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    25 April 2017, Volume 37 Issue 2 Previous Issue    Next Issue
    Research Progress and Applications of Macromolecular Polysaccharide-based Hydrogels for Functional Materials
    JIANG Jianxin, LIU Yantao, ZHOU Ziyuan, DUAN Jiufang, SUN Dafeng
    2017, 37 (2):  1-10.  doi: 10.3969/j.issn.0253-2417.2017.02.001
    Abstract ( 1068 )   PDF (2331KB) ( 2388 )   Save
    Compared with the traditional polymer hydrogel materials, polysaccharide hydrogels are getting more attention of the people, because of its environmentally friendliness, biocompatibility, special functional and biodegradable advantages. The production methods of hydrogels from plant polysaccharides, marine polysaccharide, microbial polysaccharide and its blending polysaccharide were summarized, as well as the functional characteristics and characterization methods. And the applications of hydrogel materials in medicine and health care, food, cosmetics, agriculture, environmental protection and other fields were introduced. The application prospects of polysaccharide hydrogel in biosensor, bioreactor, artificial intelligence materials and antibacterial materials were discussed, and the main focus of future polysaccharide research were proposed, such as improving material performance and features, studying gel formation mechanism, and simulating function materials.
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    Progress of Application of Solid Catalysts in Levulinic Acid and Alkyl Levulinates Produced from Biomass
    CHANG Chun, DENG Lin, QI Xiaoge, BAI Jing, FANG Shuqi
    2017, 37 (2):  11-21.  doi: 10.3969/j.issn.0253-2417.2017.02.002
    Abstract ( 766 )   PDF (1323KB) ( 559 )   Save
    The synthetic pathways of levulinic acid and alkyl levulinates were introduced. The synthetic routes of levulinic acid mainly includes catalyzed hydrolysis of furfuryl alcohol, direct hydrolysis of biomass and hydrolysis of hemicellulose. The synthetic pathways of alkyl levulinate were esterification of levulinic acid, direct alcoholysis of biomass, alcoholysis of furfuryl alcohol and alcoholysis of 5-chloro methyl furfural. Recent research of solid catalysts used in conversion of biomass into levulinic acid and alkyl levulinates were reviewed, and the brief overview of the solid catalyst types that used in biomass conversion such as super acid, molecular sieve, heteropoly acid and resin was conducted. Furthermore, the development and application in the future of solid catalyst were also prospected.
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    Progress on Reaction and Catalyst for Production of C5/C6 Alkane Fuels from Cellulose by Catalytic Conversion
    CHEN Lungang, LIU Yong, ZHANG Xinghua, ZHANG Qi, WANG Tiejun, MA Longlong
    2017, 37 (2):  22-34.  doi: 10.3969/j.issn.0253-2417.2017.02.003
    Abstract ( 702 )   PDF (3326KB) ( 555 )   Save
    The reactions and catalytic systems for the production of C5/C6 alkanes from cellulose or lignocellulosic biomass were summarized. The reaction pathways mainly included one-pot conversion of cellulose to alkanes by hydrolysis-hydrodeoxygenation; and hydrocarbon fuels produced from C6 platform compounds by hydrodeoxygenation. The reaction pathways and catalysts of alkanes production from raw lignocelluloses, cellulose, glucose and sorbitol were summarized. And the reaction pathways mainly included sorbitol, isosorbide, HMF and caprolactone routes. The metal-acid multifunctional catalysts were widely used; acid catalysts included metal oxides, zeolites, heteropoly acids, ionic liquid acid and inorganic acid, etc., and the metal catalysts were mainly Pd, Pt, Ni, Ru, Ir, etc. The metal Ru was popularly studied due to its excellent catalytic performance under the acidic hydrothermal environment. Finally, for the state-of-the-art technologies in the conversion of biomass to C5/C6 alkanes, the main uncertainties, bottlenecks and research needs were concluded and prospected.
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    Formation and Evolution of Surface Nitrogen Functionalities on Activated Carbons by Ammonia Modification
    ZHANG Wenbin, ZUO Songlin, WANG Yiwang
    2017, 37 (2):  35-41.  doi: 10.3969/j.issn.0253-2417.2017.02.004
    Abstract ( 825 )   PDF (1251KB) ( 685 )   Save
    Three types of ammonia modification was carried out in 300-1 000 ℃ using nitric acid oxidized activated carbon obtained commercially from steam activation using coconut shell as raw materials. The formation and evolution of surface nitrogen functional groups of the activated carbon were investigated. Element analysis, Boehm titration and X-ray photoelectric spectroscopy (XPS) were employed to determine the element contents, acid and basic functional groups contents and the types of nitrogen-containing functional groups of activated carbons. The results showed that when the activated carbon were treated at the temperature below 700 ℃, nitrogen functional groups were mostly nitrogen oxides(N-X, such as amides, imides and lactams) generated mainly by combining ammonia and surface oxygen-containing functional groups, and some pyridinic(N-6) and pyrrolic(N-5) groups by the reaction of ammonia and carbon atoms in the carbon matrix. when the temperature increased to 800 ℃, the formation of nitrogen functional groups were contributed to the combination of ammonia and carbon atoms and pyridinic, pyrrolic and quaternary(N-Q) groups were predominantly generated. With the temperature increasing, amides, lactams and imides were progressively converted into pyridinic, pyrrolic groups and eventually into quaternary groups. Besides, there was no quaternary surface group below 800 ℃.
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    Liquefaction of Eucalyptus Sawdust Catalyzed by [C4H8SO3Hmim] HSO4
    WU Honglou, CHEN Fangeng, WANG Jing
    2017, 37 (2):  42-48.  doi: 10.3969/j.issn.0253-2417.2017.02.005
    Abstract ( 586 )   PDF (1273KB) ( 332 )   Save
    Eucalyptus sawdust was liquefied in ethylene glycol under atmospheric pressure using 1-(4-sulfobutyl)-3-methylimidazolium hydrosulfate([C4H8SO3Hmim] HSO4) as catalyst. The effects of the reaction time, temperature and dosage of catalyst on the liquefaction yield and the distribution of liquefaction products were studied. The results showed that the optimal conditions of liquefaction were: 10g eucalyptus sawdust, 60g ethylene glycol, 10 mmol [C4H8SO3Hmim] HSO4, 160 ℃ and 150 min. The liquefaction yield was up to 96.41% under the optimal conditions. The Fourier transform-infrared (FT-IR) spectra, thermal gravimetric and the X-ray diffraction analysis of the residual showed that the major component in the residue was cellulose with high crystallinity. The FT-IR analysis of water-insoluble products showed that water-insoluble products mainly included degradation products from lignin. The GC-MS analysis showed the water-soluble products mainly included levulinic acid and methyl levulinate which was originated from cellulose.
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    Preparation and Properties of Formed Activated Carbon Coated by Ethyl Cellulose
    XU Wei, LIU Junli, MIAO Cunbiao, SUN Kang, SONG Yaoguang
    2017, 37 (2):  49-56.  doi: 10.3969/j.issn.0253-2417.2017.02.006
    Abstract ( 767 )   PDF (5195KB) ( 492 )   Save
    The coated liquid was prepared with ethyl cellulose as coating material and ethanol as the solvent by dissolving at 50 ℃. In order to prepare activated carbon products coated by EC, the coated liquid was uniformly sprayed on the surface of formed activated carbon before heat treatment. The influences of the mass fraction of coated liquid, spray volume and heat treatment temperature on the strength and adsorption properties of coated activated carbon were studied. It was found that under the mass fraction of coated liquid was 4.23%, the weight of activated carbon was 30 g, the spray volume was 20 mL, and the heat treatment temperature was 140 ℃, the strength of the coated activated carbon reached 93.66% and increased 7.35 percentage points compared with that of raw activated carbon and the butane working capacity reached 86.0 g/L and decreased by 9.6 g/L, a thin film with thickness 3-4 μm was formed on the surface of the activated carbon. EC coating did not change the pore structure of activated carbon, but it would affect the wet ability of activated carbon surface, the water contact angle of coated activated carbon was 89.76°, which of the raw activated carbon was 15.41°, and it meant the hydrophobic performance was significantly improved. The surface of the activated carbon products prepared by this method was smooth, no dust, and the shape kept well.
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    Extractives of Organics from Eucalyptus APMP Effluents and Its Inhibition Effect on Growth of Microcystis aeruginosa
    CHENG Fujiang, LIU Tingzhi, LI Xiangxiang, QI Hui, ZHONG Liming
    2017, 37 (2):  57-64.  doi: 10.3969/j.issn.0253-2417.2017.02.007
    Abstract ( 496 )   PDF (1381KB) ( 336 )   Save
    Eucalyptus APMP effluents were extractedby ethyl acetate (EA) and methyl tertiary butyl ether (MTBE) and the extractives were anaylyzes by GC-MS. The results showed that the yield of EA extractive was 204 mg/L with 44 kinds of organic compounds, and the yield of MTBE extractive was 132 mg/L with 49 kinds of organic compounds. The extractives were composed by acids, alcohols and esters, in which acids were the main compounds accounting for about 76% (extracted by EA) and 80% (extracted by MTBE), respectively. Inhibition effect of EA extractives on the growth of Microcystis aeruginosa was investigated. The results showed that the extractives from APMP effluents inhibited the growth of M. aeruginosa with different effect in different concentrations. The inhibition effect was not remarkable at low extractive concentrations, and the inhibition effect was significant when the concentrations were over 50 and 100 mg/L, with the inhibition rates of 24.8% and 77.2%, respectively. The inhibition effect would be further investigated through the absorbent under 446 nm.
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    Monosaccharide Compositions of Yunnan Bitter Cherry Tree Gum and Synthesis and Properties of Graft Copolymer
    WANG Dawei, ZHAO Ning, JI Mei, FENG Xiaofei, HU Lianrong
    2017, 37 (2):  65-71.  doi: 10.3969/j.issn.0253-2417.2017.02.008
    Abstract ( 668 )   PDF (2544KB) ( 314 )   Save
    The high-performance anion exchange chromatography (HPAEC) system was used to determine the monosaccharide compositions of Yunnan bitter cherry tree gum. Then, the hetero polysaccharide of tree gum was used as raw material to graft copolymerize with acrylamide and then the tree gum-acrylamide graft copolymer product (TG-AM) was prepared. The TG-AM was characterized by FT-IR and scanning electron microscope (SEM) analysis, and the adsorption properties of Cu2+ on TG-AM were investigated. The results indicated that the most abundant monosaccharide compositions of the tree gum hetero polysaccharide were D-galactose and L-arabinose, and the relative percents were 41.56% and 38.72%, respectively. The FT-IR analysis revealed that acrylamide had successfully grafted onto hetero polysaccharide molecules. The SEM images showed that the surface and inside of the graft copolymer had a lot of independent or conjoint micropores with the pores diameter of 2-10 μm. The adsorption of Cu2+ on TG-AM was affected by the solution pH with the optimal pH of 6-7, and agreed with the Langmuir isothermal model with the maximum theoretical adsorption quantity (Qm) of 27.93 mg/g at 20 ℃.
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    Chemical Constituents from Tripterygium wilfordii Hook. f. and Their Thermal Stability
    LIU Jianqun, WU Qiushan, YU Zhaofen
    2017, 37 (2):  72-78.  doi: 10.3969/j.issn.0253-2417.2017.02.009
    Abstract ( 636 )   PDF (1250KB) ( 514 )   Save
    Seven compounds were isolated from the radix of Tripterygium wilfordii Hook. f.. Their structures were identified as β-sitosterol(1), syringaldehyde(2), tripdiolide(3), β-hydroxypropiovanillone(4), 5, 5'-dimethoxylariciresinol(5), neociwujiaphenol(6) and wilfordoside A(7). Compounds 2, 4, 5 and 6 were isolated from genus of T. wilfordii for the first time. Thermal decomposing curves of compounds 3, 6, wilforlide A and demethylzeylasteral were obtained in the nitrogen atmosphere by TG-DTG and DTA techniques. The results indicated that the four tested compounds should be stable under 200 ℃. This study could lay a foundation for the quality standard and roasting mechanism of T. wilfordii.
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    Synthesis and Antibacterial Activity of Bis-alkanoyl-amines Heterocyclic Derivatives of cis-1,8-p-Menthane Diamine
    ZHU Shouji, YANG Xuebing, XU Shichao, ZHAO Zhendong, JIANG Jianxin
    2017, 37 (2):  79-84.  doi: 10.3969/j.issn.0253-2417.2017.02.010
    Abstract ( 545 )   PDF (1215KB) ( 342 )   Save
    Using dichloroacetonitrile as solvent, Eight bis-alkanoyl-amines heterocyclic derivatives B1-B8 were synthesized through nucleophilic addition-elimination reaction of carboxylic acid chloride containing heterocycle and cis-1, 8-p-menthane diamine. And the yields of derivatives were 53%-100%. The structures of the products were characterized by FT-IR, ESI+-MS, 1H NMR and 13C NMR. The antibacterial activities were determined, and the results showed that some products had excellent antibacterial activities against Staphylococcus aureus and Candida albicans. The minimum inhibitory concentration (MIC) of compound B8 against S. aureus and C. albicans were both 56.25 mg/L.
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    Biomimetic Synthesis of CMC@PANI and Its High Efficient Adsorption of Dyes in Aqueous
    ZHANG Qing, SONG Bingqing, MENG Lingyi, YAN Mei, XIE Huifang, KONG Jinming
    2017, 37 (2):  85-92.  doi: 10.3969/j.issn.0253-2417.2017.02.011
    Abstract ( 660 )   PDF (1750KB) ( 358 )   Save
    Cellulose-based polyaniline(CMC@PANI) absorbent was synthesized biomimetically by using sodium carboxymethyl cellulose (CMC-Na) as the raw material. And aniline was polymerized from CMC-Na in the presence of hemin used as the catalyst. The main factors in preparation were optimized based on the yield of CMC@PANI and its capacity of the removal of methyl orange (MO) in aqueous. And the preparation conditions were chosen as pH value of 4, CMC-Na mass concentration of 2.5 g/L, mass ratio of aniline to CMC-Na of 1.8, hemin dosage of 0.1 g/L, H2O2 dosage of 0.07 mol/L, HCl dosage in acid doping of 0.9 mol/L and reaction temperature of 25 ℃. The yield of as-prepared CMC@PANI was about 0.7 g/g aniline. The results that obtained from SEM, BET, BJH and FT-IR characterization, indicated that the mutual load of CMC-Na and PANI was successful and the adsorbent was particle with diameter of 0.5-10 μm and rough surface. The BET specific surface area was 19.96 m2/g. For 20 mg/L solution of anionic dye, MO, CMC@PANI could absorb over 98% within 30 min and the adsorption capacity could be reached 294.12 mg/g. At the same time, CMC@PANI showed nice adsorption for cationic dye Rhodamine B (RhB) and the removal ratio could be reached 89.8% in 20 mg/L RhB aqueous within 180min. The CMC@PANI that synthesized through the green biomimetic process catalyzed by hemin was an ideal alternative adsorbent with high adsorption capacity for dyes in aqueous.
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    Optimization of Ultrasonic Assisted Extraction of Geniposide from Gardenia Fruits by Using Ethanol/Salt Aqueous Two-phase System with Response Surface Method
    LIU Leilei, ZHAO Shuai, WANG Huan, PENG Sheng, GUO Jie
    2017, 37 (2):  93-100.  doi: 10.3969/j.issn.0253-2417.2017.02.012
    Abstract ( 591 )   PDF (2065KB) ( 364 )   Save
    An ultrasonic-assisted technology combined with ethanol/NaH2PO4 aqueous two-phase system (UAATPE) was developed for the extraction and purification of geniposide (GP) from gardenia fruits. Based on the results of single factor experiments, the Box-Behnken Design combined with response surface methodology was applied to optimize the operating parameters. Furthermore, the comparisons with ultrasonic solvent extraction, heat reflux extraction, and ultrasonic-assisted aqueous two-phase extraction were also assessed. GP was mainly extracted into the top ethanol-rich phase. And the optimal experimental conditions were 10.0 g ethanol/salt aqueous two-phase system, NaH2PO4 mass fraction 15.00%, ethanol 4 mL(ethanol mass fraction 31.56%), extraction temperature 30 ℃, extraction time 30 min and sample loading 0.03 g. And the maximum yield of GP in top phase was 51.77 mg/g. The comparison results indicated that ultrasonic-assisted aqueous two-phase extraction was more efficient and environmentally friendly than ultrasonic solvent extraction and heat reflux extraction, for the technique had the shorter extraction time, the lower extraction temperature and the higher extraction efficiency.
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    Preparation and Performance of Luminous Wood with Modified Aromatic Diacyl Rare-earth Complexes
    WANG Fangfang, XU Qingjing, WANG Di, LI Jian
    2017, 37 (2):  101-107.  doi: 10.3969/j.issn.0253-2417.2017.02.013
    Abstract ( 605 )   PDF (3392KB) ( 300 )   Save
    In order to improve the utilization of wood and achieve the functionalization of wood surface, the luminous woods were prepared. Firstly, the modified ligands were synthesized by the reaction between 3-aminopropyltriethoxysilane and phthaloyl dichloride. Then the modified ligands and the luminous terbium complexes that prepared with the terbium nitrate hexahydrate were concatenated on the surface of poplar veneer via hydrolysis condensation reaction to form the luminous wood. The elementary composition and micro morphology of wood surface were analyzed by FT-IR, EDXA and SEM. According to fluorescence spectrum, the mechanism of reaction was speculated. The results showed that the modified rare-earth complexes were combined on the surface of wood with the formation of hydrogen bond and the dehydration condensation. The compact membrane of the modified terbium complexes on the surface of wood endowed the wood with the fluorescence property. The fluorescence intensity of the modified wood promoted to the maximum when the reaction was carried out for 8 hours and the temperature of reaction rose to 60 ℃. But the fluorescence intensity would descend when the temperature of reaction was more than 60 ℃.
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    Influence of Addition of CMC Before Refining on the Yield Stress of Refined Poplar APMP Pulp Fiber Suspension
    CHEN Shurun, SHA Jiulong, HE Jing, WANG Chen, SHEN Jun, ZHANG Hui
    2017, 37 (2):  108-114.  doi: 10.3969/j.issn.0253-2417.2017.02.014
    Abstract ( 704 )   PDF (1261KB) ( 296 )   Save
    In order to study the influence of the addition of CMC-Na before refining on the yield stress of refined poplar APMP pulp fiber suspension, a certain amounts of CMC-Na were added to the APMP and the APMP were pretreated for 10 min before individually refining by Valley beater and PFI mill. The influences of the refining and CMC-Na pretreatment on the beating degree and yield stress (τy) of poplar APMP fiber suspension were analyzed respectively. It was found that the yield stress of the poplar APMP fiber suspensionwith a similar beating degree increased rapidly with the rising of CMC-Na concentration, and the yield stress was accordance with the concentration (Cm)via a power relationship of τy=aCmb(the values of a and b were closely related with the beating ways and beating degree). After refining under a low concentration by free beating device(e.g. Valley beater), the yield stress of the poplar APMP fibers suspension decreased with the increased beating degree, while reverse results were observed under the medium concentration refining by shiny beating device (e.g. PFI mill). After 2% CMC-Na (based on the dry pulp weight) was added the pulp and pretreated for 10 min, the beating degree of poplar APMP was increased to 48°SR from 45°SR with valley beater refining and ascended to 50°SR from 40°SR with PFI refining. Meanwhile, the yield stresses of the poplar APMP fibers suspension were reached to the minimum value with the same beating conditions, the minimum values of the yield stresses were 16.4 Pa and 22.8 Pa (PFS mass fraction was 3%), respectively.
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    Preparation and Properties of Complex Auto-catalytic Polyurethane Foams from Cardanol and Lignin
    HUO Shuping, CHEN Jian, WU Guomin, LIU Guifeng, JIN Can, KONG Zhenwu
    2017, 37 (2):  115-120.  doi: 10.3969/j.issn.0253-2417.2017.02.015
    Abstract ( 579 )   PDF (3127KB) ( 367 )   Save
    Novel auto-catalytic cardanol-based polyols (CPO) with tert-butyl on the main chain were synthesized from cardanol and used to prepare the cardanol-based polyurethane foam(CPUF) with polyaryl polymethylene isocyanate (PAPI) under catalyst-free conditions. Subsequently, CPUFs were modified by lignin to prepare lignin and cardanol based polyurethane foam(LCPUF). The influences of lignin on the structure and performance of the polyurethane foam were further investigated. The results showed that lignin significantly improved the apparent density and mechanical properties of the CPUF. When the dosage of lignin was 20%, the cell diameter of the synthesized foam LCPUF slightly decreased and had the maximal apparent density and compressive strength of 81.48 kg/m3 and 0.44 MPa. Thermogravimetric (TG) analysis demonstrated that lignin had no significant effect on the thermostability of polyurethane foam.
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    Chemical Constituents and Bioactivities of Xanthones from Polygala sibirica L. var. megalopha Fr.
    ZHOU Lingyun, YU Xiaohong, GENG Yuanyuan, HUA Yan
    2017, 37 (2):  121-128.  doi: 10.3969/j.issn.0253-2417.2017.02.016
    Abstract ( 915 )   PDF (1350KB) ( 457 )   Save
    Eighteen compounds were isolated by ethanol extraction, silica gel column chromatography, Sephadex LH-20 column chromatography, MCI-gel column chromatography and semi-preparative HPLC from the dried roots of Polygala sibirica L. var. megalopha Fr. Their structures were identified as 1, 7-dihydroxy xanthone (1), 3, 6-dihydroxy-1, 2, 7, 8-tetramethoxy xanthone (2), 1, 7-dihydroxy-5, 6- dimethoxy xanthone (3), 1, 5-dihydroxy-6, 7-dimethoxy xanthone (4), 6-hydroxy-l, 7-dimethoxy xanthone (5), 7-hydroxy-1-methoxy xanthone (6), 3, 8-dihydroxy- 1, 2, 4-trimethoxy xanthone (7), 6, 8-dihydroxy-1, 2, 3-trimethoxy xanthone (8), 1, 3, 6-trihydroxy-2, 7, 8-trimethoxy- xanthone (9), 3-hydroxy-1, 2, 8-trimethoxy xanthone (10), 1, 3, 7-trihydroxy xanthone (11), 1, 6-dihydroxy-2, 3-methylene-dioxy-7, 8-dimethoxy xanthone (12), 1, 7-dihydroxy-2, 3-dimethoxy xanthone (13), 1, 6-dihydroxy-5, 7-dimethoxy xanthone (14), 3, 7-dihydroxy-1, 2-dimethoxy xanthone (15), 3, 7- dihydroxy- 1, 2, 8-trimethoxy xanthone (16), 1, 2, 3, 7-tetramethoxy xanthone (17), 1, 6-dihydroxy-3, 5, 7, 8-tetramethoxy xanthone (18) by ESI-MS, 1H NMR, 13C NMR. All compounds except 13 were isolated from this plant for the first time. The antioxidant and antimicrobial activities of compound 1-7 were studied. And the results showed that the compound 4(IC50=12 mg/L) and compound 1(IC50=13 mg/L) showed good ABTS scavenging activity and compound 3(MIC=217 μmol/L) had certain inhibitory activity against Staphylococcus aureus.
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    Synthesis and Properties of Polymerized Terpene Maleic Anhydride Polyethelene Glycol Ester Polymer Surfactants
    YAN Xinyan, RAO Xiaoping, SONG Zhanqian, SHANG Shibin
    2017, 37 (2):  129-134.  doi: 10.3969/j.issn.0253-2417.2017.02.017
    Abstract ( 647 )   PDF (1373KB) ( 413 )   Save
    The terpene maleic anhydride was synthesized by catalytic isomerization and D-A addition from dipentene. And then, the polymerized terpene maleic anhydride polyethelene glycol ester polymer surfactants(Ⅰ-Ⅴ) were synthesized by the reactions of the terpene maleic anhydride and different polyethelene glycol(400, 600, 1 000, 2 000, 4 000). The structures of surfactants were characterized by IR and GPC, respectively. The critical micelle concentration (CMC), surface tension(γCMC), emulsifying property(EP), foaming property(FP) and hydrophile-lipophile balance(HLB) value were evaluated. The results showed that CMC values of productsⅠ-Ⅴ were 6.5, 2.1, 2.7, 3.3 and 5.5g/L, respectively, and the corresponding γCMC values were 42.0, 38.2, 39.8, 42.1, 33.7mN/m. With the increment of molecular weight of polyethylene glycol, the CMC and γCMC decreased and then increased, while the emulsifying property decreased and hydrophile-lipophile balance value increased gradually.
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    Preparation and Antioxidant Activity of Proanthocyanidins Dimers from Acacia mearnsii De Willd
    ZHOU Meng, LIU Gongjun, HE Lingxiao, WANG Fei
    2017, 37 (2):  135-140.  doi: 10.3969/j.issn.0253-2417.2017.02.018
    Abstract ( 704 )   PDF (1281KB) ( 468 )   Save
    Proanthocyanidins were ultrasonic extraction was adopted to extract proanthocyanidins (PC) from Acacia mearnsii De Willd bark powders. Oligomeric proanthocyanidins (OPC) (ethyl acetate extract) were obtained by solvent extraction. Sephadex LH-20 and fast protein liquid chromatography (FPLC) were applied to the separation and purification of PC dimers. The compound was characterized by HPLC-MS. The results indicated that the yield of PC was about 50.21%. The extract was separated by Sephadex LH-20 to obtain the sample Ⅰ with the purity of 60% and the yield of about 5%. The sample Ⅰ was further separated by FPLC with water-methanol as mobile phase, and then the dimer were obtained with the purity of 91.72% and the yield of about 13%. The result of HPLC-MS analysis showed that the relative molecular weight of dimer was 578 and the structure was supposed to be procyandin-(4, 6)-prorobinetinidin. Meanwhile, the results of radical scavenging ability assay indicated that the antioxidant activity of PC dimer was higher than that of catechin and epigallocatechin gallate (EGCG). The scavenging rate of dimer (60 μmol/L) was ≥80% which is higher than that of EGCG (68%) and catechin (50%).
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    Influence of CaO on Hydrogen-rich Gas Production by Steam Gasification of Sawdust
    SUN Ning, YING Hao, XU Wei, SUN Yunjuan, XU Yu, JIA Shuang
    2017, 37 (2):  141-147.  doi: 10.3969/j.issn.0253-2417.2017.02.019
    Abstract ( 565 )   PDF (1206KB) ( 415 )   Save
    The steam gasification experiments of sawdust for production of hydrogen-rich gas were carried out in the high-temperature fixed bed reactor using steam as gasification agent and CaO as catalyst. The effects of the molar ratio of CaO and carbon element of sawdust (n(Ca)/n(C)), temperature and steam flow rate on gasification characteristics were investigated. The results showed that with the increament of n(Ca)/n(C) from 0 to 1.0, the volume fraction of hydrogen increased from 45.58% to 58.62%, and the dry gas yield increased from 1.04 m3/kg to 1.38 m3/kg; the hydrogen content and dry gas yield only showed a modest increase as the n(Ca)/n(C) increased to 1.5. With increasing the gasification temperature from 700 to 750 ℃, the volume fraction of hydrogen significantly increased from 51.78% to 58.62%, and that of carbon dioxide decreased from 19.89% to 12.60%; as the temperature kept rising, the hydrogen content and the low heating value decreased. By increasing the steam flow rate from 0.1 g/(min·g) to 0.34 g/(min·g), the volume fraction of hydrogen increased from 58.62% to 62.55%. However, the hydrogen content, the hydrogen yield and the low heating value decreased when the steam flow rate was higher than 0.34 g/(min·g). The optimized conditions with CaO as catalyst were n(Ca)/n(C)=1, the gasification temperature 750 ℃ and the steam flow rate 0.34 g/(min·g). Under these conditions, the volume fraction of hydrogen was 62.55%, the hydrogen yield was 85.08 g/kg, the low heating value was 11.41 MJ/m3.
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    Beating Characteristics of Rice Straw Alkali-oxygen Pulp
    SHAO Sicheng, WU Chuzhu, CHEN Keli
    2017, 37 (2):  148-154.  doi: 10.3969/j.issn.0253-2417.2017.02.020
    Abstract ( 427 )   PDF (3592KB) ( 376 )   Save
    The effects of different beating levels on drainability and fiber morphologies of rice straw alkali-oxygen pulps were investigated by PFI mill, and the strength performances of hand-sheets prepared by this pulp were also analyzed. The results showed that the changes of the beating degree and water-retention value were similar in the initial stage and later stage of beating. In the initial stage, the beating degree was rapidly increased to 55-60°SR. Meanwhile, the water-retention value was increased to about 45°SR. When the beating degree was increased to 75°SR from 35°SR, the fiber length changed little with the maximum decrease rate of the pulp without non-fibrous cells (Pnof) of 7.3% and that of the pulp with non-fibrous cells (Pf) of 4%, and more fibrillated fibers were observed during the beating process. The non-fibrous cells played negative roles on both the improvement of pulp drainabilityand the strength properties. The best burst index and tensile index were obtained as the beating degree was 65°SR. In addition, an ever-increasing tendency was found in terms of burst index and tensile index of paper sheets of Pnof with higher beating degree(above 65°SR).
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