• 한국의류학회지
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• 제13권2호
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• pp.128-136
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• 1989

In order to investigate a practical application of fibrous adsorbents to heavy metal ions, amidoxime fibers, as a particular class of solid chelate agents, were prepared by hydroxylamine treatment for acrylic fibers in a recipe of neutralization. Among the important problems from plant effluents are toxic concentrations of heavy metals such as copper. Accordingly, the properties of Cu (II) adsorption and its chelates were studied. The results obtained are as follows; The fibrous adsorbents have the property of increasing the swelling volumes by amidoximation. The adsorption of Cu (II) ion is characterized by an endothermic reaction, which is estimated as the plus values in the enthalpy change ($\delta$H=1.30 Kcal/mol. and 3.14 Kcal/mol.). The Cu (II) ions are adsorbed in the range of pH $3\~8$ and the maximum adsorptions are occurred about pH 8. Owing to the anions $(NO_3^-,\;Cl^-)$ of copper salts, amidoxime fibers form 1:1 and 2:1 (ligand: metal) chelating complexes with Cu (II). The nitrate anion chelates to amide I (NH) of amidoxime groups and the chlorine anion does to nitrosyl (NO). These effects relate to the crystallization of the complex and the thermal property.

• Membrane and Water Treatment
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• 제5권1호
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• pp.31-40
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• 2014

Papermaking tobacco sheet is an important reclaimed process for cigarette making. Traditionally, the pressure driven membrane was often used to isolate the effective compounds from the tobacco sheet extract. However, this method is difficult to remove small ionic compounds. Besides, membrane fouling is a major problem for effective use of these pressure driven membrane technologies. In this study, the electrodialysis process is used to removal the chloride ions and nitrate ions, thus the smoking quality of papermaking tobacco sheet extract can get improved. Three types of electrolytes ($Na_2SO_4$, NaCl and HCl) are chosen to prevent the generation of precipitation. The results indicate that 0.1mol/L HCl at current density of $30mA/cm^2$ is the optimal condition for the electrodialysis process. The removal rates of the Cland $NO{_3}^-$ in tobacco sheet extract are 97% and 98.4%, respectively. The electrodialysis process cost was estimated to be 0.11$/L. Naturally, electrodialysis is not only technological feasible, environmental-friendly and economical-attractive for tobacco extract treatment.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2607-2610
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• 2011

Monodispersed Ag/$TiO_2$ core/shell nanoparticles were synthesized in solution via colloid-seeded deposition process using Ag nanoparticles as colloid seeds and $Ti(SO_4)_2$ as Ti-source respectively. Silver nitrate was reduced to Ag nanoparticles with $N_2H_4{\cdot}H_2O$ in the presence of CTAB as stabilizing agent. The titania sols hydrolyzed by the $Ti(SO_4)_2$ solution deposited on the surface of Ag nanoparticles to form the Ag/$TiO_2$ core/shell nanoparticles. Inductively coupled plasma atomic emission spectrometry (ICP-AES) showed low amount of Ag ion leaching from the Ag/$TiO_2$ core/shell nanoparticles. The Ag/$TiO_2$ core/shell nanoparticles indicated excellent antibacterial effects against Escherichia coli and maintained long-term antibacterial property.

• 공업화학
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• 제8권1호
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• pp.108-113
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• 1997

본 연구에서는 질산매질에서 UV 광조사에 의한 옥살산 분해연구가 수행되었다. UV 광원은 $2537{\AA}$의 파장을 방출하는 수은램프가 사용되었다. UV 광조사에도 불구하고 옥살산 자체는 분해되지 않았다. 그러나 질산매질하에서 UV 광조사에 의해 옥살산은 쉽게 분해되었다. UV광조사에 의해 $NO_3{^-}$으로부터 발생되는 산소라디칼이 옥살산을 분해시키는 것으로 조사되었다. 옥살산 분해율은 질산 0.5M 부근에서 최대를 이루다가 질산농도 증가에 따라 점차 감소하였다. 이것 역시 산소라디칼과 $NO_3{^-}$ 사이에서 반응으로 쉽게 설명될 수 있다.

• The Korean Journal of Ceramics
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• 제6권1호
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• pp.43-46
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• 2000

$H_4Nb_6/O_{17}$/CdS nanocomposites which intercalated CdS particles, less than 0.8nm thickness, in the interlayer of $H_4Nb_6/O_{17}$ were prepared by the successive ion exchange reactions of $H_4Nb_6/O_{17}$ with $Cd^{2+}$ and $C_3H_7NH_3_+$, followed by the reaction with $H_2S$ gas. $H_4Nb_6/O_{17}$/CdS photocatalytically reduced $NO_3$￣ to $NO_2$￣ and $NH_3$in the presence of sacrificial hole acceptor such as methanol under visible light irradiation (wavelength>400nm), although unsupported CdS showed no noticeable photocatalytic activity for $NO_3$￣ reduction. The catalytic activity of $H_4Nb_6/O_{17}$/CdS greatly enhanced with co-doping of Pt particles in the interlayer.

• 한국세라믹학회지
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• 제27권7호
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• pp.851-860
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• 1990

The hydrolysis-precipitation reaction of mixed aluminum salt solutions of aluminum sulfate, aluminum nitrate, and urea has been investigated to obtain narrow-sized and unagglomerated fine spherical precipitates of aluminum hydroxide required for coating core particles. The hydrolysis-precipitatin reaction could be controlled to be appropriate to coating processes by usign urea as a pH control-agent. As the concetration of total Al3+ ion and the molar ratio of SO42-/Al3+ in starting solutions became smaller and also as the vol. ratio of water/solution for hydrolyzing mixed aluminum salt solution became larger, the morphology of precipitates tended to be more unagglomerated and spherical, while their size(0.5longrightarrow0.05${\mu}{\textrm}{m}$) to be smaller. The optimum hydrolysis condition for coating processes was to hydrolyze the mixed aluminum salt solution, in which the molar ratio of SO42-/Al3+ was 0.75, while the amount of water corresponding to the vol. ratio of water/solution of 15. The precipitate was the aluminum hydroxide which sulfate ions were strongly adsorbed on and the maximum yield in the hydrolysis-precipitation reaction was about 20%.

• 한국자원식물학회지
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• 제5권1호
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• pp.57-68
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• 1992

The effects of various kind and amount of nitrogen fertilizers on the plant grorth. physiological , yield and extracts. ligustilide, butylidene phthalide contents of curdsdrug "Tou-ki" (AnTelica acutiloba Kitagawa) were investigated in 1989. Five plots variouskind of nitrogen fertilizers. Namely, no nitrogen, urea. ammonium nitrate, ammoniumchloride and control plot of ammonium sulfate. The other, by providing five plotsdifferent composed ratio of nitrogenous fertilizers. containing no nitrogen (No. o) .0.5-fold nitrogen (No s), control plot of 1.0-fold nitrogen(Nl.o). 1.5-fold nitrogen(Nl s)and 2.0-fold nitrogen Na. o), but nitogen was used the ammonium sulfate. The results showedthat the crude drug "Tou-ki" can ammonium chloride be produced in good yield, displayingboth good plant growth and remarkable physiologically-active conditions, and it can beproduced such that the extracts is maximized. Additionally, using methods of gaschromatography (GC) , it was established that ligustilide and butylidene phthalide, majorcomponents in the crude drug was recovered in a good yield from the fully grown plants.The other, the plant growth, the physiologically-active, the weight of whole plant, theyield of extracts and ligustilide, butylidene phthalide were seen to be best at the plotof 2.0-fold nitrogen and according to the increase or decrease of nitrogen decreasedgradually. Therefore. about 2 fold of standard quantity seems to be the most suitablequantity of nitrogen for "Tou-ki" cultivation .uot;Tou-ki" cultivation .ion .

• 한국물환경학회지
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• 제22권4호
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• pp.666-671
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• 2006

Effects of a rainfall event (July 28, 2005) on the hydrochemical characteristics of the Jungrang river, the biggest tributary of the Han river, was investigated. Significant spatial variations in the hydrochemical characteristics were observed. At JR2 location, concentrations of T-N and T-P were relatively low indicating occurrence of active oxidation in the stepped drop structure. At JR3 location, concentrations of Na, K, Cl, $NH_4-N$ and EC were elevated suggesting increased discharge from the nearby waste-water treatment plant and tributaries. The rain event diluted major dissolved ion concentrations in the river by 12~52%. The $NO_3-N$ levels were preserved during the rain then increased about twofold after rainfall, suggesting increased discharge of nitrate-contaminated groundwater. Heavy metals including Cd, Co, Cr, Cu and Pb were not detected in all water samples and the leachates from surface sediment samples. Concentrations of Fe, Mn, Al and Zn were below the Korean Drinking Water Guideline. Results of this study suggested that establishment of water-quality monitoring protocols describing temporal and spatial variations in parameters sensitive to rainfall events, relatively steady factors, and contaminant sources is required.

• 한국환경과학회지
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• 제12권3호
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• pp.325-335
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• 2003

An agricultural land application of swine slurry is one of the best management practices in Jeju island whose ground water must be protected. So as to study the effect of appling swine slurry on ground water or aquifer, incubation-leaching technique was used by assuming the incubating period of 1, 2, 4, 8, 16, or 32 days, and application rate of 3200.0 mgT-N/$\ell$ , 820.0 mgT-P/$\ell$, and 1887.0 mgK$\^$+/$\ell$ in swine slurry. The leachates were collected from the soil columns(PVC 30 cm L${\times}$5.5 cm D) packed 15cm in depth with Gangjeong soil series by washing with 100 mL distilled water. The leached components were measured by using ion chromatography far Cl$\^$-/, NO$_3$-N, F$\^$-/, Br$\^$-/, Na$\^$+/, K$\^$+/, Ca$^2$$\^$+/, and Mg$^2$$\^$+/ , atomic absorption spectrophotometry for Fe and Mn, and UV-Vis spectrophotometry for T-N and T-p. Application of swine slurry in naked soil could influence on the ground water or aquifer by increasing nitrate-nitrogen in leachate with time, or leaching the cations present in soils in accompany with anions because of H$\^$+/produced in nitrification. Therefore, careful consideration should be taken about what amount, when, where, and how fur protecting ground water system.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.68-71
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• 2002

SPAD공법은 탈질을 위한 전자공여체로 입자상의 황과 소량의 메탄올을 이용하는 생물학적 공법이다. 이번 연구에서 SPAD공법은 특정 폐수에의 적용가능성을 평가하기 위해 고농도의 칼슘이온을 함유한 울산의 S특수강 폐수(200-300$NO_3\;^-$ -N/L)에 적용되었다. 운전기간은 2001년 11월부터 2002년 3월 초까지였으며 반응조 내부의 온도는 약 $20^{\circ}C$ 부근으로 유지되었고, 그러한 낮은 온도조건하에서도 탈질 효율은 90%이상으로 유지되었으며 유출수 농도는 약 20mg $NO_3\;^-$ -N/L정도로 유지되었다. 따라서 SPAD공법은 고농도의 칼슘이온을 함유한 폐수에 대해 적용이 가능한 것으로 사료되어진다.