• 전기화학회지
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• 제15권4호
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• pp.256-263
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• 2012

본 연구에서는 전기화학적 이온교환체 중의 하나인 nickel hexacyanoferrate($KNiFe(CN)_6$) 막 전극을 사용하여 세슘 양이온을 분리하는 실험을 수행하였다. 1.0M $NaNO_3$와 1.0M $CsNO_3$의 단일성분계 및 이성분계 수용액에서 순환전위곡선을 측정하여 전극전위, 전류, 전기량의 변화 거동을 조사하였으며, 실험 전과 후에 $KNiFe(CN)_6$ 막의 구조 형태와 원자조성의 변화를 각각 SEM과 EDS 분석을 통하여 조사하였다. 또한 나트륨과 세슘 용액에서 교대로 이온교환 반응을 수행하여 측정한 순환전위곡선과 원자조성으로부터 $KNiFe(CN)_6$의 이온 선택성을 조사하였다. 본 연구의 실험 결과에 의하면, 전기를 인가한 $KNiFe(CN)_6$ 이온교환체는 화학적 유 무기물 이온교환체에 비해 약 40배 이상의 우수한 내구성을 가짐을 알 수 있었다. 또한 $KNiFe(CN)_6$ 이온교환체는 나트륨보다 세슘에 대해 보다 높은 선택도를 가짐을 확인할 수 있었다.

• 한국산업융합학회 논문집
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• 제19권4호
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• pp.176-184
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• 2016

Electrochemical ion exchange method is expected to be one of the most acceptable techniques for the separation of radioactive cations from nuclear wastewater. In this study a thin film of hexacyanoferrate on nickel surface was derivatized chemically in an aqueous potassium-ferricyanide solution. Electrochemical redox behavior of the nickel hexacyanoferrate(NiHCNFe) film electrode was investigated with the use of cyclic voltammetry potentiostated from -100 to 800 mV versus SCE. The electro-reduction characteristics of the NiHCNFe film were examined in the cobalt solutions. The NiHCNFe ion exchanger was more useful at lower concentration, lower temperature, and pH7 of the cobalt solution. The capacity loss of NiHCNFe was 0.018%/cycle that was less than the average loss of 2~3%/cycle of the convective organic exchanger. The 45~55% of the initial cobalt ions was electro-deposited on the NiHCNFe by using continuous recirculating reactor system. As a result, it was found that the electroactive NiHCNFe films showed better performance than the organic resins for the separation of cobalt ion from the aqueous solutions.

• 공업화학
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• 제21권1호
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• pp.52-57
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• 2010

중금속 이온이나 방사성 양이온을 처리하는 공정으로서 화학약품에 의한 침전법이나 일반 이온교환법을 가장 보편적으로 활용하고 있으나, 이 공정들은 약품의 과다 투여, 유효 금속의 폐기, 고형 폐기물에 의한 2차적인 토양 오염 유발 등과 같은 문제점을 가지고 있다. 이에 따라 최근 들어 선진국을 중심으로 전해환원 전착반응과 이온교환 반응을 결합시킨 전기화학적 이온교환법을 대체 신기술로 개발하고자 많은 관심과 연구가 집중되고 있다. 본 연구에서는 전기화학적 이온교환체 중의 하나인 nickel hexacyanoferrate (NiHCNFe)의 최적 제조조건을 규명하기 위해, 기지금속인 니켈판 표면에 화학적 방법과 전기화학적 방법으로 NiHCNFe 막을 생성하였으며, NiHCNFe의 구조 형태와 조성을 각각 SEM과 EDS 분석을 통하여 조사하였다. 또한 NiHCNFe 막이 생성된 니켈판을 운전전극으로 설치한 단일 평행평판 이온교환 전극반응기에서 산화-환원 전위를 연속적으로 순환시켜 순환전위곡선을 측정하고 피크 전류의 변화 거동을 조사하였다. 본 연구의 실험 결과에 의하면, 화학적으로 제조한 NiHCNFe가 전기화학적으로 제조한 경우보다 우수함을 알 수 있었고, 특히 118 h 화학반응시킨 NiHCNFe 이온교환체의 조밀도, 밀착성, 내구력이 가장 우수하게 나타났다.

• 한국산업융합학회 논문집
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• 제19권4호
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• pp.198-205
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• 2016

For the study on the ion exchange of nickel hexacyanoferrate(NiHCNFe) electrode with the several cations, the film of hexacyanoferrate was prepared on the bare nickel surface by the electrochemical and chemical methods in the solution composed with 5mM K3Fe(CN)6 and 100mM KNO3. To compare the capability of the ion exchange of NiHCNFe film electrode, the repeated cyclic voltammograms were measured in the 0.5M cation nitrate solutions at $25^{\circ}C$ and pH7. It was found that the capacity of the electrochemically derivatized NiHCNFe reduced in the rate of 0.5~0.7%/cycle and was nearly exhausted at the 150th potential cycle. Better result was obtained from that the capacity loss of the chemically assembled NiHCNFe was less than 0.02%/cycle for 5,000cycles. Furthermore, the residual capacity was more than 30% at the 5,000th cycle.

• 수산해양교육연구
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• 제17권1호
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• pp.106-114
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• 2005

This paper is a study on the prevention of crevice corrosion for a stainless steel heat exchanger in various pH solutions and with Cl ion concentrations. The electrochemical polarization test and crevice corrosion test of STS 304 for a heat exchanger were carried out. The crevice corrosion aspect, a passive behavior, crevice corrosion behavior, and corrosion protection characteristics of STS 304 using Al-alloy and Mg-alloy galvanic anode were considered. The main results are as follows: 1. The crevice corrosion of STS 304 occurs in the crevice and this corrosion increases pitting according to depth direction. On the other hand, the exterior crevice becomes passive. 2. With changing from a neutral to acid environment and increasing Cl ion concentration, the pitting potential of STS 304 lowers, and thus the crevice corrosion of STS 304 is sensitive. 3. The cathodic protection potential of STS 304 in the crevice is cathodically polarized by increasing Cl ion concentration. Therefore, an Al-alloy galvanic anode is more suitable than a Mg-alloy galvanic anode to protect the crevice corrosion of STS 304.

• 한국수소및신에너지학회논문집
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• 제16권2호
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• pp.103-110
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• 2005

Proton conducting solid polymer electrolyte (SPE) membranes have been used in many energy technological applications such as water electolysis, fuel cells, redox-flow battery, and other electrochemical devices. The availability of stable membranes with good electrochemical characteristics as proton conductivity at high temperatures above 80 $^{\circ}C$ and low cost are very important for its applications. However, the presently available perfluorinated ionomers are not applicable because of high manufacturing cost and high temperature use to the decrease in the proton conductivity and mechanical strength. In order to make up for the weak points, the block copolymer (BPSf) of polysulfone and poly (phenylene sulfide sulfone) were synthesized and sulfonated. The electrolyte membranes were prepared with phosphotungstic acid (HPA)/sulfonated BPSf via solution blending. This study would be desirable to investigate the interaction between the HPA and sulfonated polysulfone. The results showed that the characteristics of SPSf/HPA blend membrane was a better than Nafion at high temperature, 100 $^{\circ}C$. These membranes proved to have a high proton conductivity, $6.29{\times}10-2$ S/cm, a water content, 23.9%, and a ion exchange capacity, 1.97 meq./g dry membrane. Moreover, some of the membranes kept their high thermal and mechanical stability.