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    30 July 2017, Volume 51 Issue 4 Previous Issue    Next Issue
    Isolation and Characterization of Water-soluble and Alkali-soluble Lignin from Bagasse
    PENG Feng, FU Genque, WANG Xiaojun, HU Yajie, YUE Panpan
    2017, 51 (4):  1-7.  doi: 10.3969/j.issn.1673-5854.2017.04.001
    Abstract ( 826 )   PDF (1170KB) ( 765 )   Save
    The lignin fractions(water-soluble lignin L1 and alkali-soluble lignin L2, L3)were extracted by H2O, 1% NaOH and 3% NaOH aqueous solution from the dewaxed bagasse. The components of three lignin fractions were analyzed by nitrobenzene oxidation and high performance liquid chromatography, the molecular weights were detected by gel permeation chromatography, and the structure units and linkages were studied by UV and 2D HSQC NMR. The results reflected that the yields of L1, L2 and L3 were 0.4%, 5.7% and 3.7%, and they occupied 54.1% of the original lignin.And the molecular weight of water-soluble lignin was higher than that of alkali-soluble lignin. Furthermore, the L2 and L3 were from the secondary wall of bagasse and the dominating constituents of them were syringyl units and large amounts of noncondensed ether structures. The lignin structural units were linked to each other mainly by β-O-4' ether bonds, β-β', β-5', β-1'. And the lignin was GSH lignin composed by syringyl, guaiacyl and little p-hydroxylphenyl units. The linkage between p-coumaric and lignin was ester bond, whereas the linkages between ferulic acid and lignin were both ether and ester bonds.
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    Analysis Method of Cellulose Pyrolysis Dynamics
    BAI Bin, ZHOU Weihong, DING Yifei, XU Anzhuang, WANG Yujie, DING Weijing
    2017, 51 (4):  8-16.  doi: 10.3969/j.issn.1673-5854.2017.04.002
    Abstract ( 1262 )   PDF (1019KB) ( 967 )   Save
    With microcrystalline cellulose as raw material, cellulose pyrolysis experiments under different heating rates were carried out in nitrogen atmosphere by thermogravimetric analyzer, and the pyrolysis kinetic characteristics of cellulose were analyzed. The most probable reaction mechanism function was selected from 41 mechanism functions of thermal analysis kinetics by using the double equal-double steps method and Popescu method, meanwhile, four different thermal analysis methods (Freeman-Carroll method, Coats-Redfern method, Starink method, double equal-double steps method) were used to calculate the activation energy (E) and pre exponential factor (A) of pyrolysis reaction, and the results were analyzed and compared. The results showed that with the increase of the heating rate, the initial pyrolysis temperature of cellulose increased and the rate of pyrolysis weight loss increased; the pyrolysis process of cellulose could be divided into 4 stages, dehydration preheating section (40-120℃), the early period of pyrolysis (120-260℃), the main pyrolysis section (260-400℃) and carbonization section (400-900℃); the main cellulose pyrolysis section was divided into two stages and the activation energies at low temperature (260-350℃) and high temperature (350-400℃) were 166-176 kJ/mol and 171-216 kJ/mol, respectively; anti Jander kinetic model could describe the reaction process of main pyrolysis well; by using single scanning rate method (Freeman-Carroll and Coats-Redfern), the analysis result had a great deviation from the actual value, and the results obtained by the multiple scan rate method were more reliable.
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    Preparation of Xylose Metabolic Fusant D2 and Its Ethanol Fermentation Characteristics
    ZHOU Lin, QIU Ruijiao, LIN Shanglong, XU Shaoping, ZHANG Ying
    2017, 51 (4):  17-24.  doi: 10.3969/j.issn.1673-5854.2017.04.003
    Abstract ( 576 )   PDF (1009KB) ( 706 )   Save
    The xylose metabolic fusants were prepared by fusion of inactivated parental protoplasts with Pichia stipitis 1960(Ps1960) and Saccharomyces cerevisiae AADY(ScAADY) as parental strains. And the preparation conditions were optimized. The results showed that the Ps1960 protoplast was prepared by enzymolysis with 2% snailase and 1% cellulase for 45 min at 28℃, and then inactivation with 20 W ultroviolet lamp 10 cm away from the culture for 3 min. While ScAADY protoplast was prepared by enzymolysis with 1.5% snailase and 1% cellulase for 50 min at 28℃, and inactivation in water bath for 50 min at 55℃. And 0.6 mol/L sorbitol was used as osmotic stabilizer. And then, 22 fusants were obtained. The biomasses of the fusants under different culture medium conditions were determined to evaluate the ability of metabolism of xylose and ethanol tolerance. Thus, from 22 fusants, the fusant D2, which could ferment ethanol from xylose, with good hereditary feature was selected for ethanol fermentation. Furtherly, fusant D2 could produce 40.58 g/L ethanol under the conditions of 8% mixed sugar, mass ratio of xylose and glucose 6:1, inoculum size of 5% and cultured for 72 h with shaking 160 r/min at 30℃.
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    Adsorption of Cefradine on Activated Carbon Prepared from Chinese Medicine Residue
    YU Ying, SUN Xiantao, CHEN Jianqiu, MING Guangqi, SHANG Jingge
    2017, 51 (4):  25-32.  doi: 10.3969/j.issn.1673-5854.2017.04.004
    Abstract ( 776 )   PDF (2752KB) ( 778 )   Save
    Citron activated carbon(AC-CM), cassia twig activated carbon(AC-RC) and isatis roots activated carbon(AC-IT) were prepared from the residues of citron(CM), cassia twig(RC) and isatis roots(IT) by Na2CO3 activation at 800℃ for 1.5 h. Scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy and Brunauer-Emmett-Teller(BET) measurements were used to characterize the activated carbons, and the pH value and pHpzc of the activated carbons were also determined. Three kinetic and two isotherm models were applied to analyze the dynamic and isotherm experiment data of the adsorption of cefradine on the activated carbons, respectively. The effects of initial pH and NaCl mass concentration on the adsorption were also studied. The results indicated that the specific surface areas of AC-CM, AC-RC and AC-IT were 453.32, 413.78 and 230.06 m2/g, the corresponding pH values were 9.70, 8.23 and 9.24, and the pHpzc values were 9.28, 9.21 and 9.38. The FT-IR spectra showed that the surface groups of the activated carbons were main C=O, C=C and nitrogen containing group, and the SEM images showed there were many pore structures. The pseudo-second order and intraparticle diffusion model fit the kinetics for the adsorption of cefradine on three activated carbons and the adsorption rate were controlled by intraparticle diffusion and chemisorption. The Freundlich isotherm model matched the isotherm experiment data more appropriate than Langmuir model and the n>1 showed that the adsorption process was easy to carry out. And the initial pH value of the solution had an obvious effect on adsorption process, the maximum cefradine adsorption quantities on AC-CM, AC-RC and AC-IT were 74.76, 79.44 and 62.55 mg/g, respectively, with the initial pH value 3, 100 mg/L cefradine solution, 0.1 g activated carbon and adsorption for 48 h. And the existence of NaCl in the solution increased the adsorption quantity of activated carbon.
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    Preparation and Characterizations of Cellulose Nanocrystals from Hybrid Poplar Residue by Ammonium Persulfate Oxidation
    HAN Binbin, HAN Yuanshuai, WU Yu, JIANG Hua, ZHANG Yang
    2017, 51 (4):  33-38.  doi: 10.3969/j.issn.1673-5854.2017.04.005
    Abstract ( 804 )   PDF (2063KB) ( 741 )   Save
    The cellulose nanocrystals (CNCs) were prepared by ammonium persulfate oxidation of hybrid poplar residue obtained after the extraction of hemicellulose. The starting material was treated by 1.5 mol/L ammonium persulfate solution at 70℃ for 16 h, and the ratio of the solid to the liquid was 1:100(g:mL). The resulting CNCs were white powder and the yield(calculated by the mass of cellulose in the starting material) was 57%, the oxidation degree of CNCs was 0.156 and the surface charge was -42.15 mV. The CNCs were mainly characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and nuclear magnetic resonance. The results showed that ammonium persulfate could remove the lignin and residual hemicellulose in the starting material and selectively oxidize the hydroxyl groups at the position of cellulose C6 to carboxyl groups. The cellulose nanocrystals kept the structural characteristics of the raw cellulose. The crystal structure of the CNCs, which had a crystallinity index of 77%, was dominated by Iβ, and 88.4% of them had a width of 10-24 nm.
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    Effects of NaOH/AQ Pretreatment on Delignification and Enzymatic Digestibility of Corn Stover
    LIU Wenwen, LIANG Long, SHEN Kuizhong, FANG Guigan, TIAN Qingwen
    2017, 51 (4):  39-46.  doi: 10.3969/j.issn.1673-5854.2017.04.006
    Abstract ( 1020 )   PDF (1093KB) ( 869 )   Save
    The optimized conditions of NaOH/AQ pretreatment and the effects of the lignin removing rate on the enzymatic digestibility of the pretreated corn stover were investigated. The optimized conditions of the NaOH/AQ pretreatment obtained by the orthogonal experimental design were the reaction temperature 160℃,the reaction time 60 min, the NaOH dosage(based on the mass of dried material)2.8%,the anthraquinone(AQ) dosage 0.05% and the solid to liquor ratio 1:5(g:mL). Under these conditions,the lignin removing rate reached 75% and the polysaccharides conversion rate of the enzymatic digestibility reached 73.79%. The enzymatic efficiency of the pretreated samples improved with the increase of the lignin removing rate. The maximum polysaccharide conversion rate of the pretreated biomass could be obtained as the lignin removing rate reached some degree and then the polysaccharides conversion rate decreased with the continued increase of the lignin removing rate. The optimized conditions of enzymatic hydrolysis by using response surface experimental design were as follows:the temperature 50℃,the time 72 h,the substrate consistency 2.5%, the cellulase dosage 30 FPU/g and the cellubiase enzyme dosage 10 IU/g. Then the reducing sugar yield was 85.62%. The HPLC analyses showed that the glucose and xylose mass concentrations in the enzymatic hydrolyzates were 14.83 and 4.83 g/L,respectively. The results of XRD showed that the crystal form of cellulose before and after pretreatment didn't change and the crystallinity of the pretreated corn stover was increased to 46.91% from 31.40% because of the dissolving of lignin and hemicellulose.
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    Synthesis and Characterization of Ester of Acrylic Rosin Adduct and GMA
    XU Jianben, YU Caili, BIAN Feng, ZHANG Faai
    2017, 51 (4):  47-52.  doi: 10.3969/j.issn.1673-5854.2017.04.007
    Abstract ( 718 )   PDF (846KB) ( 790 )   Save
    The ester(RAG) was synthesized with acrylic rosin adduct(RA) and glycidyl methacrylate(GMA) as monomers, triethylamine as catalyst, hydroquinone as inhibitor in toluene solution. The esterification reaction conditions were optimized by single factor experiment and orthogonal experiments. The RAG was analyzed and characterized by Fourier transform infrared spectroscopy(FT-IR), gel permeation chromatography(GPC), viscometer, nuclear magnetic resonance(1H NMR), and thermal gravimetric(TG) analysis. The results showed that the optimum conditions were the molar ratio of GMA and RA at 2:1, the dosage of triethylamine 0.5% (based on RA weight), 120℃ and 4 h. Under these conditions, the ester was deep yellowish brown clear liquid, the esterification rate was 99.5%, the number average relative molecular weight was 547, the weight average relative molecular weight was 848, and the viscosity of the ester in toluene was 10 mPa·s at 25℃ with the mass fraction of 51%. The FT-IR and 1H NMR showed that RAG was successfully prepared. The TG showed that the thermal stability of the ester was higher than that of the acrylic rosin adduct.
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    Combustion and Kinetics of Straw and Sludge Briquette Fuel
    SUN Wenyang, WANG Liming, MA Chao, MA Yanru, LÜ Yang, FENG Kang
    2017, 51 (4):  53-58.  doi: 10.3969/j.issn.1673-5854.2017.04.008
    Abstract ( 676 )   PDF (782KB) ( 773 )   Save
    In order to explore the combustion performance of agricultural biomass, three kinds of briquette fuels of sludge and straws (corn stalk, bean stalk, wheat straw) were used as experimental materials for isothermal combustion experiment, the combustion characteristics of briquette fuels were studied and analyzed. And the reaction kinetics were analyzed. The results showed that with the increase of temperature, the maximum peaks of combustion of 3 briquette fuels were advanced, the burn-off times decreased significantly and the maximum weight loss rates increased, but the burning weight loss curves were consistent at last. The reaction orders of the isothermal reaction processes of 3 briquette fuels at the temperature of 750-950℃ were 1.2-1.4, 0.9-1.1 and 1.0-1.2, respectively, the activation energies were 55-57, 50-53 and 49-55 kJ/mol, and the frequency factors were 57-113, 35-74 and 76-103 s-1. The combustion of 3 briquette fuels followed the essential dynamic equation of combustion and could be described by first order reaction. The straw type had no significant influence on the combustion performance of blended briquette.
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    Environmental Impact Assessment of Biomass-derived Hydrothermal Carbon Material Production
    YU Ruidong, DONG Yue, GUO Minghui
    2017, 51 (4):  59-65.  doi: 10.3969/j.issn.1673-5854.2017.04.009
    Abstract ( 773 )   PDF (937KB) ( 739 )   Save
    The environmental impact of biomass hydrothermal carbon material production was assessed by using life cycle assessment(LCA). A life cycle inventory including input and output processes of biomass hydrothermal carbon material production was established based on inventory analysis. GaBi 6.0 software was used to model and calculate the original data to obtain the corresponding environmental impact potentials on global warming potential(GWP), acidification potential(AP), abiotic depletion potential(ADP), etc. The results showed that the effect order of production process on the environmental impacts was GWP, AP, photochemical ozone creation potential(POCP), eutrophication potential(EP), ADP and ozonospher disturbance potential(ODP). The power consumption was the uppermost environment impact factor. As the power generation of our country was carbon intensive, the emissions of CO2, SO2, NOx from thermal power were the main environmental impact factors. The key environmental influencing link in hydrothermal carbon production was hydrothermal carbonization. According to this result, it would be helpful for reducing the environmental impact of biomass hydrothermal carbon material by reducing hydrothermal carbonization temperature or shortening the time of hydrothermal carbonization.
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    Prospects for the Utilization of Biochar on Remediating Soils Polluted by Heavy Metal
    SUN Kang, MIAO Cunbiao, HE Yue
    2017, 51 (4):  66-74.  doi: 10.3969/j.issn.1673-5854.2017.04.010
    Abstract ( 987 )   PDF (1184KB) ( 899 )   Save
    The role of biomass charcoal porous,surface activity,selective adsorption and high based properties in the effective control of heavy metal biological migration was given in order to provide reference for heavy metal contaminated soil remediation technology. The general situation of heavy metal contaminated soil in China was introduced and the application of biomass carbon in heavy metal contaminated soil remediation was reviewed. The effects of phytoremediation,chemical leaching,soil performance improvement,curing/stabilization,thermal desorption repair and electrokinetic repair were highlighted. The effects of raw material types,pyrolysis temperature and surface functional groups on biomass carbon and biomass carbon on soil environment were briefly introduced. The future of biomass charcoal application in heavy metal contaminated soil remediation was prospected.
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