• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.132-138
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• 2005

Objective of this research was to evaluate the fate of nitrogen and phosphorous in hydroponic waste solution from the plastic film house cultivation applied to the upland soil by column leaching and field experiment. The pH and EC of leachate were decreased by the reaction with the upland soil in the column leaching experiment. The EC and concentrations of $H^+,\;K^+,\;and\;{NH_4}^+$ of leachate were decreased as the column length (soil depth) was increased. But these were increased as the amounts of the hydroponic waste solution were increased field experiment growing red pepper (Capsicum annum L.) to monitor the nutrients movement using ion exchange resin capsule demonstrated that the nutrient concentration of soil solution was increased in the orders of $PO_4-P. Nitrate concentration of resin capsule inserted into the soil was relatively higher than other nutrients $(NH_4-N\;and\;PO_4-P)$ at the 45 cm of soil depth. The overall results demonstrated that the hydroponic waste solution could be recycled as plant nutrients to enhance fertility of soils. But nitrate leaching was a major factor for safe use of the hydroponic waste solution in soil.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.193-198
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• 1997

The purpose of this study was to find out a suitable resin to remove $NO_3-N$ from groundwater. Four different commercial resins differentiated by type, porosity and nitrate selectivity were used to compare the performance of nitrate removal. Gel type, Type 2 anion exchange resin was preferable when anion concentration of raw water was low. But efficiency of this resin decreased as flow rate increased. However, macroporous type resins were not affected by increasing flow rate. Macroporous resins were preferable when anion concentrations in raw water were high and high flow rate was proposed. And the general type resin showed better efficiency when sulfate concentrations were low. However the nitrate selective resin had better efficiency in treating raw water of high sulfate concentration. From the results, it may be drawn that nitrate selective resins are preferable to general type when a sulfate concentration in groundwater is over 50mg/l.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.1
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• pp.37-43
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• 2013

Conductivity of LSGMC materials were affected by secondary phase segregation, composition and synthetic route. $La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.1}Co_{0.1}O_{3-{\delta}}$ (LSGMC) powders were prepared using the glycine nitrate process to produce high surface area and compositionally homogeneous powders. The powders were synthesized with different 0.5, 1, 1.5, 2, 2.5 of glycine/cation molar ratios. A single perovskite phase from the synthesized powders was characterized with X-ray diffraction patterns. The obtained sintered pellets showed the dense grain microstructure. In case of 1.5 molar ratio, its density was higher than the others. The electrical conductivity measured at $800^{\circ}C$ was observed to be 0.131 $Scm^{-1}$. In addition, the linear thermal expansion behavior was indicated between $25^{\circ}C$ and $800^{\circ}C$.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.433-441
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• 2007

This work investigated the stability of a Sn-modified Pt electrode, which was used for reduction of nitrate, fabricated by an adsorption or electro-deposition of Sn on Pt. In order to find the causes for instability of the electrode, the effects of the solutions in which the electrode was used and the potential applied to the electrode on the electrochemical and metallurgical behaviors of Sn on Pt were studied. The Sn of freshly- prepared modified-Sn Pt electrode existed as Sn hydroxide form, which brought about an easy loss of the electro-activity of the electrode even staying in water, especially in acid solution. When the Sn-modified Pt electrode was used for the reduction of nitrate, the electro-activity of the electrode was affected depending on the potential applied to the electrode. When a more negative potential than the redox equilibrium potential between $Sn(OH)_2$ and Sn was applied to the electrode, the Sn hydroxide was converted to Sn that could diffused into Pt, which leaded to the loss of electro-activity of the electrode as well. The solid diffusion of Sn increased linearly with the applied potential. The Sn-electrodeposited Pt electrode which had more Sn on the electrode was more favorable to maintaining the integrity of the electrode during the reduction of nitrate than the Sn-adsorbed Pt electrode prepared in the under-potential deposition way.

• Journal of the Korean Chemical Society
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• v.50 no.2
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• pp.163-177
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• 2006

Alpha Nickel hydroxide samples have been synthesized by electrodeposition on platinum and nickel substrates at current densities of 1, 5, 6, 7 and 10 mAcm？2 at a controlled temperature of 30.00 oC from Ni(NO3)2 bath. Platinum substrate shows a tendency to incorporate less nitrate ions with increase in current density thus producing less hydroxy-deficient nickel hydroxide layers. On the whole the interlayer distance (d003) is found to be inversely proportional to the amount of nitrate ions incorporated in-between the lattice. For the first time we have observed a decrease in lattice spacing with increase in concentration of intercalant (anions) and the reason for lattice contraction is attributed to the columbic attractive forces exerted by the oppositely charged nitrate ion and positively charged slabs. The Infrared spectra of the samples with expanded interlayers show two types of OH vibrations corresponding to hydrogen bonded and non-hydrogen bonded OH groups whereas the contracted interlayers show only hydrogen-boded OH groups. Although the faradaic efficiency is found to increase with increase in applied current there is a local minimum at 6.0 mAcm？2 current density on both platinum and nickel substrates. In this manuscript, GC-MS data is provided which clearly demonstrates the electrodeposited nickel hydroxide sample to consist of huge amount of carbonate ions although the electrolyte solution in nickel nitrate.

• Journal of the Korean Chemical Society
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• v.20 no.6
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• pp.486-493
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• 1976

The PVC mixed silver iodide pellet was prepared by means of the Infrared Pellet presser and the pellet was used as an indicating membrane electrode, to measure the potentials for various silver ion activities, ranging from $10^{-1}$ to $10^{-6}$ M. The potential responses to silver ion activities were linear and the slope was much close to Nernstian relation as compared with that of the pure silver iodide pellet membrane electrode and the PVC coated silver iodide pellet membrane electrode. The mechanical property and chemical durability of this electrode were found much better than the others. This electrode did not show significant response to the other except silver ion, but had good response to halide ions, i.e., iodide, chloride, bromide and cyanide ions, in the concentration range $10^{-1}$ to $10^{-6}$ M. This electrode could be used as an indicating electrode in potentiometric titrations of single halide ion and also halide mixture with standard solution of silver nitrate.

• Membrane and Water Treatment
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• v.8 no.4
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• pp.381-393
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• 2017

The inorganic components in tobacco sheet extract have significant influence on the sensory taste of the cigars and the harmful component delivery in cigarette smoke. To identify the contributions of the divalent inorganic components on harmful components delivery in cigarette smoke, a self-made selective electrodialysis was assembled with monovalent ion-selective ion exchange membranes. The influences of current density and extract content on the desalination performance were investigated. Result indicates that the majorities chloride, nitrate, and sulfate ions were removed, comparing with 50-60% of potassium and only less than 10% of magnesium and calcium ions removed in the investigated current density. The permselectivity of the tested cations across the Selemion CSO cation exchange membranes follows the order: $K^+>Ca^{2+}>Mg^{2+}$. A current density of $15mA/cm^2$ is an optional choice by considering both the energy consumption and separation efficiency. When the extract contents are in the range of 7%-20%, the removal ratios the potassium ions are kept around 60%, while the removal ratios of the calcium and magnesium ions fluctuate in the range of 16-27% and 8-14%, respectively. The tobacco smoke experiments indicated that the divalent metal ions have dual roles for the harmful component delivery in cigarette smoke. The divalent potassium and calcium ions were unfavorable for the total particulate matter emission but beneficial to decrease the HCN delivery in the mainstream cigarette smoke. The selective electrodialysis is a robust technology to decrease the harmful component delivery in cigarette smoke.

• Membrane Journal
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• v.20 no.2
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• pp.142-150
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• 2010

A series of anion exchange composite membranes were prepared and characterized for electrodialysis processes used in the removal of nitrate nitrogen and ions in groundwater. The membranes were prepared as follows; first, fabric substrates were fully impregnated with monomer mixtures of vinylbenzylchloride (VBC), divinylbenzene (DVB), Styrene (ST) and $\alpha,\alpha$-Azobis(isobutyronitrile) (AIBN). Second, they were thermally polymerized to yield crosslinked poly (VBCST- DVB)/fabric composite membranes. Finally, the membranes were treated with trimethylamine (TMA) / acetone to give $-N^+(CH_3)_3^-$-containing poly(VBC-ST-DVB)/fabric membranes. The basic membrane properties such as ion exchange capacity (IEC), electric resistance and water content of the resulting membranes were measured as a function of VBC/DVB and TMA/Acetone content. As a result, the composite membranes showed lower electric resistance and higher IEC than commercial anion exchange membranes (AMX, Astom). Electrodialysis tests using the prepared membranes were carried out for the removal of various ions such as $NaNO_3$, $MgSO_4$ and NaF for 60 minutes. The results showed that the ions were removed below 1 mg/L within about 15 minutes which indicates that the anion exchange membranes prepared here could be applied to the electrodialysis process. as can be seen in the following that the ion conductivity values were almost no change after 15 minutes electrodialysis.

• Analytical Science and Technology
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• v.29 no.5
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• pp.219-224
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• 2016

불산 중 극미량 음이온의 고상추출과 이온크로마토그래프를 이용한 고감도 분석법이 개발되었다. 불산 중 불소이온이 고상에 의해 제거하였고 이어서 음이온 (F⁻, CH₃COO⁻, Cl⁻, Br⁻, NO₃⁻, PO₄³⁻, SO₄²⁻)들이 이온크로마토그래프를 이용하여 연속적으로 분리하였다. 고상 추출법에 영향을 주는 각 인자들 (흡착제의 선택, 시료의 부피 및 pH, 용출 용액과 용출용액의 부피)을 결정하였으며 그 결과 흡착제로서 Oasis WAX 컬럼이 가장 우수하였고 1.0 mL의 시료부피, 용출용액으로 50 mM 초산암모늄염 5 mL가 분리능에서 가장 우수하였다. 개발한 방법에 의한 음이온 (Cl⁻, Br⁻, NO₃⁻, PO₄³⁻, SO₄²⁻)들의 방법검출한계는 25 % 불산용액 (w/w) 중에 0.04~0.30 µg/L의 범위를 보였고 정밀도는 20.0와 40.0 µg/L의 농도에서 5 % 이내를 보였다. 한 제조회사에 의한 25 % 불산 중 음이온의 4.2에서 47.5 µg/L의 범위로 모두 검출되었다. 이 방법은 시험절차가 간단하고, 재현성 및 감도가 좋아서 반도체회사에서 불산 중 음이온 불순물을 정도 관리하는데 매우 유용한 방법이 될 것으로 판단된다.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.86-94
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• 1984

The single crystal ion-selective electrode,$ {\beta}-Ag_3SI/PVC-THF $membrane electrode has showed a linear potential response to the activities of iodide ion (10-1${\sim}$10-7M). The $ {\beta}-Ag_3SI$ membrane electrode was compared with AgI/PVC-THF membrane and copper metal plate membrane electrodes. In order to measure the selectivity coefficient of the electrodes toward $Cl^-$ and $Br^-$, the separation and mixed solution method were employed. The potential-time curve was obtained by the usual immersion technique and pH effect was also examined. The orders of selectivity for $Br^-$, $Cl^-$ and stability of response time are ${\beta}-Ag_3SI/PVC-THF $membrane > AgI/PVC-THF membrane > copper metal plate membrane. These electrodes could be used as indicating electrodes in the potentiometric titration of a single halide and mixed halides with the standard solution of silver nitrate.