• 한국안전학회지
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• 제13권4호
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• pp.206-212
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• 1998

The water permeation in protective coatings, which may greatly influence the corrosion protective property of these coatings, was studied using the electrochemical impedance spectroscopy technique. During the absorption of water in protective coatings immersed in electrolyte solution, the change of coating capacitance with concentration of electrolyte was determined from impedance measurements. When water absorption or desorption of coatings occured by exposing the coatings to electrolyte solutions of different concentration, increase in impedance caused by desorption of water was found to be higher in the case of thicker film. The amount of water absorbed in coatings changed with concentration of electrolyte. The water taken up in coatings from the solution of lower electrolyte concentration was deserted by contact with the solution of higher concentration. The uptake of water in protective coatings varied depending on the type of coating ingredient especially binder.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.346-349
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• 2004

Surfactant-enhanced electrokinetic (EK) process was investigated to remove polycyclic aromatic hydrocarbons (PAHs) from low-permeable soils. Phenanthrene and kaolinite were selected as a representative PAH and a model soil, respectively. A nonionic surfactant Tergitol 15-S-12 was applied to improve the solubility of phenanthrene and sodium chloride was used as an electrolyte at the various concentrations from 0.001 to 0.1M. The addition of electrolyte affected both the removal efficiency and operation cost. When electrolyte was introduced, the electrical potential gradient became low and thus power consumption was reduced. However, as electrolyte concentration increased, the electroosmotic flow also decreased, so the removal efficiency of contaminant decreased. Therefore, the removal efficiency and power consumption should be considered simultaneously to determine the iptimum surfactant concentration, so a relatively lower concentration of electrolyte than certain value is desired.

• Corrosion Science and Technology
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• 제9권4호
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• pp.171-174
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• 2010

MAO (micro-arc oxidation) is an eco-friendly convenient and effective technology to deposit high-quality oxide coatings on the surfaces of Ti, Al, Mg and their alloys. The roles of the electrolyte concentration and relative cathode electrode area sizes in the grown oxide film during titanium MAO were investigated. The higher the concentration of the electrolyte, the lower the $R_{total}A$ value. The oxide film produced by the lower concentration of the electrolyte is thinner and less uniform than the film by the higher concentration, which is thick and porous. The cathode area size must be bigger than the anode area size in order to minimize the voltage drop across the cathode. The ratio of the cathode area size to the anode area size must be bigger than 8. Otherwise, the cathode will be another source for voltage drop, which is detrimental to and slows down the oxide growth.

• Current Applied Physics
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• 제18권12호
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• pp.1513-1522
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• 2018

Bismuth telluride ($Bi_2Te_3$) thin films were prepared with various electrolyte temperatures ($10^{\circ}C-70^{\circ}C$) and concentrations [$Bi(NO_3)_3$ and $TeO_2:1.25-5.0mM$] in this study. The surface morphologies differed significantly between the experiments in which these two electrodeposition conditions were separately adjusted even though the applied current density was in the same range in both cases. At higher electrolyte temperatures, a dendrite crystal structure appeared on the film surface. However, the surface morphology did not change significantly as the electrolyte concentration increased. The dendrite crystal structure formation in the former case may have been caused by the diffusion lengths of the ions increasing with increasing electrolyte temperature. In such a state, the reactive points primarily occur at the tops of spiked areas, leading to dendrite crystal structure formation. In addition, the in-plane thermoelectric properties of $Bi_2Te_3$ thin films were measured at approximately 300 K. The power factor decreased drastically as the electrolyte temperature increased because of the decrease in electrical conductivity due to the dendrite crystal structure. However, the power factor did not strongly depend on the electrolyte concentration. The highest power factor [$1.08{\mu}W/(cm{\cdot}K^2$)] was obtained at 3.75 mM. Therefore, to produce electrodeposited $Bi_2Te_3$ films with improved thermoelectric performances and relatively high deposition rates, the electrolyte temperature should be relatively low ($30^{\circ}C$) and the electrolyte concentration should be set at 3.75 mM.

• 융합정보논문지
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• 제11권2호
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• pp.117-123
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• 2021

수계 아연 이온 전지의 신규 전극 활물질로서 헥사시아노 철산철(Fe4[Fe(CN6)]3, FeHCF)의 전기화학적 특성에 미치는 전해질 농도의 영향에 관하여 조사하였다. FeHCF 전극의 전기화학 반응 및 구조적 안정성에 전해질 농도가 크게 영향을 준다는 것이 전위 주사, 충전-방전 시험, X-선 회절 분석에 의해 확인되었다. 1.0-7.0 mol dm-3의 전해질 용액에서는 농도가 증가함에 따라 FeHCF 전극의 충전 및 방전 용량이 증가하였으나 사이클이 진행됨에 따라 서서히 감소하였다. 반면에 9.0 mol dm-3의 전해질 용액에서는 초기 용량은 상대적으로 작았으나 사이클 특성이 우수하였다. 전자의 전해질 용액에서 5사이클 진행된 FeHCF 전극은 반응 전과 비교하여 결정 구조에 변화가 있었으며, 후자의 경우에는 변화가 없었다. 이것은 FeHCF 전극의 전기화학적 성능이 전해질 용액 중에 존재하는 아연 이온의 수화 구조와 크게 관련이 있음을 시사하는 것이다.

• 한국전기전자재료학회논문지
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• 제29권4호
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• pp.225-230
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• 2016

Effect of electrolyte composition and concentration on PEO coating layer were investigated. Mg alloy, Surface of AZ31 and AZ91 were oxidized using PEO with different electrolyte system, Na-P and Na-Si. and applied voltage and concentration. We measured thickness, roughness, X-ray crystallographic analysis and breakdown voltage of the oxidized layer. When increasing concentration of electrolyte, the thickness of oxide layer also increased too. And roughness also increased as concentration of electrolyte increasing. Breakdown voltage of coated layer showed same behavior, the voltage goes high as increasing thickness of coating layer, as increasing concentration of electrolyte, and increasing applied voltage of PEO. $Mg_2SiO_4$ phase were observed as well as MgO.

• 한국환경보건학회지
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• 제35권3호
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• pp.201-208
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• 2009

Oxidation of phenol in aqueous media by electro-Fenton process using Ru-Sn-Sb/graphite electrode has been studied. Hydrogen peroxide was electrically generated by reaction of dissolved oxygen in acidic solutions containing supporting electrolyte and $Fe^{2+}$ was added in aqueous media. Phenol degradation experiments were performed in the presence of electrolyte media at pH 3. Effect of operating parameters such as current, electrolyte type (NaCl, KCl and $Na_2SO_4$) and concentration, $Fe^{2+}$ concentration, air flow rate and phenol concentration were investigated to find the best experimental conditions for achieving overall phenol removal. Results showed that current of 2 A, NaCl electrolyte concentration of 2g/l, 0.5M concentration of $Fe^{2+}$, air flow rate of 1l/min were the best conditions for mineralization of the phenol by electro-Fenton.

• Membrane and Water Treatment
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• 제11권3호
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• pp.217-222
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• 2020

An electrochemical oxidation process was applied to remove cyanide (CN^-) from real plating wastewater. CN^- removal efficiencies were investigated under various operating factors: current density and electrolyte concentration. Electrolyte concentration positively affected the removal of both CN^- and Chemical Oxygen Demand (COD). As the electrolyte concentration increased from 302 to 2,077 mg Cl^-/L, removal efficiency of CN^- and COD increased from 49.07% to 98.30% and from 23.53% to 49.50%, respectively, at 10 mA/㎠. Current density affected the removal efficiency in a different way. As current density increased at a fixed electrolyte concentration, CN^- removal efficiency increased while COD removal efficiency decreased, this is probably due to lowered current efficiency caused by water electrolysis.

• Journal of Electrochemical Science and Technology
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• 제9권2호
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• pp.99-108
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• 2018

Proton exchange membrane (PEM) water electrolysis systems offer several advantages over traditional technologies including higher energy efficiency, higher production rates, and more compact design. In this study, all the experiments were performed with a self-designed PEM electrolyser operated at 1 atm and $25^{\circ}C$. Two types of electrolyte were used: (i) potassium hydroxide (KOH), and (ii) sulfuric acid ($H_2SO_4$). In the experiments, the voltage, current, and time were measured. The concentration of the electrolyte significantly affected the electrolyser performance. Overall the best case was with 15 wt% $H_2SO_4$ at the anode channel and 20 wt% at the cathode channel with. In addition, increasing the difference in concentration of the sulfuric acid had an effect on the diffusion. The diffusion flux became larger when the difference in concentration became larger, increasing electrolyser efficiency without the addition of extra energy.

• 한국세라믹학회지
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• 제40권3호
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• pp.293-300
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• 2003

알루미나 분말과 전해질의 농도가 제타전위 및 등전점에 미치는 영향에 대하여 고찰하였다. 0.1~l $\mu\textrm{m}$의 입도 범위를 지닌 알루미나 분말시료와 NH$_4$NO$_3$를 사용하여 실험을 수행하였으며, 전기영동법을 이용하여 제타전위를 측정하였다. 현탁액 내의 시료량이 증가할수록 제타전위와 등전점은 큰 값을 나타내었으며, 현탁액의 농도가 0.0l wt%일 때 제타전위 측정에 가장 적합한 것으로 나타났다. 또한 전해질 농도가 증가할 경우, 제타전위의 값은 다소 증가하는 경향을 보였으나 큰 변화는 없었고, 등전점 값은 오히려 조금 감소하였다. 제타전위 측정에 가장 적합한 전해질 농도는 10 mM인 것으로 나타났으며, 전해질의 종류에 따라서 제타전위와 등전점의 값이 조금 변하는 경향이 있으나 큰 차이를 발생시키지는 않는 것으로 확인되었다.