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    25 August 2018, Volume 38 Issue 4 Previous Issue    Next Issue
    Application Progress of Nano-cellulose in Paper-based Functional Materials
    CHEN Qijie, KANG Meicun, ZHENG Xueming, ZHOU Liling, WANG Ping
    2018, 38 (4):  1-8.  doi: 10.3969/j.issn.0253-2417.2018.04.001
    Abstract ( 1017 )   PDF (1891KB) ( 1295 )   Save
    The classification and properties of nano-cellulose were introduced. The nano-cellulose was divided into nano-cellulose crystal(NCC), microfibrillated cellulose(MFC) and bacterial nano-cellulose(BNC). NCC has a rod-like whisker structure with high crystallinity and high mechanical properties. MFC is filamentous, with wide size range and larger aspect ratio, large specific surface area and strong hydrogen bonding ability. BNC has ultrafine network structure with high degree of chemical purity and polymerization, and strong water retention ability. The application status of nano-cellulose in paper-based reinforced materials, paper-based antimicrobial materials, paper-based filter materials, paper-based conductive materials, paper-based luminescent materials, paper-based insulating materials, paper-based hydrophobic materials and paper-based sensor materials was reviewed. The future development of nano-cellulose in paper-based functional materials was also prospected.
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    Evaluation Method of Solubility of Wheat Straw in LiCl/DMSO Solvent
    YANG Yan, REN Hao, ZHAI Huamin
    2018, 38 (4):  9-12.  doi: 10.3969/j.issn.0253-2417.2018.04.002
    Abstract ( 579 )   PDF (654KB) ( 558 )   Save
    In order to solve the quantitative problem of the solubility of lignocellulosic biomass in the solvent system, wheat straw was studied as raw material for a ball milling time on its dissolution behavior in the LiCl/DMSO system. The dissolution performance was evaluated by visual method, optical microscopy and turbidity method respectively. By comparison of visual colorimetry method and the optical microscopy method at the condition of wheat straw dissolved in 8% LiCl/DMSO, it was found that the turbidimetric method is accurate, simple and quantitative. The turbidimetric method can be used to evaluate the dissolution behavior of lignocellulosic biomass during pretreatment and refining.
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    Synthesis and Properties of Fumaropimaric Acid Modified RTV Silicone Rubber
    Qiaoguang, LIU He, LI Jianfang, SHANG Shibin, SONG Zhanqian
    2018, 38 (4):  13-19.  doi: 10.3969/j.issn.0253-2417.2018.04.003
    Abstract ( 523 )   PDF (1536KB) ( 667 )   Save
    Fumaropimaric acid modified aminopropyltriethoxysilane(FA) was prepared by derivative reaction with rosin as raw material and the structure of the product was confirmed by FT-IR, 1H NMR and 13C NMR. Fumaropimaric acid modified room temperature vulcanized(RTV)silicone rubber was prepared by the dealcoholization condensation reaction of crosslinking agent(FA) and hydroxyl end-blocked dimethylsiloxane(PDMS). And the effects of hydrogenated phenanthrene ring of rosin on the morphology, mechanical and thermal properties of fumaropimaric acid modified RTV silicone rubber were studied, it was found that fumaropimaric acid modified RTV silicone rubber had better the mechanical and thermal properties compared to the unmodified silicone rubber. The tensile strength and elongation at break were 1.22 MPa and 315%; and The 10% mass loss temperature increased to 472℃ (SRFA-1), the greatest rate of mass loss temperature increased to 569℃, and the residual rate was 3.88%, respectively.
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    Preparation and Metal Ion Adsorption Performance for Heavy Metals of Nitrogen-doped Carbon Aerogels Prepared from Cellulose via Hydrothermal Carbonization Method
    SUN Jiaming, E Lei, MA Chunhui, LI Wei, LIU Shouxin
    2018, 38 (4):  20-28.  doi: 10.3969/j.issn.0253-2417.2018.04.004
    Abstract ( 562 )   PDF (1839KB) ( 830 )   Save
    Nitrogen-doped carbon aerogel (NCA) was prepared via hydrothermal carbonization with microcrystalline cellulose(MCC) as precursor and ovalbumin (OVA) as dopant. Here, ovalbumin acted double roles:One was the donor of nitrogen source, the other was the structural directing agent. Morphology, pore structure, crystal structure and surface chemical properties of NCA were characterized by scanning electron microscope (SEM), nitrogen adsorption-desorptiom, X-ray diffraction(XRD), Fourier transform infrared-spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS). Pb2+ and Cr6+ were used as adsorption substrates to explore the adsorption properties of NCA in the aqueous phase. Adsorption equilibria and kinetic behaviour of Pb2+ and Cr6+ were assessed by altering parameters such as agitation time and metal ions' concentration through implementing batch experiments. The results showed that the NCA was amorphous with three-dimensional network structure; specific surface area of NCA was 134.48 m2/g; average pore diameter was 12.28 nm; total pore volume was 0.413 0 m3/g. NCA was mainly composed of element of C, N, O. C=O, -COOH and C-N functional groups were detected on the surface of NCA. N was mainly existed in the form of nitrosyl, amino, pyridine and quaternary ammonium. The adsorption process of Pb2+ and Cr6+ on NCA followed Langmuir model and the pseudo-second-order kinetic model better. NCA exhibited higher adsorption capacity and faster kinetics than CA. The maximum adsorption capacities of Pb2+ and Cr6+ on NCA at 25℃ achieved 223.98 mg/g, 35.12 mg/g, respectively and the correspondind capacities on CA were 65.78 and 16.65 mg/g.
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    Preparation of 1,8-p-Menthane Diacetamide from p-Menthadienes
    ZENG Xiaojing, XU Shichao, WANG Jing, DONG Huanhuan, LU Yanju, ZHAO Zhendong
    2018, 38 (4):  29-34.  doi: 10.3969/j.issn.0253-2417.2018.04.005
    Abstract ( 507 )   PDF (767KB) ( 721 )   Save
    Using p-menthadienes and acetonitrile as raw materials, 1,8-p-menthane diacetamide was prepared in sulfuric acid solution via Ritter reaction. The effects of the mass fraction of sulfuric acid solution, the molar ratio of p-menthadienes to sulfuric acid solution and acetonitrile, reaction temperature, reaction time and the type of p-menthadienes on the yield of 1,8-p-menthane diacetamide were optimized. The results showed that when c(H2SO4)=60%, n(H2SO4):n(p-menthadienes)=2.2:1, n(acetonitrile):n(p-menthadienes)=2.4:1, T=55℃, t=6 h, the yield of 1,8-p-methane diacetamide is the highest. Among different pure component compounds in p-menthadienes, limonene is the most efficient starting material and got the highest yiled of 61.6%. The structure of the product was identified and characterized by FI-IR、ESI+-MS and 1H NMR.
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    Regulating Effect of P-factor on Lignin Mass Concentration in Prehydrolysis Liquor of Triploid Poplar
    FENG Nianjie, WANG Jiming, XIE Yimin, YANG Xin, LIU Da'an
    2018, 38 (4):  35-40.  doi: 10.3969/j.issn.0253-2417.2018.04.006
    Abstract ( 508 )   PDF (656KB) ( 631 )   Save
    In order to regulate the lignin mass concentration in prehydrolysis liquor, the mass concentrations of Klason lignin and acid-soluble lignin in the prehydrolysis liquor of triploid poplar were studied at different P-factor. The results showed that there was a regulating effect of P-factor on lignin mass concentration in poplar prehydrolysis liquor. The increasing processes of the mass concentration of two kinds of lignins were both divided into a fast phase (P-factor <1 200) and a following slow phase (P-factor >1 200). The mass concentration ratio of Klason lignin to acid-soluble lignin(r) was revealed at (0.50±0.03). The prehydrolysis lignin in the form of lignin-carbohydrate complex was found at P-factor <306. Klason lignin fragmentation and pseudo lignin formation were obviously indicated at P-factor>691.
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    Effects of Liquid Crystalline Epoxy Resin on the Properties of Bio-based Cardanol-furfural Resin
    ZHANG Kaiqiang, TANG Gongwen, YAN Zhishan, MA Linrong, HUANG Xin
    2018, 38 (4):  41-46.  doi: 10.3969/j.issn.0253-2417.2018.04.007
    Abstract ( 516 )   PDF (2440KB) ( 752 )   Save
    By using polarized optical microscopy, differential scanning calorimetry, scanning electron microscopy and impact strength measurements,the effects of liquid crystalline on the morphologies, thermal properties and mechanical properties of the composite resins were studied. It was found that the synthesized 4,4-diglycidyloxybiphenyl (BP) and sulfanilamide (SAA) were used to generate novel liquid crystalline (LC) epoxy resins notably. The results revealed that the curing of the cardanol-furfural resins was accelerated and the thermal properties were considerably improved by adding the LC epoxy resins.When the addition of BP-SAA was 50%, the glass transition temperature increased from 60.4℃ to 70.2℃, and the thermal decomposition temperature increased from 300.3℃ to 377.4℃, respectively. When the addition of BP-SAA was 30%, the impact strength of the modified resins was 15 kJ/m2 and about three-fold higher than that of the unmodified counterpart.
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    Synthesis and Antitumor Activity of Selective Oxidation Products of Betulin
    TAO Ran, WANG Chengzhang, ZHANG Changwei, ZHOU Hao, CHEN Hongxia
    2018, 38 (4):  47-51.  doi: 10.3969/j.issn.0253-2417.2018.04.008
    Abstract ( 573 )   PDF (542KB) ( 653 )   Save
    Based on the betulin with terpenoid as lead structure, the C-28 and C-29 of betulin were modified by the oxidants including the mixture of CrO3 and TEMPO and the m-CPBA, and aldehyde groups were selectively introduced into C-28 and C-29 sites, respectively. The compounds were further oxidized to betulinic acid at C-28 and C-29 sites, respectively. Finally, four oxidized derivatives were obtained and characterized by 1H NMR. The results showed that the yield of C-28 betulinaldehyde oxidized by the mixed oxidant of CrO3 and TEMPO was increased to 36.98% compared with that oxidized by single oxidant. When m-CPBA was used as oxidant and acetone was used as solvent, the yield of C-29 betulinaldehyde was 39.06%,which was the highest compared with others. The inhibitory rate and IC50 of betulin and its oxidized derivatives on the proliferation of two cell lines (HepG2 and A549) were measured by modified MTT method. The results showed that there was no significant difference in the antitumor activity between betulin and betulinaldehyde at the C-28 and C-29 sites. The antitumor activity of betulinic acid at C-28 and C-29 sites was significantly higher than that of betulin and betulinaldehyde at the same site. There was no significant difference in the toxicity of HepG2 and A549 cells between the oxide of betulin C-28 and C-29 sites.
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    Depolymerization of Lignin Catalyzed by Complex Metal Oxide in Supercritical Methanol
    YE Jiewang, JIANG Jianchun, JIN Zhenfu, ZHANG Weigang, ZHANG Xiaochun
    2018, 38 (4):  52-60.  doi: 10.3969/j.issn.0253-2417.2018.04.009
    Abstract ( 577 )   PDF (895KB) ( 630 )   Save
    Cu-Ni doped layered double oxide (LDO) catalysts were prepared from hydrotalcite-like precursors. The effects of reaction conditions on the catalytic lignin depolymerization productswere investigated in supercritical methanol. The results showed that in the condition of n(Cu):n(Ni)=1:1, at 280℃ for 8 h,Cu0.5Ni0.5Mg3Al-LDO used as catalyst with 30% dosage, the monomer yield from lignin depolymerization was up to 67.5%, while the yields of tetrahydrofuran(THF) insoluble residue and charwere least. The liquid phase product were qualitatively and quantitatively analyzed by GC-MS, and it was observed that the yield of the cyclic compound was 64.43%, and the acyclic product was only 10.65%, indicating Cu/Ni-LDO catalyst can effectively break the bonds between the lignin structural units, while with a lowactivity to break the aromatic ring structure.Charforming reactions in lignin depolymerization were effectively suppressed by Cu/Ni co-doped LDO catalyst, and the monomer yield was significantly improved. Hydrogenolysis and hydrogenation reaction in lignin depolymerization were promoted obviously at higher temperature,leading to a higher monomer yield. The supercritical temperature of methanol showed a significant effect on the depolymerization of lignin:When the reaction temperature was higher than 240℃, the yield of monomer increased significantly and the yields of insoluble residue and char decreasedon the other hand. The degradation rate of lignin remained above 90% after the catalyst was recycled for three times. XRD, ICP and N2 adsorption and desorption experiments showed that leaching of Mg was the main cause for catalyst deactivation. Cu/Ni-LDO catalyst can effectively promote the depolymerization of lignin into small molecule monomer compounds in supercritical methanol medium.
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    Ultrasonic-assisted Radical Process for Directed Degradation of Arabinogalactan
    ZHANG Haiyun, HE Liang, LI Qin, YANG Bo, YANG Guang
    2018, 38 (4):  61-68.  doi: 10.3969/j.issn.0253-2417.2018.04.010
    Abstract ( 419 )   PDF (4730KB) ( 651 )   Save
    Arabinogalactan (AG) was extracted from the sawdust of larch (Larix gmelinii(Rupr.) Kuzen). The arabinogalactan obtained was physically degraded by ultrasound-assisted free radicals. The free radical scavenging ability of decomposed AG was selected as an indicator on the evaluation of the antioxidant activity. On the basis of single-factor test, response surface optimization was used to determine the optimal degradation conditions, and the optimum conditions are found as follows:the dpolysaccharide concentration was 10 g/L; ultrasonic temperature was 60℃; the H2O2 volume fraction was 6%;and the ultrasonic time was 60 min. Under this optimum degradation condition, the·OH scavenging rate of arabinogalactan was 89.6%, and Mr of AG was degraded from 52 ku to around 25 ku, and the cumulative weight fraction of this molecular weight reached 60%.Compared with AG, the antioxidant activity of arabinogalactan oligosaccharide(AG-O) obtained in the anti-oxidative activity was significantly enhanced, and its IC50 value decreased from 2.058 g/L to 0.497g/L.
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    Levulinic Acid Synthesis from Furfural Residue with Synergistic Effect of Catalyst and NaCl
    LI Miao, LIU Qiumei, CAI Qinjie, ZHANG Suping
    2018, 38 (4):  69-73.  doi: 10.3969/j.issn.0253-2417.2018.04.011
    Abstract ( 489 )   PDF (541KB) ( 643 )   Save
    The effect of four kinds of metal chlorides (FeCl3, LiCl, AlCl3 and ZnCl2) were compared for the preparation of levulinic acid(LA) with furfural residue as raw material using Brønsted acid combined with Lewis acid as catalyst, and NaCl as promoter. The process conditions for the preparation of levulinic acid were also optimized. Results showed that the conversion of furfural residue into levulinic acid was promoted by FeCl3. The dissolution of cellulose was promoted and the yield and selectivity of levulinic acid were improved by adding NaCl. The reaction conditions for the preparation of levulinic acid were optimized as the follows:temperature of 200℃, H2SO4 mass fraction of 3%, ratio of solution containing catalyst and furfural residue 6:1 (mL:g), FeCl3 addition amount of 1.8%, and NaCl addition amount of 7%. The levulinic acid yield of 69.18% and selectivity of 89.46% can be obtained at the optimum conditions, which were 15.3 and 21.9 percent point higher than that of without NaCl addition respectively.
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    Molecular Structure and Curing Characteristics of Lignin-phenol-formaldehyde Resin Prepared with the Use of Magnesian Ion as Catalyst
    YANG Sheng, WANG Jun, LI Gaiyun, FAN Dongbin
    2018, 38 (4):  74-78.  doi: 10.3969/j.issn.0253-2417.2018.04.012
    Abstract ( 572 )   PDF (663KB) ( 574 )   Save
    The narometer magnesium oxide (MgO) was used as catalysis for the preparation of lignin-phenol-formaldehyde (MLPF) resin. MgO was added in the initial stage of resin reaction. The molecular structure and thermal behavior of the curing reaction of MLPF resin were characterized by Fourier transform infrare spectroscopic (FT-IR), 13C nuclear magnetic resonance (13C NMR) and different scanning calorimetry (DSC), respectively. A comparisons to phenol-formaldehyde (PF) resin and lignin-phenol-formaldehyde(LPF) resin without adding MgO were also carried out to investigate the effects of Mg2+ on the structure and curing characteristics of MLPF resin. The research results indicated that Mg2+ could promote the formation of hydroxymethyl group, increase the amounts of methylene, restrict the formation of ether bond bridge during MLPF resin synthesis, and lead to the higher structure condensation degree of MLPF resin than that of LPF resin. MgO seemed to make MLPF resin cure faster and decrease its curing reaction temperature.
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    Catalytic Liquefaction of Spartina alterniflora in Ethanol-water Co-solvent for Bio-oil
    XU Guisheng, HE Zhixia, XU Zhixiang, JI Changhao, WANG Qian
    2018, 38 (4):  79-86.  doi: 10.3969/j.issn.0253-2417.2018.04.013
    Abstract ( 613 )   PDF (3750KB) ( 545 )   Save
    In the paper invading plants Spartina alterniflora Lois. (S. alterniflora) was chosen as raw materials and catalytic liquefied (CL) in ethanol-water with the participation of the readily available alkaline catalyst KOH. The effects of different process conditions on the bio-oil yield and residue yield of S. alterniflora were investigated. Additionally, to investigate the effect of the action of KOH on bio-oil yield, residue yield and the composition of bio-oil, direct liquefaction (DL) was carried out with the same reaction parameters as comparison. The results showed that the conditions of liquefaction reaction of S. alterniflora could be alleviated with the cation of catalyst KOH and the maximum bio-oil yield (52.30%) as well as fractional conversion (90.17%) were observed at the optimal conditions of 320℃, ethanol volume fraction 75%, ratio of liquid to material 10:1 (mL:g) and reaction time 60 min. SEM micrographs of solid residue indicated that volatiles were vented during initial stages of depolymerisation of S. alterniflora with the participation of KOH. GC-MS analysis and FT-IR analysis of bio-oil indicated that the composition of main ingredients of bio-oil was not significantly changed by the action of KOH but the mass fraction was impacted to a certain degree. Phenolic compounds of bio-oil increased significantly from 29.88% to 40.98% and ester compounds reduced evidently of which the mass fraction was 10.40%.
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    Preparation of Core-shell Magnetic Rosin-based Polymer Microspheres and Their Adsorption Kinetics and Thermodynamics of Mn2+
    LI Kechun, LEI Fuhou, LU Jianfang, ZHOU Juying, ZHAO Yanzhi
    2018, 38 (4):  87-94.  doi: 10.3969/j.issn.0253-2417.2018.04.014
    Abstract ( 535 )   PDF (1858KB) ( 728 )   Save
    The core-shell magnetic rosin-based polymer microspheres Fe3O4@RPM were synthesized by chemical precipitation and suspension polymerization with maleic rosin ethylene glycol acrylate as cross-linking agent, methacrylic acid and methyl methacrylate as monomers, and Fe3O4 as a magnetic core. The preparation conditions were optimized. The structure of Fe3O4@RPM was characterized by Fourier transform infrared spectrometer(FT-IR), field emission scanning electron microscope (FESEM), X-ray diffraction instrument(XRD), and thermogravimetric analysis(TGA), and so on. The adsorption kinetics and thermodynamics for adsorbing Mn2+ were studied through static adsorption experiments. The results showed that the preparation conditions of the polymeric magnetic microspheres with phenanthrene framework were shaking at the speed of 400 r/min,adding 1 g azodiisobutyronitrile as initiator and reacting for 4 h at 70℃. The second-order kinetics model could well describe the adsorption process of Mn2+ in the experimental range of concentration and temperature, the adsorption thermodynamic studies showed that ΔH >0,ΔG <0,ΔS >0,which indicated that the adsorption was a spontaneous endothermic process.
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    Characterization and Kinetic of Co-pyrolysis of Coal and Salix Under CO2/N2 Atmospheres
    GONG Juhui, SHAO Tingting, WANG Kebing
    2018, 38 (4):  95-102.  doi: 10.3969/j.issn.0253-2417.2018.04.015
    Abstract ( 513 )   PDF (1264KB) ( 605 )   Save
    The pyrolysis of coal,Salix psammophila and mixture of salix and coal(mass ratio coal of salix 1:4,5:5,4:1) under different V(CO2):V(N2) (1:4,5:5,4:1) atmosphere were analyzed by using temperature programmed thermogravimetric analysis. Pyrolysis kinetic parameters were obtained by Coats-Redfern method after the experiment. The interaction between salix and coal were studied. The experimental results showed that the two main pyrolysis temperature sections overlapped each other.When V(CO2):V(N2) was 5:5, the co-pyrolysis of coal and salix with different blends of coal and salix mixtures had promoting effect and the effect was weaker and weaker with the increase of the content of salix. When m(coal):m(salix) was 5:5, the larger the proportion of CO2 atmosphere under different atmosphere proportion at high temperature pyrolysis was, the stronger the interaction between Salix psammophila and coal was. The pyrolysis kinetics analysis by Coats-Redfern method showed that the activation energies were 15-70 kJ/mol, and the activation energy of salix was higher than that of coal. The activation energy required for the high temperature section was greater than that for the low temperature section. Both the CO2/N2 atmosphere ratio and the salix/coal ratio had a certain influence on the activation energy and pre-exponential factors. When V(CO2):V(N2) was 5:5, with the increase of salix in the mixture, and when m(coal):m(salix) was 5:5, with the increase of CO2, the activation energy of the mixture and the change trend of the pre-exponential factor both increased first and then decreased.
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    Simultaneous Determination of Isobiflorin and Biflorin in Fujian Euscaphis japonica by HPLC
    NI Lin, QIU Yatie, LI Yanlei, ZOU Xiaoxing, XU Huiyou
    2018, 38 (4):  103-108.  doi: 10.3969/j.issn.0253-2417.2018.04.016
    Abstract ( 521 )   PDF (585KB) ( 690 )   Save
    The method for simultaneous determination of isobiflorin and biflorin in Euscaphis japonica(Thunb.) Dippel was established by HPLC, and their contents in twigs, leaves, epicarp, and seeds of E. japonica from 10 different producing areas in Fujian province were determined. The determination was carried out on Dikma Diamonsil C18 column (250 mm×4.6 mm, 5 μm) with anisocraticmobile phaseof 25% methanol.The flow rate was 1.0 mL/min, the UV detection wavelength was set at 256 nm, the column temperature was 30℃, and the detection time was 15 min. The isobiflorin(A) and biflorin(B) showed good linearity in the range of 2.000 2-20.002 0 μg (r=0.999 9) and 2.001 6-20.016 0 μg (r=0.999 9), respectively. The average recoveries of isobiflorin and biflorin were 98.42% and 99.77% with the RSD of 0.88% and 0.96%, respectively. The developed method was found to be rapid, stable and accurate, and could be used to control the quality of E. japonica development and application of traditional Chinese medicine.
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    Technology of Microwave-assisted Extraction of Sapindus Peel Polysaccharide and Its Antioxidant Activity
    LIU Dandan, HAN Weifan, JIANG Jianxin, ZHU Liwei
    2018, 38 (4):  109-116.  doi: 10.3969/j.issn.0253-2417.2018.04.017
    Abstract ( 594 )   PDF (1486KB) ( 776 )   Save
    The microwave extraction technology and in vitro antioxidant capacity of polysaccharides from Sapindus peel were studied in this work, and the primary structure of the polysaccharide was also characterized. The effects of microwave extraction temperature, extraction time and liquid-solid ratio on the yield of polysaccharides were investigated. The microwave extraction process was optimized by response surface analysis. The results showed that the optimum extraction process conditions were as follows:extraction temperature 92℃, extraction time 26 min, liquid-solid ratio 25:1(mL:g). The maximal yield of polysaccharides reached 3.47%. Sapindus peel polysaccharide is mainly composed of glucose, xylose, galactose, arabinose and fructose, with typical polysaccharide IR characteristics. In addition, the anti-oxidative activity of polysaccharides was evaluated by the scavenging ability on hydroxyl radicals and DPPH free radicals. Sapindus peel polysaccharides showed strong antioxidant activity in a concentration-dependent manner, and the antioxidant activity of the crude polysaccharides was significantly higher than that of purified polysaccharides. The antioxidant activity of polysaccharides has a certain correlation with the glycoprotein structure.
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    Preparation of Aspergillus niger Mycelium-chitosan Biosorbent and Its Cu2+ Adsorption Mechanism
    XIA Yuantao, YANG Meihong, SUN Huijie, GAO Yating, ZHOU Gui
    2018, 38 (4):  117-123.  doi: 10.3969/j.issn.0253-2417.2018.04.018
    Abstract ( 530 )   PDF (622KB) ( 613 )   Save
    The waste Aspergillus niger mycelium and chitosan were cross-linked by epichlorohydrin and then solidified sodium tripolyphosphate to prepare the Aspergillus niger mycelium-chitosan biosorbent for Cu2+. The effects of adsorption time, pH value, temperature, the initial concentration of Cu2+ and the amount of biosorbent on the adsorption efficiency were investigated. Kinetics, intragranular diffusion model, adsorption isotherm equation, thermodynamic model were used to fit the experimental data. The results showed that the adsorption rate increased by increasing the adsorption temperature, adsorption time and pH value. The adsorption rate of Cu2+ reached 99.42% at the adsorption conditions of 0.4 g Aspergillus niger mycelium-chitosan biosorbent, adsorption time 180 min, adsorption temperature 50℃, mass concentration of Cu2+ 20 mg/L. The adsorption process conformed to the Freundlich isotherm model. The adsorbed Gibbs free energy became negative, and ΔHɵ were ΔSɵ are 6.104 2 kJ/mol and 45.258 1 J/(mol·K), respectively, ie the adsorption was a spontaneous endothermic process. Kinetic data analysis showed that the adsorption of Cu2+ by Aspergillus niger mycelia-chitosan biosorbents fitted quasi-second-order kinetic model.
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    Isomerization of Resin Acid Under Desorption-distillation Processes with Different Medium
    YUE Xiantian, ZENG Tao, LING Qinghua, WANG Xueyuan
    2018, 38 (4):  124-128.  doi: 10.3969/j.issn.0253-2417.2018.04.019
    Abstract ( 529 )   PDF (452KB) ( 540 )   Save
    The variation regularity of isomerization reaction of rosin resin acid was discussed after desorption-distillation dissolution of rosin liquid with H2O,N2,CO2 as distillation medium. The effects of desorption-distillation temperature, kinds of medium and medium flow rates on the isomerization of resin acid were investigated. The results showed that the isomerization reaction of abietic resin acid was more intense when water vapor was used as desorption-distillation medium, while the isomerization reaction was mild when N2 and CO2 were used as desorption-distillation medium, and the effect of medium flow on isomerization reaction was not obvious. The resin acid composition of rosin was analyzed by gas chromatography(GC) and gas chromatography-mass spectrometry(GC-MS).The crystal tendency of the product was observed. The resin acid composition of the crystalline rosin at the low temperature stage was analyzed by GC. The results of crystallization tendency showed that the three kinds of desorption-distillation medium showed different degrees of crystallization tendency at the low temperature stage, the desorption-distillation temperature of N2 desorption-distillation medium was the lowest, and the crystallization tendency of the product rosin was the smallest; Crystallization mechanism showed that the abietic acid and palustric acid content level and its ratio determined the size of the product rosin crystallization tendency.
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