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    25 December 2017, Volume 37 Issue 6 Previous Issue    Next Issue
    Research Progress of Hydrogen Donor Assisted Fast Pyrolysis of Biomass
    LU Qiang, GUO Haoqiang, YE Xiaoning, WANG Xin, ZHOU Mingxing
    2017, 37 (6):  1-9.  doi: 10.3969/j.issn.0253-2417.2017.06.001
    Abstract ( 579 )   PDF (1660KB) ( 523 )   Save
    During biomass fast pyrolysis process, the occurrence of free radical reactions generates a certain amount of free radical intermediates. Hydrogen free radicals from hydrogen donors will stabilize these intermediates to effectively regulate the distribution of char and high grade bio-oil to achieve value-added utilization of biomass. This paper summarizes the effects of hydrogen donors(1,2,3,4-tetrahydronaphthalene, linear alcohols, organic macromolecule polymer, etc.) on the fast pyrolysis of biomass, and the hydrogen free radicals supply mechanisms from different hydrogen donors. Afterwards, the commonness and the characteristics of biomass pyrolysis with the addition of different hydrogen donors are concluded. Finally, perspective researches are proposed to extend the selection of hydrogen donors and optimize the regulation of pyrolytic products.
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    Research Progress in Hemicellulose-based Functional Materials
    ZHOU Shuai, MIAO Qingxian, HUANG Liulian, CHEN Lihui
    2017, 37 (6):  10-18.  doi: 10.3969/j.issn.0253-2417.2017.06.002
    Abstract ( 822 )   PDF (3259KB) ( 735 )   Save
    The research progresses in recent years in the functional materials of hemicelluloses including membrane, hydrogel, absorbent, medical material and catalyst support were reviewed. In addition, the application prospect of hemicelluloses-based functional materials was addressed. Hemicelluloses-based membrane can be used as packing material and food wrapping material, but the problem of lower strength and flexibility should be solved. Hemicelluloses-based hydrogel can be prepared by chemical and physical cross-linking and utilized in medical and environmental fields, but the biocompatibility of chemical cross-linking hydrogel and strength of physical cross-linking hydrogel should be further improved. Furthermore, the hemicelluloses can be applied as absorbent for cleaning waster water and air, as medical material for drug sustained release and antibiosis, and as catalyst support for chemical synthesis. In the future, the hemicelluloses would be expected to be used in the fields of photoelectrical material, tissue engineering material, et al.
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    Vacuum Desorption of Volatile Organic Compounds from Activated Carbons
    ZUO Songlin, ZHANG Jie, LIU Junli, SUN Kang
    2017, 37 (6):  19-27.  doi: 10.3969/j.issn.0253-2417.2017.06.003
    Abstract ( 1110 )   PDF (1139KB) ( 664 )   Save
    In order to elucidate the patterns of vacuum desorption of volatile organic compounds(VOCs) from activated carbons, the vacuum desorption curves of the VOCs as a function of the temperature were investigated in a fixed bed by choosing 11 types of VOCs (including alkanes, aromatics, alcohols and ketones, and so on) of different chemical structures and molecular sizes. The results showed that vacuum desorption was a highly potential technology for recovering VOCs. Compared with conventional thermal desorption methods, vacuum desorption significantly reduced VOCs desorption temperatures, and allowed high desorption efficiency of greater than 99% and more reuse of activated carbons. The polar surfaces of activated carbon significantly weakened the desorption of alcohols while the non-polar surface was conducive. The surface property of activated carbons barely affected the desorption of the non-polar VOCs. Further, adsorbed alcohols molecules such as methanol and ethanol were arranged perpendicular to the surface of activated carbon in a way that hydroxyls of alcohols directly contacted with the carbon surface. This arrangement led to carboxyl groups of activated carbons prone to be removed or be changed into lactone in the vacuum thermal desorption process.
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    Effects of Cardanol-based Epoxidized Phosphate on the Properties of E-51/IPDA Epoxy Resin System
    HUO Shuping, CHEN Jian, LIU Guifeng, WU Guomin, KONG Zhenwu
    2017, 37 (6):  28-34.  doi: 10.3969/j.issn.0253-2417.2017.06.004
    Abstract ( 662 )   PDF (4393KB) ( 490 )   Save
    A cardanol-based phosphate epoxidized(CGEP) was synthesized using cardanol.as feedstock. The curing system of bisphenol A epoxy resin(E-51) and isophorone diamine(IPDA) was modified by CGEP in different mass ratios. The influences of CGEP on the viscosity of E-51 and on the properties of cured epoxy resins were investigated. The microstructure of fracture surface of cured epoxy resins was characterized by scanning electron microscope(SEM). It was found that CGEP has significantly diluted the E-51 and involved in the curing reaction of epoxy resin. When the content of CGEP was 15 wt% with respect to E-51, the impact strength of cured epoxy resins reached the maximum 22.06 kJ/m2. When the content of CGEP was 20% with respect to E-51, the tensile strength and bending strength of cured epoxy resins reached the maximum 96.19 MPa and 99.70 MPa, respectively. With the increase of the amount of CGEP from 0% to 25%, the glass transition temperature(Tg) of the cured product decreased from 144.82℃ to 119.10℃, while the oxygen index increased from 19.0 to 23.0. SEM analysis showed that the toughness of cured epoxy resins improved obviously.
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    Effect of Alkali Lignin on Corn Stalk Pelleting Process
    LI Weizhen, JIANG Yang, RAO Shu, YIN Xiuli, JIANG Enchen
    2017, 37 (6):  35-42.  doi: 10.3969/j.issn.0253-2417.2017.06.005
    Abstract ( 631 )   PDF (4616KB) ( 490 )   Save
    In order to study the effect of alkali lignin on corn stalk pelleting process and the bonding mechanism, the influences of four parameters(alkali lignin adding amount, temperature, moisture and pressure) on three technical indicators(relaxed density, radial compressive strength and specific energy consumption) were investigated. The compression molding experiment showed that when alkali lignin adding amount increased from 0 to 20%, the relaxed density of corn stalk pellets increased from 1 005 kg/m3 to 1 157 kg/m3 and the radial compressive strength increased from 1 353 N to 1 930 N. This results suggested that increasing of alkali lignin could promote the corn stalk pelleting process. The thermal transition temperatures of corn stalk and alkali lignin were also studied by differential scanning calorimetry(DSC). The results showed that the glass transition temperatures of corn straw and alkali lignin were between 92.5-103℃ and 61-137℃, respectively. In the thermal transition temperature range, 100℃ was the lowest specific energy consumption with suitable moisture content. The suitable temperature range for alkali lignin bonding was 100-130℃.The microstructure of pellets showed that alkali lignin occurred melting transition after melting temperature and then formed ‘molten combination’ and ‘mechanical interlocking’ inside the particles. The suitable alkali lignin adding amount for bonding was 10%-15%.
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    Synthesis and Characterization of Thermoplastic Materials Derived from Cellulose, Furfural and Grease
    LU Chuanwei, LIU Shaofeng, WANG Chunpeng, CHU Fuxiang, WANG Jifu
    2017, 37 (6):  43-48.  doi: 10.3969/j.issn.0253-2417.2017.06.006
    Abstract ( 625 )   PDF (879KB) ( 526 )   Save
    Biomass-based thermoplastic elastomer materials derived from cellulose, furfural and grease were prepared by "graft from" ATRP using ethyl cellulose(EC), tetrahydrofurfuryl methacrylate(THFMA) and lauryl methacrylate(LMA). FT-IR, 1H NMR and GPC were applied to characterize the structure of graft copolymers, and proved the successful preparation of graft copolymer. The DSC analysis showed that the Tg of EC graft copolymers were between 13℃ and 27℃. The mechanical properties test showed that the tensile strength increased from 5.1 MPa to 13.7 MPa with the increasing of THFMA content in the feed. Compared to the linear copolymer which has the same THFMA/LMA composition, the EC graft copolymer possessed 3.7 times higher tensile strength. It is worth noting that the EC content in the feeding is between 0.91%-1.42%, which indicated that a small amount of EC could greatly improve the mechanical properties of graft copolymer.
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    Microwave Irradiation Synthesis, Characterization and UV-curing Reaction of Allyl Acrylpimarate
    LU Yanju, ZHAO Zhendong, GU Yan, WANG Jing, XU Shichao
    2017, 37 (6):  49-55.  doi: 10.3969/j.issn.0253-2417.2017.06.007
    Abstract ( 616 )   PDF (1095KB) ( 512 )   Save
    A new polymerized monomer with two allyl groups was synthesized by Diels-Alder reaction, which could introduce the characteristic fused ring structure of rosin acids to the polymers. Allyl acrylpimarate was synthesized by using sodium acrylpimaric rosinate and allyl chloride as raw materials with molar ratio of 1:2, 5% cetyltrimethyl ammonium bromide as catalyst, 0.02% hydroquinol as polymerization inhibitor and N, N-dimethylformamide as solvent under microwave irradiation. Under the reaction conditions of microwave energy 400 W, reaction time 2.5 h, reaction temperature 50℃, the yield of allyl acrylpimarate(AA) was 72.9%. The structure of the product was characterized by gas chromatography, gas chromatography mass spectrometry, infrared spectrum, and nuclear magnetic resonance spectra. The IR spectra showed that the characteristic absorption peak of C=C on AA addition appeared at 1686 and 1648 cm-1. The GC content of AA was determined as 98.6% by gas chromatography. Mass spectrometry and nuclear magnetic resonance spectra were used to verify the correctness of the structure of AA. The UV curing reaction of AA was studied. The results of infrared spectroscopy showed that the polymerization monomer was a free radical polymerization reaction. The surface curing time of AA decreased with the increasing of photo initiator dosage, decreasing of illumination distance and increasing of illumination intesity. TG and DSC analysis results showed that the UV curing product had good thermal stability with the initial decomposition temperature of 292.9℃ and initial glass transition temperature of 49.6℃.
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    Catalytic Ozonation Advanced Treatment of Pulping Effluent Catalyzed by γ-Al2O3 Loaded with Binary Metal Oxides
    WANG Congcong, MO Lihuan, YANG Zhen, LI Jun, XU Jun, TAN Jinqiang
    2017, 37 (6):  56-64.  doi: 10.3969/j.issn.0253-2417.2017.06.008
    Abstract ( 490 )   PDF (2124KB) ( 486 )   Save
    A loading binary metal oxide Mn-Ni/γ-Al2O3 catalyst was synthesized with γ-Al2O3 as support and with the transition metals Mn, Ni as active ingredients. The catalyst was characterized by XRD, XRF, BET. Then the catalyst was used for the ozonation advanced treatment of pulping effluent. The relationship between wastewater CODcr and affecting factors was established via the response surface analysis with Box-Behnken mathematical model. The results showed that the Mn and Ni were loaded on the surface and in the internal hole-channel successfully; After the load of these metals, the particle size decreased, and the specific surface area, pore volume and average pore size decreased by 11.96%, 16.48% and 5.28% respectively. The optimal condition for treatment was initial pH 8.7, catalyst dosage 9.2 g/L and ozone concentration 29.6 mg/L. Under this condition, the removal rates of CODCr and AOX with Mn-Ni/γ-Al2O3(mole ratio of Mn and Ni 6:4) as catalyst were 75.1% and 85.98% after 30 min treatment (40℃). Furthermore, the removal rate for this catalyst still reached 70.6% after being repeatedly used for 6 times. And the ionic releases of Mn and Ni was remained below 1 mg/L during the reaction, indicating of the high stability and good performance of the Mn-Ni/γ-Al2O3 catalyst had for repeated use.
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    Chemical Component and Antibacterial Activity of Essential Oil from Myanmar Pterocarpus macrocarpus
    CHEN Hongxia, KANG Xiutang, YOU Longjie, WANG Chengzhang, YE Jianzhong
    2017, 37 (6):  65-72.  doi: 10.3969/j.issn.0253-2417.2017.06.009
    Abstract ( 995 )   PDF (2488KB) ( 613 )   Save
    The essential oils of Myanmar Pterocarpus macrocarpus Kurz were obtained by using steam distillation(SD), solvent thermal extraction(STE) and subcritical fluid extraction(SFE), with the comparative analysis of the chemical composition of three methods. The results showed that SFE exhibited the highest essential oil yield of 1.95%, SD exhibited the lowest essential oil yield of 1.03%, the yield of STE was 1.74%. About 38 constituents of the essential oil obtained by SD were identified by GC-MS analysis with the main compounds of β-eudesmol(69.897%) and machilol(18.055%). About 48 constituents of the essential oil obtained by STE were identified with the main compounds of β-eudesmol(50.907%), homopterocarpin(13.322%), machilol(9.333%), 1-(1,1-dimethylethyl)-4-methoxy-benzene(2.481%) and espatulenol(2.285%). About 48 constituents of the essential oil obtained by SFE were identified with the main compounds of β-eudesmol(47.786%), homopterocarpin(13.516%), dimethyl 2,3-dicyano-2-butenedioate(5.429%), machilol(5.232%), 1-(1,1-dimethylethyl)-4-methoxy-benzene(2.699%) and espatulenol(2.636%). The antimicrobial activity of the essential oils obtained by threee extraction methods were tested by zone of inhibition test, MIC and MBC assays. The essential oil obtained by SD showed no antimicrobial activity against Klebsiella pneumoniae, Candida albicans and Bacillus subtilis. However, it showed higher antimicrobial activity with the MIC values against the Klebsiella pneumoniae, Candida albicans and Bacillus subtilis of 6.25, 25 and 6.25 g/L, respectively.
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    Liquefaction of Corncob with Solid Acid as Catalyst in Near-critical Methanol-cyclohexane
    PAN Qingqing, ZHANG Jun, WU Zhen, LI Xun, ZHANG Yu, WANG Fei
    2017, 37 (6):  73-80.  doi: 10.3969/j.issn.0253-2417.2017.06.010
    Abstract ( 574 )   PDF (1155KB) ( 461 )   Save
    SO42-/TiO2-ZrO2 solid acid catalyst was prepared by co-precipitation and impregnation. The catalysts were characterized by Fourier transform infrared spectrometer(FT-IR), energy dispersive X-ray spectrometer(EDS) and nitrogen physisorption. The effects of solvent ratio, reaction temperature, reaction time and catalyst dosage on corncob conversion were investigated. The chemical compositions of liquefaction production with and without catalysts were determined by FT-IR and gas chromatography/mass spectrometry(GC-MS). The results indicated that SO42- was successfully loaded on the TiO2-ZrO2 and SO42-/TiO2-ZrO2 was a mesoporous material. The optimal conditions of liquefaction were 1 g corncob with 4% SO42-/TiO2-ZrO2 at 250℃ for 1.5 h when the volume ratio of methanol to cyclohexane was 2 and the solid-liquid ratio of corncob and solution was 1:15(g:mL), under which the liquefied rate reached the maximum of 76.67%. The main components of the liquefaction product were phenols and ester compounds.
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    Preparation of Methyl Glucoside and Phenols from Pressurized Liquefaction of Bamboo
    SU Qiuli, JIANG Jianchun, FENG Junfeng, LI Fanglin, XU Junming
    2017, 37 (6):  81-88.  doi: 10.3969/j.issn.0253-2417.2017.06.011
    Abstract ( 674 )   PDF (1022KB) ( 522 )   Save
    Bamboo sawdust was used as the raw material for pressurized liquefaction to obtain methyl glucoside and four kinds of phenols at different temperatures. The products composition and structure were analyzed by various methods. In addition, the variation of structure of lignocellulosic biomass in liquefaction process and the formation mechanism of liquefied products were investigated. The results showed that when liquefaction conditions were 40 g bamboo sawdust, m(bamboo):m(CH3OH)=1:12, the dosage of sulfuric acid 1 g, reaction time 10 min, and reaction temperature 200℃, the yield of liquefied product was 87.83% with 48.17%methyl glucoside and 39.66% phenols. The components and contents of methyl glucoside and phenols were characterized by gas chromatography-mass spectrometer(GC-MS) and high performance liquid chromatography(HPLC) analysis. The results showed that the degradation temperatures of cellulose and hemicellulose were low and the high temperature was beneficial to the degradation of lignin. The liquefaction residue was characterized by X-ray diffraction(XRD) and Fourier transform infrared spectrum analysis(FT-IR). The results showed that the crystal index of cellulose in the residue of 120-200℃ degradation was 6.12%-40.33% higher than that in the raw material. The reason could be explained as that the decomposition of lignin and hemicellulose in the amorphous region was destroyed partly during 120-200℃, however, the structure of amorphous region and crystalline region was destroyed completely in the 220℃.
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    Microwave Pyrolysis Characteristics of Poplar Sawdust Under Different Atmosphere
    GUO Liang, QI Wei, LIAO Lifang, WEI Ting, XU Qingli, YAN Yongjie
    2017, 37 (6):  89-94.  doi: 10.3969/j.issn.0253-2417.2017.06.012
    Abstract ( 628 )   PDF (3932KB) ( 460 )   Save
    Microwave pyrolysis of sawdust under CO2 and N2 atmosphere was investigated respectively. The results showed that different atmosphere had effects on the composition of pyrolytic oil, the nature of coke and the composition of gas. The maximum bio-oil yield(28.42%) was obtained under N2 atmosphere at 900 W, the percentages of esters and phenols in the oil were 67.2% and 20.5% at 800W,respectively. The contents of acid, aldehydes and alcohols in pyrolytic product were low. The BET specific surface area of obtained coke was 125.44 m2/g. CO2 affected the nature of bio-oil and coke by participating in the reaction. The maximum bio-oil yield(30.05%) under CO2 atmosphere was obtained at 800 W, the percentage of esters reduced to 45.8%, and the phenols increased to 26.4%. The contents of acid, aldehydes and alcohols had nearly doubled. The BET specific surface area of coke increased to 136.85 m2/g. The CO2 atmosphere reduced the H2 content and increased the CO content in gas product.
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    Preparation and Application of Cardanol Polyoxyethylene Ether Compounded Deinking Agent
    WANG Feng, LONG Zhu, CHEN Jie, WANG Bin, ZHANG Fengshan
    2017, 37 (6):  95-100.  doi: 10.3969/j.issn.0253-2417.2017.06.013
    Abstract ( 694 )   PDF (2241KB) ( 563 )   Save
    Cardanol polyoxyethylene ether(CPE) was prepared from natural cardanol and characterized by FT-IR and 1H NMR. By combining with other commercially available surfactants(fatty alcohol polyoxyethylene ether (AEO-9),fatty alcohol polyoxyethylene ether sulfate(AES),sodium dodecyl sulfate (K12),Tween-60 and Tween-80), CPE was used as flotation deinking agent of mixed office waste paper. The experimental results showed that CPE was effective and compatible, which could achieve better effect when mixed with a variety of surfactants. The deinking effect of CPE compounded with other two surfactants was better than that of double components and CPE alone. Results showed that the blend of three surfactants, composed of CPE:AES:AEO-9 with mass ratio of 1:1:1, could provide best effect, and the brightness of the recycled paper product reached to 90.45%(ISO), ink removal efficiency was 91.96% and pulp yield reached to 75.7%.
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    Synthesis and Perfomances of Dehydroabietylamine Schiff Base Containing Furfural and Its Derivatives
    SONG Yanpei, WANG Jue, DIAO Kaisheng, CHEN Houfa, DUAN Yunming
    2017, 37 (6):  101-109.  doi: 10.3969/j.issn.0253-2417.2017.06.014
    Abstract ( 599 )   PDF (1430KB) ( 460 )   Save
    Four new dehydroabietylamine Schiff bases, i.e.,(E)-1-DHAA-N-((5-nitrofuran-2-yl)methylene)(1),(E)-N-(furan-2-ylmethylene)-1-DHAA(2),(E)-N-((5-bromofuran-2-yl)methylene)-1-DHAA(3), (E)-1-DHAA-N-((5-methylfuran-2-yl)methylene)(4), were prepared from furfural derivative and dehydroabietylamine(DHAA). The process conditions were optimized by single factor and orthogonal experiment. The yields of Schiff bases 1-4 were 89.5%, 89.1%, 90.2% and 88.1%, respectively. Their structures were characterized and confirmed by X-ray single crystal diffraction, NMR, MS, IR. Both Schiff base 1 and 2 belonged to orthorhombic system, space group P2(1)2(1)2(1), Schiff base 3 belonged to monoclinic system, space group P2(1). The practical structural parameters were in agreement with the calculated chemical simulation results. The bond lengths of the DFT algorithm were 0.127 67, 0.127 91 and 0.127 88 nm, respectively, while the results of the single crystal diffraction analysis were 0.127 5(5), 0.126 1(5) and 0.124 5(7) nm. The simulated values of bond angle of C(20)-N(1)-C(21) were 121.610 1, 120.760 7 and 120.813 5°, respectively, and the actual values of the single crystal test were 119.1(3), 117.3(3), and 117.4(5)°. The antibacterial activities of 4 Schiff bases were studied, which showed that the minimum inhibitory concentration of Schiff base 1 on Staphylococcus aureus was 0.31 g/L, which was equivalent to the positive control of cephanisisi, indicating a higher antibacterial activity; the minimum bacteriostatic concentrations of Schiff base 1, 3 and 4 against Escherichia coli were 0.62 g/L, and the antimicrobial activity was significantly better than Schiff base 2.
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    Compositions and Functional Properties of Soluble Dietary Fiber from Olive Pomace
    DING Shasha, HUANG Lixin, ZHANG Caihong, XIE Pujun, DENG Yejun, WANG Xiaojie
    2017, 37 (6):  110-116.  doi: 10.3969/j.issn.0253-2417.2017.06.015
    Abstract ( 638 )   PDF (989KB) ( 397 )   Save
    The crude soluble dietary fiber(SDF) from Olive pomace(Olea europaea L.) was obtained by using alkaline extraction method. The chemical composition, monosaccharide composition and functional groups were characterized by gas chromatography(GC) and infrared spectrometry. Furthermore, the effects of olive pomace SDF on the in vitro NO2- adsorption and antioxidant activity were investigated. The results showed that the content of SDF in the crude olive pomace SDF was 60.90%. The monosaccharide of crude SDF was composed of xylose, arabinose, rhamnose, glucose, galactose and mannose with the molar ratio of 64.0:9.4:3.9:3.9:2.6:1.6. The major component was xylose, followed by arabinose. Infrared spectra showed that the crude SDF had the characteristics absorption peaks of polysaccharide. The maximal adsorption capacity of SDF for NO2- in simulated gastric environment at pH=2(98.92%) was greater than that in the intestine environment at pH=7(8.69%). The maximum scavenging ratio of the crude SDF for hydroxyl radical(·OH) was 46.34% at the mass concentration of 6 g/L and weaker than that of Vc. The crude SDF had strong DPPH radical scavenging activity with the IC50 of 0.06 g/L. The DPPH radical scavenging activity of the crude SDF was weaker than that of Vc at low concentrations and close to that of Vc at high concentrations.
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    Synergetic Mechanism of Three Components of Biomass Liquefaction in Polyethylene Glycol
    JIANG Xiaoxiang, LI Jingdan, WANG Jing, SHI Yan, YANG Hongmin, JIANG Jianchun
    2017, 37 (6):  117-124.  doi: 10.3969/j.issn.0253-2417.2017.06.016
    Abstract ( 683 )   PDF (1173KB) ( 543 )   Save
    The thermogravimetric analysis(TG) was carried out on the synthesized biomass samples with different proportions of microcrystalline cellulose, xylan and lignin. The co-solvent liquefaction behavior and the synergistic effect of the three-components in the co-solvent liquefaction process were obtained. When the temperature was lower than 350℃, the hemicellulose had a certain promoting effect on the degradation of cellulose; when it was higher than 350℃, there was a significant inhibitory effect. Hemicellulose and cellulose inhibited the lignin degradation; and then the extreme vertex method was used to select the typical ratio of synthesized biomass. The pyrolysis liquefaction products of the co-solvent of synthesized biomass were investigated by pyrolysis chromatography mass spectrometry(Py-GC/MS). The effects of the components of biomass on the co-solvent pyrolysis products were obtained. The results indicated that higher percentage of lignin in synthesized biomass promoted the formation of acids. The existence of cellulose and hemicellulose restrained the production of phenols during lignin co-solvent pyrolysis. More esters were obtained from synthesized samples co-solvent pyrolysis, different proportion of three-components promote the formation of esters.
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    Ultrasonic-assisted Extraction of Total Flavonoids from Branches and Leaves of Taxus cuspidata Sieb. et Zucc. and Its Antioxidant Activity
    JIANG Ping, CHEN Huafang, HUANG Haibin, BAO Xinye, XU Lan
    2017, 37 (6):  125-132.  doi: 10.3969/j.issn.0253-2417.2017.06.017
    Abstract ( 747 )   PDF (1491KB) ( 569 )   Save
    The total flavonoids from branches and leaves of Taxus cuspidata were extracted by using the method of ultrasonic assisted extraction. The interaction effects between the factors were analyzed and the optimal extraction process conditions of the total flavonoids were optimized by the response surface method. The results showed that the optimal extraction conditions were as follows:the volume fraction of ethanol was 60%, the extraction temperature was 64℃, the extraction time was 60 min, the ratio of liquid to material was 14:1 (mL:g), the ultrasonic power was 168 W, the maximum extraction yield of total flavonoids was up to 4.48%(extraction rate 69.14%). After the ethanol crude extract from branches and leaves of Taxus cuspidata was extracted by different solvents, the antioxidant activity of extract had good dose-effect relationship with the mass concentration of 0.01-0.20g/L.The ethyl acetate extract had strong DPPH radical scavenging ability, and its IC50 value was 0.018 g/L, similar to the IC50 value of Vc(0.012 g/L). 16 fractions contained the total flavonoids were obtained from the ethyl acetate extract separated by macroporous resin AB-8. The total flavonoids content in 16 separated fractions had good correlation with their DPPH radical scavenging ability. The correlation coefficient R was 0.958 1, and the significant P<0.000 1.
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    Effect of Ultrafiltration Fractionation on Performance of Lignosulfonate as Dust Suppressant
    JIANG Xinyi, WANG Guanhua, HANG Jiahui, WANG Dan, SI Chuanling
    2017, 37 (6):  133-140.  doi: 10.3969/j.issn.0253-2417.2017.06.018
    Abstract ( 717 )   PDF (3475KB) ( 454 )   Save
    Three lignosulfonate fractions(LG-1, LG-2 and LG-3) were obtained by ultrafiltration with two cut-off molecular weight membrane of 6 000 and 20 000 u. The yield, purity, molecular weight and hydrophilic group content of lignosulfonate fractions were characterized and the performances of lignosulfonate fractions as dust suppressant were also compared. The results showed that ultrafiltration could effectively fractionate the lignosulfonate and the yields of LG-1, LG-2 and LG-3 were 58.32%, 24.50% and 17.18%, respectively. The weight average molecular weights of the three fractions were 4 841, 15 239 and 37 768 and the polydispersities were 2.78, 2.40 and 2.06, respectively. With the increase of lignosulfonate molecular weight, the ash and sulfonic acid group content decreased while the total sugar content increased. The ultrafiltration fractionation had significant effects on the performance of lignosulfonate as dust suppressant. With the increase of molecular weight cut-off, the water absorption capacity, compression strength and anti-wind erosion ability of lignosulfonate increased by 96.43%, 55.11% and 63.07%, respectively, which suggested that lignosulfonate fraction LG-3 with higher molecular weight performed better as dust suppressant. SEM analysis suggested that after spraying of lignosulfonate solution, a bonding layer was formed between sand grains and played the role of cohesiveness and incrustation for the sand grains. Moreover, the phenomenon was more obvious with the increase of lignosulfonate molecular weight.
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