above-mentioned surface pretreatment methods on the bonding of SE adhesives to dentin. Materials and Methods: An electronic search was performed using the following databases: Scopus, PubMed and ScienceDirect. The online search was performed using the following keywords: 'dentin' or 'hypochlorous acid' or 'sodium hypochlorite' and 'self-etch adhesive.' The following categories were excluded during the assessment process: non-English articles, randomized clinical trials, case reports, animal studies, and review articles. The reviewed studies were subjected to meta-analysis to quantify the effect of the application time and concentration of sodium hypochlorite (NaOCl) and hypochlorous acid (HOCl) deproteinizing agents on bonding to dentin. Results: Only 9 laboratory studies fit the inclusion criteria of this systematic review. The results of the meta-analysis revealed that the pooled average microtensile bond strength values to dentin pre-treated with deproteinizing agents (15.71 MPa) was significantly lower than those of the non-treated control group (20.94 MPa). Conclusions: In light of the currently available scientific evidence, dentin surface pretreatment with deproteinizing agents does not enhance the bonding of SE adhesives to dentin. The HOCl deproteinizing agent exhibited minimal adverse effects on bonding to dentin in comparison with NaOCl solutions.

• 한국해양공학회지
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• 제31권3호
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• pp.248-255
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• 2017

Many rivers and seas have been affected by environmental contamination. Therefore, city water supplies often require a high-degree purification treatment to provide safe drinking water. However, in order to achieve a high-degree purification treatment, a large amount of chlorine has to be added to sterilize city drinking water. The added chlorine reacts chemically with water and forms hypochlorous and chlorine ions. The hypochlorous ionizes with hypochlorous ions and hydrogen ions. As a result, the city water contains a large amount of chlorine ion. As such, when city water is used with domestic boilers, many kinds of heat exchangers, and the engines of vehicle and ships, there are often corrosion problems. In this study, alkali water was electrochemically made by electrolysis of city water, and corrosion properties between alkali and city water were investigated with an electrochemical method. Most of the chlorine ions are thought to not be contained in the alkali water because the alkali water is created in the cathodic chamber with an electrolysis process. In other words, the chlorine ion can be mostly removed by its migration from a cathodic chamber to an anodic chamber. Moreover, the alkali water also contains a large amount of hydroxide ion. The alkali water indicated relatively good corrosion resistance compared to the city water and the city water exhibited a local corrosion pattern due to the chlorine ion created by a high-degree purification treatment. In contrast, the alkali water showed a general corrosion pattern. Consequently, alkali water can be used with cooling water to inhibit local corrosion by chlorine ions in domestic boilers, various heat exchangers and the engine of ships and for structural steel in a marine structure.

• Membrane and Water Treatment
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• 제9권3호
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• pp.189-194
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• 2018

Electrochemical reduction of nitrate was studied using Zn, Cu and (Ir+Ru)-Ti cathodes and Pt/Ti anode in a cell divided by an ion exchange membrane. During electrolysis, effects of the different cathode types on operating parameters (i.e., voltage, temperature and pH), nitrate removal efficiency and by-products (i.e., nitrite and ammonia) formation were investigated. Ammonia oxidation rate in the presence of NaCl was also determined using the different ratios of hypochlorous acid to ammonia. The operating parameter values were similar for all types of cathode materials and were maintained relatively constant. Nitrate was well reduced and converted mostly to ammonia using Zn and Cu cathodes. Ammonia, produced as a by-product of nitrate reduction, was oxidized in the presence of NaCl in the electrochemical process and the oxidation performance was enhanced upon increasing the hypochlorous acid-to-ammonia ratio to 1.09:1. Zn and Cu cathodes promoted the nitrate reduction to ammonia and the produced ammonia was finally removed from solution by reacting with hypochlorite ions. Using Zn or Cu cathodes, instead of noble metal cathodes, in the electrochemical process can be an alternative technology for nitrate-containing wastewater treatment.

• 실내환경 및 냄새 학회지
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• 제17권4호
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• pp.381-388
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• 2018

In this study, various conditions and phenomena that occur in the process of removing odorous VOCs by using electrolyzed oxidant were examined. The formation of hypochlorous acid, which is an oxidant produced by electrolysis, was investigated and the properties of the oxidizing agent used to decompose toluene, xylene, and cyclohexane were investigated. As a result, it was found that the production rate and the final concentration of the oxidizing agent increased with the current density. It was found that the degree of removal varies depending on the property of each pollutant. Interestingly, in the batch experiments in which the pH of the produced oxidant was controlled, it was found that the degree of elimination varied depending on the pH of the substance. These results suggest that the difference in the concentration and distribution of hypochlorous acid (HOCl) and hypochlorite ($OCl^-$) due to the pH change leads to the difference in oxidizing power on the oxidation characteristics of each substance. Styrene and terpineol showed better degradation characteristics than toluene and xylene in odorous VOC removal experiments by spraying electrolytic oxidant using a lab-scale continuous reactor. In conclusion, the removal of odorous VOCs by the electrolytic oxidant can have various applications in that it can oxidize pollutants of various spectra.

• 한국균학회지
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• 제41권4호
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• pp.274-279
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• 2013

미산성 차아염소산수는 다양한 종류의 미생물들에 대해 강력한 살균력을 나타내지만 인간과 자연에 무해한 살균제로 잘 알려져 있다. 4%의 희석된 염산만으로 무격막 전해조에서 전기분해를 통해 만들어졌으며 유효염소 농도가 20~30 ppm(HOCl 97%)이고 pH 5.0~6.5인 미산성 차아염소산수의 식물병원균들에 대한 살균효과를 조사하였다. Botrytis cinerea, Colletotrichum acutatum, Phytophthora capsici 등의 포자들에 대해서는 대략 10초 정도의 처리시간으로도 100% 살균효과가 나타났으나 Penicillium hirsutum의 경우는 3분 이상의 처리시간이 요구되었다. 희석농도에 따른 C. acutatum에 대한 살균효과를 조사한 결과 1:1(미산성 차아염소산수:멸균수)의 비율로 희석한 처리구에서는 포자발아가 100% 억제되었으나 1:2 처리구에서는 63%로 억제율이 낮아졌다. 고추탄저병균 C. acutatum을 고추열매에 접종한 후 24시간이 지나서 처리된 미산성 차아염소산수의 병방제 효과를 조사한 결과 방제가는 70.4%였다. 본 연구를 통해 미산성 차아염소산수의 강하고 광범위한 살균력이 확인되었으며 식물병 방제를 위한 살균제로 유용하게 활용될 수 있을 것으로 예상됐다.

• 생명과학회지
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• 제30권2호
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• pp.178-185
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• 2020

벼키다리병은 Fusarium fujikuroi의 감염에 의해 발생하는 대표적인 종자전염성 병이다. 이 병의 방제는 화학약제를 이용한 종자소독이 가장 효율적이지만 최근 약제에 저항성을 갖는 균주의 출현이 증가하고 있다. 미산성 차아염소산수는 환경이나 사람의 건강에는 유해성이 낮지만 바이러스, 박테리아, 곰팡이에 강력하고 광범위한 항균활성을 갖는 살균소독제로 알려져 있다. 본 연구는 화학 약제 저항성 또는 민감성 균주를 포함하는 16개의 F. fujikuroi 균주를 대상으로 미산성 차아염소산수의 항균활성을 조사하고, 이를 이용한 친환경적 병 방제 기술 개발을 목적으로 하였다. 미산성 차아염소산수는 화학약제 저항성 균주를 포함한 조사한 F. fujikuroi 균주 모두에 대해 유리염소 5±2.5 ppm 농도에서 비특이적이고 강한 항균 활성을 나타냈고, 처리 후 5분 이내에 F. fujikuroi 세포의 치명적 손상과 함께 완전한 살균 효과를 나타났다. F. fujikuroi 균주로 감염된 벼 종자를 20±10 ppm의 유리염소를 포함하는 미산성 차아염소산수로 12시간 침지 소독하였을 경우, 종자 소독 효과와 병 방제율은 각각 95~98%와 90.1~92.6%였다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 춘계학술발표논문집
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• pp.84-88
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• 1999

In chlorine dioxide delignigication or bleaching, chlorate is mainly formed by the reaction between chlorite and hypochlorous acid, thus scavengers of chlorine or hypochlorous acid can be used to reduce the formation of chlorate which is unfavorable to environment. In this study, additives such as sulfamic acid, DMSO, hydrogen peroxide, or sodium chlorite was added to chlorine solution or pure $ClO_2$ solution to check their reactivity with $Cl_2$ and $ClO_2$. These additives were also added directly into general $ClO_2$ solution which contained certain amount of chlorine, then the additive-treated $ClO_2$ solution were used in bleaching stages. The aim of this procedure was to remove the original amount of chlorine that was thought to be possibly the main reason for the formation of chlorate and AOX. The additives were found to be able to eliminate chlorine very fast and selectively, but $H_2$ $O_2$ should be used under pH4, otherwise it also reacts with $ClO_2$. After the additives reacted With $Cl_2$, DMSO turned into an inactive product $(CH_3)_2SO_2$, While Sulfamic acid turned into $HClSO_3H$ that still remained active in oxidation, and $NaClO_2$ produced $ClO_2$. The addition of $HNaClO_2$ showed significant improvement in delignification but the deeper delignification led to higher formation of chlorate. When the additive-treated chlorine dioxide solutions were used in bleaching, both sulfamic acid, DMSO, and hydrogen peroxide showed no significant changes of DE brightness and Kappa number. The formation of chlorate was reduced by addition of sulfamic acid, DMSO and hydrogen peroxide.

• 한국식품위생안전성학회지
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• 제37권2호
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• pp.55-62
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• 2022

세균성 무름병은 배추와 같은 채소의 주요 질병중의 하나이며, 특히 김치의 주원료인 배추의 저장에 있어서 발생할 경우, 품질 저하로 인한 경제적 손실을 유발한다. 우리는 무름병이 발생한 배추로부터 원인이 되는 세균들을 분리하였고, 해당 세균이 신선한 배추 조직에 인위적으로 접종하였을 경우, 무름병이 발생하는 것을 확인하였다. 해당 원인균 2종을 동정한 결과, Pseudomonas kribbensis와 Pantoea vagans로 확인되었다. 이러한 원인 세균을 제어하기 위하여 차아염소산수 처리와 항균활성 유산균의 배양 상등액을 이용하여 제어하는 테스트를 진행하였다. 본 테스트에 사용한 항균활성 유산균은 리스테리아와 같은 병원성 미생물과 Pseudomonas 속 계열을 저해하는 Lactobacillus plantarum PL203 유산균을 선별하여 사용하였다. 제어 테스트는 정상 배추 조직에 무름병 원인균 2종을 각각 10⁵ cfu/g 이 되도록 접종한 후, 차아염소산수를 농도별로 분무하거나 항균활성 유산균 배양상등액을 0.5 mL 분무한 후, 25℃에서 5일간 배양한 결과, 차아염소산수 120 ppm 이상 첨가한 구간과 항균활성 유산균 배양 상등액을 처리한 구간에서 대조구와 비교하여 배추 무름 원인세균을 완전하게 제어하는 것을 확인하였다.

• Journal of Photoscience
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• 제9권2호
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• pp.424-426
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• 2002

Recently, much attention has been paid to the physiological functions of flavonoids associated with their antioxidant properties. However, there was a lack of information on the molecular mechanism at which flavonoids play the antioxidative role. We have already studied on the oxidation of quercetin with hydrogen peroxide and sodium hypochlorite in alcoholic aqueous solution and determined the oxidation products. Through the structural analysis of the oxidation products, it was clarified that the hydroxyl group at C-3 in the C ring plays the important role in the antioxidative action of quercetin. Successively, rutin and (+)-catechin were oxidized with sodium hypochlorite and their mono- and di-chlorinated derivatives were obtained. These facts indicate that these flavonoids can directly scavenge hypochlorous acid and the active site in this scavenging reaction is not the hydroxyl group at C-3.