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    30 January 2020, Volume 54 Issue 1 Previous Issue    Next Issue
    Research Report
    Research on Capability of Semi-solid Anaerobic Digestion of Rice Straw Using Percolation Bed Reactor
    Ke LIU,Jing HE,Xiuli WEI,Tao JIANG,Ning TANG,Deyong ZHANG
    2020, 54 (1):  1-8.  doi: 10.3969/j.issn.1673-5854.2020.01.001
    Abstract ( 233 )   HTML ( 358 )   PDF (806KB) ( 392 )   Save

    The effects on the gas production and the energy conversion rate of straw anaerobic fermentation, the performance of biogas slurry and the gas production cost after fermentation were comparative researched under four different temperatures(20, 25, 30 and 35℃) and three different pretreatment methods(NaOH, biological reagents and biogas slurry) by self-designed leach bed reactors using rice straw as raw material. The results showed that the total solid(TS) mass fraction of substrate after fermentation reached a stable level at 13% to 15%-semi-solid anaerobic fermentation; also the cumulative gas production and temperature, the changes of COD and NH3-N after fermentation were significantly correlated. It also showed that the TS biogas yield of rice straw after pre-treatment was higher than that of the untreated under the same temperature(20-30℃). The TS biogas production was 154.0 mL/g and volatile solids(VS) methane yield was 55.2 mL/g under 35℃, which increased 25.1% and 52.5% respectively comparing with those of the untreated sample. At the same time, the methane volume fraction in anaerobic fermentation gas production could be significantly improved by biogas slurry pretreatment. The methane yield of TS and VS increased, while the elevation rate of methane production gradually decreased with the increase of temperature (20-30℃). The methane production of all treatments could be increased by 90% when the fermentation temperature rose from 20 to 25℃. According to the analysis of gas production cost, the self-produced biogas slurry had better treatment effect and lower production cost. The variable cost for each 1 m3 of biogas produced was 1.62 yuan. Considering the warming of biogas fermentation tank and energy input-output balance, temperature control at 25℃ might be the optimal economic strategy mode.

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    Separation and Purification of Levulinic Acid from Hydrolysate of Biomass by Using Compression Vacuum Distillation
    Chen GONG,Xuejuan CAO,Xing TANG,Xianhai ZENG,Yong SUN,Lu LIN
    2020, 54 (1):  9-15.  doi: 10.3969/j.issn.1673-5854.2020.01.002
    Abstract ( 346 )   HTML ( 97 )   PDF (430KB) ( 351 )   Save

    The simulative hydrolysate containing levulinic acid(LA) and sulfuric acid was used to study the effect of sulfuric acid on LA distillation and purification. The effect of H+ concentration, the sulfate concentration and the distillation temperature were comprehensively studied for the separation of LA. Further investigation of the alkali neutralization revealed that the neutralization of H+ by sodium hydroxide could effectively increase the recovery of LA. The presence of sulfuric acid was not conducive to the separation and purification of LA, and the concentration of H+ was the main negative factor for LA recovery. The higher concentration of sulfate was beneficial to the LA recovery to a certain extent and the optimal distillation temperature was 170-180℃ at a constant H+ concentration. Using sodium hydroxide to neutralize hydrogen ions in the simulated hydrolysate, desirable LA recovery with high purity could be expected. When the simulative hydrolysate contained 100 mL water, 0.1 mol LA and 0.03 mol sulfuric acid, LA recovery of 84.5% with the purity of 93.3% could be obtained with the addition of 0.06 mol NaOH and distillation in vacuum at 170℃. Furthermore, the separation of LA from the hydrolysate derived from the acid-catalyzed hydrolysis of raw biomass was also studied. The separation of LA was carried out after the neutralization by adding sodium hydroxide, and the final recovery rate of LA(purity 93.5%) up to 91.8% was achieved when the molar ratio of NaOH to sulfate was 1.4.

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    Preparation, Characterization and Adsorption Performance of Hydroxymethylated Lignin/Cellulose Aerogel Particles
    Jianan WANG,Ying YI,Yongjun BIAN,Yuanyuan MA,Zhiming LIU
    2020, 54 (1):  16-22.  doi: 10.3969/j.issn.1673-5854.2020.01.003
    Abstract ( 400 )   HTML ( 92 )   PDF (3636KB) ( 384 )   Save

    Hydroxymethylated lignin/cellulose composite aerogel particles were prepared by freeze-drying with NaOH/urea aqueous solution as the solution system using hydroxymethylated lignin and cellulose as raw materials. The structure of the product was characterized by scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), specific surface area and aperture analyzer. The results showed that the methylated lignin was attached to the cellulose skeleton by hydrogen bonding, and the aerogel still maintained three-dimensional network structure. The aerogel surface shrank significantly with the introduction of methylated lignin, and the density of the network structure gradually decreased with the increase of the content of methylated lignin. At the same time, aerogel particles had cellulose Ⅱ type infrared absorption peak and XRD diffraction peak; the particles showed Ⅱ isothermal adsorption/stripping isotherm, and the apertures were all below 15 nm, and with hydroxymethyl lignin content increasing, the specific surface area, entrance reduced, and the specific surface area of HKL-4 was 105.3 m2/g, entrance was 0.336 6 cm3/g, pore size was 13.67 nm. The adsorption performance analysis showed that the unit adsorption capacities of HKL-4 aerogel particles to auramine O, methylene blue and rhodamine B at 25℃ for 5 h were 33.06, 96.06 and 43.26 mg/g, respectively, and the saturated adsorption capacity of methylene blue was up to 208.7 mg/g. The adsorption process was more consistent with the Langmuir isothermal adsorption model, mainly monolayer adsorption.

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    On-line Detection of Corncob Rapid Pyrolysis Products Based on Py-GC×GC-qMS
    Wenbin LI,Yunwu ZHENG,Yi LU,Zhifeng ZHENG
    2020, 54 (1):  23-30.  doi: 10.3969/j.issn.1673-5854.2020.01.004
    Abstract ( 283 )   HTML ( 73 )   PDF (1159KB) ( 414 )   Save

    The pyrolysis products of corncob at different temperatures were analyzed on-line by using the pyrolysis-comprehensive two-dimensional gas chromatography-mass spectrometry(Py-GC×GC-qMS). The results showed that the 191 compounds were detected by GC×GC-qMS, including alcohols, acids, aldehydes, ketones, esters, furans, hydrocarbons, phenols, nitrogens and sugars when the corncob was pyrolyzed at 550℃ with 18 s. The main compounds included benzofuran, 2, 3-dihydro-, 1, 6-anhydro-beta-d-talopyranose and furfural, with GC contents of 9.15%, 8.8% and 5.21%, respectively. However, GC-qMS detected only 58 compounds, and no sugars were detected. The types of corncob pyrolysis products gradually increased with temperature increasing, reaching a stable value at 550℃. The influence of temperature on the contents of aldehydes, ketones and furans was not obvious, and the GC contents reached the maximum at 450, 550 and 500℃, which were 4.80%, 13.57% and 21.01%, respectively. Alcohols, acids and esters were easily be formed at low temperatures. Hydrocarbons were more easily be formed at high temperature, and the GC content was 10.77% at 600℃. The contents of phenols increased first and then decreased, and the maximum GC content was 23.77% at 450℃. The effect of temperature increase on the GC content of nitrogens and sugars was not obvious.

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    Preparation and Kinetic Analysis of Novel Antioxidants of Biodiesel
    Yonghui WU,Fashe LI,Jiaxu SHEN,Shuang WANG,Wei DU,Xuehua WU
    2020, 54 (1):  31-36.  doi: 10.3969/j.issn.1673-5854.2020.01.005
    Abstract ( 287 )   HTML ( 18 )   PDF (1089KB) ( 327 )   Save

    A new antioxidant biodiesel isopropyl gallate was prepared by using gallic acid and isopropanol as raw materials, pyridine bisulfate ionic liquid as catalyst. Through the single factor analysis, the optimal reaction conditions of catalytic esterification reaction were obtained as reaction time 4 h at 85℃, the ratio of alcohol to acid 35:1, catalyst dosage 12%, the yield of isopropyl gallate under these conditions was 89.1%. Based on the catalytic esterification reaction dynamics analysis, the reaction apparent activation energy and the frequency were obtained as 60.942 kJ/mol and 7 060 313.404, respectively. The addition of 0.05% isopropyl gallate in gallate in gutter oil biodiesel significantly improved the oxidation stability, and the induction period increased from 0.61 h to 6.34 h, which completely reached the national standard for biodiesel(induction period 6 h). The experimental results showed that isopropyl gallate had good performance as new biodiesel antioxidant.

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    Analysis of Fiber Characteristics of Caragana korshinskii Kom. and Study on Twin-screw Chemi-mechanical Pulping
    Shuying BI,Yanchao LIU,Hongfei WU,Chen JIANG,Yimin XIE
    2020, 54 (1):  37-42, 54.  doi: 10.3969/j.issn.1673-5854.2020.01.006
    Abstract ( 291 )   HTML ( 7 )   PDF (4708KB) ( 382 )   Save

    The chemical composition and fiber morphology from Caragana korshinskii Kom. were analyzed. The twin-screw CMP pulping process of the C. korshinskii and the fiber morphology of the pulp and the physical properties of the handsheet were discussed. The results showed that the contents of cellulose and holocellulose in the raw material of C. korshinskii Kom. were lower than that of softwood and hardwood. The contents of benzene-alcohol extractive and hot water extractive were high. C. korshinskii fibers were generally short; the weight-average lengths of xylem fibers and phloem fibers were 0.621 and 0.819 mm, respectively. There were also some non-fiber cells. The yield of the obtained CMP pulp reached 73% after pretreatment with 3.5% Na2SO3 and 1.5% NaOH for 12 h at normal temperature, steaming at 90℃ for 1 h, and then refining with twin-screw at the mass fraction of 35%, and finally refining with high-concentration disc refiner. The CMP pulp from C. korshinskii basically maintained the original length of the fiber with the weight-average length of 0.650 mm. The aspect ratio was 32.7, and the fiber dissociation was better, but the separation of filaments was not ideal, and it contained some fiber bundles and miscellaneous cells. When the Canadian freeness was 300 mL, the ring crush index and bulk of the handsheets were high, reaching 8.67 (N·m)/g and 2.56 cm3/g, respectively. And the tensile index was 19.6 (N·m)/g. The whiteness of the handsheet was high, reaching 50%(ISO). The CMP pulp from C. korshinskii was suitable for packaging paper such as corrugated medium, and could be used for newsprint and whiteboard paper after bleahing.

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    Compositions of the Essential Oil of Helianthus annuus Head and Its Antioxidant Activities
    Changyi HE,Xiaohan GAO,Zewen LI,Lingling LIU,Tongtong SUN,Xiaoqiang CHEN
    2020, 54 (1):  43-48.  doi: 10.3969/j.issn.1673-5854.2020.01.007
    Abstract ( 435 )   HTML ( 30 )   PDF (464KB) ( 332 )   Save

    The essential oil of Helianthus annuus head which harvested in autumn was extracted by water-steam distillation, and it's components was characterized by gas chromatography-mass spectrometry(GC-MS). The in vitro antioxidant activities of essential oil were studied by 2, 2-di(4-tert-octylphenyl)-1-picrylhydrazyl(DPPH) and 2, 2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical scavenging assay. The GC-MS analysis showed 49 kinds of chemical components(comprising 91.16% of the essential oil) were identified from the essential oil of H. annuus head, and α-pinene(28.22%), limonene(6.55%), α-humulene(4.99%), trans-β-farnesene (3.58%) and camphene (3.39%) were the main ingredients. The essential oil had some in vitro antioxidant activity, and the half effective concentration(EC50) of the essential oil against DPPH and ABTS radical were 0.47 and 0.30 g/L, respectively, which significantly higher than that of BHT(8.21 and 6.16 mg/L).

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    Regulation Effect of P Factor on Mass Concentration of Chemical Composition in Prehydrolysis Liquor of Poplar
    Haimei LIU,Si ZHAO,Nianjie FENG
    2020, 54 (1):  49-54.  doi: 10.3969/j.issn.1673-5854.2020.01.008
    Abstract ( 272 )   HTML ( 7 )   PDF (578KB) ( 253 )   Save

    In order to reveal the regulation mechanism of P factor on the mass concentration of chemical composition in prehydrolysis liquor of lignocellulose, the mass concentration changes of solid content, lignin, xylose and glucose were studied at different prehydrolysis temperature(170-210℃) and time(30-120 min). The results showed that the mass concentration of solid content, lignin and glucose gradually increased with the increase of prehydrolysis temperature and time. While the mass concentration of xylose rapidly decreased with the increase of temperature and prehydrolysis time at 190℃. There was a regulation effect of P factor on mass concentration of chemical composition in prehydrolysis liquor of poplar. The mass concentration of solid content, lignin and glucose presented an exponential increase with the increase of P factor. However, a conspicuous decrease of mass concentration of xylose was found with the increase of P factor when P factor < 3 300.

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    Review Comment
    Preparation of Nanocellulose by Cellulase Hydrolysis Under Sonication-assisted
    Linna LU,Qilin LU
    2020, 54 (1):  55-59.  doi: 10.3969/j.issn.1673-5854.2020.01.009
    Abstract ( 318 )   HTML ( 146 )   PDF (1742KB) ( 342 )   Save

    Nanocellulose(NCC) was prepared with cellulose pulp as raw material by using cellulase hydrolysis under sonication-assisted technology. Orthogonal test was used to optimize the preparation of NCC on the basis of single factor test. The structure and properties of NCC were analyzed and characterized by transmission electron microscope(TEM), X-ray diffraction(XRD), infrared spectroscopy(FT-IR), thermogravimetry(TG) and Zeta potential measurement. The results showed that the yield of 62.3% for NCC could be achieved when the cellulase dosage was 7%, reaction temperature was 50℃ and reaction time was 10 h. TEM image showed that the prepared NCC was short rod-like, which interacted with each other to form a web-like network. XRD results suggested that the crystal structure of NCC was cellulose I, and the crystallinity increased from 54.2% to 73%. FT-IR implied that the original chemical structure of NCC was not altered. TGA analysis indicated that the thermal stability of NCC was significantly improved compared with that of cellulose pulp. The Zeta potential test showed that NCC suspension had good dispersion stability in aqueous medium.

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    Research Progress in Synthesis and Application of δ-Valerolactone Base on Furfural
    Ronghui XU,Guosheng WANG
    2020, 54 (1):  60-66.  doi: 10.3969/j.issn.1673-5854.2020.01.010
    Abstract ( 439 )   HTML ( 527 )   PDF (528KB) ( 460 )   Save

    Study on three main synthetic routes of δ-valerolactone by cyclopentanone, 1, 5-pentanediol by furfuryl alcohol and tetrahydrofurfuryl and by tetrahydrofuran are reviewed using furfural as raw material. The synthesis of δ-valerolactone by other furfural derivatives is also described. The applications of δ-valerolactone in pharmaceutical intermediates and polyesters are summarized, which is used in pharmaceutical industry because its structure is widely found in bioactive and optically active compounds. It is easy to polymerize, and can also form polylactide with other compounds.The polymer has biocompatibility and biodegradability, which makes its application in the field of biodegradable materials attractive. Therefore the preparation of the δ-valerolactone production technology using furfural as raw material is a hot topic in the future.

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