• Title/Summary/Keyword: Background Electrolytes

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Effects of Ionic Strength, Background Electrolytes, Heavy Metals, and Redox-Active Species on the Reduction of Hexavalent Chromium by Ecklonia Biomass

  • PARK DONGHEE;YUN YEOUNG-SANG;JO JI HYE;PARK JONG MOON
    • Journal of Microbiology and Biotechnology
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    • v.15 no.4
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    • pp.780-786
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    • 2005
  • The biomass of the brown seaweed, Ecklonia, was used to remove Cr(VI) from wastewater. Previously, Cr(VI) was removed through its reduction to Cr(III) when brought into contact with the biomass. In this study, the effects of ionic strength, background electrolytes, and Cr(III), Ni(II), Zn(II), and Fe(III) on the Cr(VI) reduction were examined. An increased ionic strength inhibited the Cr(VI) reduction. The presence of other heavy metals, such as Cr(III), Ni(II), or Zn(II), only slightly affected the Cr(VI) reduction, while Fe(III) enhanced the reduction. Although the above various parameters could affect the reduction rate of Cr(VI) by Ecklonia biomass, these effects were relatively smaller than those of pH and temperature. In addition, the previously derived rate equation was found to be applicable over a range of ionic strengths and with different background electrolytes. In conclusion, Ecklonia, bioniass may be a good candidate as a biosorbent for the removal of Cr(VI) from wastewaters containing various other impurities, and scale-up to a practical process may be accomplished using the previously derived rate equation.

Efficient use of ferrate(VI) in the oxidative removal of potassium hydrogen phthalate from aqueous solutions

  • Tiwari, Diwakar;Sailo, Lalsaimawia;Yoon, Yi-Yong;Lee, Seung-Mok
    • Environmental Engineering Research
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    • v.23 no.2
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    • pp.129-135
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    • 2018
  • The aim of this study is to assess the applicability of ferrate(VI) in the efficient treatment of aqueous waste contaminated with potassium hydrogen phthalate (KHP) which is known to be a potent endocrine disrupting chemicals. Simulated batch reactor operations were conducted at a wide range of pH (7.0 to 12.0) and molar ratios of KHP to ferrate(VI). Kinetic studies were performed in the degradation process and overall rate constant was found to be 83.40 L/mol/min at pH 8.0. The stoichiometry of ferrate(VI) and KHP was found to be 1:1. Further, lower pH values and higher KHP concentrations were favoured greatly the degradation of KHP by ferrate(VI). Total organic carbon analysis showed that partial mineralization of KHP was achieved. The presence of several background electrolytes were studied in the degradation of KHP by ferrate(VI).

A study on the Healing Mechanism of Herbal Medicine, Oryoungsan (오령산의 작용기전(作用機轉)에 대한 고찰(考察))

  • Nam, Hyoung-sin;Cho, Chung-sik;Kim, Chul-jung
    • Journal of Haehwa Medicine
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    • v.10 no.1
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    • pp.157-166
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    • 2001
  • Oryoungsan which first recorded in Sanghanron, the clinical medical book consists of treating acute febrile disease according to its change, is one of the frequently used oriental medicines. these days, it has been prescribed in symptoms accompanied by edema mostly. therefore it is easy to consider it as a type of diuretics. In Sanghanron it was originally used in the symptoms of perspiration, decreased urine volume, thirsty, flatulence. these symptoms indicate loss of body fluid and the prescription which orders "taking warm water sufficiently" supports this. On this background, it is supposed that Oryoungsan treats dehydration after providing water and electrolytes. To consider that herbal medicines consisted of Oryoungsan make electrolytes go out of the body, The healing mechanism of dehydration doesn't meet this. Because Oryoungsan was used in condition of fever or in similar condition, it is more resonable to understand that restoration of increasing blood flow to the subcutaneous venous plexus regulating body temperature in febrile condition into body circulation, resulting into maintaining main blood volume and into treating decreased urine volume and thirsty is Oryoungsan's function in the dehydration or febrile condition. That is, symptoms are decreased or disappeared through restoring unbalance of internal body fluid. The other target is pain controls, especially chronic headache, facial pain and trigeminal neuralgia. it is suggested that the function of pain control of Oryoungsan is related to 5-HT(5-hydroxytrypamine), nerve transmitter in the endogenous analgesic system. Moreover it is also suggested that Oryoungsan is relate to 5-HT, considering the fact that gastroparesis, a symptom of cyclic vomiting syndrome treated with 5-HT1D receptor agonist is similar to the 'bi', symptoms appeared in the Oryoungsan-related disease.

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Application of Reused Powdered Waste Containing Aluminum Oxide on the Treatment of Cr(VI) (6가 크롬 처리를 위한 알루미늄 산화물을 함유한 재생 분말 폐기물의 적용)

  • Lim, Jae-Woo;Kim, Tae-Hwan;Kang, Hyung-Sik;Kim, Do-Son;Kim, Han-Seon;Cho, Seok-Hee;Yang, Jae-Kyu;Chang, Yoon-Young
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.3
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    • pp.179-185
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    • 2009
  • In this research, the removal capacity of Cr(VI) by the reused powdered wastes (RPW) containing aluminium oxides was studied. As a pre-treatment process for the preparation of calcined wastes, calcination was conducted at $550^{\circ}C$ to remove organic fraction in the raw wastes. In order to study the adsorption trend of Cr(VI) ions from aqueous solutions, the pH-edge adsorption, adsorption kinetic and adsorption isotherm were investigated using a batch reactor in the presence of four different background electrolytes($NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-},\;PO_4\;^{3-}$). Cr(VI) adsorption was greatly reduced in the presence of $SO_4\;^{2-}$ and $PO_4\;^{3-}$ over the entire pH range. Meanwhile the inhibition effect by $NO_3\;^-$ and $CO_3\;^{2-}$ was relatively lower than that by $SO_4\;^{2-}$ and $PO_4\;^{3-}$. Cr(VI) adsorption was maximum around pH 4.5 in the presence of $NO_3\;^-$ and $CO_3\;^{2-}$. As the concentration of background electrolytes increased, Cr(VI) adsorption decreased. This result mightly suggests that adsorption between the surface of RPW and Cr(VI) occurs through outer-sphere complex. Cr(VI) adsorption onto the RPW was well described by second-order kinetics. From the Langmuir isotherm at initial pH 3, the maximum adsorbed amount of Cr(VI) onto the RPW was 11.1, 10, 3.3, 5 mg/g in the presence of $NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-}$, and $PO_4\;^{3-}$, respectively.

Effect of feeding mixed microbial culture fortified with trace minerals on ruminal fermentation, nutrient digestibility, nitrogen and trace mineral balance in Sheep

  • Kwak, W.S.;Kim, Y.I.;Choi, D.Y.;Lee, Y.H.
    • Journal of Animal Science and Technology
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    • v.58 no.5
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    • pp.21.1-21.8
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    • 2016
  • Background: The aim of the present study was to determine the effects of feeding trace mineralsfortified mixed microbial culture (TMC) on ruminal fermentation, nutrient digestibility, blood electrolyte status, nitrogen balance, and trace mineral balance in sheep. Methods: Mixed microbes [0.6 % (v/w) of Enterobacter sp., Bacillus sp., Lactobacillus sp., and Saccharomyces sp.] were cultured with 99 % feedstuffs and 0.4 % trace minerals including zinc and copper for ensiling. Six sheep (a mean body weight of $46.5{\pm}1.2kg$) were fed two diets: a control diet (concentrate mix and rye straw) and an experimental diet (a control diet + 3.1 % TMC). Results: TMC feeding did not induce negative effects on ruminal fermentation, nutrient digestibility, blood electrolytes, and nitrogen balance in sheep. Feeding with TMC increased the intake of trace minerals (p < 0.05) and did not affect absorption of trace minerals in the whole digestive tract. Feeding with TMC increased fecal excretion and absorbable intake, and retention of zinc and copper (p < 0.05) by 71 % and 77 %, respectively. Conclusion: Feeding with TMC resulted in higher zinc and copper bioavailability and retention without any adverse effects on sheep performance.

Effects of Yuldahansotang and Jowisokmyungtang on the Blood Pressure and Renal Function in Spontaneously Hypertensive Rats (태음인(太陰人) 열다한소탕(熱多寒少湯)과 조위속명탕(調胃續命湯)이 자연발증(自然發證) 고혈압(高血壓) 백서(白鼠)의 혈압(血壓)과 신장(腎臟) 기능(機能)에 미치는 영향(影響))

  • Yun, Hong-sik;Lee, Ho-seob;Kim, Kyung-yo
    • Journal of Sasang Constitutional Medicine
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    • v.10 no.2
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    • pp.565-588
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    • 1998
  • 1. Background and Purpose : I intended to investigate the effects of Taeumin Yuldahansotang and Jowisokmyungtang experimentally to hypertension and renal function and contrived to approach these diseases by constitutional medicine. 2. Methods : I adapted two groups, normal rats and spontaneously hypertensive rats, to the same environment for more than 2 weeks and adminstrated water extracts of Yuldahansotang and Jowisokmyungtang. After adminstration of water extracts, I observed significant changes of values of the blood pressure and the urinary excretion of creatininine, electrolytes, osmolarity, renin, atrial natriuretic peptide and the plasma level of aldosterone, triglyceride, phospholipid, cholesterol. 3. Results : Yuldahansotang and Jowisokmyungtang decrease the blood pressure in the spontaneous hypertensive rats, the one by increasing the plasma level of atrial natriuretic peptide and decreasing the plasma level of aldosterone, the other by decreasing the plasma level of aldosterone, from which we could detect the therapeutic difference between Yuldahansotang and Jowisokmyungtang.

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Competitive Adsorption of Cd and Cu on Surface of Humic Acid Extracted from Peat (피트에서 추출한 부식산 표면에 대한 카드뮴과 구리의 경쟁 흡착)

  • Lim, Soo-Kil;Chung, Chang-Yoon;Ok, Yong-Sik;Kim, Jeong-Gyu
    • Korean Journal of Soil Science and Fertilizer
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    • v.35 no.6
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    • pp.344-351
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    • 2002
  • Chemical speciation and transport of heavy metals in soil environment could be controlled by humic acid. In order to understand the mechanism on competitive adsorption of Cd and Cu on the surface of humic acid extracted from peat, the charge development of humic acid were investigate through a batch adsorption experiment with a series of different background electrolytes levels. The competitive adsorption of Cd and Cu to the humic acid were estimated according to the model using the proton binding constant obtained from the above batch test. The affinity of Cu to the carboxyl group on the humic acid was higher than that of Cd, but the affinity to the phenolic group was lower than to the carboxyl group. It seems that the amount of adsorbed Cd and Cu could be estimated using the proton binding constant obtained from a solution with single background ion. However, it is difficult to interpret the competitive adsorption of Cd and Cu with the constant for single background ion.

Influence of Manufacturing Conditions for the Life Time of the Boron-Doped Diamond Electrode in Wastewater Treatment (폐수처리용 붕소 도핑 다이아몬드 전극의 수명에 미치는 제조공정 변수의 영향)

  • Choi, Yong-Sun;Lee, Young-Ki;Kim, Jung-Yuel;Kim, Kyeong-Min;Lee, You-Kee
    • Korean Journal of Materials Research
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    • v.27 no.3
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    • pp.137-143
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    • 2017
  • Boron-doped diamond (BDD) electrode has an extremely wide potential window in aqueous and non-aqueous electrolytes, very low and stable background current and high resistance to surface fouling due to weak adsorption. These features endow the BDD electrode with potentially wide electrochemical applications, in such areas as wastewater treatment, electrosynthesis and electrochemical sensors. In this study, the characteristics of the BDD electrode were examined by scanning electron microscopy (SEM) and evaluated by accelerated life test. The effects of manufacturing conditions on the BDD electrode were determined and remedies for negative effects were noted in order to improve the electrode lifetime in wastewater treatment. The lifetime of the BDD electrode was influenced by manufacturing conditions, such as surface roughness, seeding method and rate of introduction of gases into the reaction chamber. The results of this study showed that BDD electrodes manufactured using sanding media of different sizes resulted in the most effective electrode lifetime when the particle size of alumina used was from $75{\sim}106{\mu}m$ (#150). Ultrasonic treatment was found to be more effective than polishing treatment in the test of seeding processes. In addition to this, BDD electrodes manufactured by introducing gases at different rates resulted in the most effective electrode lifetime when the introduced gas had a composition of hydrogen gas 94.5 vol.% carbon source gas 1.6 vol.% and boron source gas 3.9 vol.%.

Effect of Argon Addition on Properties of the Boron-Doped Diamond Electrode (아르곤 가스의 주입이 붕소 도핑 다이아몬드 전극의 특성에 미치는 효과)

  • Choi, Yong-Sun;Lee, Young-Ki;Kim, Jung-Yuel;Lee, You-Kee
    • Korean Journal of Materials Research
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    • v.28 no.5
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    • pp.301-307
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    • 2018
  • A boron-doped diamond(BDD) electrode is attractive for many electrochemical applications due to its distinctive properties: an extremely wide potential window in aqueous and non-aqueous electrolytes, a very low and stable background current and a high resistance to surface fouling. An Ar gas mixture of $H_2$, $CH_4$ and trimethylboron (TMB, 0.1 % $C_3H_9B$ in $H_2$) is used in a hot filament chemical vapor deposition(HFCVD) reactor. The effect of argon addition on quality, structure and electrochemical property is investigated by scanning electron microscope(SEM), X-ray diffraction(XRD) and cyclic voltammetry(CV). In this study, BDD electrodes are manufactured using different $Ar/CH_4$ ratios ($Ar/CH_4$ = 0, 1, 2 and 4). The results of this study show that the diamond grain size decreases with increasing $Ar/CH_4$ ratios. On the other hand, the samples with an $Ar/CH_4$ ratio above 5 fail to produce a BDD electrode. In addition, the BDD electrodes manufactured by introducing different $Ar/CH_4$ ratios result in the most inclined to (111) preferential growth when the $Ar/CH_4$ ratio is 2. It is also noted that the electrochemical properties of the BDD electrode improve with the process of adding argon.

Electrochemical Noise Analysis on the General Corrosion of Mild steel in Hydrochloric Acid Solution

  • Seo, Do-Soo;Lee, Kwang-Hak;Kim, Heung-Sik
    • Corrosion Science and Technology
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    • v.7 no.6
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    • pp.319-323
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    • 2008
  • The polarization resistance of mild steel in 0.5M hydrochloric acid has been evaluated by using impedance (Z) and linear polarization (LPR) techniques and compared to the noise resistance obtained from electrochemical noise data. The degree of localization of this general corrosion has also been discussed by evaluating localization index and power spectral density. Polarization resistance obtained by LPR technique ($28\Omega$) was higher than that obtained by impedance technique ($15\Omega$). Noise resistance ($11\Omega$) was much lower than polarization resistance measured by both of above techniques. Higher polarization resistance obtained by LPR technique is generally caused by passivation effect in the presence of scales or deposits which can introduce an increased resistance as can low conductivity electrolytes. The reason why noise resistance is lower than polarization resistance is the effect of background noise detected by using three platinum electrodes cell in 0.5M hydrochloric acid. Slope($-\beta$) of power spectral density (PSD) obtained from analysis of noise data ($-\beta$ = 3.3) was much higher than 2 which indicates mild steel corroded uniformly. Localization index (LI) calculated from statistical analysis (LI=0.08) is much lower than 1 which indicates that mild steel did not corroded locally. However, LI value is still higher than $1x10^{-3}$ and this indicates that mild steel corroded locally in microscopic point of view.