• Journal of Veterinary Science
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• v.22 no.1
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• pp.11.1-11.7
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• 2021

Background: The spore-forming bacterium Bacillus anthracis causes anthrax, an often-fatal infection in animals. Therefore, a rapid and reliable strategy to decontaminate areas, humans, and livestock from B. anthracis is very critical. Objectives: The aim of this study was performed to evaluate the efficacy of sodium hypochlorite, calcium hypochlorite, and quaternary ammonium compound (QAC) sanitizers, which are commonly used in the food industry, to inhibit spores and vegetative cells of B. anthracis surrogate. Methods: We evaluated the efficacy of sodium hypochlorite, calcium hypochlorite, and a QAC in inhibiting vegetative cells and spores of a B. anthracis surrogate. We treated a 0.1-mL vegetative cell culture or spore solution with 10 mL sanitizer. The samples were serially diluted and cultured. Results: We found that 50 ppm sodium hypochlorite (pH 7), 1 ppm calcium hypochlorite, and 1 ppm QAC completely eliminated the cells in vegetative state. Exposure to 3,000 ppm sodium hypochlorite (pH 7) and 300 ppm calcium hypochlorite significantly eliminated the bacterial spores; however, 50,000 ppm QAC could not eliminate all spores. Conclusions: Calcium hypochlorite and QAC showed better performance than sodium hypochlorite in completely eliminating vegetative cells of B. anthracis surrogate. QAC was ineffective against spores of the B. anthracis surrogate. Among the three commercial disinfectants tested, calcium hypochlorite most effectively eliminated both B. anthracis vegetative cells and spores.

• KSBB Journal
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• v.17 no.3
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• pp.314-316
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• 2002

The disinfection effects of trichloroisocyanuric acid (TICA) and calcium hypochlorite on E. coli in aqueous suspension were comparatively characterized at various concentrations and exposure times of each disinfectant. When the E. coli ($10^{7}$ CFU/mL) cells were exposed with a solution containing 12 ppm each of TICA and calcium hypochlorite, a 90% of the initial cells were killed in 4 sec and 390 sec, respectively. In addition, calcium hypochlorite lost its disinfection effect in about 1 hr exposure under the sun light, whereas TICA maintained its disinfection effect up to 6 hrs under the same condition. These comparative studies demonstrate that TICA is a more effective and stable disinfectant than calcium hypochlorite to sterilize E. coli in aqueous suspension.

• Restorative Dentistry and Endodontics
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• v.7 no.1
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• pp.125-130
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• 1981

The purpose of this study is to determine the effect of concentration and temperature on the bactericidal action of sodium hypochlorite by means of comparing the killing time of several kinds of microorganism on each different concentration and temperature of sodium hypochlorite. The results were as follows: 1. As the concentration of sodium hypochlorite was increased, the bactericidal action of sodium hypochlorite was increased in all specimens. 2. The bactericidal action of sodium hypochlorite at $37^{\circ}C$ was more potent than that of sodium hypochlorite at $21^{\circ}C$. 3. Among the 3 experimental microorganisms, Pseudomonas aeruginosa was the most resistant to sodium hypochlorite, then comes staphylococcus aureus, and the least resistant microorganism was Streptococcus mutans.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.32-36
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• 2023

In this study, the effect of sodium hypochlorite on biofilm removal was evaluated using three bacterial strains; Aeromonas hydrophila, Streptococcus mutans, and Yersinia enterocolitica. For maximum biofilm removal in 10 min, sodium hypochlorite is required at 1.65, 0.83, and 0.41 g/l for A. hydrophila, S. mutans, and Y. enterocolitica, respectively. Resistance to sodium hypochlorite was increased by the biofilms of all three tested strains, while the change in bactericidal activity according to sodium hypochlorite concentration was strain-specific. Therefore, we aimed to determine the effective concentration of sodium hypochlorite required for hygiene, considering that higher concentrations are needed to remove biofilms than to kill cells.

• The KSFM Journal of Fluid Machinery
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• v.20 no.2
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• pp.69-74
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• 2017

Sodium hypochlorite, used as water disinfectant, is generated by electrolysis of salt. Compared to chlorine gas disinfection, it is free from high-pressure gas regulation and does not generate toxic gas, so it is increasingly used as a safe disinfectant. Despite these advantages, the concentration of sodium hypochlorite decreases with temperature during long-term storage, and the amount of chlorate increases when a large amount is added, it has mainly been applied to small-scale waterworks. To solve this problem, high sodium hypochlorite generation was developed. In this study, the changes of concentration and chlorate of sodium hypochlorite with time has been studied. As a result of the test, it was found that the usable period of sodium hypochlorite produced at a certain temperature or less was increased from 1.5 days to 13 days. Overall, sodium hypochlorite can be applied even in large-scale waterworks, which makes operation more stable and also reduces the disinfection byproducts, thus it contributed greatly to securing water quality.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.1-6
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• 1961

It is important to study hydrazine because of the development of new uses for its derivatives. The Rasching method is the only satisfactory one for synthesizing hydrazine; it involves the oxidation of ammonia by sodium hypochlorite in the presence of some such catalyst as gelatin. Calcium hypochlorite was substituted for the sodium hypochlorite particularly in this work, applying agar-agar as catalyst. The results of the experiments are as follow: 1. The yield is proportional to the mole-ratio of ammonia to available chlorine in calcium hypochlorite and about 60% is obtained when the ratio is 20. 2. Agar-agar can be used as a catalyst and its proper concentration in the solution is 0.005%. 3. Proper concentration of available chlorine in the reaction solution is 0.23 mole/l. 4. The most effective condition for the reaction is a temperature of $60{\sim}65^{\circ}C.$ maintained for $20{\sim}25min$. 5. The reaction takes place equally well in either an open or closed container. 6. When calcium hypochlorite is applied in place of sodium hypochlorite, the yield of hydrazine is increased as much as 17%. 7. The yield of hydrazine is decreased by eliminating the suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite. 8. When $Ca(OH)_2$ is added to Rasching process, the yield of hydrazine is raised normally. 9. The fact that some metal ions, such as $Cu^{++},$ inhibit the formation of hydrazine was proved. 10. The suspension of $Ca(OH)_2$ acted as a remarkable adsorbent for $Cu^{++}$ like gelatin. The suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite acts as a catalyst, absorbing metal ions, to increase the yield of hydrazine. So I think that calcium hypochlorite is a more efficient oxidant than sodium hypochlorite in hydrazine syntheses.

• Research in Plant Disease
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• v.20 no.4
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• pp.259-263
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• 2014

For application of sodium hypochlorite as a seed disinfectant to the control of bakanae disease caused by Gibberella fujikuroi in rice, we investigated the effects of sodium hypochlorite for antifungal activity, eliminating fungus from seeds and reducing disease occurrence in vitro and greenhouse. The viability of the pathogen was significantly reduced at $80{\mu}l/l$ concentration of sodium hypochlorite, and the pathogens did not grow at over $100{\mu}l/l$ concentration of sodium hypochlorite. The effect of eliminating fungus was 90% at treatment of 0.3% sodium hypochlorite solution to infected rice seeds for eight hours. When the rice seeds were soaked into 0.5% and 0.3% sodium hypochlorite solutions for twelve hours, the disease incidences of rice seedling were remarkably reduced to 4.3% and 4.7%, respectively, compared to 97.3% of non-treatment control. The rates of seedling stand were 29.1% and 26.9% higher with the sodium hypochlorite treatment than that of non-treatment control. When prochloraz and sodium hypochlorite was treated to naturally severely infested rice seeds with bakanae disease, the disinfection effect was higher than that of prochloraz alone treatment. When the seeds were soaked in sodium hypochlorite before or after prochloraz, the rate of seed contamination was low as 4.0% or 6.3%, respectively, compared to prochloraz alone as 13.7%. The disease incidence was low as 3.7% or 8.3%, respectively, compared to prochloraz alone as 14.3%. The disinfection effect of treatment with prochloraz after sodium hypochlorite was higher than that of treatment with prochloraz before sodium hypochlorite.

• Membrane and Water Treatment
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• v.14 no.2
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• pp.55-63
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• 2023

In this study, the influence of different IEMs (ion exchange membranes) to performance of the hypochlorite electrolysis unit with Cl₂ recovery stream was investigated. More specifically, Nafion 117-a representative cation exchange membrane (CEM)-and aminated polypheylene oxide (APPO)-an anion exchange membrane (AEM)-were installed in the hypochlorite electrolysis unit, and the performance and the energy efficiency of the units were evaluated and compared. Regardless of whether CEM (Nafion 117) or AEM (APPO) was installed, the rate of hypochlorite generation was increased (by up to 24.3% and 22.2% for Nafion 117 and APPO, respectively) compared with the unit without an IEM. On the other hand, the power efficiency and the optimum operation condition of hypochlorite production units seem to depend on the conductivity and stability of the installed IEM. As the result, between Nafion 117 and APPO, higher performance and efficiency were achieved with Nafion 117, due to excellent conductivity and stability of the membrane.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.115-121
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• 1982

Sodium hypochlorite solution has been widely used as endodontic irrigant due to its ability to dissolve pulp tissue debris and its antimicrobial action. This in vitro study was conducted to evaluate the solvent action of sodium hypochlorite solution on vital pulp tissue under various conditions include concentration, exposure time, and temperature. The percentage of weight loss due to pulp tissue dissolution was calculated with weight difference of lyophilized specimens before and after the exposure to test solutions. The results were as follows; Statistical analysis indicated that the ability of both 5.0% and 2.5% sodium hypochlorite solutions to dissolve pulp tissue was significantly greater than that of distilled water, but no significant difference was found between 5.0% and 2.5% sodium hypochlorite solutions. There was no significant increase in the pulp tissue dissolving ability of sodium hypochlorite solutions; as exposure time increased 2 minutes, 5 minutes, and 10 minutes. Of the given temperatures, no significant difference was found in the solvent aciton of sodium hypochlorite solution on pulp tissue between $20^{\circ}C$ (room temperature) and $37^{\circ}C$(body temperature).

• Mycobiology
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• v.28 no.3
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• pp.123-126
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• 2000

Sodium hypochlorite alkaline was tested against Pseudomonas tolaasii causing bacterial blotch on cultivated oyster mushroom (Pleurotus ostreatus). The minimum inhibitory concentration of sodium hypochlorite against P. tolaasii contained active chlorine (AC) at 1.4 mg/l on plate assay. The highest cultivation yield was obtained from the treatment of AC 5.7 mg/l. Treatment of sodium hypochlorite at the rate of higher than AC 11.4 mg/l resulted in reduced yields at the harvest. However, the population of total bacteria on the bed surface treated with AC 5.7 mg/l of sodium hypochlorite was maintained to some extent. Inhibitory concentration against total bacteria on the bed surface was over AC 22.8 mg/l. Mushroom mycelium was damaged and its growth strongly inhibited at the concentration of AC 200 mg/l. Mushroom caps showed yellowish symptom by chemical injury by treatments of AC 74.1 mg/l or higher. Sporocarps infected by P. tolaasii were irrevocable at any concentration of sodium hypochlorite. Routine watering with AC 5.7 mg/l from mushroom initiation to the end of picking resulted in reduced bacterial blotch incidence of 40% and 86% at two mushroom farms. The treatment resulted in higher quality mushroom production compared to that conventionally watered with tap water alone.