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2008, Vol.9, No.2

  • 1.

    Surface Modified Agave sisalana as an Adsorbent for the Removal ofNickel from Aqueous Solutions - Kinetics and Equilibrium Studies

    Padmini. E | Helen Kalavathy M | Lima Rose Miranda | 2008, 9(2) | pp.97~104 | number of Cited : 0
    Abstract
    In the present study Sisal fiber obtained from the leaves of Agave sisalana has been chosen to validate its viability as anadsorption of Nickel was also studied. Agave sisalana fiber was found to be a cheap and effective adsorbent doing away withthe need to activate the material therby reducing processing cost. The equilibrium studies indicated that the adsorptioncapacity of raw fiber and the surface modified fiber was 8.66 and 9.77 mg/g respectively with the Langmuir isothermdescribing the adsorption phenomena better than the Freundlich and Temkin isotherm. The adsorption was found to beexothermic from the thermodynamic studies and the kinetics showed that the adsorption phenomena were second order.
  • 2.

    Preparation and Characterization of Highly Conductive NickelcoatedGlass Fibers

    Byung-Joo Kim | Woong-Ki Choi | 송흥섭 and 3other persons | 2008, 9(2) | pp.105~107 | number of Cited : 3
    Abstract
    In this work, we employed an electroless nickel plating on glass fibers in order to enhance the electric conductivity offibers. And the effects of metal content and plating time on the conductivity of fibers were investigated. From the results,island-like metal clusters were found on the fiber surfaces in initial plating state, and perfect metallic layers were observedcconductivity showed similar trends. The nickel cluster sizes on fibers decreased with increasing plating time, indicating thatsurface energetics of the fibers could become more homogeneous and make well-packed metallic layers, resulting in the highconductivity of Ni/glass fibers.
  • 3.

    Electrospun Nanocomposite Fiber Mats of Zinc-Oxide LoadedPolyacrylonitrile

    S. K. Nataraj | B. H. Kim | J. H. Yun and 3other persons | 2008, 9(2) | pp.108~114 | number of Cited : 4
    Abstract
    We have demonstrated the feasibility of using electrospinning method to fabricate long and continuous composite nanofiberan important step toward utilizing carbon nanofibers (CNFs) as materials to achieve remarkably enhanced physico-chemicalproperties. In an attempt to derive these advantages, we have used a variety of techniques such as field emission scanningelectron microscopy (FE-SEM), transmision electron microscopy (TEM) and high resolution X-ray diffraction (HR-XRD) toobtain quantitative data on the materials. The CNFs produced are in the diameter range of 10 to 350 nm after carbonizationat 1000˚C. Electrical conductivity of the random CNFs was increased by increasing the concentration of ZnO. A dramaticimprovement in porosity and specific surface area of the CNFs was a clear evidence of the novelty of the method used. Thisphysico-chemical properties.
  • 4.

    Properties of Activated Carbon Blacks Filled SBR Rubber Composites

    Geyou Ao | Quanli Hu | Myung-Soo Kim | 2008, 9(2) | pp.115~120 | number of Cited : 3
    Abstract
    Rubber reinforcing carbon black N330 was treated by physical activation under CO2 to different degrees of burn-off. The mechanical properties indicating the reinforcement of SBR (Styrene-Butadiene Rubber) vulcanizates filled by activated carbon blacks, such as tensile strength, modulus at 300% strain and elongation at break were determined. During CO2 activation of fresh carbon blacks, the development of microporous structure caused an increase of extremely large specific surface area and the porosity turned out to be an increasing function of the degree of burn-off. The tensile strength and modulus at 300% of activated carbon blacks filled rubber composites were improved at lower loading ratios of 20 and 30 phr, but decreased drastically after 30 phr, which is considered that it might be difficult to get a fully dispersed rubber mixture at higher loading ratios for fillers having very large specific surface areas. However, the Electromagnetic Interference (EMI) shielding effectiveness of SBR rubber composites having activated carbon black at 74% yield were improved at a large extent when compared to those having raw carbon black and increased significantly as a function of increasing loading ratio.
  • 5.

    Oxidation Kinetics of Pitch Based Carbon Fibers

    Jae-Seung Roh | 2008, 9(2) | pp.121~126 | number of Cited : 3
    Abstract
    High modulus pitch based carbon fibers (HM) were exposed to isothermal oxidation using tube furnace in carbon dioxideoC. The kinetic equation f=1exp(atb) was introducedand the constant b was obtained in the range of 1.02~1.42. The oxidation kinetics were evaluated by the reaction-controllingregime (RCR) depending upon the apparent activation energies with the conversion increasing from 0.2 to 0.8. The activationenergies decrease from 24.7 to 21.0 kcal/mole with the conversion increasing from 0.2 to 0.8, respectively. According to theRCR, the reaction was limited by more difusion controlling regime for the HM fibers with the conversion increasing.to the core of the fiber.
  • 6.

    Structural Study of the Activated Carbon Fiber usingLaser Raman Spectroscopy

    Jae-Seung Roh | 2008, 9(2) | pp.127~130 | number of Cited : 3
    Abstract
    This study aims to find a correlation between XRD and Raman result of the activated carbon fibers as a function of itslaser Raman spectroscopy. The basic structural parameters of the fibers were evaluated by XRD as well, and compared withRaman result. The La of the carbon fibers were measured to be 25.5 from Raman analysis and 23.6 from XRD analysis.La of the ACFs were 23.6 and 20.4 , respectively, representing less ordered through activation process. It seems that theID/IG of Raman spectra were related to crystallite size(La). Raman spectroscopy has demonstrated its unique ability to detectstructural changes during the activation of the fibers. There was good correlation between the La value obtained from Ramanand XRD.
  • 7.

    Anion co-doped Titania for Solar Photocatalytic Degradation of Dyes

    Lee, Young-Seak | Kim SangJin | P.Venkateswaran and 3other persons | 2008, 9(2) | pp.131~136 | number of Cited : 2
    Abstract
    In order to investigate the effect of doping C, N, B and F elements on TiO2 for reducing the band gap, the heat treatment ofTiO2 was carried out with tetraethylammonium tetrafluoroborate. Through XRD and XPS analysis, the C, N, B and F dopedanatase TiO2 was confirmed. According to the increase of temperature during treatment, the particle size was increased due toaggregation of TiO2 with elements (B, C, N and F). To investigate the capacity of photocatalyst for degradation of dye undersuccessfully under solar light indicating the effect of doping elements (B, C, N and F) on TiO2 for reducing the band gap effectively.
  • 8.

    Electrochemical Properties of EDLC Electrodes Prepared by Acid andHeat Treatment of Commercial Activated Carbons

    Jingyu Wu | Ikpyo Hong | Sei-Min Park and 2other persons | 2008, 9(2) | pp.137~144 | number of Cited : 8
    Abstract
    The comercial activated carbons are typicaly prepared by activation from coconut shel char or coal char contain-ing lots of inorganic impurities. They also have pore structure and pore size distribution depending on nanostructure ofremoving impurities with acid treatments, and controlling pore size distribution and contents of functional group withheat treatment. The effect of the surface functional groups on electrochemical performance of the activated carbon elec-trodes was investigated. The initial gravimetric and volumetric capacitance of coconut based activated carbon electrodewhich was acid treated by HNO3 and then heat treated at 80oC were 90 F/g and 42 F/cc respectively showing 94% ofcharge-discharge efficiency. Such a good electrochemical performance can be possibly applied to the medium capaci-tance of EDLC.