• Analytical Science and Technology
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• v.11 no.6
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• pp.495-498
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• 1998

The effect of high concentration ion matrix on the analysis of low anion concentration in the suppressed ion chromatography was studied. The anions studied were $Br^-$, $NO_3{^-}$, $HPO_4^{2-}$, $SO_4^{2-}$, and $C_2O_4^{2-}$ in the presence of excess NaCl and $CaCl_2$. In this study we suggested that the erroneous results in the suppressed ion chromatographic determination of small concentration of anions were not caused by the interaction of large amount of cation in the suppressor, but by the interaction of cation with concerned anion in the original solution. The error in the analysis of such anion can not be eliminated just by dilution. Therefore, we suggested that standard addition method might be adequate for analyses of those samples.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.157-164
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• 1998

preliminary study on the chemical compositions of forty seven precipitations from March 1994 to May 1995 In Yeoncheon-gun, which Is adjacent to the southern boundary of demilitarized zone (DMZ) in the northernmost tip of Kyunggi Province has been Performed. The metal cation and anion concentrations were measured by atomic absorption spectrometer and ion chromatography, respectively. pH/lon meter and direct nesslerization method were used for the concentration measurements of $H^+$ ion and $NH_46+$ ions, respectively Based on the data, the quantitative orders of the cation and anion average concentrations were $Ca^{2+}>NH_4^+>Na^+>K^+>Mg^{2+}>H^+ and SO_4^{2+}>Cl^-> NO_3^-$, respectively..The ratio of average total anion concentration to average total cation concentration was 0.97. The average pH value of the precipitations was 5.60. These results, correlation coefficients between the ion concentrations, and monthly variations of pH value and precipitation amount are used for chemical analysis on the environmental Pollution and Pollutant sources In Yeoncheon-gun of Kyunggi province near DMZ.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.727-732
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• 2006

The object of this study was to investigate the influence of composition and concentration of electrolyte, ratio of cation to anion exchange resin of mixed ion exchange column in the performance of ion exchange. Also this work examined the removal capability of suspended solids by ion exchange resin and the effect of particule on the characteristics of ion exchange. Breakthrough time was extended as the amount of ions and particles present in liquid was decreased. The case of anion, the breakthrough sequence is $Cl^{-}, but the case of cation, the breakthrough sequence is $Na^{+}. As for the ratio of cation to anion exchange resin of 1:2, the breakthrough time was prolonged compared with that of 1:1 and 1:3. For the electrolyte of equal concentration containing suspended solid, breakthrough time was contracted less than 20%. It results in the increase in the removal capacity of cation exchange resin. For the higher ratio of cation exchange resin, suspended solids are shorten the cation's breakthrough time so that the runtime of ion exchange resin tower is increased.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.5
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• pp.593-601
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• 2004

In this study, we are going to compare the chemical composition of the precipitation that falls in the Dangjin and Anmyon-do areas by analyzing the water soluble components (anion and cation). We also examined the effects of seasonal change and regional difference in those data sets. The [$NO_3\;^- \;+\;SO_4\;^{2-}$] at 49.2${\mu}$eq/l is 67% of the total anion of 73.1${\mu}$eq/l, while that of [$NH_4\;^+\;+\;Ca^{2+}$] at 37.7${\mu}$eq/l is 62% of the cation in Dangjin area. Also, the [$NO_3\;^-\;+\;SO_4\;^{2-}$] concentration of 151.8 (${\mu}$eq/l) is 62% for the total anion of 143.5 (${\mu}$eq/l), and the [$NH_4\;^+\;+\;Ca^{2+}$] concentration of 119.7 (${\mu}$eq/l) is 47% for the cation of 254.3 (${\mu}$eq/l) in Anmyon-do area. The ion composition ratio is shown for the order by 22% of $SO_4\;^{2-}$, 20.8% of $NH_4\;^+$ and 15.4% of $Cl^-$ that is the sum of 58.7% for the total ion composition in Dangjin area, and is the order by 33.8% of $NH_4\;^+$, 16.3% of $SO_4\;^{2-}$ and 11.1% of $Cl^-$ in Anmyon-do area. Furthermore, We predicted that even areas which were previously clean will get acid rain if there is large scale construction there or nearby.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.2
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• pp.98-104
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• 1994

Precipitation samples were collected at Kosan, Cheju Island over a period of 6 months An automatic rain sampler was manufactured domestically and installed at Kosan station. All samples were collected on a weekly basis. Samples were analyzed for S $O_4$$^{=}$, N $O_3$$^{[-10]}$ , C $l^{[-10]}$ , N $H_4$$^{+}$, N $a^{+}$, $K^{+}$, $Ca^{++}$, $Mg^{++}$, and pH and specific conductivity. The quality analysis of rain sample data were performed based on ion balance and specific conductivity. The pH of rain samples ranged between 4.6 to 6.6. Bicarbonate ion concentration were included in ion balance and specific conductivity calculations. The sum of cation concentrations were slightly greater than the sum of anion concentrations. Calculated specific conductivity was greater than measured specific conductivity. The most probable explanations for this discrepancy is "an anion too low or anion missing." Two criteria were used to identify outliners. They are 1) the difference between the sum of anion concentrations and cation concentration is more than 50 $\mu$eq./1 and 2) the difference between calculated and measured specific conductivity is more than 25%. Chemical analysis from several samples did not satisfy these quality control criteria. Volume weighted average concentrations were calculated. Dominant free acids in rain samples were N $a^{+}$, C $l^{[-10]}$ , S $O_4$$^{=}$, N $O_3$$^{[-10]}$ ions in order of abundance. Non-seasalt sulfate comprises 76% of total sulfate.sulfate.e.ate.e.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.6
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• pp.941-948
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• 2020

Objective: This study was carried out to determine the effects of elevated dietary cation and anion difference (DCAD) on dry matter intake (DMI) and ruminal fermentation pattern in lactating dairy goats under tropical conditions. Methods: Ten dairy goats were divided into two groups of five animals each. The groups received diets at different DCAD levels, either a control diet (22.81 mEq/100 g dry matter [DM], DCAD-23) or a DCAD-39 diet (39.08 mEq/100 g DM, DCAD-39). After parturition, DMI and water intake were recorded daily. Ruminal fluid and urine were collected, and nutrient digestibility measurements were carried out at 8th weeks postpartum (PP-8). Blood samples were collected at PP-4 and PP-8 to measure plasma leptin. Results: Dry matter intake/body weight (DMI/BW) at PP-8 of the animals fed the DCAD-39 diet was significantly higher than those fed with DCAD-23 diet (p<0.05). Animals fed with DCAD-39 consumed more water than those fed DCAD-23 over 24 h, particularly at night (p<0.05). Ruminal pH, acetate concentration, and urinary allantoin excretion increased with the DCAD-39 diet, whereas ruminal butyrate concentration was lower with the DCAD-39 diet. On the other hand, other ruminal parameters, such as total volatile fatty acid concentration, propionate molar proportion and acetate/propionate average ratio, were not affected by increased DCAD supplementation. Apparent digestibility was improved by increased DCAD supplementation. Plasma leptin concentration was higher with DCAD supplementation. Conclusion: When feeding goats with DCAD-39 under tropical conditions, an increase in DMI was associated with improved apparent digestibility of nutrients, ruminal fermentation and microbial protein synthesis. An increase in plasma leptin concentration could not explain the effect of high DCAD on DMI.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.104-109
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• 2007

The amount of nitrate in the tobacco leaf has been shown to be correlated with the levels of alkaloids and nitrosamines. Also the nitrate content of the tobacco correlated closely with the smoke delivery of nitric oxide and tobacco-specific nitrosamines (TSNAs). These are related with the effect of the reconstituted tobacco leaf(Recon) using the tobacco stems. Adsorption process is gaining interest as one of the effective processes of advanced liquid treatment for liquid containing unnecessary materials. This study is focused on the evaluation of four anion exchangers, a cation exchanger and an activated carbon, as adsorbents for reduction of nitrate anion from Recon extract. In order to analyze the nitrate anion, the IC method used in this work was carried out with a Dionex ICS-2000 system. The effects of dosages of adsorbents and concentration of extract on the removal of nitrate anion were examined. Experimental results showed that for nitrate-anion exchanger, nitrate-cation exchanger and nitrate-activated carbon adsorption system, approximately 70 %, 10 %, and 4 % removal efficiencies were achieved at the Brix 10 and the 20 % addition. Although the activated carbon was little efficient for removal of nitrate ion, the removal of nicotine was very efficient at given conditions.

• Journal of Environmental Science International
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• v.18 no.6
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• pp.595-601
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• 2009

The effects of the cation-to-anion resin ratio and bed depth on ion exchange performance of mixed-bed were studied at ultralow solution concentration. Breakthrough curves were experimentally obtained for NaCI solution as functions of resin ratio and bed depth. The bed depth affects the pattern of the sodium breakthrough curve but not the chloride breakthrough curve in beds because of the selectivity difference. Resin selectivity determines the shape of breakthrough curves, Some sodium and chloride breakthrough curves crossed at a point as a function of resin ratio. The lower cation-to-anion resin ratio showed the higher effluent concentration or treated volume of the crossover point regardless of the total resin weight.

• KSBB Journal
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• v.6 no.2
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• pp.207-213
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• 1991

In this study poly (1-methyl-4-vinylpyridinium iodide-co-styrene) membrane with pyridinium cation as a fixed carrier was synthesized and the transport characteristics of the membrane was examined over various factors. As the concentration of the fixed carrier in the membrane was increased, the water content was increased. Meanwhile, the counter current of the organic anion and the chloride ion, the following results were obtained. Initial flux of Cl-, organic anion and Na+ decreased with the increasing thickness of membrane, and as the concentration of the fixed carrier increases, the initial flux of Cl- and organic anion increase but the initial flux of Na+ decreased. The flux equation of the organic anion, CCl3COO- was obtained from saturation kinetics as follows;$V_{o}=\frac{(8.67{\times}10^{-5}){\cdot}[NaCl]}{9.63{\times}10^{-2}+[NaCl]} mol/cm^2h$

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.206-211
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• 1999

Mixed-bed ion exchange performance was studied experimentally with variations of cation to anion resin ratio, resin weight and temperature at ultralow sodium chloride solution concentrations of less than $1.0{\times}10^{-4}M$. Analyzing the effluent concentration histories the performance test was examined as a function of tested solution volume for a laboratory-scale continuous flow column until both the cation and anion-exchange resins were exhausted. Initial leakage was observed for both cation and anion breakthrough curves, but serious at cation breakthrough curve because of low selectivity coefficient. The slope of breakthrough curve was affected by selectivity coefficient and temperature. The slope of anion breakthrough curve was steep because of the large selectivity coefficient, and ion exchange rates increased as temperature increased. The temperature effect decreased as the total volume was increased or as the resins were exhausted.