• Membrane and Water Treatment
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• 제3권1호
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• pp.63-76
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• 2012

Mother liquid discharged from a salt-manufacturing plant was electrodialyzed at 25 and $40^{\circ}C$ in a continuous process integrated with $SO_4{^{2-}}$ ion low-permeable anion-exchange membranes to remove $Na_2SO_4$ and recover NaCl in the mother liquid. Performance of electrodialysis was evaluated by measuring ion concentration in a concentrated solution, permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions, current efficiency, cell voltage, energy consumption to obtain one ton of NaCl and membrane pair characteristics. The permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions was low enough particularly at $40^{\circ}C$ and $SO_4{^{2-}}$ transport across anion-exchange membranes was prevented successfully. Applying the overall mass transport equation, $Cl^-$ ion and $SO_4{^{2-}}$ ion transport across anion-exchange membranes is evaluated. $SO_4{^{2-}}$ ion transport number is decreased due to the decrease of electro-migration of $SO_4{^{2-}}$ ions across the anion-exchange membranes. $SO_4{^{2-}}$ ion concentration in desalting cells becomes higher than that in concentration cells and $SO_4{^{2-}}$ ion diffusion is accelerated across the anion-exchange membranes from desalting cells toward concentrating cells.

• 한국환경과학회지
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• 제5권6호
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• pp.739-748
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• 1996

This study was carried out to investigate the chemical characteristics ol rainwater sampled in Cheju City from July 1994 to June 1996. Concentrations of major ions (Cl-,$SO_4^{2-}$, NO_3^-$, $Na^+$, $K^+$, Ca^{2+}$, $Mg^{2+}$ and NH_4^+$) were determined. The pH of rainwater, calculated from the volume weighted H+ concentration, was found to be 5.61, indicating extensive neutralization of the acidity in the rain. The relative magnitude of average ionic concentrations followed the relation Cl-> $SO_4^{2-}$) $Na^+$> Ca^{2+}$> NH_4^+$> NO_3^-$> $Mg^{2+}$> $K^+$. The ions associated with sea salt, namely $Na^+$ and $Cl^-$, dominated the total concentration of ions in the rainwater and the $SO_4^{2-}$ ion accounts for 20% of total concentration. [H+][nss-SO42-+NO3] ratio and a multiple regression for $SO_4^{2-}$ and NO3- ions against $H^+$, $Ca^{2+}$ and $NH_4^+$ suggested that all of $SO_4^{2-}$ and $NO_3^-$ in rainwater was not necessarily associated with $H_2SO_4$ and $HNO_3$, but might also occur in combination with $NH_4^+$ or Ca^{2+}$. The monthly mean concentrations of $SO_4^{2-}$-, Ca^{2+}$ and $NH_4^+$ in spring time was higher than those in other seasons. These results may De attributed to the fertilizer application as the local sources and the yellow sand phenomina as a regional-scale sources.

• 한국환경과학회지
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• 제25권5호
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• pp.727-736
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• 2016

The ambient mass concentration and chemical composition of the $PM_{2.5}$ were determined at the highland site with 1,100 m above sea level on Jeju Island from June 2013 to November 2014. Yearly averaged mass concentration of $PM_{2.5}$ was $11.97{\pm}8.63{\mu}g/m^3$. $PM_{2.5}$ concentrations were highest during the spring, while they tended to be lowest during the summer. Eight water soluble ionic species attributed 45.5% to $PM_{2.5}$ mass. $SO{_4}^{2-}$, $NO_3{^-}$ and $NH_4{^+}$ were major ions, which occupied to 27.9%, 3.7% and 12.3%, respectively. The greatest contributors to total mass concentration of water-soluble ions contained in $PM_{2.5}$ were sulfate, ammonium and nitrate. These three ions accounted for 96.6% in total ions mass concentration of $PM_{2.5}$. We could infer that these three secondary ions exist mostly in the form of $(NH_4)_2SO_4$ and $NH_4NO_3$. $Ca^{2+}$ and $Mg^{2+}$ had a good relationship and with r=0.9. The molar ratio of $Mg^{2+}/Ca^{2+}$ in this study was lower than the value observed in sea water and higher than that in soil dust, indicating that these two ions originated from other sources rather than ocean and soil dust in this study.

• The Korean Journal of Ecology
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• 제21권3호
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• pp.195-201
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• 1998

This study was carried out to investigate characteristic of ions in rainwater by throughfall, stemflow and rainfall at air polluted area(Kure city industrial city) and non-air polluted area (Higashihiroshima city non industrial city). pH of rainwater in air polluted area were all low as compared with those in non-air polluted area. EC of rainwater in ir polluted area were high in throughfall and stemflow, but there was no difference between both areas in rainfall. The concentration of major ions in rainwater were generally high at air polluted area, especially of $Mg^{2+}$, $Ca^{2+}$, $Cl^{-}$ and $SO_4^{2-}$ in stemflow. But there was little difference in $NH_4^{+}$, and there was also cases had a high concentration in non-air polluted area. By comparison with forest type, in stemflow concentration of ions in coniferous forest were higher than those in broad-leaved, but in throughfall they were higher in mixed forest rather than coniferous forest. There was no correlation between the amount of rainwater and pH, and also EC. $NO_4^{-}$ and $SO_{4}^{2-}$ had high correlations between major ions besides $Na^{+}$ and $NH_{4}^{+}$ in air poluted area.

• 한국환경과학회지
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• 제24권6호
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• pp.785-792
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• 2015

This study investigates weekday/weekend characteristics of $PM_{10}$ concentration and chemical composition of water-soluble ions in Busan in the spring of 2013. Contribution rate of water-soluble ions to PM10 concentration in weekday/weekend were 41.5% and 38.5%, respectively. Contribution rate of SO_4{^{2-}}$ to total ion mass in weekday/weekend were 30.4% and 33.8%, respectively. Contribution rate of total inorganic water-soluble ions in PM10 in weekday/weekend were 42.2% and 39.1% (mean 41.4%), respectively. $[NO_3{^-}/SO_4{^{2-}}]$ ratio in weekday/weekend were 1.01 and 0.97(mean 0.99), respectively, which indicated that weekday ratio was higher. Contribution rate of sea salts and $Cl^-/Na^+$ ratio in PM10 in weekday/weekend were 8.1% and 7.6%, 0.37% and 0.41%, respectively. This research will help understand chemical composition of water-soluble ions during the weekday/weekend and will be able to measure the contribution level of artificial anthropogenic source on urban air.

• 한국대기환경학회지
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• 제9권2호
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• pp.147-153
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• 1993

From March 1990 to August 1991, every each 5mm bulk precipitation samples were collected at one residental area in Taejon City to investigate chemical characteristics of acid rain. Major ion concentrations of rain samples $(pH, SO_4^{2-}, NO_3^-, CL^-, NH_4^+, Na^+, K^+, Ca^{2+}, Mg^{2+})$ were analysed and compared with the concentration of air pollutants (T. S. P, $SO_2, NO_x$) that were measured by Ministry of Environment. The results of statistical analysis are as followings. Rain pH was relatively high on October and January and relatively low on August, November and February. Major anion is sulfate, and it's concentration is 2.36 times higher than nitrate's, and major cations are ammonium, sodium and calcium ion. Monthly variation of sulfate and calcium concentrations are higher than the others. Ion concentration and rain pH were correlated negatively with rainfall amount. Major ions in rain samples were $SO_4^{2-}, NO_3^-, NH_4^+, Ca^{2+}$ and regression equations are proposed by multiple regression of measured data. Also, regression equation between air pollutants(T. S. P, $SO_2$) and $SO_4^{2-}, Na^+, K^+, Ca^{2+}, Mg^{2+} ions in rain samples were made. From this wer can predict rain pH.

• 대한토목학회논문집
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• 제28권5A호
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• pp.757-764
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• 2008

본 연구는 농도조건을 달리한 시험용액에 침지한 모르타르의 내구성을 평가하기 위하여 수행되었다. 3종류 시멘트 모르타르를 제조한 후, ${SO_4}^{2-}$ 이온의 농도가 4225, 8450, 16900 및 33800 ppm인 4종류 황산나트륨 용액에 540일간 침지하였으며, 침지재령별 압축강도 및 선형팽창을 측정하므로써 모르타르의 황산염침식 저항성을 실험적으로 평가하였다. 실험결과에 의하면, 고농도 황산나트륨 용액에 침지한 모르타르 공시체가 가장 심한 성능저하 현상을 나타내었다. 특히, 고농도 환경에서 모르타르의 팽창 특성은 사용된 시멘트의 $C_3A$량과 직접적인 관련이 있었으며, GGBS를 대체한 SGC 모르타르는 조직구조의 투수성이 상대적으로 낮은 탓으로 인하여 시험용액의 농도조건에 관계없이 우수한 황산염침식 저항성을 나타내었다.

• 한국환경과학회지
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• 제25권5호
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• pp.715-726
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• 2016

This study investigates the characteristics of metallic and ionic elements concentration, concentration according to transport path, and factor analysis in $PM_{10}$ at Guducsan in Busan in the springtime of 2015. $PM_{10}$ concentration in Guducsan and Gwaebeopdong were $59.5{\pm}9.04{\mu}g/m^3$ and $87.5{\pm}20.2{\mu}g/m^3$, respectively. Contribution rate of water-soluble ions and secondary ion in $PM_{10}$ concentration in Guducsan were 37.0% and 27.8% respectively. [$NO_3{^-}/SO{_4}^{2-}$] ratio and contribution rate of sea salt of $PM_{10}$ in Guducsan and Gwaebeopdong were 0.91 and 1.12, 7.0% and 5.3%, respectively. The results of the backward trajectory analysis indicates that $PM_{10}$ concentration, total inorganic water-soluble ions and total secondary ions were high when the air parcels moved from Sandong region in China than non-Sandong and northen China to Busan area. The results of the factor analysis at Guducsan indicates that factor 1 was anthropogenic source effects such as automobile emissions and industrial combustion processes, factor 2 was marine sources such as sea salts from sea, and factor 3 was soil component sources.

• 자원리싸이클링
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• 제11권1호
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• pp.26-31
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• 2002

음이온 교환막을 사용하는 확산투석법으로 폐$H_2$$SO_4$용액으로부터 $H_2$$SO_4$을 회수하는 연구를 수행하였다. 유속. 온도, $H_2$$SO_4$농도, 금속이온 등이 $H_2$$SO_4$의 회수율에 미치는 영향을 조사하였다 $H_2$$SO_4$의 회수율은 유속과 $H_2$$SO_4$농도가 증가함에 따라 감소하였으며 온도가 높아짐에 따라 증가하였다. 물/$H_2$$SO_4$용액의 유속비가 높아짐에 따라 $H_2$$SO_4$의 회수율이 증가하였으나 유속비가 1 이상에서는 더 이상 증가하지 않았다 Fe와 Ni의 배제율은 유속의 영향을 거의 받지 않았다. 유속을 0.26 $1/hr-m^2$로 하여 4.5M유리$-H_2$$SO_4$이 존재하는 폐$H_2$SO$_4$용액으로부터 80%의 $H_2$$SO_4$을 회수할 수 있었으며 이 때 회수산의 $H_2$$SO_4$농도 및 순도는 각각 4.3M, 99.8%이었다.

• 한국물환경학회지
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• 제34권1호
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• pp.77-83
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• 2018

This paper aims to evaluate the results of toxicity testing with Daphnia magna and Vibrio fischeri on wastewater samples which might be influenced by ion imbalance. The effluents from factories were found to be more toxic with high salinity levels than those from public wastewater treatment plant (WTP) and sewage treatment plant (SWP). Clion composition was highest in the effluent, in terms of percentage, which was followed by $Na^+$, $SO_4^{2-}$ and $Ca^{2+}$. $K^+$ and $Mg^{2+}$ ion was relatively low. The sensitivity of D. magna test results was higher than V. fischeri. Among samples which were proved by V. fischeri testing to be nontoxic, the composition ratio of each ion whether toxic samples or nontoxic samples which were decided by D. magna toxicity testing, were compared. $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$ ion composition ratio showed high level in nontoxic samples whereas $SO_4^{2-}$ and $Cl^-$ ion composition ratio was high in toxic samples. Accordingly, $SO_4^{2-}$ and $Cl^-$ ion seemed to be considered the ions causing toxicity in effluent. Toxicity from some categories of industries (Mining of non-metallic minerals, Manufacture of basic organic petrochemicals, Manufacture of other basic organic chemicals, Manufacture of other chemical products etc.) seemed to be influenced by salinity. The Ion concentration in influent and effluent were similar. Concentration of $Na^+$, $Cl^-$, $K^+$, $Ca^{2+}$ ions were high in influent, however $Mg^{2+}$ and $SO_4^{2-}$ ions were high in effluent.