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pISSN : 1976-4251 / eISSN : 2233-4998

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2016, Vol.20, No.

  • 1.

    Adsorption capability of activated carbon synthesized from coconut shell

    Md Shariful Islam | Bee Chin Ang | Samira Gharehkhani and 1other persons | 2016, 20() | pp.1~9 | number of Cited : 2
    Abstract
    Activated carbon was synthesized from coconut shells. The Brunauer, Emmett and Teller surface area of the synthesized activated carbon was found to be 1640 m2/g with a pore volume of 1.032 cm3/g. The average pore diameter of the activated carbon was found to be 2.52 nm. By applying the size-strain plot method to the X-ray diffraction data, the crystallite size and the crystal strain was determined to be 42.46 nm and 0.000489897, respectively, which indicate a perfect crystallite structure. The field emission scanning electron microscopy image showed the presence of well-developed pores on the surface of the activated carbon. The presence of important functional groups was shown by the Fourier transform infrared spectroscopy spectrum. The adsorption of methyl orange onto the activated carbon reached 100% after 12 min. Kinetic analysis indicated that the adsorption of methyl orange solution by the activated carbon followed a pseudo-second-order kinetic mechanism (R2 > 0.995). Therefore, the results show that the produced activated carbon can be used as a proper adsorbent for dye containing effluents.
  • 2.

    Nanoporous carbon synthesized from grass for removal and recovery of hexavalent chromium

    Shahin A. Pathan | Nancy S. Pandita | 2016, 20() | pp.10~18 | number of Cited : 0
    Abstract
    Nanoporous carbon structures were synthesized by pyrolysis of grass as carbon precursor. The synthesized carbon has high surface area and pore volume. The carbon products were acid functionalized and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller, transmission electron microscopy, and Energy Dispersive X-ray microanalysis. Acid functionalized nanoporous carbon was explored for use in removal of toxic Cr(VI) ions from aqueous media. An adsorption study was done as a function of initial concentration, pH, contact time, temperature, and interfering ions. The experimental equilibrium data fits well to Langmuir isotherm model with maximum monolayer adsorption capacity of 35.335 mg/g. The results indicated that removal obeys a pseudo-second-order kinetic model, and that equilibrium was reached in 10 min. A desorption study was done using NaOH. The results of the present study imply that acid functionalized nanoporous carbon synthesized from grass is an efficient, renewable, cost-effective adsorbent material for removal of hexavalent chromium due to its faster removal rate and reusability.
  • 3.

    NO gas sensing ability of activated carbon fibers modified by an electron beam for improvement in the surface functional group

    박미선 | 이상민 | 정민정 and 2other persons | 2016, 20() | pp.19~25 | number of Cited : 10
    Abstract
    Activated carbon fiber (ACF) surfaces are modified using an electron beam under different aqueous solutions to improve the NO gas sensitivity of a gas sensor based on ACFs. The oxygen functional group on the ACF surface is changed, resulting in an increase of the number of non-carbonyl (-C-O-C-) groups from 32.5% for pristine ACFs to 39.53% and 41.75% for ACFs treated with hydrogen peroxide and potassium hydroxide solutions, respectively. We discover that the NO gas sensitivity of the gas sensor fabricated using the modified ACFs as an electrode material is increased, although the specific surface area of the ACFs is decreased because of the recovery of their crystal structure. This is attributed to the static electric interaction between NO gas and the non-carbonyl groups introduced onto the ACF surfaces.
  • 4.

    Preparation of gold nanoparticle/single-walled carbon nanotube nanohybrids using biologically programmed peptide for application of flexible transparent conducting films

    MinHo Yang | Bong Gill Choi | 2016, 20() | pp.26~31 | number of Cited : 1
    Abstract
    In this study, we report a general method for preparation of a one-dimensional (1D) arrangement of Au nanoparticles on single-walled carbon nanotubes (SWNTs) using biologically programmed peptides as structure-guiding 1D templates. The peptides were designed by the combination of glutamic acid (E), glycine (G), and phenylalanine (F) amino acids; peptides efficiently debundled and exfoliated the SWNTs for stability of the dispersion and guided the growth of the array of Au nanoparticles in a controllable manner. Moreover, we demonstrated the superior ability of 1D nanohybrids as flexible, transparent, and conducting materials. The highly stable dispersion of 1D nanohybrids in aqueous solution enabled the fabrication of flexible, transparent, and conductive nanohybrid films using vacuum filtration, resulting in good optical and electrical properties.
  • 5.

    Morphologies and surface properties of cellulose-based activated carbon nanoplates

    Seulbee Lee | Min Eui Lee | Min Yeong Song and 3other persons | 2016, 20() | pp.32~38 | number of Cited : 1
    Abstract
    In this study, cellulose nanoplates (CNPs) were fabricated using cellulose nanocrystals obtained from commercial microcrystalline cellulose (MCC). Their pyrolysis behavior and the characteristics of the product carbonaceous materials were investigated. CNPs showed a relatively high char yield when compared with MCC due to sulfate functional groups introduced during the manufacturing process. In addition, pyrolyzed CNPs (CCNPs) showed more effective chemical activation behavior compared with MCC-induced carbonaceous materials. The activated CCNPs exhibited a microporous carbon structure with a high surface area of 1310.6 m2/g and numerous oxygen heteroatoms. The results of this study show the effects of morphology and the surface properties of cellulose-based nanomaterials on pyrolysis and the activation process.
  • 6.

    Effects of maleic anhydride content on mechanical properties of carbon fibers-reinforced maleic anhydride-grafted-polypropylene matrix composites

    김현일 | HAN WOONG | 최웅기 and 3other persons | 2016, 20() | pp.39~46 | number of Cited : 3
    Abstract
    In this work, the effects of maleic anhydride (MA) content on mechanical properties of chopped carbon fibers (CFs)-reinforced MA-grafted-polypropylene (MAPP) matrix composites. A direct oxyfluorination on CF surfaces was applied to increase the interfacial strength between the CFs and MAPP matrix. The mechanical properties of the CFs/MAPP composites are likely to be different in terms of MA content. Surface characteristics were observed by scanning electron microscope, Fourier transform infrared spectroscopy, and single fiber contact angle method. The mechanical properties of the composites were also measured by a critical stress intensity factor (KIC). From the KIC test results, the KIC values were increased to a maximum value of 3.4 MPa with the 0.1 % of MA in the PP, and then decreased with higher MA content.
  • 7.

    Activating needle coke to develop anode catalyst for direct methanol fuel cell

    Young Hun Park | uisu_im | 이병록 and 4other persons | 2016, 20() | pp.47~52 | number of Cited : 1
    Abstract
    Physical and electrochemical qualities were analyzed after KOH activation of a direct methanol fuel cell using needle coke as anode supporter. The results of research on support loaded with platinum-ruthenium suggest that an activated KOH needle coke container has the lowest onset potential and the highest degree of catalyst activity among all commercial catalysts. Through an analysis of the CO stripping voltammetry, we found that KOH activated catalysis showed a 21% higher electrochemical active surface area (ECSA), with a value of 31.37 m2/g, than the ECSA of deactivated catalyst (25.82 m2/g). The latter figure was 15% higher than the value of one specific commercial catalyst (TEC86E86).
  • 8.

    Improving dispersion of multi-walled carbon nanotubes and graphene using a common non-covalent modifier

    권유빈 | Shim Wonbo | Jeon, Seung-Yeol and 2other persons | 2016, 20() | pp.53~61 | number of Cited : 3
    Abstract
    The reportedly synergistic effects of carbon nanotubes (CNTs) and graphene hybrids have prompted strong demand for an efficient modifier to enhance their dispersion. Here, we investigated the ability of poly(acrylonitrile) (PAN) to overcome the van der Waals interaction of multi-walled CNTs (MWCNTs) and graphene by employing a simple wrapping process involving ultrasonication and subsequent centrifugation of PAN/MWCNT/graphene solutions. The physical wrapping of MWCNTs and graphene with PAN was investigated for various PAN concentrations, in an attempt to simplify and improve the polymer-wrapping process. Transmission electron microscopy analysis confirmed the wrapping of the MWCNTs and graphene with PAN layers. The interaction between the graphitic structure and the PAN molecules was examined using proton nuclear magnetic resonance, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy. The obtained results revealed that the cyano groups of the PAN molecules facilitated adhesion of the PAN molecules to the MWCNTs and graphene for polymer wrapping. The resulting enhanced dispersion of MWCNTs and graphene was verified from zeta potential and shelf-life measurements.
  • 9.

    Effects of coal tar pitch addition on the wear behavior of carbon/carbon composites

    정영찬 | Duk Soo Kang | Rhee Kyong Yop and 2other persons | 2016, 20() | pp.62~65 | number of Cited : 0
    Abstract
    Carbon/carbon (C/C) composites are acknowledged as high performance materials because of their good mechanical properties such as wear resistance, even at the higher temperature, due to their low thermal expansion [1-5]. Their hardness and light weight in addition to their superior mechanical properties at high temperature make C/C composites the best material to make brakes for aircrafts and other high weight vehicles. Accordingly, a number of studies have been conducted on the performance of C/C composites brake [6-9]. Generally, C/C composites are produced by the carbonization of the matrix precursors of carbon composites. However, some defects, such as porosity and micro-cracks, are also induced during carbonization, and these defects degrde the mechanical properties. Therefore, various methods have been adopted to reduce the development of defects during the manufacture of C/C composites [10-14]. On the other hand, coal tar pitch extracted from the recycling of petroleum-based fuel is relatively inexpensive to manufacture; therefore, it is extensively used as a source of carbon precursors [15-16].
  • 10.

    Effect of acid catalysts on carbonization temperatures for ordered mesoporous carbon materials

    Jeong Kuk Shon | Xing Jin | Choi Yun Seok and 5other persons | 2016, 20() | pp.66~71 | number of Cited : 0
    Abstract
    Highly ordered mesoporous carbon (OMC) materials have attracted much attention in many fields including catalysis, adsorption and energy storage, due to their high porosity, high surface area and controllable regular pore-structure [1-6]. Successful synthesis pathways for obtaining OMC materials include the direct synthesis of OMC materials through the organic-organic self-assembly method (soft templating process) and nano-replication of OMC materials from mesoporous silica templates (hard templating process) [7-11]. The direct synthesis method is suitable for large-scale production of carbon materials due to its easier process compared to the nano-replication method [7,8]. However, the nano-replication method has still several advantages for synthesizing OMC materials. It is possible to synthesize various kinds of mesostructured OMC materials, which can be controlled by the mesostructure of the silica templates [12,13].
  • 11.

    Effects of carbon additives on heat-transfer and mechanical properties of high early strength cement mortar

    LEE DAE GEUN | Kyung Hoon Kim | 김형기 and 1other persons | 2016, 20() | pp.72~75 | number of Cited : 0
    Abstract
    The repair of mortar-based structures is critically important because mortar-based structures such as buildings, bridges, tunnels, highway and roads are inevitably degraded by deterioration or damage. To save expense during construction and to avoid traffic congestion during repair work, it is very important to reduce construction time as much as possible. In order to reduce construction time, therefore, the setting time of mortars has to be shortened. The mortars which have short setting times are called high early strength cement mortars. These high early strength cement mortars usually have a short working time of under 40 min and a compressive strength of over 24 MPa [1].
  • 12.

    Biologically activated graphite fiber electrode for autotrophic acetate production from CO2 in a bioelectrochemical system

    임채호 | Young Eun Song | Byong-Hun Jeon and 1other persons | 2016, 20() | pp.76~80 | number of Cited : 2
    Abstract
    Recently, microbial electrosynthesis (MESs) has been highlighted for the purpose of biological CO2 reduction with simultaneous production of intermediates and value-added chemicals. The bioelectrochemical system (BES), which employs microorganisms and a bacterial community as a biocatalyst, has been developed to convert CO2, a greenhouse gas, into liquid biofuels, such as ethanol and butanol, as well as platform chemicals [1]. Several bacterial species, called cathodophilic microorganisms (e.g., Sporomusa ovata and Clostridium ljungdahlii) were reported to interact with a carbon electrode by accepting electrons supplied externally from a power supply [2-4]. Through this process, oxidized chemical molecules, such as CO2, can be converted to more reduced products, such as acetate and ethanol [4,5]. Since the first report of MESs with S. ovata [3,4], performance has been improved by efforts to optimize the reactor design, regulate the applied potential, and improve the bacterial enrichment method [6-8]. On the other hand, the interaction between microorganism and carbon materials is still unknown, which is the main factor limiting further improvement of the performance of the MES process. For example, insufficient information about microbe-carbon interactions is delaying the advance of the process significantly when the input potential is <−410 mV vs standard hydrogen electrode (SHE), which is the theoretical minimum potential for hydrogen production [9].
  • 13.

    Density functional theory study of CH4 and CO2 adsorption by fluorinated graphene

    Doh Gyu Hwang | Euigyung Jeong | Seung Geol Lee | 2016, 20() | pp.81~85 | number of Cited : 3
    Abstract
    Phenomena related to global warming have been of particular interest among researchers, strongly encouraging them to identify various methods of adsorbing contributing gases, such as CH4 and CO2 [1,2]. Many adsorbents have been widely proposed and studied to remove greenhouse gases from the atmosphere and protect the environment [3,4]. Carbon-based materials for adsorption are an intriguing subject owing to their very high specific surface area, low weight, and elasticity [5,6]. Among various carbonaceous materials, graphene has attracted much attention from researchers for these reasons; consequently, this material has been empirically and theoretically investigated for possible applications, such as gas sensors [7-10].