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    30 May 2014, Volume 48 Issue 3 Previous Issue    Next Issue
    Effect of Activated Charcoals and a Coupled Biochar on Growth of Crops
    YU Zhong-dong, REN Zheng-zheng, PENG Shao-bing, ZHANG Shuai
    2014, 48 (3):  1-5.  doi: 10.3969/j.issn.1673-5854.2014.03.001
    Abstract ( 816 )   PDF (1186KB) ( 603 )   Save
    Seedlings growth of Chinese lettuce were dated under combination of 3 kinds of activated charcoal and 3 use patterns of soil respectively in Yangling region. An activated fir charcoal was picked up for making coupled biochar with endophytic bacteria, Bacillus sp., and the coupled fir biochar was further tested in pot planting with winter wheat. Results showed that of three charcoals, activated coal, activated coconut carbon and activated fir charcoal, significantly affected the growth of Chinese lettuce, as well as interactions between charcoal and soil. Fir charcoal showed 178.8%/90.9% and 178.9%/106.1% net carbon rate of promotion on hypocotyl/radicle of lettuce seedlings in agriculture soil and peach orchard soil respectively. Whereas, the acid activated coal showed -120.7% inhibition net rate to the growth of hypocotyl in the acid soil from Cedar stands. Therefore, fir charcoal was picked up for preparing an innovative biocharcoal by coupling with endophytic bacteria Bacillus sp. under 40 ℃ for 30 min, and then incubated at 27 ℃ for 1 d. The coupled biochar was found with potential function for growth of wheat stressed in 1% salt soil. The coupled mixture can improve the water holding capacity of soil. Seedlings in the group with combination of 3 g coupled fir charcoal and 1 250 g agriculture soil significantly promoted height rate at 37.3% (α=0.05 ) in 10 d, and the promoted biomass rate in the group with combination of 6 g coupled fir charcoal and 1 250 g agriculture soil were 18.8% (α=0.05) in 20 d. The latter was thought to be the optimal dosage in the tested groups for winter wheat with good height promotion and biomass promotion.
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    Effect of Carbonization Conditions on the Combustion Performance of Wheat Straw Carbon Sticks
    CHEN Chao, JIANG Jian-chun, SUN Kang, ZHANG Yan-ping, JIA Yu-jie
    2014, 48 (3):  6-10.  doi: 10.3969/j.issn.1673-5854.2014.03.002
    Abstract ( 707 )   PDF (1324KB) ( 653 )   Save
    In order to solve the shortcomings of straw briquettes, such as producing large amount of smoke during burning, failing to improve the calorific value due to its high volatile matter content, the briquettes were further carbonized for enhancing the calorific value and decreasing the amount of volatile component. The carbonization conditions, including carbonization temperature, heating rate and time, were investigated. Results showed that the calorific value of the produced carbon stick was increased obviously from 14.48 MJ/kg to 19.08 MJ/kg after heating at 300 ℃ for 1 h, with heating rate at 5 ℃/min. Density decreased from 1.31 g/cm3 to 0.99 g/cm3, and the fixed carbon increased obviously to approximately 40% after carbonization. Besides, smoking time and fume decreased dramatically due to the drastical decrease of violate matters from 60% to 40%, approximately, while the yield was 52.5%. This meets the demand of industry and daily life utilization.
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    Effects of Temperature and Catalysts on CO2 Gasification of Sawdust Charcoal
    WANG Yan-jie, YING Hao, YU Wei-jin, SUN Kang
    2014, 48 (3):  11-18.  doi: 10.3969/j.issn.1673-5854.2014.03.003
    Abstract ( 681 )   PDF (2988KB) ( 681 )   Save
    The effects of temperature (850, 900, 950, 1000 ℃) and catalysts (CaCO3 and K2CO3) on CO2 gasification of sawdust charcoal were investigated using thermal gravimetric analyzer and tubular reactor. Higher temperature had stimulative effect on the reactivity of sawdust charcoal reacting with CO2. With the increase of temperature from 850℃ to 1000 ℃, the CO content of gaseous product increased from 28.86 % to 54.45 %, and the heating value rised from 4.50 MJ/m3 to 7.95 MJ/m3. Meanwhile, the CO2 content decreased from 64.34 % to 36.54 %. With the sawdust charcoal sample of 2 g after gasification, the solid product decreased from 1.32 g to 0.79 g. The catalysts also had positive effects on CO2 gasification of sawdust charcoal that the CO content and heating value of gaseous product and reactivity were enhanced. And the CO2 content in gaseous product and solid product were decreased by the addition of CaCO3 and K2CO3. However, the catalytic effect of K2CO3 was more effective than that of CaCO3. The hybrid reaction model was applied to investigate the kinetics of sawdust charcoal CO2 gasification with different catalysts in this literature and the temperature range was 850-1 000 ℃. With the addition of CaCO3 and K2CO3, the activation energy and pre-exponential factor were lowered, the activation energy of charcoal without catalyst, charcoal with CaCO3 and charcoal with K2CO3 were 94.509, 81.740, 50.271 kJ/mol, and the pre-exponential factor were 1 208.428, 428.825, 19.965 min-1, respectively.
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    Research on Pyrolysis Dynamics of Pine Sawdust under Pressure and with CaO as Catalyst
    YU Wei-jin, YING Hao, JIANG Jun-fei, WANG Yan-jie
    2014, 48 (3):  19-24.  doi: 10.3969/j.issn.1673-5854.2014.03.004
    Abstract ( 639 )   PDF (2513KB) ( 707 )   Save
    The influences of different pressures, heating rate and addtion of CaO catalyst on pine sawdust pyrolysis process and dynamics analysis were studied. The experimental results show that: 1) Increasing the reaction pressure will reduce eventually weight loss rate of pyrolysis process, and the final remaining material will increase, increasing the reaction pressure is not conducive to the volatile analysis. This study found that a certain range of pressure increase can reduce the activation energy of pyrolysis process, which is advantageous to the pyrolysis reaction, but after the pressure exceeds 0.7 MPa,activation energy began to increase. 2)Increasing the heating rate can enhance the volatile releases, which is advantageous to the pyrolysis reaction, but a large amount of precipitation temperature rang of volatile was not obvious. It was found that with the increase of heating rate, the reaction activation energy trendth decrease. It shows that with the increase of heating rate, pine sawdust pyrolysis reaction is more intense. 3) Addition of CaO in the pine sawdust, has a larger effect on pyrolysis reaction process. With the increase of CaO catalyst additives,pine sawdust weight loss rate reduces gradually from 72.81 % to 59.61 %. Total reduction is 18.13 %. DTG curves show that weight loss peaks increased to four,the other two peaks are the decomposition weight loss caused by Ca(OH)2 and CaCO3, respectively. With the increase of addition of CaO, the first and second peaks of weight loss peak decreases gradually. The temperature corresponding to the peak point of the biggest change is not obvious. The third and fourth weight loss peaks increase gradually, and the maximum peak corresponding to the temperature appears obvious trend of increase.
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    Characterization and Properties of Activated Carbon from Several Nut Shells
    LI Yong, ZHANG Hong, LI Qing, LIU Xian
    2014, 48 (3):  25-29.  doi: 10.3969/j.issn.1673-5854.2014.03.005
    Abstract ( 915 )   PDF (3829KB) ( 634 )   Save
    A series of activated carbon was prepared using almond shell, walnut shell and white apricot shell as raw materials by microwave radiation with H3PO4 as activating agent. Activated carbon was carbonized and activated by the nut shell immersed in the mass fraction of H3PO4 40% solution, liquid ratio 1:3. After 24 h of immersion, the microwave with power of 640 W irradiated for 16 min. Pyrolysis mechanism, micromorphology, microstructure, components, nitrogen adsorption-desorption isotherm and pore size distribution of activated carbon were analyzed by TG, XRD, FT-IR, SEM, BET etc. The activated carbon obtained from nut powder by almond shell, walnut shell and white apricot shell have the approximate consistent on the thermal decomposition process and functional groups. They are a typical non-graphitizable. The nut shell of activated carbon has abundant interconnected pores and pore spaces, which size is about 0.4 to 1.2 nm of micropore and 3 to 6 nm of mesopore. It is shown that white apricot shell activated carbon has porous characteristic structure with 981.5 m2/g for specific surface area and 0.570 cm3/g for total pore volume. The adsorption value for methylene blue by white apricot shell activated carbon is 269.6 mg/g, and the iodine value is 1 162.8 mg/g.
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    Preparation of Carbon Quantum Dots by Biologic Matters and Its Spectrum Properties
    ZHANG Zheng-wei, PENG Ke-rui, CHEN Jian-qiu, YAN Zheng-yu
    2014, 48 (3):  30-35.  doi: 10.3969/j.issn.1673-5854.2014.03.006
    Abstract ( 1105 )   PDF (34222KB) ( 392 )   Save
    Using activated carbon prepared by sawdust and PEG2000 as surface coated agent, water-soluble carbon quantum dots were synthesized by chemical oxidation method. The method of synthesis of CQDs was optimized. The optimed synthesis condition of CQDs was 0.3 g of standast activated carbon, the mixed oxidant of 40 mL HAc-80 mL 30% H2O2, at the temperature of 100 ℃ for 12 h. In order to repair the surface defect of CQDs, a passivation treatment is perfermed using ultrasonic and micromave methods. The structures and optical properties of the obtained CQDs were characterized by transmission electron microscope (TEM), Ultraviolet-Visible (UV-Vis) spectroscopy, photoluminescence (PL) spectroscopy and Fourier transform infrared spectrophotometer (FT-IR). The prepared CQDs feature the excellent optical performance and high dispersion without agglomeration. The effects of ambient temperature, light and pH value on the property of CQDs were studied. Experimental results show that CQDs have lots of advantages, such as good stability, excellent anti-light bleaching, pH value dependence and feasible surface functionalization.
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    Optimization of Synthesis of 2,3,4-Trihydroxybenzoic Acid with Water by Response Surface Method
    JIANG Ping, HU Hai-ke, DU Qing-lin
    2014, 48 (3):  36-39.  doi: 10.3969/j.issn.1673-5854.2014.03.007
    Abstract ( 718 )   PDF (918KB) ( 694 )   Save
    2,3,4-trihydroxy benzoic was prepared using pyrogallic acid and sodium bicarbonate. On the basis of single factor test,Design-Expert software was used for response surface optimization. A quadratic polynomial regression model and the optimum conditions were obtained. To keep the test simple, the optimum synthesis conditions were as follows: m(pyrogallic acid)/m(sodium bicarbonate)1:3, reaction temperature 90 ℃, reaction time 4.5 h. Under optimal conditions, the yield of 2,3,4-trihydroxybenzoic acid was 37.57%. The final product was confirmed with melting point, FT-IR and 1H NMR spectra.
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    Determination of Polysaccharides from Bamboo Leaves in Different Regions
    YU Jin, YUE Yong-de, TANG Feng, YAO Xi, WANG Kun
    2014, 48 (3):  40-43.  doi: 10.3969/j.issn.1673-5854.2014.03.008
    Abstract ( 704 )   PDF (903KB) ( 703 )   Save
    The content of polysaccharides from ten species of bamboo leaves was determined by phenol-sulfuric acid method. The content difference among the different bamboo leaves was analyzed. The monosaccharide composition of polysaccharides from ten species of bamboo leaves was studied using high performance anion exchange chromatography (HPAEC) respectively. The results indicated that the content range of polysaccharides was 0.18% to 0.93%, the highest was Bambusa tuloides Munro in Fujian, and the lowest was Bambusa ventricosa McClure in Changning. Significant differences were found among the content of polysaccharides from different species of bamboo leaves in the same area. Bamboo polysaccharides in different species were composed of arabinose 18.32%-36.63%, galactose 19.16%-38.19%, glucose 16.90%-54.45%, xylose 5.88%-16.32%, and mannose 1.53%-10.89%, respectively.
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    Study on the Extraction Conditions of Cinnamon Oil
    LI Gui-qing, LU Shun-zhong, JING Yan, LI Gui-zhen
    2014, 48 (3):  44-47.  doi: 10.3969/j.issn.1673-5854.2014.03.009
    Abstract ( 820 )   PDF (844KB) ( 695 )   Save
    Cinnamon oil is distilled with steam distillation. Cinnamon oil from industrial production extraction conditions by steam distillation were redistilled. The experimental results showed that the optimum condition was 1 600 kg of cinnamon leaf, the amount of steam 12 kg/min, distillation time 2.0 h. Under this condition, cinnamon oil yield was 1.18%. The paper also showed that the content of cinnamon oil in aromaticwater was considerable. It makes up more than 60% of total cinnamon oil, and also had a high content of cinnamic aldehyde. It could reach 89.2%.
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    Extraction and Sulfonation Technology of Acacia mangium Tannin Extracts, and the Correlation Between Baume Degree of Tannin Extracts and Concentration
    HUANG Ren-zheng, ZHOU Meng, LIANG Fa-xing
    2014, 48 (3):  48-52.  doi: 10.3969/j.issn.1673-5854.2014.03.010
    Abstract ( 873 )   PDF (1050KB) ( 621 )   Save
    Acacia mangium tannin extract is a new tannin variety developed in recent years. The process parameters of A.mangium tannin extract are studied in this paper. The results show thas the relation of the baume degree(y,°Bé) and concentration (kg/L) at 20 ℃ is: y=1.2+40x. And the relation of the baume degree(y) and concentration at different temperature(y') is: y=y'+(T-20)/15. Extraction process was that 400 g of A.mangium barks with water absorption rate of 210% were extracted with 1 200 mL water and then 800 mL of water in the following steps. First digestion extract temperature is 100 ℃, and last digestion extract temperature is 128 ℃. The extract time is 12 h, sodium pyrosulfite which is 1.8% of gas dried materials weight is added. The yield of tannin extract is 81.9%, and the sield of tannins is 90.6%. Sulfonation process is that sodium pyrosulfite (Na2S2O5) which is 6% of extract solution oven dried weight is added, and the reaction is carried on at 85 ℃ for 2 h. The tannin content of sulphonated tannin extract is 67.8%, insoluble content is 3.2%, pH value is 4.5, and Lovibond color is 9.6. Other processes are the same as Waxberry tannin extracts production.
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    A Review on the Formation Mechanism of Levoglucosan during Fast Pyrolysis of Cellulose
    ZHANG Yang, HU Bin, LU Qiang, DONG Chang-qing, YANG Yong-ping
    2014, 48 (3):  53-59.  doi: 10.3969/j.issn.1673-5854.2014.03.011
    Abstract ( 1090 )   PDF (1818KB) ( 751 )   Save
    During the fast pyrolysis of cellulose at medium temperature, levoglucosan (LG) is the most abundant product. Its formation pathway has gained extensive attention. This paper firstly concludes and compares the different LG formation pathways proposed by scholars from home and abroad. The formation mechanisms of LG are classified into 4 kinds, namely homolysis cleavage mechanism, heterolysis cleavage mechanism, mechanism via glucose and concerted decomposition mechanism. Drawbacks of analyzing reaction mechanism using experimental methods are also pointed out. The paper then summarizes the recent development, i.e. application of the Density Functional Theory (DFT). Its contents and results are compared in detail. Finally, future investigation in determination of the LG formation pathway is proposed.
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