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    30 September 2019, Volume 53 Issue 5 Previous Issue    Next Issue
    Research Report
    Characterization of Modified Apricot Shell Activated Carbon and Its Adsorption Properties on Ethylene
    Congjing DENG,Huanhuan MA,Jianbin ZHOU
    2019, 53 (5):  1-8.  doi: 10.3969/j.issn.1673-5854.2019.05.001
    Abstract ( 502 )   HTML ( 1215439033 )   PDF (2896KB) ( 727 )   Save

    The effects of modifiers(AgNO3, Cu(NO3)2 and H2O2·Cu(NO3)2) and modification conditions(particle size of activated carbon, immersion time, roasting time and roasting temperature) on the ethylene adsorption properties of modified activated carbon were studied with apricot shell activated carbon(AC) as raw material. the structure and surface chemical composition of modified activated carbon were studied by means of ESEM-EDS, FT-IR, XPS and so on. The adsorption mechanism of ethylene on modified activated carbon was also discussed. The results showed that 15% H2O2 and 2% Cu(NO3)2 were the best modifier. The particle size, roasting time and temperature had greater influence on the adsorption properties than the immersion time. Under the conditions of 15% hydrogen peroxide and 2% copper nitrate as modifier, the particle size of activated carbon 0.83-0.38 mm, immersion time 6 h, roasting temperature 400℃ and the roasting time 4 h, the modified activated carbon had better ethylene adsorption properties, and the adsorptive capacity was 0.163 g/g, which increased by 136.23% than that of unmodified activated carbon(the adsorptive capacity was 0.069 g/g). The active component copper was uniformly dispersed on the surface and inside the pores of activated carbon. The pore structure and surface functional groups of activated carbon were changed by the modifier, the specific surface area decreased from 1 047.50 m2/g in AC to 1 012.65 m2/g, the total pore volume decreased from 0.467 1 cm3/g in AC to 0.434 7 cm3/g, and the pore diameter was distributed in a wider direction, among them, the pore diameter proportion of < 10 nm decreased from 58.16% to 53.95%, the pore diameter proportion of 10-20 nm increased from 18.01% to 19.10%, and the pore diameter proportion of >20 nm increased from 23.83% to 26.94%. The oxygen-containing functional groups increased, and the relative contents of C1, C3 and C5 decreased, the proportion of C1 peak area decreased from 77.468% to 76.827%, the proportion of C3 peak area decreased from 6.684% to 5.675%, and the peak area proportion of C5 decreased from 0.844% to 0.749%, the relative contents of C2 and C4 increased, and the proportion of C2 peak area increased from 13.514% to 15.225%, the proportion of C4 peak area increased from 1.490% to 1.524%.

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    Rheological Behaviors and Curing Properties of Synergistic Cross-linked Soybean Based Adhesives
    Guangbin WANG,Lijun WANG,Jiabao CHEN,Ling LI,Chunpeng WANG,Fuxiang CHU,Yuzhi XU
    2019, 53 (5):  9-14.  doi: 10.3969/j.issn.1673-5854.2019.05.002
    Abstract ( 418 )   HTML ( 1181 )   PDF (576KB) ( 597 )   Save

    Soybean-based adhesives with good rheological behaviors and curing properties were made of soybean flour by synergistic modification of aqueous polyamide and isocyanate. The effect of various modifiers on the rheological behaviors was investigated by using rotational rheometer. The results showed that the soy-based adhesives were pseudoplastic fluid, and the rheological behavior was better when 10% aqueous polyamide was added, but the isocyanate cross-linking agent had no influence on the rheological behavior of these adhesives at room temperature. Through the dynamic temperature scan mode of the rheometer test, it was found that the amount of isocyanate had great influence on the storage modulus and loss modulus of soybean adhesive. The bonding strength was 0.74 MPa and meeting the national board Ⅱ requirements(≥ 0.70 MPa) when 10% aqueous polyamide and 4% isocyanate were added simultaneously, which indicated that the cross-linking reaction happened between the aqueous polyamide/isocyanate synergistic cross-linking system and soy protein molecules.

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    Catalytic Synthesis of 5-Hydroxymethylfurfural and Levulinic Acid from Agarose with ZrOCl2 as Catalyst
    Xinjun HE,Jiao MA,Kangjun WANG,Zhanwei XU,Songyan JIA
    2019, 53 (5):  15-20.  doi: 10.3969/j.issn.1673-5854.2019.05.003
    Abstract ( 529 )   HTML ( 6533720 )   PDF (2004KB) ( 663 )   Save

    Agarose was used as the starting material, and CuCl2, NiCl2, MnCl2, MgCl2, FeCl3, AlCl3, ZrOCl2 and SnCl4 were respectively used as catalysts to convert agarose into 5-hydroxymethylfurfural(5-HMF) and levulinic acid(LA). Preferred catalysts were screened out for the conversion of agarose. The effects of reaction parameters such as water content, catalyst loading, reaction temperature and reaction time on the reaction were investigated in detail. The results demonstrated that when 50 mg of agarose was used as the feedstock with ZrOCl2 as the catalyst and DMSO as the solvent, 5-HMF yield of 26.9% and LA yield of 24.7% could be achieved in 1 mL DMSO/H2O mixed solvent with a volume ratio of 8:2 and ZrOCl2 loading of 10% to the amount of substance of monosaccharide in agarose at 140℃ for 60 min. Mechanism analyses indicated that agarose was hydrolyzed into aldose, which underwent subsequent isomerization and dehydration to produce 5-HMF. 5-HMF could be further converted into LA catalyzed by acid catalyst.

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    Comparison of Preparation and Properties of Polysaccharide Gums from Gleditsia sinensis Lam. and Gymnocladus dioicus(L.) K. Koch
    Siyi JU,Changyou GUO,Miaoxin ZHU,Yantao LIU,Jianxin JIANG
    2019, 53 (5):  21-26.  doi: 10.3969/j.issn.1673-5854.2019.05.004
    Abstract ( 609 )   HTML ( 8639256 )   PDF (489KB) ( 737 )   Save

    The Gleditsia sinensis Lam. and Gymnocladus dioicus(L.) K. Koch were used as raw materials for 4, 6, and 8 min photo-wave baking pretreatment and mechanical separation, and then polysaccharide gums were prepared by micro water solid phase method and purified. The effects of different photo-wave baking pretreatment time on the apparent viscosities and compositions of the polysaccharide gums with two raw materials were compared. The results showed that the apparent viscosities of the two polysaccharides pretreated for 6 min were the highest, which were 461.90 and 703.85 mPa·s under the shear rate of 5.1 s-1, respectively. The longer the baking time was, the higher the protein content in the G. sinensis gum was, while the protein content in the G. dioicus gums barely changed. The water insoluble contents of G. sinensis gum were generally higher than those of G. dioicus gum.The lowest water insoluble contents of G. sinensis gums and G. dioicus gums were 32.30% and 32.50% after pretreatment by baking for 8 and 6 min, respectively. The galactomannan content(79%-83%) of purified polysaccharide gums significantly was higher than the pristine polysaccharide gums, and the M/G value(about 3.0) of purified polysaccharide gum was significantly lower than that of the pristine polysaccharide gums.

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    Effects of Temperature on Pelletization of Four Typical Types of Biomass
    Weizhen LI,Yang JIANG,Wei WANG,Xiuli YIN,Mingfeng WANG
    2019, 53 (5):  27-33.  doi: 10.3969/j.issn.1673-5854.2019.05.005
    Abstract ( 575 )   HTML ( 3200657 )   PDF (4111KB) ( 603 )   Save

    Four typical types of biomasses, corn stover, eucalyptus sawdust, bamboo sawdust and hardwood sawdust, were used as raw materials to analyze the effects of temperature and material chemical composition on the properties of pellets by conducting single pellet making experiments. The characteristic thermal transition temperatures of the four raw materials were measured using a differential scanning calorimetry and found the glass transition temperatures(Tg) were in the temperature range of 80-100℃. It was found that the relaxed density(DRS) and radial maximum stress(MRS) were lower and the specific energy consumption(ESC) was higher at 40℃, the relaxed density and radial maximum stress increased and the specific energy consumption decreased in the temperature range of 70-100℃, the relaxed density increased and the radial maximum stress did not present consistent change law and the specific energy consumption increased in the temperature range of 100-160℃. The lowest specific energy consumption located at 100℃ during the characteristic thermal transition temperature range. Besides, the higher the raw material lignin content was, the higher the specific energy consumption and the radial maximum stress were. The micromorphology of the internal cross section of the pellets showed that there were large gaps between the particles at the temperature of lower than the onset of the glass transition temperature and there were few gaps between the particles at the temperature of higher than the endpoint of the glass transition temperature.

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    Analysis of Ultrasonic Assisted Wood-chip Impregnation at Atmospheric Pressure and Bleaching
    Cunxin XIE,Yongjun DENG,Jian JIAO,Hongbin LI,Ting WU,Guigan FANG
    2019, 53 (5):  34-38.  doi: 10.3969/j.issn.1673-5854.2019.05.006
    Abstract ( 415 )   HTML ( 15250319 )   PDF (482KB) ( 780 )   Save

    The ultrasound assisted impregnation at atmospheric pressure and its bleaching properties were studied with eucalyptus and poplar as raw materials by chemical thermomechanical pulp(CTMP) process. The effects of external factors such as impregnation temperatures, impregnation time and impregnation alkali amount on ultrasound assisted impregnation system were explored by continuously monitoring the change of amount of liquid absorbed and residual sodium hydroxide in impregnation system. The experimental results show that the optimum conditions for ultrasonic assisted impregnation were the temperature of 75℃, the time of 30 min and the alkali amount of 6% for eucalyptus, and the temperature of 75℃, the time of 30 min and the alkali amount of 5% for poplar. In this case, for eucalyptus, the brightness increased by 2.83%(ISO) and the residual hydrogen peroxide content increased by 4.4 percent point, the alkali absorption was 41.5 kg/t, which was 5.06% higher than that without ultrasonic treatment; for poplar, the brightness didn't change, the residual hydrogen peroxide content increased by 2.73 percent point and the alkali absorption was 38.75 kg/t, which was 6.15% higher than that without ultrasonic treatment.

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    Preparation and Antibacterial Properties of Cellulose/Superfine ZnO Composite Aerogels
    Rongsheng YANG,Junfang ZHU,Shubo FENG
    2019, 53 (5):  39-43.  doi: 10.3969/j.issn.1673-5854.2019.05.007
    Abstract ( 426 )   HTML ( 127 )   PDF (6004KB) ( 576 )   Save

    Cellulose(CE) was first dissolved by alkali method, and its hydrogen bond was destroyed. Then cellulose aerogels were prepared by cross-linking technology and freeze drying technology. It had good formability and flexibility. The cellulose aerogels were composited with superfine ZnO, which was obtained by solvothermal method, by immersion method to prepare cellulose/superfine ZnO(CE/ZnO) composite aerogels. The composite aerogels were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and elemental energy scattering(EDS). The results showed that the compositing was successful. At the same time, the composite aerogels were endowed with antibacterial properties. The antibacterial properties of the composite aerogels were also studied, and the results showed that the antibacterial activity of the composite aerogels improved with the increase of ZnO dosage. When the mass ratio of cellulose to ZnO was 1:2, the antibacterial effect of the obtained composite aerogel CE/ZnO-020 was the best, and the antibacterial rate reached 95.25%.

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    Comparative Analysis of Antioxidant Properties of Gallate Esters for Biodiesel Oxidation Stability
    Yishui ZHANG,Fashe LI,Shuang WANG
    2019, 53 (5):  44-48.  doi: 10.3969/j.issn.1673-5854.2019.05.008
    Abstract ( 332 )   HTML ( 74 )   PDF (435KB) ( 574 )   Save

    Seven kinds of gallic acid esters with different ester structure were prepared from gallic acid and alcohols and characterized by infrared spectroscopy. The results showed that the oxidation stability of 22 kinds of biodiesel was quite different. Seven different ester base structure of gallic acid ester antioxidant of 22 kinds of biodiesel significantly the antioxidant effect of ascension, the ester base different gallic acid ester antioxidant vary widely with the antioxidant effect of biodiesel such as adding gallic acid methyl ester(a), a small seed of tung tree of biodiesel induction period increased from 0.96 to 9.79 h, and adding the gallic acid butyl ester(f), a small seed of tung tree of biodiesel induction period increased from 0.96 to 5.92 h, both differ 3.87 h. Methyl gallate had the best antioxidant effect on biodiesel. After adding a, the induction period of 22 types of biodiesel was greater than that of the other six types of gallate antioxidants. The same kind of gallic acid ester antioxidant antioxidant effects of different biodiesel was different, the difference was bigger also. And the methyl gallate had the best antioxidant effect on biodiesel, the same kind of gallate ester antioxidant had different antioxidant effects to different biodiesel, such as methyl gallate had the best antioxidant effect on the biodiesel oil of Elsholtzia ciliata seed oil, which improved the induction time from 0.79 to 9.07 h, the antioxidant effect increased by 10.48 times, and the antioxidant effect on the palm oil biodiesel was poor, but the antioxidant effect also increased by 6.12 times, improving the induction time from 7.82 to 55.68 h. The antioxidant effects of gallate ester antioxidants with branched ester group or linear ester group on vegetable oils had very small difference.

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    Review Comment
    Research Advances in Catalytic Methanation of Bio-syngas
    Hang YIN,Wei XU,Yunjuan SUN,Yu XU,Hao YING,Siyun NING
    2019, 53 (5):  49-56.  doi: 10.3969/j.issn.1673-5854.2019.05.009
    Abstract ( 492 )   HTML ( 9883652 )   PDF (629KB) ( 663 )   Save

    Natural gas is becoming more and more advantageous than other kinds of fossil energy because it is clean, efficient and convenient to use. With the increasing demand of natural gas, the conflict between supply and demand of natural gas has gradually become increasingly prominent. The catalytic synthesis of synthetic natural gas from biomass synthesis gas has become one of the major technologies to solve the conflict.In allusion to the methanation of biomass synthesis gas, the research status of biomass synthesis gas methanation was explained from the aspects such as reaction process, catalyst and the reactor. Through comparing with the catalytic performance of different catalysts, it was analyzed that Ni-based catalyst was the most suitable for methanation catalyst for industrialization. Some cases of fixed and fluidized bed industrialization from abroad were showed and analyzed their production processes, advantages and disadvantages, it proved that the fluidized bed was very promising in the methanation reactor. Finally, the orientation of developing of biosynthesis gas catalytic synthesis of synthetic natural gas technology was outlooked.

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    Research Progress in Formation Mechanism of Typical Pyrolysis Products of Cellulose
    Zixiang GAO,Shengnan ZHANG,Weiming YI
    2019, 53 (5):  57-66.  doi: 10.3969/j.issn.1673-5854.2019.05.010
    Abstract ( 875 )   HTML ( 31815306 )   PDF (876KB) ( 924 )   Save

    It received increasing attentions to adopt the pyrolysis of biomass to produce liquid fuels and value-added chemicals. Study of the pyrolysis mechanism of biomass individual components could provide a better understanding of the biomass pyrolysis and was helpful for the regulation of the pyrolysis process. In this paper, the mechanisms of the cellulose pyrolysis and some typical products formation pathway were reviewed. And that further research should choose the representative model compounds was pointed out and the cellulose pyrolysis mechanism under different kinds of catalysts should be investigated.

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