• Environmental Analysis Health and Toxicology
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• v.16 no.2
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• pp.67-74
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• 2001

In a previous study by Kim et al. (2000), sodium hypochlorite (NaOCl) has been demonstrated to be effective against algae that cause red tides. To secure the environmental safely of the chemical in practical use, effect of NaOCl, at concentrations required for algicidal activity, on the histology of rockfish and little neck clam was examined. When the animals were exposed to NaOCl at concentrations of 0.5 or 2ppm for 1 hr, there was no exposure-associated histological change in either animal. As the experimental exposure condition was set in consideration of the use, our results provide safety information necessary for practical application to marine fields.

• Membrane and Water Treatment
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• v.4 no.1
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• pp.69-81
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• 2013

The pH-dependent inter-conversion of the three free chlorine species ($Cl_2$, HOCl, OCl-) present in the aqueous hypochlorite solution was theoretically investigated. Each species was found overwhelmingly present in a characteristic pH range. Hypochlorite treatment of the polyamide membrane was carried out over these pH ranges and various membrane responses were observed. As pH is less than 8, membrane tends to be N-chlorinated by $Cl_2$ and HOCl, and N-chlorinated membrane showed reduced water permeance and salt rejection. As pH rises to 10-12, $OCl^-$ appears to be the dominating chlorine species. Membrane hydrolysis was found to well interpret the improved water permeance and salt rejection. When the pH is between 8-10, both N-chlorination and hydrolysis contribute to the response of the membrane, and the treated membrane showed improved salt rejection but reduced water permeation. Excessive hydrolysis occurred while the membrane was treated at pH 13 for the much stronger alkalinity.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.52-56
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• 1992

The ability of chemicals, 10% sodium hypochlorite, 28% ammonium hydroxide, 5% sodium hydroxide, 5% sodium bicarbonate, 0.1% hydrochloric acid, 5% hydrogen peroxide, and 5% acetone, to destroy aflatoxins in laboratory waste water containing 3.26 ppb of B$_{1}$ 7.64 ppb of B$_{6}$3 ppb of G$_{1}$, and 11.39 ppb of G$_{2}$ with the total of 29.11 ppb was investigated. High performance liquid chromatograph (HPLC) was used for the separation and quantitation of aflatoxins. Treatment for 2 hours by the chemicals affected the destruction of aflatoxins and the most effective chemical was 10% sodium hypochlorite (p<0.05). Sodium hypochlorite concentrations more than 1% significantly reduced aflatoxin B$_{2}$, G$_{1}$, G$_{2}$ and total aflatoxins and more than 3% reduced B$_{1}$ (p<0.05). No further significant decreases were observed above the concentration of 5% for all 4 aflatoxins. Complete destruction of aflatoxins B$_{2}$, G_{1}$, and G$_{2}$ was achieved by 5% sodium hypochlorite at 48 hours and B$_{1}$ at 72 hours.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.147-153
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• 1982

The purpose of this study is to observe the effect of cleansing action of irrigation solutions which are 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA solution on the root canal wall. After the root canal wall is enlarged with K-file in distilled water, the canal wall which is irrigated with each irrigant for 2 minutes, is compared with the. control group without using any irrigants. Each sample is dehydrated, and coated with 200-250${\AA}$ of gold, and observations are made with the use of scanning electron microscope. The results are as follows: 1. The canal walls irrigated with 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA solution are cleaner than the walls without using irrigants. 2. There are no significant difference of cleansing effect among 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA. 3. After using 3% hydrogen peroxide and 5% sodium hypochlorite solution, large debris are removed on root canal walls, but micro debris remain on the canal walls. 4. The root canal walls irrigated with 15% EDTA solution are decalcifed slightly and show clean surfaces.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.51-59
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• 1997

Dissolving pulp is a low yield(30∼35%) bleached chemical pulp that has a high cellulose content (95% or higher) suitable for use in cellulose derivatives such as rayon, cellulose acetate. This research was studied for dissolving pulp preparation as the raw material of viscose rayon from commertial pulps. (TMP, CP, DIP) In the change of pulp(cellulose) characteristics after sodium hypochlorite and solvolysis treatment. the following results were obtained In the case of sodium hypochlorite pretreatment, we have obtained pulp that high purity cellulose, but degree of polymerization was inclined to decrease less than 170∼240. Comparing sodium hypochlorite pretreatment and solvolysis pretreatment, solvolysis pretreatment is superior to sodium hypochlorite process for making dissolving pulp. We think that the low degree of polymerization of cellulose because of increasing degradation of cellulose during delignification treatment.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2004.01a
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• pp.55-56
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• 2004

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.3
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• pp.183-189
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• 2017

Sodium hypochlorite used in water disinfection processes is generally in the production of chlorine to 0.8％. As the dose of chlorine increases, disinfection by-products (Chlorate) also increase simultaneously and exceed water quality standards. In this study, the electrolytic cell of a sodium hypochlorite generator (12％ chlorine) was adjusted to control the production of the disinfection by-products. As a result, it was possible to reduce Chlorate concentrations by more than 95％ by adjusting the pH of the electrolytic cell from 1.53 to 4.2 (normal pH of the electrolytic cell). As a low current is required to obtain these results, a 15％ improvement in the efficiency of the positive electrode is also observed. For the development of High Sodium Hypochlorite Generation can be used in a safe sodium hypochlorite solution, which is expected to contribute to improvement in the safety of the disinfection process.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1094-1100
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• 1997

Effects of sodium hypochlorite (NaOCl) concentration, temperature and pH on oxidation mechanism of corn starch were investigated. The rate of oxidation was dependent on the concentration of hypochlorite, pH and temperature of oxidation. The reaction was either first or second order depending on the concentration of NaOCl. At oxidant concentration of $0.75{\sim}3.0%$ active Cl/g starch, the reaction was first-order and it was second-order at $3.75{\sim}4.5%$ active Cl/g starch. The first-order rate constants were increased with increasing oxidant concentration. The rate of oxidation of starch was highest at pH 7 and decreased with increasing acidity or alkalinity of the medium. As the reaction temperature increased, the rate of oxidation was increased.

• Membrane Journal
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• v.25 no.5
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• pp.447-455
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• 2015

In this study, Polysulfone (PSf) and polyetherimide (PEI) as the anion exchange polymers were aminated in the different ratio whereas the polyether ether ketone (PEEK) as the cation exchange polymer was sulfonated. The bipolar membranes of SPEEK (sulfonated PEEK)/APSf (aminated PSf) and SPEEK/APEI (aminated PEI) were prepared by the double-casting method. The surfaces of bipolar membranes were fluorinated in accordance with the amination ratio and applied to produce the hypochlorite. As the amination increased, the hypochlorite concentration is also increased. Typically, for SPEEK/APSf 3 : 1 membrane, the produced hypochlorite concentration was 61.0 ppm and its durability was 220 min for the non-fluorinated membrane while for the fluorinated membrane, the concentration of 58.6 ppm and its durability lasted 570 min. Also for SPEEK/APEI 3 : 1 membrane, the hypochlorite concentrations of 60.1 ppm and 58.3 ppm for before- and after-fluorination, respectively were observed whereas the durability was remarkably developed from 150 min to 440 min. Therefore, the surface fluorination takes an important role for the development of the membrane durability.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.476-478
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• 1987