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    25 October 2017, Volume 37 Issue 5 Previous Issue    Next Issue
    Research Progress of Carbon Precursors of Biomass Based Carbon Aerogels
    XU Juan, CHEN Minzhi, ZHOU Xiaoyan
    2017, 37 (5):  1-8.  doi: 10.3969/j.issn.0253-2417.2017.05.001
    Abstract ( 596 )   PDF (5413KB) ( 516 )   Save
    The research progress of preparation of biomass based carbon aerogels based on carbohydrates, phenol-containing biological small molecules and other biomass as carbon precursors was reviewed.The emphasis was put on the preparation and performance of the cellulose, chitosan, lignin and tannin based carbon aerogels. The application situation in catalyst carrier, supercapacitor, adsorbent, fire-resistant materials and other fields was also introduced. The future research on biomass based carbon aerogels was also prospected.
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    Review on Research Progress of Biomass Carbon-based Magnetic Solid Acid Catalysts
    LI Xiangyu, LI Xueqin, SHI Junyou, LEI Tingzhou
    2017, 37 (5):  9-18.  doi: 10.3969/j.issn.0253-2417.2017.05.002
    Abstract ( 574 )   PDF (1314KB) ( 337 )   Save
    From preparation technology of biomass carbon-based precursor and magnetic Fe3O4 material, this paper reviewed the preparation method of carbon-based magnetic solid acid catalyst at home and abroad. The synthesis methods(adsorption function, load effect, embedding technology and grafting technology) and development prospect of biomass carbon-based magnetic solid acid catalyst were summarized. We focus on introduces using the co-precipitation method and the hydrothermal method to prepare magnetic Fe3O4 material synthesized into the production process of biomass carbon-based solid acid catalyst magnetic further, and described to use the high temperature decomposition method and mic-roemulsion method to prepare magnetic Fe3O4 materials synthesized into the current situation of biomass carbon-based solid acid catalyst magnetic. The progress of the application of biomass carbon-based magnetic solid acid catalyst to hydrolysis of lignocellulose was described in detail, and the application of the catalyst in esterification reaction and condensation reaction was also introduced. The problems of biomass carbon-based magnetic solid acid catalyst industry were put forward at present, and clearly pointed out the next step of the research work. The future research priorities were forecasted, which provided the basis for the future development and industrialization of biomass carbon-based magnetic solid acid catalyst industry.
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    Study of Pyrolysis Behavior and Reaction Mechanism of Tea Polyphenols
    YAO Fengqi, TAO Junjun, WANG Haihui, HU Guoqing, CHEN Shuai, TAHIR Mudassir Hussian
    2017, 37 (5):  19-27.  doi: 10.3969/j.issn.0253-2417.2017.05.003
    Abstract ( 846 )   PDF (1396KB) ( 372 )   Save
    The mass change and gaseous products of pyrolysis of black tea polyphenols (RM) and green tea polyphenols(YS) were tested by using simultaneous thermal analyzer(TGA/DSC), on-line Fourier transform infrared spectrometer(FT-IR)in conjunction with mass spectroscopic(MS)instrument. The chemical compositions of solid residue at different heating temperatures were also monitored, and the pyrolysis mechanism of tea polyphenols was analysed. It was observed that tea polyphenols could be classified as aromatic compounds with rich side chains, mainly consisting of C, H and O elements as well as tiny N element. The weight loss of pyrolysis below 200℃ was essentially the result of evaporation of free water and bound water. Pyrolysis began at about 200℃, which could be attributed to the stability of the side chains in the chemical structure of the samples. At the temperatures between 200 and 350℃, tea polyphenols dramatically decompased by breaking side chains in their structure and the recombination of free radicals, leading to the generation of enormous gaseous products such as H2O and CO2, etc. At the temperatures between 350 and 800℃, the pyrolysis reactions became sustainably slow, highlighting the generation and accumulation of more stable chemical structure containing polycyclic aromatic hydrocarbons in the pyrolysed residues. The established understanding provides the guidelines for effective utilization of tea polyphenols and the development of new application prospects in fire prevention and protection field.
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    Research on Application of PEG400 with Epsilon-caprolactone in Waterlogged Planted Scotch Pine Wood for Dehydration and Reinforcement
    LI Ren, ZHANG Zhiguo, LAN Xinyuan, PU Junwen
    2017, 37 (5):  28-38.  doi: 10.3969/j.issn.0253-2417.2017.05.004
    Abstract ( 469 )   PDF (3736KB) ( 242 )   Save
    The 50% PEG400 aqueous and a hybrid solution of PEG400 (50%) and ε-caprolactone(ε-CL) (50%) were separately used to investigate the dehydration and reinforcement of waterlogged scotch pine wood simulating the archaeological waterlogged wood. The dehydration process included catalyst pre-treatment, impregnation under room temperature and 50℃ hot dry aggregate. And the weight and dimensional changes of the different stages were analyzed, which was applied to evaluated the effects of process on the dimensional stability, weight gain percentage and reversibility of wood. And then the treated wood was characterized by FT-IR, TGA-DTA and SEM. The results showed that the PEG400 and the hybrid solution of PEG400 and ε-CL both had good dehydration and reinforcement effect on waterlogged scotch pine wood with good reversibility. The weight gain percentage of the wood samples treated by the hybrid solution of PEG400 and ε-CL increased obviously and the value of was 124.1%. After the dehydration and reinforcement, the shrinkages of tangential direction, radial direction and volume were 0.01%、0 and 0.01%,respectively, indicating of the dimensional stability. The ring opening polymerization (ROP) of CL was carried out inside the wood structures to form polycaprolactone(PCL). The wood cell walls were coated and filled by PCL and PEG400, resulting in the increased thickness of the cell wall. However, the thermostability of wood filled with PLC and PEG400 was turned to decrease. PLC would firstly degrade at 150℃ to protect the cell wall of wood.
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    Preparation and Properties of Waterborne EP/PU Composites Modified with Polysiloxane
    LIU Di, WU Guomin, LIU Guifeng, CHEN Jian, KONG Zhenwu
    2017, 37 (5):  39-44.  doi: 10.3969/j.issn.0253-2417.2017.05.005
    Abstract ( 433 )   PDF (3184KB) ( 272 )   Save
    Waterborne epoxy resin(EP)/polyurethane(PU) composite polymers were prepared from anionic polysiloxane modifying terpene-base epoxy resin based polyol dispersions(ASTP) and hydrophilically modifying hexamethylene diisocyanate(D80). The silicon concentration on the uppermost surfaces of the composite polymers was higher than that at the polymer-substrate interfaces. This result implied that the hydroxypropyl terminated polydimethy-siloxane(HTPDMS) segments enriched at the polymer-air interface and formed the hydrophobic film surface. When the amount of the HTPDMS reached 10% by weight based on the weight of ASTP, siloxane content on the uppermost surfaces was saturated and the contact angle increased to about 95°. Due to the good thermal stability of siloxane segment, the introdution of HTPDMS to the polyurethane improved the thermal stability of composite. However, due to the low glass transition temperature of siloxane segment, the attachment of HTPDMS to the polyurethane decreased the glass transition temperature of the composite, and the formation of microphase separation between HTPDMS segment and the resin matrix also led to a decrease of glass transition temperatures of the composite polymers.
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    Detoxification of Lignocellulosic Prehydrolyzate by Hydrophobic Ionic Liquid[C4mim] [PF6]
    CHENG Yichao, YANG Jinlong, ZHU Junjun, XU Yong, YONG Qiang, YU Shiyuan
    2017, 37 (5):  45-52.  doi: 10.3969/j.issn.0253-2417.2017.05.006
    Abstract ( 502 )   PDF (1184KB) ( 257 )   Save
    In this study, a new green detoxification technology named-ionic liquid extraction was used for detoxification of the prehydrolyzate obtained from the washed acid-catalyzed steam-exploded corn stover in order to improve the ethanol fermentability of yeast. 1-butyl-3-methyl imidazole hexafluorophosphate([C4mim] [PF6]) was selected as the extraction agent and its extraction conditions had been optimized. The optimal extraction conditions were as follows:the ratio of aqueous to organic phase 1:2, 35℃, 250 r/min, and 60 min. Under these conditions, the removal rate of formic acid, acetic acid, levulinic acid, 5-hydroxymethylfurfural, furfural and total phenols in the hydrolysate reached 24.72%, 21.84%, 47.99%, 82.76%, 100% and 39.7% respectively, the extraction efficiencies of the main inhibitors were high and the loss of sugars was negligible. The results of detoxification mechanism indicated that the extraction efficiency of the inhibitors decreased with the increase of alkyl chain length on the cation of ionic liquid[Cnmim] [PF6] (n=4, 6, 8); the more hydrophobic the inhibitors were, the stronger the hydrogen bonding with ionic liquid was; the lower the pH value was, the better the extraction efficiency of inhibitors was.The removal rate of acetic acid, 5-hydroxymethylfurfural and 4-hydroxybenzaldehyde in[C4mim] [PF6] did not change with the initial mass concentration of inhibitors.
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    Effects of Different Pretreatment Methods on Chemical Composition and Enzymatic Hydrolysis of Wheat Straw
    ZHOU Jing, SHEN Kuizhong, FANG Guigan, LIANG Long, TIAN Qingwen, LI Man
    2017, 37 (5):  53-60.  doi: 10.3969/j.issn.0253-2417.2017.05.007
    Abstract ( 478 )   PDF (1103KB) ( 302 )   Save
    Wheat Straw was pretreated by four kinds of pretreatment methods, namely, liquid hot water(LHW), soaking aqueous ammonia(SAA),sodium hydroxide(NaOH) and sodium hydroxide combined with ethanol(NaOH-ET). The effects of pretreatments on chemical composition and enzymatic hydrolysis were investigated. The results showed that LHW pretreatment resulted in the highest level of polypentose reduction. The removal rates of xylan and araban were 73.11% and 83.10% respectively at 188℃ for 40 min, but the delignification rate was only 21.32%. NaOH had a good capability in the removal of lignin and ash. The removal rates of lignin and ash were 72.00% and 75.93% respectively by 1% NaOH at 140℃ for 3 h. Because of the good solubility of lignin in the ethanol, the removal rate of the lignin pretreated by the combination of NaOH with 50% ethanol pretreatment was up to 84.11%. XRD results showed that the crystallization index of four pretreated wheat straw were greater than that of the raw material because of the removal of lignin and hemicellulose; the crystallization index of pretreated samples increased from 28.80% to 31.23%-33.61%. As lignin and hemicellulose were partly removed by pretreatment, the accessibility of cellulose and enzyme inereased. Under the conditions of cellulose enzyme 30 FPIU/g(of cellulose) and β-glucose glycosides enzyme 30 IU/g, enzymatic hydrolysis temperature 50℃, and reaction time 72 h, conversion ratio of total sugar increased obviously. Especially, total sugar conversion rate of NaOH-ET treated wheat straw reached 90.05%, which improved 7.5 times compared with that of raw material.
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    Preparation and Application of Carbonized Sugarcane Bagasse Supported Ruthenium Catalysts
    LI Zengyong, LIU Ying, WU Shubin
    2017, 37 (5):  61-67.  doi: 10.3969/j.issn.0253-2417.2017.05.008
    Abstract ( 538 )   PDF (3558KB) ( 265 )   Save
    Carbon supported ruthenium catalysts(Ru/CSB) were prepared with sugarcane bagasse as raw material by carbonization and impregnation method, which were used in the conversion of glucose to sorbitol. The structures of catalysts were characterized by XRD, SEM and TEM. The effects of reaction conditions on the performance and reusability of catalysts were investigated. Characterization results showed that Ru particles were well dispersed throughout the carbonized sugarcane bagasse(CSB). The glucose conversion of 99.41%, sorbitol yield of 98.13% and sorbitol selectivity of 98.71% could be obtained under the conditions of carbonization temperature of sugarcane bagasse 450℃, catalyst dosage(the mass percent of reaction system) 1%, H2 pressure 3 MPa, reaction temperature 120℃, reaction time 2 h. The reusabilities of catalysts were excellent. After using for five times, the dispersity of Ru declined, and the sorbitol yield slightly decreased to 94.80%.
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    Synthesis and Antifungal Activity of Verbenone-based Oxime Sulfonate Compounds
    ZHANG Rui, DUAN Wengui, LIN Guishan, CHEN Zhicong, HE Ran, LEI Fuhou
    2017, 37 (5):  68-78.  doi: 10.3969/j.issn.0253-2417.2017.05.009
    Abstract ( 535 )   PDF (1012KB) ( 274 )   Save
    Verbenone was prepared by the selective oxidation of α-pinene at first. Then, twenty-two novel verbenone-based oxime sulfonate compounds(4a-4v)were synthesized by the oximation and O-sulfonylation reaction of the carbonyl group in verbenone. The target compounds were analyzed and characterized by FT-IR,1H NMR,13C NMR, and ESI-MS. Antifungal activity test showed that, at the mass concentration of 50 mg/L, the target compounds exhibited certain inhibition activity against the eight tested fungi. Inhibition rate of verbenone-based n-butyl oxime sulfonate(4u,R=(CH2)3CH3) against Rhizoctonia solani was 83.2%,inhibition rate of verbenone-based 2,4-difluorophenyl oxime sulfonate(4d,R=2,4-FPh) against Fusarium graminearum was 89.6% (better than the positive control chlorothalonil),and inhibition rate of verbenone-based p-nitrophenyl oxime sulfonate(4n,R=p-NO2Ph)and 4u(R=(CH2)3CH3) against Cercospora arachidicola was 72.5%。
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    Interactions Between Drugs and Bovine Serum Albumin in the Presence of Metal Ions by Spectral Methods
    CAO Hongkun, JIN Xiaowei, ZHANG Enfeng, YU Hui, SHI Jingnan, BIAN Hedong
    2017, 37 (5):  79-87.  doi: 10.3969/j.issn.0253-2417.2017.05.010
    Abstract ( 459 )   PDF (1796KB) ( 208 )   Save
    The mechanisms of the interaction between xanthotoxol(XAL) and bovine serum albumin(BSA) were investigated by fluorescence and circular dichroism(CD) spectrometry, as well as the effects of common metal ions(Fe3+, Cu2+, Zn2+, Cr3+) on the XAL-BSA binding. The quenching constants (kq) calculated by Stern-Volmer equation under 290,297 and 304 K were 6.316×1013,4.402×1013 and 3.554×1013 L/(mol·s), respectively. The result indicated that XAL could quench the intrinsic fluorescence of BSA strongly, and the quenching mechanism was static quenching process. The binding constant (K) of XAL to BSA at 297 K was 3.47×105 L/mol. The addition of metal ions changed the binding constant. The distance between the tryptophan residues in BSA and XAL was 5.29 nm by using Föster's equation, and it decreased after interaction with metal ions. The CD spectrometry demonstrated that the secondary structure of BSA changed after its interaction with XAL, and α-helix content decreased; the secondary structure of BSA was also changed by addition of metal ions and α-helix content further reduced.
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    Simulation of Continuous Distillation of Industrial Dipentene
    YE Guoliang
    2017, 37 (5):  88-92.  doi: 10.3969/j.issn.0253-2417.2017.05.011
    Abstract ( 394 )   PDF (918KB) ( 288 )   Save
    Continuous rectification of industrial dipentene in vacuum was simulated by Aspen plus. Effects of feed stage,reflux ratio,distillate to feed ratio and operation pressure on limonene purity and reboiler energy consumption were investigated and the optimum conditions for distillation were obtained as follows:the theoretical plate number 65, feed stage at thirtieth, reflux ratio 4:1, distillate to feed ratio 0.7, top stage pressure 6 kPa, and the clumn pressure drop 12 kPa. Limonene with the purity of 71.5% and the distillate to feed ratio of 70% was obtained in production experiment, which is similar to the simulation results.
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    Gas Chromatographic Methodology and Its Application to Analyze Intermediate Oxalates of Synthetic Borneol
    YUAN Xiaomin, ZHANG Pinghui, TU Yongyuan, WANG Jing, LI Dongmei, ZHAO Zhendong
    2017, 37 (5):  93-100.  doi: 10.3969/j.issn.0253-2417.2017.05.012
    Abstract ( 573 )   PDF (1117KB) ( 250 )   Save
    While the synthesized difenchyl oxalate(DFO), dibornyl oxalate(DBO), diisobornyl oxalate(DIBO), bornyl isobornyl oxalate(BIBO), bornyl fenchyl oxalate(BFO), and isobornyl fenchyl oxalate(IBFO) were used as reference substances, the qualitative and quantitative analytic methodologies were studied and established for the main intermediates of borneol by gas chromatography(GC), and then an external reference calibration curve method was also established to determine quantitatively difenchyl, dibornyl oxalates or the similar oxalate intermediates. As the results, it was shown that, difenchyl and dibornyl oxalates as reference substances must be dissolved in an inert solvent such as hexane, and the separation performance of the intermediate oxalates may be influenced obviously by the programmed temperature conditions. By means of reference substance addition and chromatogram comparison methods, the intermediate oxalates of synthetic borneol were separated and identified or predicted to be as difenchyl oxalate(DFO), bornyl fenchyl oxalate(BFO), isobornyl fenchyl oxalate(IBFO), dibornyl oxalate(DBO), bornyl isobornyl oxalate(BIBO), diisobornyl oxalate(DIBO) with the retention time of 46.46,49.92,50.75,53.68,54.42 and 54.89 min etc. The calibration curves for fenchyl and dibornyl oxalates were plotted linearly in the ranges of 1-25 g/L and 5-25 g/L as y=93 622x-48 633(r1=0.998 9) and y=99 480x-55 787(r2=0.999 2), by which their mean recoveries were determined as 103.2% and 106.9% with the relative standard deviations(RSDs) 1.72% and 0.76%, respectively. It is considered that the established qualitative GC method and quantitative mathematic equations would supply the demand to determine either qualitative components or quantitative contents of intermediate oxalates in research fields or industry production process. The common peak area normalization method would also be selected for the content determination for convenience.
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    Rapid and Nondestructive Identification of Dendrobium huoshanense Fengdou and Dendrobium henanense Fengdou by Portable NIR Spectrometer
    JIANG Mingzhu,HAN Bangxing, YAN Hui, JIA Junqiang, TU Jie, MA Yongkun
    2017, 37 (5):  101-106.  doi: 10.3969/j.issn.0253-2417.2017.05.013
    Abstract ( 376 )   PDF (1476KB) ( 246 )   Save
    The near infrared spectra of 231 samples of Dendrobium huoshanense and Dendrobium henanense were measured by portable near infrared spectroscopy. Nine kinds of preprocessing methods, such as first derivative(1stD), standard normal variate(SNV), mean centering(MNCN), multiplicative signal correction(MSC),normalize(N) and their combination were used to pretreat original spectrometer. The model of identifying D. huoshanense and D. henanense were established with PLS-DA method. Different spectral preprocessing methods were compared with the accuracy of model. The models were also evaluated with the accuracy, sensitivity and specificity of PLS-DA model. The results showed that the 1stD+SNV+MNCN preprocessing method had the best effect, the accuracy of the model was the highest. When the latent variable was 12, the prediction accuracy of calibration set, cross validation set and prediction set were 100%, and 100% specificity and sensitivity rate of PLS-DA model were also obtained. The results indicted that PLS-DA analysis with Near-Infrared can provide a new method for rapid and non-invasive identification of D. huoshanense Fengdou and D. henanense Fengdou.
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    Application of Nano Carboxymethyl Starch in Micro Weight Coated Paper
    CHEN Qijie, DONG Xufang, ZHOU Liling, ZHENG Xueming, WANG Ping
    2017, 37 (5):  107-112.  doi: 10.3969/j.issn.0253-2417.2017.05.014
    Abstract ( 431 )   PDF (2806KB) ( 263 )   Save
    In this study, the nano carboxymethy starch(NCMS) was prepared by dual screw extrusion and was used as coating adhesive in micro weight coated paper(MWC). The results showed that the surface of NCMS particle was smooth and it had excellent film-forming and high film strength. The tensile strength of film can reach to 4.67 MPa,breaking elongation 26.9%. The negative charge density of NCMS is lower than that of common oxidized starch. For the paper coating formula of micro weight coated paper, when the dosage of NCMS used as the coating adhesive was 14%, the water retention properties of coating was increased evidently and the water retention value was 43.6 g/m2; the IGT printing surface strength of MWC was 0.89 m/s; the longitudinal and transverse tensile index was 47.8 and 21.7(N·m)/g separately; the ink absorption of MWC was 36.8% and 61% separately. Comparing with 20% common oxidized starch coating formulation,the water retention properties of coating was increased by 25.3%, coating viscosity was decreased by 12.4%, and the IGT printing surface strength and tensile index of MWC were improved in different degree.
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    Inhibitory Effects of Bamboo Leaves Flavonoids on Fatty Acid Synthase and Human Breast Cancer Cells
    LI Xiabing, JIN Zhaojun, XUN Hang, TANG Feng, MA Xiaofeng, YUE Yongde
    2017, 37 (5):  113-118.  doi: 10.3969/j.issn.0253-2417.2017.05.015
    Abstract ( 507 )   PDF (2139KB) ( 286 )   Save
    The inhibitory effects of bamboo leaves flavonoids (BLF) from the species of Pleioblastus amarus (Keng) keng, Indocalamus latifolius (Keng) McClure, Phyllostachys heterocycla (Carr.) Mitford Pubescens and P. glauca McClure on the fatty acid synthase (FAS) and human breast cancer cell MDA-MB-231 in vitro were studied. The inhibitory effects of bamboo leaves flavonoids on FAS were determined by UV spectrophotometry, and the inhibitory effects of MDA-MB-231 were detected by CCK-8 assay. Flow cytometry was used to detect the apoptosis of MDA-MB-231. The results showed that all four bamboo leaves flavonoids had significant inhibitory effects on FAS and MDA-MB-231 cells. The IC50 values of four flavonoids against FAS were 112.43, 153.29, 161.32 and 195.09 mg/L, respectively. The inhibition effects of flavonoids on MDA-MB-231 followed the dose-effect relationship. Further studies showed that the 70% and 95% ethanol fraction of bamboo leaves flavonoids exhibited the strongest cytotoxicity. The inhibition rates against MDA-MB-231 at the mass concentration of 100, 200, 400 mg/L of 95% ethanol fraction of P. amarus were 25%, 44% and 70%, and the apoptosis rates were 11.1%, 23.1% and 38.7%, respectively.
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    Properties of Cassava Dregs Fiber/PBS Composites Modified by Starch Ester
    YUE Xiaopeng, LIU Pengjie, LEI Dan
    2017, 37 (5):  119-125.  doi: 10.3969/j.issn.0253-2417.2017.05.016
    Abstract ( 503 )   PDF (3633KB) ( 236 )   Save
    Starch ester(SE) was prepared by using octanoyl chloride as esterification reagent. SE was further used as interfacial modifier in poly(butylene succinate)(PBS)/cassava dregs fiber composites. The contact angle of SE(synthesized by octanoyl chloride, n(-COCl)/n(-OH)=2:1; the degree of substitution(DS) 2.13) was determined to 87.9°, and the hydrophobicity of SE was enhanced as compared to the original starch. The bending, tensile and impact strengths of composites modified with 5% SE were 12.57 MPa, 67.53 MPa and 4.89 kJ/m2, respectively. Compared with those of the specimen without any treatment, the tensile, bending and impact strengths were increased by 52.7%, 24.0% and 30.4%, respectively. Furthermore, the improved compatibility between treated fibers and matrix was verified by SEM images. In addition, the mechanism of starch ester as macromolecule interfacial modifier to enhance the interfacial bonding of composites was speculated. The starch ester was amphiphilic property, one end of which is hydrophobic and PBS matrix was combined with the similar surface activity. One end of the hydrophilic and the hydroxyl groups of cassava dregs fiber were bonded by hydrogen bonds. The starch ester played a bridge role between PBS matrix and cassava dregs fiber, resulting in enhancing the interfacial bonding strength of composites.
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    The Effect of Integrated Processes of Steam Explosion and Alkaline Pretreatment on the Structure of Wheat Straw and Its Enzymatic Hydrolysis
    HE Shicheng, SUN Manyu, SUN Zhongyan, SHU Yueli, JIA Shiru, ZHONG Cheng
    2017, 37 (5):  126-132.  doi: 10.3969/j.issn.0253-2417.2017.05.017
    Abstract ( 558 )   PDF (3304KB) ( 309 )   Save
    Various combined processes of steam explosion and alkaline pretreatment were experimentally compared and evaluated on wheat straw materials. The morphological characterizations of pretreated wheat straw were performed by scanning electron microscope and FT-IR spectroscopy, to qualitatively determine the composition changes of pretreated wheat straw. Comparing to the single process or the combination of alkaline pretreatment followed by steam explosion(ASP), the steam explosion followed by alkaline process(SAP) pretreatment removed most of lignin, degraded hemicelluloses, and incurred a higher surface area of the cellulose-rich substrates. And the remaining contents of cellulose, xylan and lignin in SAP sample were 88.15%, 5.55%, 4.13%, respectively. Moreover, SAP enhanced the fed batch enzymatic hydrolysis of cellulose-rich substrates to a maximum value of 80.53% even at the high cellulose loading of 18%. The results indicated that the SAP process is advantageous scheme for the enhancement of enzymatic efficiency.
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    Extraction and Antioxidant, Antiproliferative Activities of Polysaccharide from Ledum palustre L. Leaves
    LI Xue, WANG Hongwei, ZHENG Dongran, ZHANG Hongyu, WANG Yingkui
    2017, 37 (5):  133-138.  doi: 10.3969/j.issn.0253-2417.2017.05.018
    Abstract ( 471 )   PDF (890KB) ( 268 )   Save
    The polysaccharide from Ledum palustre L. leaves was obtained by ethanol precipitation, and its content was determined by phenol-sulfuric acid assay. Based on the single-factor test, a orthogonal test was designed to optimize the extracting conditions.The total antioxidant activity and the scavenging effect on DPPH free radical, OH free radical and H2O2 by the polysaccharide from L. palustre leaves in vitro were determined by the kit method and chemical method. The antiproliferative activity was evaluated on human liver cancer HepG2 cells in vivo. The results showed that the best extracting conditions of the polysaccharide were:the liquid-solid ratio 30:1(v/w), extraction temperature 80℃ and extraction time 3 h.Under these conditions,the extraction yield of the polysaccharide was 7.86%±0.16% and the purity reached 90.06%. In the range of 1-5 g/L, the antioxidant and antiproliferative activities increased with an increase of mass concentration. At the mass concentration of 5 g/L, the total antioxidant activity was(10.27±0.2) U/mL and reached more than that of 95% Vc with the same mass concentration. The scavenging effects on DPPH free radical and OH free radical in different concentration reached more than those of 90% of Vc with the same mass concentration. The scavenging effect on H2O2 reached more than that of 60% Vc with the same mass concentration and the proliferation inhibitory rate of HepG2 cells was 57.41%±0.02% at the mass concentration of 5 g/L.
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    Preparationand Characterization of Nanocellulose from Coconut Husk Fibers Based on Ionic Liquids
    CAO Fei, ZHAO Xin, HU Yingcheng, CHEN Peipei, LI Huifang
    2017, 37 (5):  139-145.  doi: 10.3969/j.issn.0253-2417.2017.05.019
    Abstract ( 637 )   PDF (5884KB) ( 356 )   Save
    The main components of coconut husk fibers was separated by the 1,4-butylene glycol/water system combined with 1-butyl-3-methylimidazolium hydrogen sulfate([Bmim] [HSO4]) as a catalyst, and the cellulose-rich material was subjected to bleaching treatment of sodium chlorite to obtain pure cellulose. Then, the nanocellulose was prepared by acid hydrolysis followed by ultrasonication. The morphological behavior, chemical characterization, crystallinity index, thermostability of nanocellulose were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and thermogravimetric analysis(TG). The effects of[Bmim] [HSO4] on the yield and properties of nanocellulose were investigated. The results showed that[Bmim] [HSO4] the extraction rate of lignin and the disposability of the cellulose, which was beneficial to the preparation of pure cellulose. Nanocellulose from coconut husk fibers still maintain the basic chemical structure and the cellulose I crystalline structure. The[Bmim] [HSO4] increased the mass loss rate of the cellulose, which led to the decrease of the nanocellulose yield. The nanocellulose from Coconut husk fiber based on ionic liquid exhibited an average length of(271±81)nm and a diameter of(6.3±1.8)nm.[Bmim] [HSO4] had no significant effect on the size of diameter(3-9 nm).
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    Effect of Adsorption and Desorption of Butanone on Micropore Structure of Activated Carbon
    HUANG Li, SUN Kang, ZHU Guangzhen, LIU Shicai
    2017, 37 (5):  146-152.  doi: 10.3969/j.issn.0253-2417.2017.05.020
    Abstract ( 566 )   PDF (1095KB) ( 292 )   Save
    Three kinds of activated carbons were chosen to be used on the study of effects of butanone on adsorption and desorption on pore structure of activated carbon.The experiment was conducted in an atmospheric dynamic adsorption reactor at different temperature conditions.The pore structures of activated carbons were characterized by N2 adsorption isothermsm, the surface function groups of activated carbon was identified by FT-IR analysis and Boehm titration.The result shows that the adsorption process of butanone by activated carbon mainly happens on micropores,the pore size distribution from 0.5-0.8 nm promotes the adsorption of butanone and the distribution around 1.2 nm trend to enhance the adsorption of butanone.The acidic groups such as carboxyl and lactone groups are good for the adsorption of butanone.Temperature has significant effect on the adsorption of butanone by activated carbons.During the adsorption process, the amount of butanone adsorbed at equilibrium decreased with the increase of temperature;during the desorption process, the rate of desorption increased with the increase of temperature.Lactonic and carboxyl groups will suppress the desorption of butanone; at the same time, the micro-pore structure of 0.5-0.8 nm and mes-pore of 1.2 nm in diameter were also in favor of activated carbon on the desorption of butanone.
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