• 제목/요약/키워드: Membrane stability

검색결과 702건 처리시간 0.023초

용액 공정으로 증착된 HfOx 감지막을 갖는 Electrolyte-Insulator-Semiconductor 소자의 두께 의존성 (Thickness Dependence of Solution Deposited HfOx Sensing Membrane for Electrolyte-Insulator-Semiconductor (EIS) Structures)

  • 이인규;조원주
    • 센서학회지
    • /
    • 제22권3호
    • /
    • pp.233-237
    • /
    • 2013
  • We fabricated electrolyte-insulator-semiconductor (EIS) devices using a solution process and measured the sensing properties of EIS devices according to the thicknesses of sensing membrane. For high pH sensitivity and better stability properties, we used $SiO_2/HfO_x$ (OH) layer as a sensing membrane. In this work, $HfO_x$ sensing membranes were deposited on 5 nm thick $SiO_2$ buffer layer by spin coater with thicknesses of 15, 31, 42, 55 nm, respectively. As a result, we founded that the thickness of $HfO_x$ sensing membrane affects to sensitivity and chemical stability of EIS device. Especially, the EIS device with 42 nm thick $HfO_x$ membrane showed superior sensing ability in terms of pH-sensitivity, linearity, hysteresis voltage and drift rate characteristics than the other devices. In conclusion, we confirmed that it is possible to improve the sensing ability and the chemical stability properties using optimized thickness of sensing membrane and proper annealing process.

Semi-interpenetrated Polymer Network of Sulfonated Poly(Styrene-Divinylbenzene-Acrylonitrile) based on PVC Film for Polymer Electrolyte Membranes

  • Yun, Sung-Hyun;Woo, Jung-Je;Seo, Seok-Jun;Park, Jung-Woo;Oh, Se-Hun;Moon, Seung-Hyeon
    • Korean Membrane Journal
    • /
    • 제11권1호
    • /
    • pp.8-14
    • /
    • 2009
  • The sulfonated poly(styrene-divinylbenzene-acrylonitrile) (ST-DVB-AN) composite polymer electrolyte membrane based on the original PVC film was successfully synthesized to improve oxidative stability using semi-interpenetrated polymer network (semi-IPN). Weight gain ratio after copolymerization was enhanced by the DVB and AN contents, and the sulfonated membranes were characterized in terms of proton conductivity (k), ion exchange capacity (IEC), and water uptake ($W_U$). The effect of DVB content and AN addition were thoroughly investigated by comparing the resulted properties including oxidative stability. The obtained ST-DVB-AN composited semi-IPN membranes showed relatively high proton conductivity and IEC compared with Nafion117, and greatly improved oxidative stability of the synthesized membrane was obtained. This study demonstrated that a semi-interpenetrated sulfonated ST-DVB-AN composited membrane reinforced by PVC polymer network is a promising candidate as an inexpensive polymer electrolyte membrane for fuel cell applications.

쥐의 간암화 과정에서 타우린의 공급이 지질과산화물 함량, 생체방어 효소 및 세포막 안정도에 미치는 영향 (Effect of Taurine Supplementation on Lipid Peroxidation, Activities of Defense Enzymes and Membrane Stability During Rat Hepatocarcinogenesis)

  • 유정순
    • Journal of Nutrition and Health
    • /
    • 제29권10호
    • /
    • pp.1080-1086
    • /
    • 1996
  • The purpose of this study was to determine the effects of taurine supplementation on the hepatic lipid peroxidation, activiteis of defense enzymes and membrane stability during rat hepatocarcinogenesis. Hepatocarcinogenesis was induced by Solt & Farber modification. Lipid peroxide contents of carcinogen treated group which was not supplemented with taurine were lower than those of control group. This might be that peroxide is decreased because of the activation of detoxifing enzyme. Glutathione S-transferase(GST) activites of carcinogen treated groups were significantly (p<0.05) increased compared to those of control groups. The GST activities of group supplemented with taurine before treatment of carcinogen and during the all period of experiment were only less increased. In carcinogen treated groups, glutathione peroxidase(GPx) activites of groups supplemented with taurine were higher than those of non supplemented group. By carcinogen treatemtn, glucose 6-phosphatase(G6Pase) activites, index of membrane stability were decreased, but in carcinogen treated groups supplemented with taurine, they were less decreased. These results suggest that taurine supplementation seems to inhibit lipid peroxidation, to change the activities of defense enzymes and to prevent to membrane disintegration during chemically induced hepatocarcinogenesis.

  • PDF

연료전지용 탄화수소 전해질 막의 산화안정성 향상을 위한 유기물 복합막의 제조 및 특성 분석 (Hydrocarbon-Organic Composite Membranes for Improved Oxidative Stability for PEMFC Applications)

  • 박샛별;이혜진;배병찬
    • 전기화학회지
    • /
    • 제19권2호
    • /
    • pp.45-49
    • /
    • 2016
  • 양이온 교환막 연료전지 운전 중에 발생하는 하이드록시 라디칼에 의한 전해질 막의 산화분해를 효과적으로 방지하기 위해 유기물 라디칼냐��쳐를 도입하였다. 술폰화 폴리아릴렌에테르술폰 고분자를 이용하여 폴리페놀 화합물의 일종인 루틴을 도입하여 복합막을 제조하였고, 제조된 고분자 전해질 복합막은 함수율 및 이온전도도의 측정을 통하여 루틴이 전해질 막의 물리화학적 성질에 미치는 영향에 대해서 조사하였다. 실제 연료전지 운전과 유사한 조건을 구현할 수 있는 과산화수소 폭로 가속화 평가장치를 이용하여 전해질 복합막의 산화안정성을 평가하였다. 루틴을 함유한 고분자 전해질 복합막은 이온전도도가 유지되면서 산화안정성이 향상된 결과를 보여주었다.

Enhanced Thermal Stability of a Silica/Stainless Steel Composite Membrane via the Soaking-Rolling Method

  • Lee, Dong-Wook;Nam, Seung-Eun;Bongkuk Sea;Ihm, Son-Ki;Lee, Kew-Ho
    • 한국막학회:학술대회논문집
    • /
    • 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
    • /
    • pp.175-178
    • /
    • 2004
  • Concerning the application of the inorganic composite membranes to high temperature process such as the catalytic dehydrogenation of hydrocarbons, important aspects to consider in the application include the improvement of the thermal stability and good permeability.(omitted)

  • PDF

Cation exchange membrane and anion exchange membrane aided electrolysis processes for hypochlorite generation

  • Seong K. Kim;Dong-Min Shin;Ji Won Rhim
    • Membrane and Water Treatment
    • /
    • 제14권2호
    • /
    • pp.55-63
    • /
    • 2023
  • In this study, the influence of different IEMs (ion exchange membranes) to performance of the hypochlorite electrolysis unit with Cl2 recovery stream was investigated. More specifically, Nafion 117-a representative cation exchange membrane (CEM)-and aminated polypheylene oxide (APPO)-an anion exchange membrane (AEM)-were installed in the hypochlorite electrolysis unit, and the performance and the energy efficiency of the units were evaluated and compared. Regardless of whether CEM (Nafion 117) or AEM (APPO) was installed, the rate of hypochlorite generation was increased (by up to 24.3% and 22.2% for Nafion 117 and APPO, respectively) compared with the unit without an IEM. On the other hand, the power efficiency and the optimum operation condition of hypochlorite production units seem to depend on the conductivity and stability of the installed IEM. As the result, between Nafion 117 and APPO, higher performance and efficiency were achieved with Nafion 117, due to excellent conductivity and stability of the membrane.

Photodegradation stability study of PVDF- and PEI-based membranes for oily wastewater treatment process

  • Ong, C.S.;Lau, W.J.;Al-anzi, B.;Ismail, A.F.
    • Membrane and Water Treatment
    • /
    • 제8권3호
    • /
    • pp.211-223
    • /
    • 2017
  • In this work, an attempt was made to compare the effects of UV irradiation on the intrinsic and separation properties of membranes made of two different polymeric materials, i.e., polyvinylidene fluoride (PVDF) and polyetherimide (PEI). The changes on membrane structural morphologies and chemical characteristics upon UV-A exposure (up to 60 h) were studied by FESEM and FTIR, respectively. It was found that cracks and fractures were detected on the PVDF-based membrane surface when the membrane was exposed directly to UV light for up to 60 h. Furthermore, the mechanical strength and thermal stability of irradiated PVDF-based membrane was reported to decrease with increasing UV exposure time. The PEI membrane surface meanwhile remained almost intact throughout the entire UV irradiation process. Filtration experiments showed that the permeate flux of UV-irradiated PVDF membrane was significantly increased from approximately 11 to $16L/m^2.h$ with increasing UV exposure time from zero to 60 h. Oil rejection meanwhile was decreased from 98 to 85%. For the PEI-based membrane, oil rejection of >97% was recorded and its overall structural integrity was marginally affected throughout the entire UV irradiation process. The findings of this work showed that the PEI-based membrane should be considered as the host for photocatalyts incorporation if the membrane was to be used for UV-assisted wastewater treatment process.

스티렌 유도체를 이용한 비불소계 고분자 전해질막의 산화적 안정성 개선 (Improvement of Oxidative Stability for Non-fluorinated Membranes Prepared by Substituted Styrene Monomers)

  • 문승현;우중제;푸롱창;서석준;윤성현
    • 멤브레인
    • /
    • 제17권4호
    • /
    • pp.294-301
    • /
    • 2007
  • 비불소계 스티렌 고분자 전해질 막의 산화안정성을 개선하기 위해 p-methyl styrene, t-butyl styrene, ${\alpha}-methyl$ styrene과 같은 스티렌 유도체를 단독 또는 복합으로 도입하고 모노머 흡수법을 이용하여 막을 제조하였다. 제조된 막의 특성분석으로 중합무게비, 함수율, 이온교환용량, 수소이온 전도도 및 가속조건에서의 산화안정성을 조사하였다. 사용된 스티렌 유도체의 구조 및 특성에 따라 모노머 흡수, 중합 및 술폰화 단계가 영향을 받는 것으로 나타났다. 산화적으로 안정한 고분자를 형성하는 ${\alpha}-methyl$ styrene은 중합 단계가 어렵기 때문에 스티렌 또는p-methyl styrene과 공중합하여 제조하였고 p-methyl styrene과 공중합된 ${\alpha}-methyl$ styrene 막은 스티렌과 공중합한 막보다 높은 전도도 및 안정성을 나타내었으나 낮은 분자량으로 인해 안정성의 개선을 크게 보이지 못하였다. 벤젠 고리에 큰 치환기를 갖는 t-butyl styrene은 모노머 흡수 및 술폰화과정이 용이하지 않기 때문에 제조된 막의 성능이 감소하였으며 이를 p-methyl styrene과 공중합할 때 우수한 성능과 스티렌막보다 크게 개선된 안정성을 보였다.

Nonlinear aerodynamic stability analysis of orthotropic membrane structures with large amplitude

  • Zheng, Zhoulian;Xu, Yunping;Liu, Changjiang;He, Xiaoting;Song, Weiju
    • Structural Engineering and Mechanics
    • /
    • 제37권4호
    • /
    • pp.401-413
    • /
    • 2011
  • The aerodynamic stability of orthotropic tensioned membrane structures with rectangular plane is theoretically studied under the uniform ideal potential flow. The aerodynamic force acting on the membrane surface is determined by the potential flow theory in fluid mechanics and the thin airfoil theory in aerodynamics. Then, based on the large amplitude theory and the D'Alembert's principle, the interaction governing equation of wind-structure is established. Under the circumstances of single mode response, the Bubnov-Galerkin approximate method is applied to transform the complicated interaction equation into a system of second order nonlinear differential equation with constant coefficients. Through judging the stability of the system characteristic equation, the critical divergence instability wind velocity is determined. Finally, from different parametric analysis, we can conclude that it has positive significance to consider the characteristics of orthotropic and large amplitude for preventing the instability destruction of structures.

막여과 정수처리공정에서 전여과공정의 효용성 평가 (Utility Estimation of Pre-filtration on the Membrane Water Treatment Process)

  • 박민구;최상일
    • 상하수도학회지
    • /
    • 제22권4호
    • /
    • pp.445-448
    • /
    • 2008
  • The application of the membrane filtration process has been increased for the drinking water treatment system because of excellent quality of treated water compared with the sand filtration process. The selection of suitable pre-treatment processes and optimum flux according to the characteristics of raw water are important factors for the design of membrane processes. In this study, the most efficient pre-treatment processes for drinking water was selected by investigating the effects of pre-treatment processes on the operational stability of the membrane filtration process. Both lab-scale and pilot-scale experiments were conducted. In the lab-scale test, the effect of pre-treatment processes on the stability of the membrane filtration process was investigated indirectly by comparing the performance of membrane flux for raw water, pre-treated water, and membrane permeated water. In the pilot-scale test, the usefulness of prefiltration processes was assessed by comparing the performance of single membrane process and hybrid coagulation-membrane process. The results indicated that the coagulation process contributed to the stabilization of trans-membrane pressure (TMP) by removing contaminants on membranes, though the pre-filtration process had little effect on the TMP.