• Journal of Animal Science and Technology
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• 제48권2호
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• pp.315-324
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• 2006

This research was conducted to clarify the characteristics of electrochemical decolorization of effluent discharged from a biological animal wastewater treatment process and to finally establish parameters or mode for optimum operation of electrolysis system. Average color unit of wastewater was about 1,200 and DSA(Dimensionally Stable Anode) was used as electrode. Experiments were performed with two different operation conditions or modes, fixed voltage-free current(Run A) and free voltage-fixed current(Run B). Color removal rate was proportional to the electrode area and electrical conductivity, and an equation subject to them at a condition of fixed voltage was derived as follows; Ct=C0ekt, k=[{0.0121×ａ(dm2)× c(mS/cm)}+0.0288], [where, C0: initial color, Ct: color unit after treatment for t, k: reaction coefficient, t: time(min.), ａ: electrode area, c: conductivity]. From the study on the effects of current density on color removal, it was revealed that the removal efficiency of color was function of the current density, showing direct proportion. However, when considered energy consumption rate, maintenance of low current density was an economical way. Based on the obtained results, it was concluded that supplementation of electrolyte is not necessary for the removal of color from the effluent of secondary treatment process and operation with the mode of free voltage-fixed current, rather than operation with fixed voltage-free current mode, would be an efficient way to increase the removal performance and capacity per consumed energy.

• 한국표면공학회지
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• 제28권1호
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• pp.34-45
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• 1995

An amphiphilic nitroxide radical(2,2'6,6'-tetramethyl-4-octadecyioxy-1-piperidinyloxyl, TEMOPO) or mixture of TEMOPO and arachidic acid(Icosanoic acid, AA), was spread on water surface by the Langmuir-Blodgett(LB) method and surface pressure-area curve was measured. Such monolayer films of TEMOPO were transferred onto surfaces of photo transferable tin oxide electrodes(PTTO) by the LB method under various surface pressure with the transfer ratio of larger than 0.95 at the surface pressure higher than 15mN/m. The electrochemical effect of functional nitroxy radical monolayer onto semi-conductive electrode to electrolyte have been investigated by using LB method. Cyclic voltammetry technique was used for the electrochemical behavior measurement of TEMOPO monolayer onto the PTTO in 0.18 mo1/$dm^3$ $H_2SO_4$ solutions. The shape of voltammograms was found to change from one electrode to another. The amount of charge for the oxidation and the re-reduction of the cation to TEMOPO were evaluated from graphical integration. The amounts of charge were always smaller than those predicted from the $\pi$-$\sigma$ curves though the transfer ratio was unity. The poor reproducibility of the cyclic voltammograms was improved by the mixing with AA. Structure and arrangement of monomolecular layer on water surface and electrode were studied. Characteristics of monolayer film applied for the mediation reaction was also discussed by electrochemical method.

• Corrosion Science and Technology
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• 제22권4호
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• pp.252-256
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• 2023

The galvanostatic polarization technique was used to accelerate corrosion in high chromium cast iron (HCCI) immersed in a simulated slurry solution of 0.1 mol dm^-3 H₂SO₄, 0.05 mol dm^-3 HCl, and 10 wt% SiC. The HCCI contained 27 wt% of Cr and 2.8 wt% of C, and its microstructure mainly comprised austenitic and carbide phases. A two-electrode system using a dense carbon rod and the HCCI sample was employed for the galvanostatic polarization by applying an anodic current for 24 hours. The corrosion rate increased upon applying the anodic current, but the increase was not significant, particularly for current densities higher than 10 µA cm^-2. Following polarization, the corrosion morphology revealed that the anodic current accelerated surface corrosion in the HCCI; however while the depth of the corroded area increased, the increase was not substantial. The propagation behavior of the anodic current and its impact on corrosion were further discussed.

• 공업화학
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• 제23권1호
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• pp.86-92
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• 2012

이온교환수지(ion exchange resin; IER)를 이용하여 이산화염소($ClO_2$)의 전구체 용액인 아염소산나트륨($NaClO_2$) 용액으로부터 아염소산이온($ClO_2^-$)을 흡착시킨 후 전기분해장치(electrolysis system)에 의한 이산화염소 가스 발생 특성을 조사하였다. 이온교환수지는 강염기성 음이온교환수지를 사용하였으며, 전극으로는 Ru, Ir이 코팅된 Ti plate를 사용하였다. 반응조의 교반속도, 온도, 아염소산 제조농도, 이온교환수지의 투입량과 형태에 따라 이온교환수지의 아염소산이온($ClO_2^-$) 흡착량에 미치는 영향을 조사하고 최대 흡착량을 나타내는 이온교환수지를 도출하였다. 전기분해장치에 의한 이산화염소의 발생 추이를 관찰하고 발생 목표값에 최적화된 조건을 실험계획법인 반응표면분석(response surface design)으로 선정하였다. 최대 흡착량을 나타내는 강염기성 음이온교환수지는 SAR-20 (TRILITE Gel type II형)이며 그 흡착량은 약 110 mg/IER (g)으로 관찰되었으며, 전기분해장치의 이산화염소 발생 최적조건은 멸균 목표값인 900~1000 ppm, 1 h에서 정전류는 전류인가 전극의 면적을 기준으로 $A/dm^2$, $N_2$ gas 유량은 4.7 L/min이었다.