• Title, Summary, Keyword: ion concentration

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Reuse of Oyster Shell Waste as Antimicrobial Water Treatment Agent by Silver Ion Exchange

  • Jo, Myung-Chan;Byeong-II Noh;Shin, Choon-Hwan
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.4 no.3
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    • pp.185-193
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    • 2000
  • A water treatment agent with antimicrobial activity(Ag-Os) was created by exchanging silver ion($Ag^{+}$) on calcined oyster shell powder. The desorption of the exchanged silver ion was negligible, thereby indicating a stable antimicrobial water treatment agent. The sterilization effect of Ag-Os on underwater microorganisms was then investigated. An MIC (Minimum Inhibitory Concentration) test result indicated that Ag-Os had an excellent sterilization effect on G-germs, such as Escherichia coli and Pseudomonas aeruginosa. Most germs were annihilated with an Ag-Os concentration of 200 ppm and contact time of 60 minutes. The sterilization effect was mainly dependent on the contact time. The zeta potential of the Ag-Os powder adsorbed on sand was measured relative to the concentration of exchanged silver ion. As the concentration of the exchanged silver ion increased, the surface charge density of the anions on the surface of the Ag-Os powder adsorbed on sand also increased. Accordingly, this result indicated that a higher silver ion than ion exchange capacity was present on the particle surface due to adsorption. Consequently, this increased concentration of exchanged silver ion would appear to significantly enhance the sterilization power.

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Equilibrium Property of Ion Exchange Resin for Silica Removal at Ultralow Concentration (초저이온농도에서 이온교환수지에 의한 실리카제거 평형특성)

  • Yoon, Tae-Kyung;Lee, Gang-Choon;Noh, Byeong-Il
    • Journal of Environmental Science International
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    • v.16 no.8
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    • pp.907-912
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    • 2007
  • Ion exchange resin was used to remove silica ion at ultralow concentration. The effects of temperature, type of ion exchange resin and single/mixed-resin systems on removal efficiency were estimated. As temperature increased, the slope of concentration profile became stiff, and the equilibrium concentration was higher. In the single resin system, the removal of silica was continued up to 400 min, but the silica concentration was recovered to initial concentration after 400 min due to the effect of dissolved $CO_2$. In the mixed-resin system it took about 600 min to reach equilibrium. Because of faster cation exchange reaction than anion exchange reaction, the effect of $CO_2$ could be removed. Based on the experimental results carried out in the mixed-resin system, the selectivity coefficients of silica ion for each ion exchange resin were calculated at some specific temperatures. The temperature dependency of the selectivity coefficient was expressed by the equation of Kraus-Raridon type.

Effects of Sulfate Ion Concentration in Nutrient Solution on the Growth and Quality of Artemisia mongolicar var. tenuifolia (배양액 내의 황산이온 농도가 참쑥의 생육과 품질에 미치는 영향)

  • Lee, Yun-Jeong;Park, Kuen-Woo;Suh, Eun-Joo;Cheong. Jin-Cheol
    • Protected Horticulture and Plant Factory
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    • v.7 no.1
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    • pp.55-61
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    • 1998
  • This experiment was conducted to evaluate the effects of sulfate ion concentration in nutrient solution on the growth and qualify of Mongolian wormwood (Artemisia mongolica var. tenuifolia). Sulfate ion concentration was treated 0, 0.5, 1, 2 and 3mM using the modified nutrient solution composition for herb plants developed by European Vegetable R & D Center in Belgium. The growth of Mongolian wormwood was good at 3mM treatment and dry weight was best at 3mM treatment, Chlorophyll content increased with sulfate ion concentration. Mineral content did not show any significant difference among treatments. But Ca content in tissue markedly decreased at 3mM treatment. Sulfate ion uptake increased in proportion to sulfate ion concentration in nutreint solution, the higher sulfate ion concentration, the more uptake of sulfate ion by plant. At 1mM sulfate ion treatment, essential oil content was best, but the higher sulfate ion concentration resulted in decrease of essential oil content.

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Distribution of Negative Air Ion Concentration in Urban Neighborhood Park by Distance to Road - A Case of Yangjae Citizen's Forest, Seoul - (도로와의 거리에 따른 도시 근린공원의 음이온 농도 분포차이 - 서울시 양재 시민의 숲을 대상으로 -)

  • Lee, Hyunjin;Lee, Dong Kun;Kim, Bomi
    • Journal of Environmental Impact Assessment
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    • v.27 no.2
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    • pp.152-169
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    • 2018
  • The purpose of this study was to analyze the effect of adjacentroads on the concentration of negative air ions in urban neighborhood park. The measured factors were negative air ion concentration, positive airion concentration, airtemperature,relative humidity, wind speed, green formation volume factor (GVZ) and distance from highway and general road. The mean negative air ion concentration was $206ea/cm^3$ and the positive air ion concentration was $416ea/cm^3$ in the influence zone of roads. On the other hand, the mean negative air ion was $339ea/cm^3$ and the positive air ion was $229ea/cm^3$ in the unaffected zone of roads, which are inner areas of the park. The difference of the negative air ion concentration according to the influence of the road was statistically significant. The negative air ion concentration model was presented by integrating the correlation analysis with the influence factors, and the explanatory power of the model was increased by adding the influence factor of the road.

Propagating Behavior Comparison of Analytes and Background Electrolytes in a Concentration Polarization Process

  • Li, Longnan;Kim, Daejoong
    • BioChip Journal
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    • v.11 no.2
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    • pp.121-130
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    • 2017
  • Concentration polarization (CP) is an electrochemical phenomenon related to the concentration gradient (under a transversal electric field) near an ion selective membrane surface. During concentration polarization process, quantitatively investigate the background electrolyte (BGE) concentration distribution is a very challenging problem. In this study, we conducted transient simulations within 2D micro-nanochannel domain to capture the dynamic nature of concentration polarization process and compared the propagating behavior of analytes and BGE. The simulation results show that the depletion area of chloride ion and analyte are both increase with time at ohmic and limiting region. The normalized depletion area (NDA) differences increases with decreasing BGE concentration. For the high applied voltage (overlimiting region), chloride ion and analyte at the anodic side microchannel are depleted everywhere that the NDA tends to 1 after an increasing step because of the electroconvection effect. This means there is no depletion area (DA) differences between two species in this plateau region. These results tell us the fluorescent ion indicator can't show the exact BGE concentration distribution during CP process and we need to find new technique to visualize the concentration field.

Effects of Selenate Ion Concentration in Nutrient Solution on the Growth and Essential Oil Content of Wormwood( Artemisia absinthium L.) (배양액 내의 Selenate 이온농도가 웜우드(Artemisia absinthium L.)의 생육 및 정유함량에 미치는 영향)

  • Park, Kuen-Woo;Lee, Yun-Jeong;Jeong, Jin-Cheol
    • Protected Horticulture and Plant Factory
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    • v.6 no.4
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    • pp.264-269
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    • 1997
  • This study was conducted to evaluate appropriate selenate ion concentration for the production of high functional vegetables. Sodium selenate was treated 0, 2, 4, 6 and 8mg/$\ell$ using herb nutrient solution developed by European R & D Vegetable Center in Belgium. Low level of Na2se04 concentration increased the growth of wormwood, but high selenate concentration decreased the growth. Total chlorophyll content was increased by sodium selenate. The higher selenate ion concentration in the nutrient solution, the more total chlorophyll content was. The vitamin C content in wormwood was high at 2 and 4mg/$\ell$ treatment, showing good growth, at higher concentration, however, the vitamin C content decreased. At 4mg/$\ell$ selenate ion concentration, essential oil content of wormwood was best. But higher selenate ion concentration decreased essential oil content. The uptake of Se by the plant increased with the increase of selenate ion concentration.

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The Effect of High Concentration Cation Matrix on the Analysis of the Low Anion Concentration in Suppressed Ion Chromatography (Suppressed 이온 크로마토그래피에서 과량의 양이온이 낮은 농도의 음이온 분석에 미치는 영향)

  • Kang, Mi-Jeong;Lee, Sueg-Geun
    • 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.

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Chloride Penetration Analysis of Concrete Structures with Chloride Concentration (염분 농도에 따른 콘크리트 구조물의 염분침투 해석)

  • Yang, Joo-Kyoung
    • Journal of the Korea Computer Industry Society
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    • v.9 no.3
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    • pp.137-142
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    • 2008
  • The major influence factor on chloride penetration into concrete structures is chloride ion concentration. In this study, chloride penetration analyses with chloride ion concentration were carried out by the developed program. Also, the service life of concrete structures was predicted. The penetration depth was 32mm in case that chloride ion concentration wad 600ppm. It was shown that the service life of concrete structures with 40mm cover depth was 167 years even though they had been exposed at chloride ion concentration 600ppm during 100 years.

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Continuous ion-exchange membrane electrodialysis of mother liquid discharged from a salt-manufacturing plant and transport of Cl- ions and SO42- ions

  • Tanaka, Yoshinobu;Uchino, Hazime;Murakami, Masayoshi
    • Membrane Water Treatment
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    • v.3 no.1
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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.

Modeling of diffusion-reaction behavior of sulfate ion in concrete under sulfate environments

  • Zuo, Xiao-Bao;Sun, Wei;Li, Hua;Zhao, Yu-Kui
    • Computers and Concrete
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    • v.10 no.1
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    • pp.79-93
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    • 2012
  • This paper estimates theoretically the diffusion-reaction behaviour of sulfate ion in concrete caused by environmental sulfate attack. Based on Fick's second law and chemical reaction kinetics, a nonlinear and nonsteady diffusion-reaction equation of sulfate ion in concrete, in which the variable diffusion coefficient and the chemical reactions depleting sulfate ion concentration in concrete are considered, is proposed. The finite difference method is utilized to solve the diffusion-reaction equation of sulfate ion in concrete, and then it is used to simulate the diffusion-reaction process and the concentration distribution of sulfate ion in concrete. Afterwards, the experiments for measuring the sulfate ion concentration in concrete are carried out by using EDTA method to verify the proposal model, and results show that the proposed model is basically in agreement with the experimental results. Finally, Numerical example has been completed to investigate the diffusion-reaction behavior of sulfate ion in the concrete plate specimen immersed into sulfate solution.