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pISSN : 1976-4251 / eISSN : 2233-4998

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2016, Vol.17, No.1

  • 1.

    Microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to sugars and ethanol: a review

    Puligundla Pradeep | Sang-Eun Oh | Chul Kyoon Mok | 2016, 17(1) | pp.1~10 | number of Cited : 2
    Abstract
    Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.
  • 2.

    A review: synthesis and applications of graphene/chitosan nanocomposites

    Hui Yuan | Long-Yue Meng | PARK SOOJIN | 2016, 17(1) | pp.11~17 | number of Cited : 1
    Abstract
    Recently, with continuous developments in the field of materials science, graphene oxide (GO) has emerged as a promising material with excellent electrical, thermal, mechanical, and optical properties, which play important roles in most fields. Researchers have achieved considerable progress with graphene. Chitosan (CS) is a natural polymer that has been studied intensively owing to its specific formation, high chemical resistance, and excellent physical properties. These outstanding properties have led to its universal use in applications such as textile fabrics, tissue engineering, medicine and health, coatings, and paints. By combining the advantages of GO and CS, different types of promising materials can be obtained. This review discusses the preparation of GO-CS fibers, hydrogel and aerogel, and the applications of GO-CS nanocomposites. In addition, directions for future research on graphene material composites are discussed.
  • 3.

    A review: methane capture by nanoporous carbon materials for automobiles

    Pil-Seon Choi | 정지문 | Choi Yong Ki and 3other persons | 2016, 17(1) | pp.18~28 | number of Cited : 1
    Abstract
    Global warming is considered one of the great challenges of the twenty-first century. In order to reduce the ever-increasing amount of methane (CH4) released into the atmosphere, and thus its impact on global climate change, CH4 storage technologies are attracting significant research interest. CH4 storage processes are attracting technological interest, and methane is being applied as an alternative fuel for vehicles. CH4 storage involves many technologies, among which, adsorption processes such as processes using porous adsorbents are regarded as an important green and economic technology. It is very important to develop highly efficient adsorbents to realize techno-economic systems for CH4 adsorption and storage. In this review, we summarize the nanomaterials being used for CH4 adsorption, which are divided into non-carbonaceous (e.g., zeolites, metal-organic frameworks, and porous polymers) and carbonaceous materials (e.g., activated carbons, ordered porous carbons, and activated carbon fibers), with a focus on recent research.
  • 4.

    Effect of nitrogen doping and hydrogen confinement on the electronic properties of a single walled carbon nanotube

    Bashir Mohi Ud Din Bhat | Jehangir Rashid Dar | Pratima Sen | 2016, 17(1) | pp.29~32 | number of Cited : 1
    Abstract
    This paper addresses the effect of dopants on the electronic properties of zigzag (8, 0) semiconducting single walled carbon nanotubes (SWCNTs), using extended Hückel theory combined with nonequilibrium Green’s function formalism. Through appropriate dopant concentrations, the electronic properties of SWCNTs can be modified. Within this context, we present our ongoing investigation on (8, 0) SWCNTs doped with nitrogen. Quantum confinement effects on the electronic properties of the SWCNTs have also been investigated. The obtained results reveal that the electronic properties of SWCNTs are strongly dependent on the dopant concentration and modification of electronic structures by hydrogen confinement.
  • 5.

    Flexural properties, interlaminar shear strength and morphology of phenolic matrix composites reinforced with xGnP-coated carbon fibers

    Jong-Kyoo Park | Jae Yeol Lee | Lawrence T. Drzal and 1other persons | 2016, 17(1) | pp.33~38 | number of Cited : 3
    Abstract
    In the present study, exfoliated graphite nanoplatelets (xGnP) with different particle sizes were coated onto polyacrylonitrile-based carbon fibers by a direct coating method. The flexural properties, interlaminar shear strength, and the morphology of the xGnP-coated carbon fiber/phenolic matrix composites were investigated in terms of their longitudinal flexural strength and modulus, interlaminar shear strength, and by optical and scanning electron microscopic observations. The results were compared with a phenolic matrix composite counterpart prepared without xGnP. The flexural properties and interlaminar shear strength of the xGnP-coated carbon fiber/phenolic matrix composites were found to be higher than those of the uncoated composite. The flexural and interlaminar shear strengths were affected by the particle size of the xGnP, while the particle size had no significant effect on the flexural modulus. It seems that the interfacial contacts between the xGnP-coated carbon fibers and the phenolic matrix play a role in enhancing the flexural strength as well as the interlaminar shear strength of the composites.
  • 6.

    Rate-capability response of graphite anode materials in advanced energy storage systems: a structural comparison

    Umer Farooq | CHILHOON DOH | Syed Atif Pervez and 5other persons | 2016, 17(1) | pp.39~44 | number of Cited : 3
    Abstract
    The work presented in this report was a detailed comparative study of the electrochemical response exhibited by graphite anodes in Li-ion batteries having different physical features. A comprehensive morphological and physical characterization was carried out for these graphite samples via X-ray diffraction and scanning electron microscopy. Later, the electrochemical performance was analyzed using galvanostatic charge/discharge testing and the galvanostatic intermittent titration technique for these graphite samples as negative electrode materials in battery operation. The results demonstrated that a material having a higher crystalline order exhibits enhanced electrochemical properties when evaluated in terms of rate-capability performance. All these materials were investigated at high C-rates ranging from 0.1C up to 10C. Such improved response was attributed to the crystalline morphology providing short layers, which facilitate rapid Li+ ions diffusivity and electron transport during the course of battery operation. The values obtained for the electrical conductivity of these graphite anodes support this possible explanation.
  • 7.

    Synthesis, characterization, and toxicity of multi-walled carbon nanotubes functionalized with 4-hydroxyquinazoline

    Hasan Tahermansouri | Atieh Mirosanloo | Saeed Heidari Keshel and 1other persons | 2016, 17(1) | pp.45~52 | number of Cited : 1
    Abstract
    The attachment of 2-aminobenzamide to carboxylated multi-wall carbon nanotubes (MWCNTs)- COOH was achieved through the formation of amide bonds. Then, the functionalized MWCNTs, MWCNT-amide, were treated by phosphoryl chloride to produce MWCNT-quin. The products were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, thermogravimetric analysis, derivative thermogravimetric, steady-state fluorescence spectroscopy, and solubility testing. MWCNT-quin showed photo-electronic properties, which is due to the attachment of the 4-hydroxyquinazoline groups to them as proved by steady-state fluorescence spectroscopy. This suggests intramolecular interactions between the tubes and the attached 4-hydroxyquinazoline. The toxicity of the samples was evaluated in human embryonic kidney HEK293 and human breast cancer SKBR3 cell lines, and the viable cell numbers were measured by 3-(4,5-dimethyl- 2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) after the cells were cultured for 24 h. Cellular investigations showed that the modified MWCNTs, particularly MWCNT- quin, have considerably significant toxic impact on SKBR3 as compared to HEK293 at the concentration of 5 μg/mL.
  • 8.

    One-step synthesis of dual-transition metal substitution on ionic liquid based N-doped mesoporous carbon for oxygen reduction reaction

    Ulziidelger Byambasuren | Yukwon Jeon | Dorjgotov Altansukh and 2other persons | 2016, 17(1) | pp.53~64 | number of Cited : 3
    Abstract
    Nitrogen (N)-doped ordered mesoporous carbons (OMCs) with a dual transition metal system were synthesized as non-Pt catalysts for the ORR. The highly nitrogen doped OMCs were prepared by the precursor of ionic liquid (3-methyl-1-butylpyridine dicyanamide) for N/C species and a mesoporous silica template for the physical structure. Mostly, N-doped carbons are promoted by a single transition metal to improve catalytic activity for ORR in PEMFCs. In this study, our N-doped mesoporous carbons were promoted by the dual transition metals of iron and cobalt (Fe, Co), which were incorporated into the N-doped carbons lattice by subsequently heat treatments. All the prepared carbons were characterized by via transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). To evaluate the activities of synthesized doped carbons, linear sweep was recorded in an acidic solution to compare the ORR catalytic activities values for the use in the PEMFC system. The dual transition metal promotion improved the ORR activity compared with the single transition metal promotion, due to the increase in the quaternary nitrogen species from the structural change by the dual metals. The effect of different ratio of the dual metals into the N doped carbon were examined to evaluate the activities of the oxygen reduction reaction.
  • 9.

    Cu nanoparticle-embedded carbon foams with improved compressive strength and thermal conductivity

    Ji-Hyun Kim | Kyung Hoon Kim | 박미선 and 2other persons | 2016, 17(1) | pp.65~69 | number of Cited : 3
    Abstract
    Carbon foams (CFms) exhibit excellent physical properties, including good thermal conductivity, low density, high porosity and specific surface area, good vibration damping and shock absorption properties, and low thermal expansion coefficients. These properties are attractive in various applications such as thermal and electrical transfer devices, electrochemical supercapacitors, catalyst supports, gas adsorbents, filtration systems, and electromagnetic shielding. However, compared to metals and polymers, CFms do not exhibit good mechanical or thermal properties because of their porous structure; these shortcomings have limited the application of CFms in various fields [1-4].
  • 10.

    Ion conducting properties of imidazolium salts with tri-alkyl chains in organic electrolytes against activated carbon electrodes

    Kyungmin Kim | PARK SOOJIN | Im Ji Sun and 3other persons | 2016, 17(1) | pp.70~73 | number of Cited : 1
    Abstract
    Electrochemical double layer capacitors (EDLCs), a type of energy storage device, are currently receiving considerable attention. They have a high power density and good cycle ability. Furthermore, they operate on a simple mechanism where electrical charges in an electrochemical double layer are accumulated at the interface between the electrode and the electrolyte [1-3]. For these reasons, capacitors are used in a wide range of applications such as mobile phones, electrical vehicles, and industry power supplies.
  • 11.

    Effects of an inorganic ammonium salt treatment on the flame-retardant performance of lyocell fibers

    Hyeong Gi Kim | Byong Chol Bai | In Se Jin and 1other persons | 2016, 17(1) | pp.74~78 | number of Cited : 1
    Abstract
    Lyocell fibers are produced by dissolving cellulose in a N-methylmorpholine-N-oxide/water solution. The resulting cellulose/N-methylmorpholine-N-oxide/water mixture is extruded through an orifice, drawn into an air gap, and then precipitated in a coagulation bath [1]. In contrast with rayon fibers, lyocell fibers have higher tenacity, a higher modulus, lower shrinkage when dried, and lower reductions of tenacity and the modulus when wet. Moreover, lyocell fibers are round and have molecular chains that are highly oriented along the fiber axis, and it is easy to control their fineness [2].
  • 12.

    Mechanical interfacial adhesion of carbon fibers-reinforced polarized-polypropylene matrix composites: effects of silane coupling agents

    최웅기 | 김현일 | 강신재 and 3other persons | 2016, 17(1) | pp.79~84 | number of Cited : 3
    Abstract
    Thermoplastic composites are used in a variety of applications such as mass transit, automotive parts, and military structures [1-6]. Their appeal compared to conventional materials such as aluminum, steel, and thermoset composites for these applications lies in their high specific strength, corrosion resistance, superior impact resistance, high toughness, and ease of recycling [1-7].
  • 13.

    Preparation and characterization of chemically activated carbon materials for CO2 capture

    전다희 | Shin-Tae Bae | PARK SOOJIN | 2016, 17(1) | pp.85~89 | number of Cited : 3
    Abstract
    Atmospheric carbon dioxide (CO2) exists as a gas at standard temperature and pressure, and it occurs in Earth’s atmosphere in this state [1,2]. Rising levels of CO2, a greenhouse gas, are a major environmental problem [3]. The main source of CO2emissions is the burning of fossil fuels, such as natural gas and coal. The combustion of these fossil fuels, such as natural gas, coal, and oil, is one of the major emission sources of CO2[4].