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    30 November 2017, Volume 51 Issue 6 Previous Issue    Next Issue
    Preparation of Chitosan/Poly(hydroxybutyrate-hydroxyhexanoate) Biodegradable Composite Films
    WANG Ling, ZHOU Jiao, MA Xiaojun
    2017, 51 (6):  1-5.  doi: 10.3969/j.issn.1673-5854.2017.06.001
    Abstract ( 570 )   PDF (3763KB) ( 538 )   Save
    Using acetic acid as solvent, chitosan(CS)/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)(PHBV) biodegradable composite films were prepared by tape casting.Scanning electron microscopy and Fourier-transform infrared were used to characterize the composite films, and the influences of different CS/PHBV mass ratio on the mechanical properties, oxygen permeability, thermal stability and biodegradation of composite films were studied. Results showed that with the increase of CS, the fractured surface of the composite films was more compact, the honeycomb structure disappeared, the number of hydroxyl and ester groups in the composite films increased. The tensile strength and elastic modulus of CS/PHBV biodegradable composite films reached the maximum when the mCS:mPHBV was 3:1, which were 3.57 and 26.84 MPa, respectively. The oxygen permeability was the smallest when mCS:mPHBV was 4:1, which was 27.7×10-15 cm3·cm/(cm2·s·Pa). Meanwhile, due to the addition of chitosan, it was also found that the biodegradation of CS/PHBV composite films had been improved.
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    Ionic Liquid Modified Magnetic Nanoparticle:An Recyclable Magnetic Catalyst for Cellulose Hydrolysis
    YANG Yanping, LUO Yunlong, SHEN Minggui, SHANG Shibin, SONG Zhanqian
    2017, 51 (6):  6-10.  doi: 10.3969/j.issn.1673-5854.2017.06.002
    Abstract ( 632 )   PDF (2544KB) ( 519 )   Save
    Dual Brønsted acidic ionic liquid 1-(propyl-3-sulfonate) imidazolium hydrogen sulfate[SO3H-(CH2)3-HIM] [HSO4] was supported onto the surface of Fe3O4@SiO2 to prepare recyclable magnetic catalyst Fe3O4@SiO2-IL by chemical modification. The magnetic catalyst was characterized by FT-IR, TEM and further utilized in the hydrolysis of cellulose. The influences of reaction temperature, reaction time, catalyst dosage and water content on the convertion of cellulose to reduction sugars were investigated. The FT-IR of Fe3O4@SiO2-IL showed absorption peaks of —SO3H and that of imidazole ring, which indicated that the ionic liquid was successfully loaded on Fe3O4@SiO2. The TEM images showed that the particles size of Fe3O4 was about 250 nm and the surface of particles had no significant change after packing and modification of ionic liquid. With the dosage of 0.1 g cellulose, 2.0 g ionic liquid [Bmim]Cl, 0.2 g magnetic catalyst, 0.2 g water and reacting under 100 ℃ for 40 min, the yield of the total reducing sugars reached 52.5 %. After magnetic separation, the catalyst could be reused for 5 recycles without the loss of catalytic activity.
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    Optimization of Graft Polymerization Conditions of Methyl Methacrylate onto Pineapple Leaf Fibers and Characterization of Copolymers
    XIONG Zengheng, LIN Yan, LIN Zhaohua, HE Zhongping, ZHANG Yucang
    2017, 51 (6):  11-18.  doi: 10.3969/j.issn.1673-5854.2017.06.003
    Abstract ( 515 )   PDF (3577KB) ( 544 )   Save
    Graft polymerizations of methyl methacrylate(MMA) onto pineapple leaf fibers by using ammonium cerium nitrate as initiator and water as medium were carried out in heterogeneous systems. The obtained optimal process conditions for the graft polymerization were ammonium cerium nitrate concentration of 0.006 mol/L, hydrogen ion of 0.06 mol/L, MMA of 0.4 mol/L and reaction for 3 h at 50 ℃. Under these conditions, the grafting rate of copolymer was 185%. The structures and physicochemical properties of pineapple leaf fibers before and after graft polymerization were characterized by SEM, FT-IR, TG and fiber strength analyzer, respectively. The results indicated that the graft polymerization changed the original arrangement of fibrous molecules, destroyed parts of crystalline areas of fibers, and decreased the tensile strength; and the grafted pineapple leaf fibers were loose and more soft, whereas the heat resistance improved. Meanwhile, the higher grafting ratio of pineapple leaf fibers was, the lower hygroscopicity as well as higher acid and alkali resistance it was.
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    Preparation of High Porosities Active Carbon Monoliths from Sawdust and Doehlert Matrix Method Optimization
    YIN Mengmeng, TANG Ruiyuan, LÜ Bingyong, QIAO Yingyun, TIAN Yuanyu
    2017, 51 (6):  19-25.  doi: 10.3969/j.issn.1673-5854.2017.06.004
    Abstract ( 604 )   PDF (1684KB) ( 551 )   Save
    Sawdust was used as precursor to prepare binderless high porosities active carbon monoliths(ACMs) with H3PO4 as activator and without binder. The influences of temperature(500-700 ℃) and activation time(1-3 h) on the properties of ACMs were analyzed by N2 adsorption-desorption, X-ray diffraction(XRD) and compression test. The results showed that the ACMs had high specific surface area, porosity, yield, apparent density, compressive strength and total pore volume and they could reach 1 022.6 m2/g, 32.2 %, 0.62 g/cm3, 5.23 MPa, 0.49 cm3/g and 91.8 % when the activation temperature was 600 ℃ and the activation time was 1 h. The Doehlert matrix method was used to optimize the reaction conditions and the optimal temperature and time were 590 ℃ and 2.1 h. Under these conditions the yield, compressive strength and density of ACMs were 31.8%, 5.54 MPa and 0.87 g/cm3. It was found that the theoretical value was consistent with experimental value and the theoretical model was reliable.
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    Determination of Monosaccharides in High Temperature Hydrolysate of Rape Straw by High Performance Liquid Chromatography
    FENG Guangrong, LU Houfang, LIANG Bin, LIU Yingying
    2017, 51 (6):  26-32.  doi: 10.3969/j.issn.1673-5854.2017.06.005
    Abstract ( 635 )   PDF (1031KB) ( 571 )   Save
    The method was developed to determine monosaccharides in the high temperature hydrolysate of rape straw catalyzed by CO2 via high performance liquid chromatography(HPLC). The monosaccharides were separated on the PrevailTM ES carbohydrate column at 35 ℃ with the mixture of acetonitrile/water(80:20,volume ratio) as mobile phase, which was under isocratic elution at the flow rate of 0.8 mL/min. They were detected by evaporative light-scattering detector(ELSD) using dry air as carrier gas at flow rate of 3.0 L/min and drift tube working at 95 ℃. The HPLC analysis method could ensure six monosaccharides(including arabinose, xylose, fructose, mannose, galactose and glucose) separate well within 20 min. The resultant correlation coefficients(R2) of monosaccharides were 0.999 1-0.999 7. The average recovery values were 95.3 %-108.0 %, and the relative standard deviation percentage(RSD) was less than 3 %.
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    Selective Adsorption of Native Inulinase by Jerusalem Artichoke Residue and Preparation of Short-chain Fructooligosaccharides
    LI Xin, ZHOU Jin, LAI Chenhuan, YONG Qiang
    2017, 51 (6):  33-37.  doi: 10.3969/j.issn.1673-5854.2017.06.006
    Abstract ( 565 )   PDF (715KB) ( 515 )   Save
    A selective adsorption method was developed to adsorb native inulinase from Aspergillus niger to reduce sucrase activity by Jerusalem artichoke residue. The inulinase activity(I)/sucrase activity(S) ratio was generally used to characterize the inulinases. Afterward, the native inulinase, selectively adsorbed by Jerusalem artichoke residue, was applied for production of short-chain fructooligosaccharides(FOSs). The results showed that the optimal conditions of the selective adsorption were as follows:Jerusalem artichoke residue loading 100 g/L, pH value 5.0, adsorption temperature 4℃. 67.92% Inulinase activity was retained and 80.84% sucrase activity was decreased in the native inulinase system after the selective adsorption. The I/S ratio increased from 1.13 to 4.02. The selective adsorption of native inulinase by Jerusalem artichoke residue improved the production of short-chain FOSs. The conditions of enzymatic hydrolysis were inulin 40 g/L, pH value 5.0, 50℃, inulinase loading 20 U/g(based on the mass of inulin). The mass concentration of short-chain FOSs was 16.06 g/L, which was 2.55 times than that of the original inulinase. The yield of short-chain FOSs was 40.16%.
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    Kinetic Study on Biomass Char CO2 Gasification at High Temperature
    YUAN Congcong, WANG Yudong, ZHANG Dingchuan, YANG Bin, DAI Yongnian
    2017, 51 (6):  38-42.  doi: 10.3969/j.issn.1673-5854.2017.06.007
    Abstract ( 551 )   PDF (719KB) ( 579 )   Save
    The kinetics of biomass char CO2 gasification reactivity at high temperature was investigated via the temperature-programmed thermogravimetry with thermal analyzer, the influence of heating rates on gasification reactivity was studied and the kinetic parameters were calculated by Friedman-Reich-Levi method. The results showed that along with the increase of heating rate, the peak temperature of DTG curves and the maximum reaction rates increased. With carbon dioxide as shielding gas, changing the heating rate to 15 ℃/min, pyrolysis biomass char owned the best reactivity. The higher the heating rate was, the more obvious the reaction rate changed with the temperature. The activation energies of biomass char gasification stage were -4 984.41-1 408.39 kJ/mol, which indicated biomass char CO2 gasification reaction process was complicated.
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    Preliminary Research on Ultrasonic Assisted Extraction Technology of Polysaccharides in Ginkgo biloba Leaves
    GUO Xiangqin, CAI Na, YANG Shanbin, ZHOU Shiyang, CHEN Yixin, KE Daoyao
    2017, 51 (6):  43-47.  doi: 10.3969/j.issn.1673-5854.2017.06.008
    Abstract ( 495 )   PDF (1465KB) ( 610 )   Save
    Polysaccharide was extracted from Ginkgo biloba fallen leaves by ultrasound-assisted water extraction and alcohol precipitation. The extraction technology was preliminarily studied by single factor and response surface method.The results showed that the optimum extraction conditions were as follows:G. biloba fallen leaves 5.0 g, ultrasound power 600 W, liquid/solid ratio 40:1(mL:g), extraction temperature 84 ℃, extraction time 50 min, the final polysaccharide yield was 6.61 %. Because this study was only a preliminary study on the extraction process of polysaccharides from the leaves of Ginkgo biloba, the extraction principle of "small amount of times and total liquid ratio is less" was not considered.
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    Research Progress on Preparation and Application of Amino Cellulose
    HU Yajie, FU Genque, YUE Panpan, LI Nan, PENG Feng, SUN Runcang
    2017, 51 (6):  48-54.  doi: 10.3969/j.issn.1673-5854.2017.06.009
    Abstract ( 1009 )   PDF (2277KB) ( 685 )   Save
    Amino cellulose is the cellulose derivative with terminal amino groups. The structure of amino cellulose is similar to that of chitosan. Because of the active amino groups in cellulose, amino cellulose exhibits good solubility, film-forming property, heavy metal ions adsorption property, and good application prospect in the field of biology such as immobilizing enzyme and controlling drug release. Now, the synthesis process is complicated, including the preparation of intermediate and the synthesis of amino cellulose. In addition, the poor selectivity and economics in the synthetic process of amino cellulose limit its applications. This paper mainly focuses on the preparation of amino cellulose, which includes the synthetic route, synthesis process conditions and synthetic prospect. At last, the applications of amino cellulose are discussed in detail, such as film-forming property, immobilization of enzyme, adsorption of impurities, and so on.
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    Advance Research on Hydrodeoxygenation Catalysts of Biofuel
    XU Haisheng, WANG Hao, WANG Bo
    2017, 51 (6):  55-61.  doi: 10.3969/j.issn.1673-5854.2017.06.010
    Abstract ( 965 )   PDF (963KB) ( 627 )   Save
    The research progresses on the hydrodeoxygenation catalysts of biofuels were reviewed. Precious metal catalyst had stronger reactivity than the traditional catalyst, but it was expensive and precious metal recovery also increased the cost of hydrodeoxygenation process; transition metal catalyst was cheap, but easy to inactivate; sulfide catalyst had high activity,but the preparation process required pre-vulcanization and the preparation process was complex; carbon and nitride catalysts were inexpensive and had electronic structures and catalytic activity similar to precious metals, known as "quasi-platinum catalysts"; phosphide catalysts as the most promising hydrogen deoxidation catalyst had high research value.
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    Research Progress on Molding Mechanism and Preparation Process of Molding Fuel of Biomass Charcoal
    LI Zeya, WU Lin, RAO Wenhao, TONG Kun, ZHANG Qi, LIU Ying
    2017, 51 (6):  62-66.  doi: 10.3969/j.issn.1673-5854.2017.06.011
    Abstract ( 577 )   PDF (760KB) ( 677 )   Save
    The preparation technologies of molding fuel of biomass charcoal were summarized. The selection of adhesives was emphasized. The advantages and disadvantages of organic adhesives, including starch-based, lignin-based and carboxymethyl cellulose-based, and inorganic adhesives were analyzed. The influences of water and particle size of biomass on the fuels were analyzed, too. In addition, the molding processes of different equipments were summarized and the research direction of developing biomass fuel with high added value in the future was pointed out.
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