• Analytical Science and Technology
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• v.12 no.5
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• pp.403-407
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• 1999

A method for detecting chlorine dioxide in drinking water was developed by the modified iodometric titration. This method requires prior removal of interfering chemicals such as chlorine and/or other oxidants: the interferents are removed by $N_2$ purging. Chlorite and chlorate were successfully quantified by the ion chromatography-conductivity detection. Stabilized chlorine dioxide that is commercially available contained only traces of chlorine dioxide (0.01-0.09%). In reality, its main component is chlorite.

• Korean Journal of Materials Research
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• v.29 no.1
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• pp.16-22
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• 2019

Indirect oxidation using chlorine species oxidizing agents is often effective in wastewater treatment using an electrochemical oxidation process. When chlorine ions are contained in the wastewater, oxidizing agents of various chlorine species are produced during electrolysis. In a ballast water management system, it is also used to treat ballast water by electrolyzing seawater to produce a chlorine species oxidizer. However, ballast water in the brackish zone and some wastewater has a low chlorine ion concentration. Therefore, it is necessary to study the chlorine generation current efficiency at various chlorine concentration conditions. In this study, the chlorine generating current efficiency of a boron-doped diamond(BDD) electrode and insoluble electrodes are compared with various chloride ion concentrations. The results of this study show that the current efficiency of the BDD electrode is better than that of the insoluble electrodes. The chlorine generation current efficiency is better in the order of BDD, MMO(mixed metal oxide), $Ti/RuO_2$, and $Ti/IrO_2$ electrodes. In particular, when the concentration of sodium chloride is 10 g/L or less, the current efficiency of the BDD electrode is excellent.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.23-24
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• 2018

Reinforced concrete is a building material that is generally used in modern society. Also, reinforced concrete structures in high salinity environments have low durability due to corrosion of reinforcing bars due to infiltrated chlorine ions. Anion exchange resins have an ability to immobilize chlorine ions in the resin while releasing their anions. As a material, it has already been shown that it is possible to fix the chloride ion inside the cementitious material through the cement mortar experiment. The purpose of this study is to confirm the compressive strength of cement mortar using powdered anion exchange resin after powdering an anion exchange resin. In order to confirm the chloride ion fixation ability of the powder anion exchange resin, chlorine ion penetration resistance test was carried out.

• Journal of Ocean Engineering and Technology
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• v.31 no.3
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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.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.3
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• pp.331-337
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• 2009

Electrolysis produces hypochlorous acid by using a small quantity of NaCl as electrolyte. This process maximizes the stabilization of drinking water through the control of chlorine residual concentration. This study investigated free chlorine generation by an electrolytic method using $Ti/IrO_2$ and stainless steel. The generation of free chlorine was increased with increasing hydraulic retention time, voltage, chlorine ion concentration and the number of electrodes. However, the change of pH did not affect the generation of free chlorine. There was no significant difference on the behavior of chlorine concentration between electrolytic method and NaOCl injection. In this study, the concentration of free chlorine predicted model based on power functional model was developed various under conditions. Electrolysis free chlorine generation model can be effective tool in the estimation of free chlorine generation.

• Membrane Journal
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• v.30 no.4
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• pp.276-281
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• 2020

A research was conducted on the removal of ion from the solution involving the alkali metal ion and chlorine ion using ion exchange resin. The cation exchange resin and anion exchange resin was used for the remove of metal ion (Na⁺ and K⁺) and chlorine ion (Cl^-), respectively. In the case of solution A (involving 36,633 ppm of Na⁺ and 57,921 ppm of Cl^-), the Na⁺ ion and Cl^- ion were removed over 99% within 20 min. In the case of solution B (involving 1,638 ppm of K⁺), the K⁺ ion was removed over 99% within 3 min.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.580-583
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• 2004

Due to the tendency of increase in demolished-concrete produced by alteration and deterioration of concrete structures, recycling of those demolished-concrete is necessary to solve the exhaustion of natural aggregate, in order to save resources and protect environment. In this an experimental study herein, the Chlorine-ion and Carbonation resistance of the recycled aggregate concrete was investigated. Coarse aggregate was replaced with $100\%$ of the recycled aggregate and cement and fine recycled aggregate was replaced with various amount. It was shown that the concrete can obtain resistance of chlorine-ion, when fly ash replaced with up to $30\%$ of cement.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.423-426
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• 2005

Until now, the quantity to recycle wasted concrete as the great supplementary value was very little. But considering a insufficiency of the present state of aggregates, the recycling of wasted aggregates is indispensable. Recycled aggregate is useful resources for concrete, but its application to structural member is not frequently. In this an experimental study here in, this study is to reinforcement orientation containing fiber of the spun-concrete using recycled aggregate, evaluation of designed chlorine-ion and carbonation resistance. The result of study chlorine-ion resistance by using replacement ratios ($0.00\%,\;0.01\%,\;0.03\%,\;0.05\%,\;0.08\%$) of fiber which it more increase. Carbonated thickness of the spun-concrete used fiber and the normal spun-concrete was similar or it appeared with the tendency which it diminishes.

• Journal of the Korean institute of surface engineering
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• v.33 no.5
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• pp.339-348
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• 2000

The study was conducted on the effect of bath composition on the surface appearance, the hardness and the crystal orientation of zinc electrodeposits from the chloride bath. (1) The hardness of the zinc electrodeposits from the chloride bath was increased by suppressing mass transfer of zinc through adding the organic additives and the chlorine ion in the electrolyte. (2) The surface whiteness of zinc deposits was decreased due to the change of the preferred orientation from (002) , (103) to (101) , (100) through increasing the organic additives and chlorine ion in the electrolyte. (3) The addition of Cu, Sn, Ni or Co in the chloride bath elevated the hardness of the zinc deposits but darkened the surface whiteness. (4) The optimum condition of the organic additives and the chlorine ion for increasing the hardness of zinc deposits and preventing dark surface ranges 0.3 m1/1 to 0.4 m1/1 and 6.5 mol/1 to 6.8mol/l respectively.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.86-92
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• 2012

A characteristic study of chlorine dioxide generation by the electrolysis system was performed after chlorite ($ClO_2^-$) is adsorbed from sodium chlorite by a polymer ion exchange resin. A strongly basic anion exchange resin was used and a Ti plate coated with Ru and Ir was used as an electrode. Various parameters such as reaction stirring velocity, reaction temperature, chlorine dioxide product concentration, ion exchange resin content and product maker type for the adsorption quantity in the chlorite adsorption of ion exchange resin were investigated and found the ion exchange resin with the maximum adsorption quantity. A generation trend of chlorine dioxide was observed by the electrolysis system and optimum conditions on the desired value were found using response surface design of DOE (Design of Experiments). The strongly basic anion exchange resin with the maximum adsorption quantity was SAR-20 (TRILITE Gel type II) and the adsorption quantity was around 110 mg/IER (g). Observed generation optimum conditions of chlorine dioxide were constant-current (electrode area base; $A/dm^2$) and flow rate of $N_2$ gas (4.7 L/min) at the desired value of sterilization (900~1000 ppm, 1 h).