• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1733-1741
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• 2020

This study analyzed the effect of meteorological factors on the concentration of PM10 (particulate matter 10) in the atmosphere and the variation of rainwater quality using multivariate statistical analysis. The concentration of PM10 in the atmosphere was continuously measured during eleven precipitation events with a custom-built PM sensor node. A total of 183 rainwater samples were analyzed for pH, EC (electrical conductivity), and water-soluble cations (Na+, Mg2+, K+, Ca2+, NH4+) and anions (Cl-, NO3-, SO42-). The data has been analyzed using two multivariate statistical techniques (principal component analysis, PCA, and Pearson correlation analysis) to identify relationships among PM10 concentrations in the atmosphere, meteorological factors, and rainwater quality factors. When the rainfall intensity was relatively strong (> 5 mm/h, rainfall type 1), the PM10 concentration in the atmosphere showed a negative correlation (r = -0.55, p < 0.05) with cumulative rainfall. The PM10 concentration increased the concentration of water-soluble ions (r = 0.25) and EC (r = 0.4), and decreased the pH (r = -0.7) of rainwater samples. However, for rainfall type 2 (< 5 mm/h), there was no negative correlation between the PM10 concentration in the atmosphere and cumulative rainfall and no statistically significant correlation between the PM10 concentration in the atmosphere and rainwater quality.

• Resources Recycling
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• v.30 no.2
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• pp.31-38
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• 2021

To investigate the separation of La(III) from sulfuric acid solutions containing Fe(III), rare earth double salt precipitation experiments were performed by adding sodium sulfate. In this work, the effect of sodium sulfate, Fe(III), and La(III) concentrations; reaction temperature; and time was investigated. The extent of precipitation of La(III) was proportional to the concentrations of Na+ and SO42- in the solution. As the reaction temperature increased to 100 ℃, the extent of precipitation of La(III) increased. The extent of precipitation of Fe(III) decreased with increasing reaction time. The concentration ratio of Fe(III) to La(III) did not have a significant effect on the precipitation of La(III). Our results indicate that it is possible to separate La(III) from a ferric sulfate solution through selective precipitation by adding sodium sulfate.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.83-89
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• 2000

Bentonite has been considered as a liner material to restrict the release of hazardous heavy metals from the landfill. The adsorption of copper onto a domestic bentonite was studied to provide the adsorption isotherm and the effect of solution chemistry and temperature. The copper adsorption was fitted well to a Freundlich isotherm, in which Freundlich constants and correlation coefficient were calculated to be $K_F=1.18$, n=1.65, and $r^2=0.97$, respectively. The distribution coefficients ($K_d$) for the adsorption of copper decreased with increasing initial copper concentration. The $K_d$ increased with increasing the pH of solution, and drastically increased at pH > 5.3 because of precipitation of most copper species. As the ion strength of $Na^+$ in solution increased the $K_d$ decreased, while it increased with increasing the concentration of $SO_4{^{2-}}$ in solution. An increase in the temperature of experimental solution decreased the $K_d$ values.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1669-1679
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• 2020

This study examines the washing effect of precipitation on particulate matter (PM) and the rainwater quality (pH, electrical conductivity (EC), water-soluble ions concentration). Of six rain events in total, rainwater samples were continuously collected every 50 mL from the beginning of the precipitation using rainwater collecting devices at Pukyong National University, Busan, South Korea, from March 2020 to July 2020. The collected rainwater samples were analyzed for pH, EC, and water-soluble ions (cations: Na+, Mg2+, K+, Ca2+, NH4+, and anions: Cl-, NO3-, SO42-). The concentrations of particulate matter were continuously measured during precipitation events with a custom-built PM sensor node. For initial rainwater samples, the average pH and EC were approximately 4.3 and 81.9 μS/cm, and the major ionic components consisted of NO3- (5.4 mg/L), Ca2+ (4.2 mg/L), Cl- (4.1 mg/L). In all rainfall events, rainwater pH gradually increased with rainfall duration, whereas EC gradually decreased due to the washing effect. When the rainfall intensities were relatively weak (<5 mm/h), PM10 reduction efficiencies were less than 40%. When the rainfall intensities were enhanced to more than 7.5 mm/h, the reduction efficiencies reached more than 60%. For heavy rainfall events, the acidity and EC, as well as ions concentrations of initial rainwater samples, were higher than those in later samples. This appears to be related to the washing effect of precipitation on PM10 in the atmosphere.

• Journal of the Korean Chemical Society
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• v.39 no.12
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• pp.910-917
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• 1995

Analytical conditions for single column ion chromatographic determination of five anions such as F-, Cl-, NO2-, NO3-, and SO42- were optimized with respect to analysis time and separation efficiency. At the optimum condition of 2.0 mM phthalic acid at pH 4.5, five anions were effectively separated in 10 minutes so that analysis time could be reduced by 40% compared to other recommended conditions. Under this condition all the calibration curves of five anions were linear with a correlation coefficient > 0.999. Analytical results for nine commercial bottled waters were presented.

• 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.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1030-1035
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• 1998

The porous alumina membrane was prepared from aluminum metal(99.8%) by anodic oxidation using DC power supply of constant current mode in an aqueous solution of sulfuric acid. To prevent the chemical dissolution of alumina membrane, $Al_2(SO_4)_3$, $AlPO_4$ and $Al(NO_3)_3$ which could be considered to supply $Al^{3+}$ ions were added to electrolyte solution at a reaction temperature of $20^{\circ}C$ and cumulative charge of $150C/cm^2$. Effects of these additives on the formation of porous alumina membrane were evaluated under various electrolyte concentration(5~20 wt%) and current densities($10{\sim}50mA/cm^2$). The membrane surfaces which were prepared in electrolyte solution with all the additives except $Al_2(SO_4)_3$ were damaged. However, when $Al_2(SO_4)_3$ was added to the $H_2SO_4$ solution, an uniform surface of porous alumina was obtained. Also, it was shown that the pore size of membrane was nearly independent on the quantity of $Al_2(SO_4)_3$ added at same electrolyte concentration and current density.

• Journal of Environmental Impact Assessment
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• v.19 no.3
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• pp.281-296
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• 2010

방그라데시 북부에 위치한 풀바리 우파질라 지역의 지하수에서 pH, EC, 주요 양이온 ($Ca^{2+}$, $Mg^{2+}$, $Na^+$, $K^+$, $Zn^{2+}$, $Cu^{2+}$, $Mn^{2+}$, $Fe^{3+}$, and $As^{3+}$), 주요 음이온 (${CO_3}^{2-}$, $HCO_3{^-}$, $NO_3{^-}$, ${SO_4}^{2-}$ and $Cl^-$) 그리고 total dissolved solids (TDS) 등의 용존물질 함량을 측정하였다. 또한 sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), 경도 등의 지표도 계산하였다. 전체적으로 지하수의 pH는 약알칼리성 (6.24 - 8.10)을 띄었으며, 주요 양이온은 $Ca^{2+}$, $Mg^{2+}$ and $Na^+$ 이었고, 주요 음이온은 $HCO_3{^-}$ and $Cl^-$ 으로서 전형적인 담수의 이온조성을 보였다. $Cu^{2+}$, $Mn^{2+}$ and $Fe^{3+}$ 의 최대 농도는 각각 1.71, 0.606, 0.125 mg/L 이었다. 방글라데시의 여러 지역에서는 비소에 의한 지하수의 오염이 흔히 나 타나고 있으나 이지역에서 비소의 최대농도가 0.41 mg/L로서 기준치인 0.05 mg/L 보다 낮은 오 염도를 보였다. TDS와 SAR, SSP 등으로 볼 때 이 지역의 지하수는 대부분 양호한 수질을 가지는 담수인 것으로 평가된다. $As^{3+}$, $Zn^{2+}$, $Mn^{2+}$, $Fe^{3+}$, ${SO_4}^{2-}$, $NO_3{^-}$ and $Cl^-$ 등의 농도는 음용수로 적합한 수준이었으나 일부 항목은 특정 산업용도로는 부적합한 농도를 보였다. 현재로서는 이지역 의 지하수는 대부분 음용이 가능하고 일부 산업용에 대해서만 부적합성을 보였다. 그러나 앞으로 지 하수의 이용과 산업활동이 증가하면 방글라데시의 많은 다른 지역의 지하수에서 발생한 사례와 같 이 용존물질의 농도가 증가하여 물의 용도에 제한을 받게 될 우려가 있다.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.176-187
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• 2013

A study has been carried out on metal materials in order to identify the quantitative relation between the concentration and damage characteristics after evaluation of the damage characteristics according to the $SO_2$ concentration. The prepared metal samples, which were categorized according to the material (silver, copper, iron, lead, brass) were exposed to 0.01, 0.12, 1, 10, 100, 1,000, and 5,000ppm of $SO_2$ for 24 hours and the optical, physical, chemical deterioration rates both before and after testing were evaluated. The results showed optical deterioration, a loss of gloss on silver specimen with $SO_2$ 100ppm, an increase of color difference on brass, iron, copper and lead specimens with $SO_2$ 5,000ppm, as well as physical changes such as an increase of thickness and corrosion rate on iron sample with $SO_2$ 5,000ppm. In the case of chemical changes such as an increase sulfate ion ($SO{_4}^{2-}$) concentration and decrease of pH on iron and brass specimens were identified. These results suggest that $SO_2$ 100ppm caused clear optical deterioration on some metals such as silver and physicochemical and optical deterioration were identified at $SO_2$ 5,000ppm regardless of metal type. Also, It was concluded that iron and brass are the most susceptible of the metal specimens to $SO_2$.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.151-152
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• 2003

대기중에는 토양입자나 해양입자와 같이 직접적으로 방출되는 입자상 물질 이외에 자연적으로 생성되거나 인간의 활동에 의하여 배출되는 유황, 질소산화물 및 유기물의 가스상 물질이 대기 화학 반응에 의하여 입자상 물질로 변환된 이차입자가 혼재되어 있다. 이러한 입자상물질은 $K^{＋}$, $Na^{＋}$, $Mg^{2+}$, NH$_4$$^{+}$, $Ca^{2+}$ 등의 양이온과 Cl$^{-}$, NO$_3$$^{-}$, SO$_4$$^{2-}$ 등의 음이온 성분으로 구성되어 있다. (중략)