• Journal of the Korean Electrochemical Society
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• 제2권4호
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• pp.195-201
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• 1999

The repassivation characteristics of Fe-Cr steels in deaerated 0.1 M $Na_2SO_4$ solution have been investigated with the variation of Cr content, applied potential and Cl- concentration. In the absence of chloride ion, abrading electrode test showed that, slope -n, of log i=k -n log t, a parameter of repassivation rate, approached to -1, regardless of Cr content but as Cr content increased, repassivation current density decreases with increasing Cr content. A.C. Impedance spectroscopy showed that the charge transfer resistance of passive film became higher as Cr content and applied potential increased. However, in the presence of chloride ion, it was observed that chloride ion suppressed the passive film formation, whose effect became greater with increasing applied potential.

• Food Science of Animal Resources
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• 제28권3호
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• pp.301-305
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• 2008

This study was carried out to develop an accurate and rapid analysis method to measure the contents of iodide and chloride in infant formula using an ion selectivity electrode. The infant formula SRM 1846 (Standard Reference Material 1846, NIST, USA) was used as a CRM (Certified reference material). Samples were dissolved in water with 3% acetic acid and filtered through filter paper and adjusted to pH 7.0 with 0.1N NaOH. At pH 7.0, the iodide content of the CRM was $1.04{\pm}0.03\;mg/kg$ compared to the specification of $1.11{\pm}0.1\;mg/kg$ of CRM, and the recovery was $93.7{\pm}2.7%$. The chloride content was $5114.3{\pm}240\;mg/kg$ compared to the specification of $4,920{\pm}300mg/kg$ of CRM, and the recovery was $103.9{\pm}4.9%$. Ion selectivity electrodes could be successful1y used to determine the concentration of iodide and chloride ions in infant formula by a simple and rapid pretreatment of sample matrixes.

• Korean Chemical Engineering Research
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• 제51권1호
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• pp.53-57
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• 2013

For the purpose of development of the extraction process of lithium ion from concentrated water eliminated from desalination process, an experimental research on the solvent extraction of lithium ion from aqueous solutions was performed. The effects of operating parameters, such as concentration of extractant, ratio of extracting solution/aqueous solution, pH of aqueous solution, were examined. The effect of sodium chloride, the major component of sea water, was also examined. Lithium ion in aqueous solutions of pH=10.2~10.6 adjusted by ammonia solution was most effectively extracted by extracting solution composed of 0.02 M TTA and 0.04 M TOPO in kerosine. The addition of sodium chloride in lithium aqueous solution significantly interfered the extraction of lithium ion.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.679-686
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• 2018

Reverse osmosis (RO) concentration of sodium chloride, sodium acetate, and sodium citrate solutions has been performed by polyamide RO membrane. Concentration polarization phenomena was also studied by changing pressure, solute kinds, and initial solution concentration. Pressure effect on permeation flux was that the increase of flux was accompanied by the increase of pressure. Flux increase was observed by the decrease of initial solution concentration. Surface concentration on the RO membrane increases and so flux declines due to the concentration polarization. In the later phase of concentration, concentration polarization effect was decreased by the back diffusion of solute from the polariztion layer. In case of sodium citrate, its large ion size and charge density resulted in the discrepancy between theory and experimental data of concentration polarization. It may be due to electric repulsion on the membrane surface.

• Analytical Science and Technology
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• 제12권2호
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• pp.99-104
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• 1999

A stepwise gradient elution with two wavelengths detection was performed for the separation and determination of some anions in saline water. The eight anions such as iodate, bromate, nitrite, bromide, nitrate, chromate, iodide and thiocyanate were successfully separated using AS-7 column and sodium chloride/sodium phosphate buffer solution as an eluant within 40 min. The separation behaviors of anions were studied at various sodium chloride concentrations. The peak shapes of anions of bromate, nitrite, bromide and nitrate gradually broadened as the concentration of sodium chloride increased until 1.0 M in the sample solutions. However, no effect was observed in the peak shapes of chromate, iodide and thiocynate. A good linearity was obtained at the range of ppm(mg/L). The detection limit was proved to be $10-720{\mu}g/L$ for the eight anions with $50{\mu}L$ injection volume. This method was applied to the determination of $Br^-$, ${NO_3}^-$ and $I^-$ in sea water.

• Journal of Applied Biological Chemistry
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• 제60권3호
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• pp.279-282
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• 2017

Chloride is known as the most important anion in salt-affected soils. We observed the degree of EC change upon AgCl precipitation was quantitatively related with the chloride concentration. Method validation and intercomparison with ion chromatography revealed the proposed method can provide rapid and moderately precise chloride concentrations in salt-affected soils.

• Journal of Korean Society of Water and Wastewater
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• 제22권3호
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• pp.307-314
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• 2008

In this study, the effects of applied voltage, solution pH and coexistence of other ions such as sulfate ion (${SO_4}^{2-}$) and chloride ion ($Cl^-$) were investigated on the removal of nitrate-nitrogen ($NO_3{^-}-N$) from ground water by electrodialysis. The examined operating conditions were evaluated for optimizing the removal efficiency of $NO_3{^-}-N$. Real ground water samples taken from a rural area of Yongin city and artificial ones with components similar to the real ground water were tested for the study, which contained $NO_3{^-}-N$ concentration of 17mg/L that exceeds current drinking water quality standard of 10 mg/L. The increase in the removal rate of $NO_3{^-}-N$ was observed as the applied voltage increased from 5V to 30V, while no significant increase in the removal rate appeared at the applied voltage beyond 20V during a given operating time. The removal rate appeared to get lower at both acidic and basic condition, compared to neutral pH. Coexistence of of ${SO_4}^{2-}$and $Cl^-$ demanded much longer operating time to achieve a given removal rate or to meet a certain level of treated water concentration. When nitrate ion was combined with ${SO_4}^{2-}$and $Cl^-$, the removal rate was reduced by 4.29% and 10.83%, respectively.

• Korean Chemical Engineering Research
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• 제43권1호
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• pp.9-15
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• 2005

In order to know the electrochemical decomposition characteristics of ammonia to nitrogen, this work has studied several experimental variables on the electrolytic ammonia decomposition. The effects of pH and chloride ion at $IrO_2$, $RuO_2$, and Pt anodes on the electrolytic decomposition of ammonia were compared, and the existence of membrane equipped in the cell and the changes of the current density, the initial ammonia concentration and so on were investigated on the decomposition. The performances of the electrode were totally in order of $RuO_2{\approx}IrO_2>Pt$ in the both of acid and alkali conditions, and the ammonia decomposition was the highest at a current density of $80mA/cm^2$, over which it decreased, because the adsorption of ammonia on the electrode surface was hindered due to the evolution of oxygen. The ammonia decomposition increased with the concentration of chloride ion in the solution. However, the increase became much dull over 10 g/l of chloride ion. The $RuO_2$ electrode among the tested electrodes generated the most OH radicals which could oxidized the ammonium ion at pH 7.

• Journal of the Korea Concrete Institute
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• 제17권6호
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• pp.931-938
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• 2005

When concrete structures are exposed under marine condition for a long time, the steel in concrete is corroded due to the ingression of chlorides in the seawater. Because the damages of corrosion resulting from the chloride ion are very serious, many researches have been performed. Silver nitrate colormetric method that can measure easily penetration depth of chloride ion has been executed, recent)y. However, characteristics of silver nitrate colormetric method were not fully examined. Therefore, the objective of this paper Is to study the applicability of colormetric method. For the purpose of this, effect factors and reaction mechanism of colormetric method were investigated, and the colormetric method is applied for marine concrete structures. According to the results of silver nitrate colored method, two reactions such as white reaction of AgCl and brown reaction of AgOH were shown when $AgNO_3$ was sprayed in splited section. And velocity constant ratio(K) of two reactions appeared that white reaction, AgCl reacts with the fast speed by 3240. When the colormetric method was applied in concrete, it is reasonable that $AgNO_3$ solution more than 0.05N concentration was sprayed. It is confirmed that the colormetric method is useful tool for estimating the chloride of concrete structures in situ. The average chloride amount of colored parts indicates $0.9kg/m^3$ per concrete unit weight.

• Journal of Conservation Science
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• 제26권4호
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• pp.397-406
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• 2010

The most ideal method to measure the water-soluble $Cl^-$ ion eluted from iron artifacts is conducting the analysis on desalting solution by Ion Chromatography. But most institutes related to cultural heritages use Cl meter by reason of lack of budget and experts. This study evaluated reliability and stability between Cl meter and Ion Chromatography by doing cross-validation with results from two methods to detect $Cl^-$ ion of desalting solution. From D.I water, extremely small quantities of $Cl^-$ ion was detected by the influence of remaining water-soluble $Cl^-$ ion at the electrode of Cl meter and water-soluble $Cl^-$ which remains in Sodium sesquicarbonate, components of reagent was detected as well. The first desalting solution had the most $Cl^-$ ions, $Cl^-$ ion slightly decreased from the second to the fourth desalting solution and tend to decrease again at the stage of dealkalified in D.I water. Each Cl meter has the standard deviation according to the measured numbers and the higher concentration of $Cl^-$ ion the desalting solution has, the wider the deviation is. But when the concentration of $Cl^-$ ion is low, it was stable to use Cl meter to detect the concentration of $Cl^-$ ion from iron artifacts because there is the small deviation, It is thought that conductivity meter method is not suitable for measuring $Cl^-$ ion, because the electrical conductivity of alkaline solution is too high to measure $Cl^-$ ion.