• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.172-172
• /
• 2016

The International Maritime Organization(IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004 to prevent the transfer of aquatic organisms via ballast water. Forty ballast water treatment systems were granted final approval. A variety of techniques have been developed for ballast water treatment including UV treatment, indirect or direct electrolysis, ozone treatment, chemical compounds and plasma-arc method. In particular, using plasma and ozone nano-bubble treatments have been attracted in the fields. However, these treatment systems have a problem such as remained toxic substance, demand for high power source, low efficiency, ets. In this paper, we present our strilization results obtained from membrane type electrolytic-reduction treatment system The core of an electrolysis unit is an electrochemical cell, which is filled with pure water and has two electrodes connected with an external power supply. At a certain voltage, which is called critical voltage, between both electrodes, the electrodes start to produce hydrogen gas at the negatively biased electrode and oxygen gas at the positively biased electrode. The amount of gases produced per unit time is directly related to the current that passes through the electrochemical cell. From the results, we could confirm the sterilization effect of bacteria such as S. aureus, E. Coli and demonstrate the mechanism of sterilization phenomena by electrolytic-reduction treatment system.

• Journal of Electrochemical Science and Technology
• /
• 제9권1호
• /
• pp.37-43
• /
• 2018

In order to improve current efficiency and decrease energy consumption in the electrosynthesis of ammonium persulfate, electrolytic properties of four cation exchange membranes, namely, the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane CMI-$7000^{(R)}$ membrane and a self-made perfluorosulfonic ion exchange membrane (PGN membrane) were investigated using a sintered platinized titanium anode and a Pb-Sb-Sn alloy cathode in a self-made electrolytic cell. The effect of cell voltage and electrolyte flow rate on the current efficiency and the energy consumption were investigated. The results indicated that the PGN membrane could improve current efficiency to 94.85% and decrease energy consumption to $1119kWh\;t^{-1}$ (energy consumption per ton of the ammonium persulfate generated) under the optimal operating conditions and the highest current efficiency of the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane and CMI-$7000^{(R)}$ membrane were 80.73%, 77.76% and 73.22% with their lowest energy consumption of $1323kWh\;t^{-1}$, $1539kWh\;t^{-1}$ and $2256kWh\;t^{-1}$, respectively. The PGN membrane has the advantages of high current efficiency and energy power consumption and has sufficient mechanical strength with the reinforced mesh. Therefore the PGN membrane will has good value in popularization in the industrial electrosynthesis of ammonium persulfate in the future.

• Computers and Concrete
• /
• 제5권6호
• /
• pp.545-558
• /
• 2008

The corrosion of RC structures demonstrates very complicated forms of deterioration intermingled together but all pointing to a decrease in the durability of RC structures due to the corrosion of reinforcing bars. Until now, nondestructive techniques, such as half-cell potential and polarization resistance, have been widely available in the world. The former provides information on the probability of corrosion while the latter is associated with information concerning corrosion rates. Inversion by the boundary element method (IBEM) was developed for considering concrete resistivity. The applicability of the procedure was examined through a numerical analysis and electrolytic tests for RC slabs. A distribution in such concrete resistivity is relatively inhomogeneous including cracks on the surface of slabs. Regarding cracks in concrete, the relative coefficient of concrete resistance was introduced to perform its analysis. Further, the procedure will be developed to identify the corroded region visually using 3-D VRML.

• 한국표면공학회지
• /
• 제29권6호
• /
• pp.724-727
• /
• 1996

Electrolytic impregnation of nickel hydroxide into porous sintered nickel plaque from various nickel solutions were carried out at room or high temperatures and current density range of 2.5mA $cm^{-2}$ to 25mA $cm^{-2}$. The morphology of the deposited surface was observed with an electron microscope and the surface products were analyzed by means of X-ray diffraction method. Nickel hydroxide was deposited in nickel nitrate electrolyte, while deposits from sulphate or chloride solutions were almost metallic nickel. The loading level of nickel hydroxide from nitrate solutions was 1.6g$cm^{-3}$ void volume and the appearance of the surface was good quality. Discharge capacity of prepared electrodes in nickel nitrate electrolyte was larger than that of the others bath. It was considered that the cell capacity was dependent on the surface roughness of active material.

• 공업화학
• /
• 제3권4호
• /
• pp.657-662
• /
• 1992

흑연 펠레트 전극으로 채워진 복극성 고정상 충전층 전극 반응기에 대하여 등가회로 모델을 적용하여 반응기에 가해진 전류에 대한 복극성 전극에 흐른 Faradaic 전류의 비를 전해액의 전도도와 순환속도에 대하여 검토하였다. 전전류에 대한 Faradaic 전류의 비는 인가전류(전압)에 따라 증가하며, 전해액 전도도와 액 순환속도의 증가에 따라 감소하였다.

• 한국표면공학회지
• /
• 제19권1호
• /
• pp.13-19
• /
• 1986

Manganese in the Anode slime and the paste-positive material of waste-dry cell was recovered by leaching with the hydrochloric acid solution. The impurities (Zn, Fe, Pb), co-leached with manganese were removed from the leached solution prior to electrolysis by hydrometallurgical techniques such as the neutralization with ammonium hydroxide and cementation on manganese powder. The electrodeposition of manganese from the purified chloride solution with sodium selenate was performed. Cathode current efficiency was found to be affected significantly by the concentration of sodium selenate and ammonium chloride salt, bath temperate, current density and PH. The current efficiency of about 88.7% was obtained by electrolysis manganese chloride solution with sodium selenate (0.1/g) at 10$^{\circ}C$.

• 한국표면공학회지
• /
• 제16권3호
• /
• pp.87-97
• /
• 1983

석출전위가 낮은 금속들을 저농도용액에서 전기분해하여 회수하는 방법에 대해 아연과 카드뮴을 모델로 삼아 채취방법을 연구하였다. Hull cell과 hyperbolic twin cell에서 시험해서 전류밀도와 효율이 낮기 때문에 기존방법으로는 회수속도가 매우 느린 것을 알 수 있었다. 전해 채취조건을 좋게 하기 위해서는 음극의 표면적을 크게 하고 흔들어 주며, 또 전해액을 강제 순환시켜 물질이동이 잘 되도록 해야만 한다. Rotating tubular bed reactor 나 impact rod reactor 같은 전해조를 사용하여 여러 종류의 용액 중의 아연과 카드뮴 전해 채취 실험을 하였다. 특히 카드뮴의 잔류농도를 낮추기 위해서는 전해법과 이온교환법을 같이 사용하는 것이 유용하다. 새로운 방법의 처리비용과 기존방법의 처리비용을 비교하여 보았다.

• Bulletin of the Korean Chemical Society
• /
• 제7권3호
• /
• pp.163-166
• /
• 1986

A new paraffin salt bridge was developed for the concentration cell in high pressure system. The emf values of the concentration cells were measured to calculate the activity coefficients of the electrolytic ions depending upon the pressure of the system. The activity coefficients of sodium, chloride and bromide ions increase with the temperature of the cell and decreased, nearly half at 2500 bars, $20^{\circ}C$, with the pressure. These results can be explained to be attributed to the volume change of the hydrated ion due to the electrostriction. The volume change decreased with pressure due to an increase in the degree of the hydration.

• Korean Chemical Engineering Research
• /
• 제59권1호
• /
• pp.1-5
• /
• 2021

PEM(Proton Exchange Membrane) 수전해는 PEM 연료전지와 동일한 PEM 전해질 막을 사용하며, 동일한 반응이지만 방향이 반대인 반응에 의해 진행된다. PEM 연료전지는 전해질 막과 촉매의 열화와 내구성에 대해 많은 연구가 진행되어 개발된 열화분석 방법이 많다. 본 연구에서 PEM 수전해 내구성 평가에 PEM 연료전지 내구성 평가 방법 적용이 가능한지 검토하였다. PEM 수전해 열화과정에서 PEM 연료전지와 동일한 조건으로 LSV(Linear sweep voltammetry), CV(Cyclic voltammetry), Impedance, SEM(Scanning Electron Microscope), FT-IR(Fourier Transform Infrared spectroscopy) 등을 분석해 비교하였다. PEM 연료전지처럼 막을 통과한 수소가 Pt/C 전극에서 산화되어 수소투과전류밀도를 측정함으로써 PEM 수전해 고분자 막의 열화정도를 분석할 수 있었다. 수소/질소 유입 조건에서 CV에 의한 전극활성면적(ECSA)을 측정해 전극열화를 분석할 수 있었다. 수소와 공기를 Pt/C 전극과 IrO2 전극에 공급하면서 각 전극의 임피던스를 측정해 전극과 고분자 막의 내구성을 평가할 수 있었다.

• 전기학회논문지P
• /
• 제67권2호
• /
• pp.94-99
• /
• 2018

Depending on how the energy storage system(ESS) is used in a system that can construct a microgrid by using an independent power source such as campus, surplus power can be generated that can not be charged to the ESS. For example, assuming that heat is supplied by a fuel cell in the case of a system in which thermal self-sustaining is prioritized, the fuel cell capacity required differs depending on the heat load. The amount of surplus power that can not be stored in the ESS will appear differently depending on the load operation of the fuel cell for each cycle. This power is hydrogenated through a water electrolytic device to present the amount of hydrogen energy that can be operated for each cycle. Therefore, this paper propose the possibility of utilizing University campus as a hydrogen station.