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2008, Vol.9, No.3

  • 1.

    Kinetic Modeling for Biosorption of Metylene Blue onto H3PO4 Activated Acacia arabica

    N. Sivarajasekar | S. Srileka | S. Samson arun prasath and 2other persons | 2008, 9(3) | pp.181~187 | number of Cited : 0
    Abstract
    Batch sorption experiments were carried out for the removal of metylene blue from its aqueous solution using H3PO4 activated Acacia arabica carbon (AAC). The prepared activated carbon was characterized and was found as an effective adsorbent material. The operating variables studied were initial metylene blue concentration, AAC concentration and solution pH. AAC activated carbon posses a maximum sorption capacity for the range of initial dye concentrations studied (60 ~ 100 mg L−1). The sorption kinetics were analyzed using reversible first order kinetics, second order, reversible first order, pseudofirst order, and pseudo-second order model. The sorption data tend to fit very well in pseudo-second order model for the entire sorption time. The average pseudo-second order rate constant, KII and regression coefficient value were determined to be 0.0174 mg g−1 min−1 and 0.9977. The biosorption process also fit well to reversible I order kinetics with a regression coefficient of 0.9878.
  • 2.

    Development of Supercapacitors Using Porous Carbon Materials Synthesized from Plant Derived Precursors

    Vilas Khairnar | Sandesh Jaybhaye | Chi- Chang Hu and 4other persons | 2008, 9(3) | pp.188~189 | number of Cited : 3
    Abstract
    Porous carbon materials synthesized from various plant derived precursors i.e. seeds of [Castor (Ricinus communis), Soap nut ( Sapindus sp.), Cashew-nut (Semecarpus anacardium), Jack fruit (Artocarpus heterophyllus), Safflower (Carthamus tinctorius), Ambadi (Crotolaria juncea), Neem (Azadirachta indica), Bitter Almond (Prunus amygdalus), Sesamum (Sisamum indicum), Date-palm (Phoenix dactylifera),Canola (Brassica napus), Sunflower (Helianthus annulus)] and fibrous materials from [Corn stem- (Zea mays) , Rice straw (Oryza sativa), Bamboo (Bombax bambusa) and Coconut fibers (Cocos nucifera)] were screened to make supercapacitor in 5M KOH solution. Carbon material obtained from Jack fruit seeds (92.0 F/g), Rice straw (83.0 F/g), Soap nut seeds (54.0 F/g), Castor seeds (44.34 F/g) and Bamboo (40.0 F/g) gave high capacitance value as compared to others. The magnitude of capacitance value was found to be inversely proportional to the scan rate of measurement. It is suggested that carbon material should possess large surface area and small pore size to get better value of capacitor. Moreover, the structure of carbon materials should be such that majority of pores are in the plane parallel to the plane of electrode and surface is fluffy like cotton ball.
  • 3.

    Improved Photo Degradation of Rhodamine B Dye using Iron Oxide/Carbon Nanocomposite by Photo-Fenton Reaction

    Min Il Kim | Im Ji Sun | Hyuk Kim and 2other persons | 2008, 9(3) | pp.195~199 | number of Cited : 1
    Abstract
    A nanocomposite consisting of Fe3O4 and MWCNT was produced via sol-gel technique using FeCl3 along with MWCNTby calcination at 300oC. The degradation effect of rhodamine B dye has been investigated under UV illumination in adarkroom. The degradation reaction was studied by monitoring the discoloration of dye as a function of irradiation time usingUV-visible spectrophotometeric technique. The Fe3O4-MWCNT samples have continuous degradation ability under the UVillumination with the first order kinetics and the dye removal was better than in the pristine Fe3O4. The resultant compositecatalyst was found to be efficient for the photo-Fenton reaction of the dye.
  • 4.

    Improvement of Thermal Stability of Electrospun PAN Fibers by Various Additives

    Lee, Young-Seak | Min Il Kim | Im Ji Sun and 1other persons | 2008, 9(3) | pp.200~202 | number of Cited : 3
    Abstract
    In order to improve the thermal stability of PAN-based electrospun fibers, AP-PER-MEL and TiO2 were added in to thefibers as additives. The polymer composite with uniformly mixed additional agents was obtained. In case of non-treatedsample, the fibers were burn off completely with high rate within 620oC. But in case of treated samples (EF-M and EF-MT), itis sure that the thermal stability was improved by studying TGA data and ISO flammability test about 20 and 30%,respectively. A synergy effect of adding two kinds of agents (AP-PER-MEL and TiO2) into PAN-based electrospun fibers wasconfirmed. Through SEM images, it is confirmed that the fiber shape can be kept even after addition of agents (AP-PER-MELand TiO2). Finally the thermal stability of fibers was largely developed with keeping the nature of PAN-based fibers effectively.
  • 5.

    Steam Activated Carbon Preparation Using HTFBR from Biomass and its Adsorption Characteristics

    Herbert Asirvatham | Nikhar Gargieya | B.G. Prakash Kumar and 1other persons | 2008, 9(3) | pp.203~209 | number of Cited : 0
    Abstract
    The objective of this work is to study the feasibility of the preparation of the activated carbon (AC) from coconut tree flowers using high temperature fluidized bed reactor (HTFBR). The activating agent used in this work is steam. The reactor was operated at various activation temperature (650, 700, 750, 800 and 850oC) and activation time (30, 60, 120 and 240 min) for the production of AC from coconut tree flowers. Effect of activation time and activation temperature on the quality of the AC preparation was observed. Prepared AC was characterized in-terms of iodine number, methylene blue number, methyl violet number, ethylene glycol mono ethyl ether (EGME) surface area and SEM photographs. The best quality of AC from coconut tree flowers (CFC) was obtained at an activation temperature and time of 850oC and 1 hr restectively. The effectiveness of carbon prepared from coconut tree flowers in adsorbing crystal violet from aqueous solution has been studied as a function of agitation time, carbon dosage, and pH. The adsorption of crystal violet onto AC followed second order kinetic model. Adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity qm was 277.78 mg/g., equilibrium time was found to be 180 min. This adsorbent from coconut tree flowers was found to be effective for the removal of CV dye.
  • 6.

    Preparation and Characterization of Pitch/Cokes Composite Anode Material for High Power Lithium Secondary Battery

    Lan Yuan | Daeyong Park | Myung-Soo Kim and 2other persons | 2008, 9(3) | pp.210~217 | number of Cited : 8
    Abstract
    Petroleum pitch and coke with wet mixture method or with dry mixture method were investigated to develop the composite anodic carbon material of high power lithium ion battery. Cokes coated with pitch were obtained by the heat treatment of mixture of cokes and pitch with different weight ratios at 800 ~ 1200oC. The charge and discharge characteristic of the consequent composite anodic carbon material assembled in batteries was tested. Cokes with wet mixture method have a smooth surface and their capacity changed little with changing temperature and content as compared to the cokes with dry mixture method. Although the reversible capacities showed different values by the anode manufacturing method, the composite anode with the mixture of 20 wt% of petroleum pitch and 80 wt% of coke showed the higher power capability and initial efficiency than the pitch based anode. However, the reversible capacity of the composite anode showed the reduced value as compared with the pitch based anode.
  • 7.

    Carbon Fibers (I): General Understanding and Manufacturing Techniques of Carbon Fibers

    Min-Kang Seo | Byung-Gak Min | PARK SOOJIN | 2008, 9(3) | pp.218~231 | number of Cited : 6
    Abstract
    Carbon fibers are a new breed of high-strength materials which have been described as a fiber containing at least 90% carbon obtained by the controlled pyrolysis of appropriate fibers. Carbon fiber composites are ideally suited to applications where strength, stiffness, lower weight, and outstanding fatigue characteristics are critical requirements. They also can be used in the occasion where high temperature, chemical inertness and high damping are important. In recent decades, carbon fibers have found wide applications in commercial and civilian aircraft, recreational, industrial, and transportation markets. Therefore, understanding the basic structure, synthesis and physicochemical properties of carbon fibers is very important to apply them as a precursor of above applications. This review paper discuss the general information and manufacture technique of carbon fibers used for improving the performance of composite materials in various industries for the present.