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    30 March 2014, Volume 48 Issue 2 Previous Issue    Next Issue
    Kinetics Studies on Adsorption of Hg2+ by Activated Carbon
    LU Xin-cheng, JIANG Jian-chun, SUN Kang, XIE Xin-ping, ZHANG Yan-ping, WANG Jin-biao
    2014, 48 (2):  1-7.  doi: 10.3969/j.issn.1673-5854.2014.02.001
    Abstract ( 862 )   PDF (1591KB) ( 687 )   Save
    Activated carbon with micropores was prepared from coconut carbon using steam activation by secondary activation. N2-adsorption isotherm, mathematical models such as D-R equation and BJH methods were used to characterize the properties of the prepared activated carbons. With mercury chloride as pollution targets, the adsorption properties of activated carbon for Hg2+ were investigated. The results indicated that the adsorption of Hg2+ was obviously influenced by surface area and pore structure of activated carbon. The process of adsorption was a two speed process with rapidly adsorption and slowly adsorption coexisting. This process could be well described by Lagergren pseudo second order model. The adsorption isotherm experiment showed that adsorption of Hg2+ on activated carbon is an exothermic and single molecular layer adsorption process. It could be fitted by Langmuir isotherm model.
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    Optimization of Lignin Extraction from Black Liquor by Phosphoric Acid Using Response Surface Methodology
    TAN Fei, LIN Yong-mei, WANG Su-mei, ZHENG Zhang-wei, HUANG Biao
    2014, 48 (2):  8-12.  doi: 10.3969/j.issn.1673-5854.2014.02.002
    Abstract ( 731 )   PDF (1710KB) ( 638 )   Save
    The process of recovering lignin from black liquor by phosphoric acid was studied. Based on single-factor experiments, three independent variables, i.e., acid extracting temperature, pH value and acid extracting time, were selected as influence factors and the Box-Behnken design (BBD) was used to optimize the preparation conditions of acid process. The optimal preparation conditions were determined as follows: pH value 2, temperature 46 ℃ and acid extracting time 50 min. Under these conditions, the lignin recovery was 190.60 g/L.
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    Effect of Dilute Acid Pretreatment on Fibre Components and Structure of Oak Shell
    YANG Jing, JIANG Jian-chun, ZHANG Ning, WEI Min, ZHAO Jian
    2014, 48 (2):  13-17.  doi: 10.3969/j.issn.1673-5854.2014.02.003
    Abstract ( 814 )   PDF (1860KB) ( 640 )   Save
    The effect of dilute acid pretreatment on the composition and enzymatic hydrolysis rate of Sawtooth Oak (Quercus acutissima) shells was investigated. And the fiber structures of pretreated residues were studied with scanning electron microscopy (SEM), infrared spectra (IR) and X-ray diffraction spectrum (XRD). Results showed that after pretreatment at room temperature with 2% H2SO4, the contents of hemicellulose and lignin were reduced by 21.6% and 6.6%, respectively. The enzymatic hydrolysis yield reached 71.4% from 42.8%, and total glucose yield was 71.2% which was 66.4% more than that of untreated oak shell. After pretreatment at 121 ℃ (0.15 MPa) for 1 h, the contents of hemicellulose and lignin were reduced by 84.6% and 24.5%, respectively. The enzymatic hydrolysis yield reached 72.1% which was 68.5% more than that of untreated oak shell. Because of the high cellulose loss, the glucose yield improvement was not so obvious. The fiber surface and pore volume increased and the crystallinity of cellulose decreased, which are favorable to increase the enzymatic hydrolysis rate.
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    Analysis of Fatty Acids in Styrax tonkinesis Seed Oil by On-line Methylation Gas Chromatography
    FU Yu-fei, SUN Yang, PAN Zai-fa, WANG Li-li
    2014, 48 (2):  18-22.  doi: 10.3969/j.issn.1673-5854.2014.02.004
    Abstract ( 711 )   PDF (1521KB) ( 640 )   Save
    A method to determine the composition of fatty acids in Styrax tonkinesis seed oil, kernel and seed shell was developed by on-line methylation and gas chromatography using a vertical microfurnace pyrolyzer. On-line methylation of S.tonkinesis samples at 350 ℃ in the presence of trimethylsulfonium hydroxide (TMSH) allowed analysis of fatty acids as their corresponding methyl derivatives. The main fatty acids were palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). The content of unsaturated fatty acid was more than 84.5% and the highest linoleic acid content was up to 47.29%. At the optimum conditions, the RSDs of the fatty acids were less than 3.81% (n=5). Furthermore, the composition of fatty acids in the samples from different growing places and different edible oil species was compared by similarity matrix. The results show roughly the same fatty acid composition of the S. tonkinesis from different growing places. It is most close to the corn oil, and the similarity is between 0.987-0.990. The content of unsaturated fatty acids (C18:2 and C18:3) in S. tonkinesis is close to soybean oil and sunflower seed oil, but higher than general vegetable oil. This can prove that it has high nutritional value. The on-line methylation gas chromatography is a simple, rapid and accurate method for the determination of the composition of fatty acids in S. tonkinesis.
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    Determination and Comparison of Mineral Elements in the Leaves and Barks of Eucommia ulmoides Oliv. from Different Places of Zhangjiajie
    ZHANG Lin-jie, PENG Sheng, ZHANG Chang-wei, WANG Zhi-hong, ZHOU Yun-lei, PENG Mi-jun, ZHANG Shui-han
    2014, 48 (2):  23-28.  doi: 10.3969/j.issn.1673-5854.2014.02.005
    Abstract ( 726 )   PDF (743KB) ( 527 )   Save
    Seven mineral elements (Fe, Zn, Cu, Mn, Mg, K and Ca) in leaves and barks of Eucommia ulmoides Oliv.from different places of Zhangjiajie were determined by FAAS (Flame Atomic Absorption Spectrophotometer). The results showed that the leaves and barks of E. ulmoides Oliv.were rich in mineral elements. The order of these mineral element contents in leaves was Mg >K >Ca >Zn >Fe >Mn≥Cu, while in the barks Mg >Ca >K >Fe >Zn >Mn≥Cu. The contents of all the mineral elements in leaves and barks were normally distributed by K-S (Kolmogorov-Smirnov) test. It was significantly different for the contents of Fe, Mn and Mg in leaves by LSD (Least Significant Difference) test. It was the same with the contents of Fe, Mn and K in barks. The results could provide the theoretical basis for the difference in pharmacological activity and quality of leaves and barks of E. ulmoides Oliv. from different places.
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    Study on the Polymerization Process of Melamine Modified Urea-formaldehyde Resin for Floor Substrate
    HU Lan-fang, SHI Juan-juan, ZHANG Wei, ZHAO Lin-wu, WANG Chun-peng, CHU Fu-xiang
    2014, 48 (2):  29-34.  doi: 10.3969/j.issn.1673-5854.2014.02.006
    Abstract ( 685 )   PDF (1932KB) ( 636 )   Save
    Melamine-urea-formaldehyde resin was synthesized by using melamine, urea and formaldehyde as raw materials. The molar ratio of F and U was (1.2-1.5):1, and the molar ratio of F and (U+M) was (1.1-1.2):1 in MUF resin. Samples in different period of reaction were analyzed by FT-IR and 13C NMR. The results showed that the main products were dimethylol melamine at the beginning of the reaction and connected mainly by methyl ether linkage and methylene in the weak acid stage. The plywood manufactured with this MUF resin conformed E0 degree required by standard with the bonding strength of 1.07 MPa and formaldehyde emission of 0.38 mg/L. The bond strength of the plywood could satisfy the requirement of type Ⅱ plywood (0.7 MPa).
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    Resource Evaluation of Lacquer Trees in West of Hubei and Quality Test of Lacquer
    YANG Zhi-bin, YANG liu, LI Hui, LU Li, HONG Hong, HONG Ke-jian
    2014, 48 (2):  35-40.  doi: 10.3969/j.issn.1673-5854.2014.02.007
    Abstract ( 675 )   PDF (4916KB) ( 618 )   Save
    Chinese lacquer tree resource in Enshi Tujia and Miao Autonomous Prefecture was surveyed. We preliminarily learned that there were 12 varieties of lacquer trees in Enshi. Six significant representatives were Rhus verniciflua Stokes.cv.Yanggangdamu, Rhus verniciflua Stokes.cv.Yanggangxiaomu, Rhus verniciflua Stokes.cv.Puxindamu, Rhus verniciflua Stokes.cv. Puxinxiaomu,Rhus verniciflua Stokes.cv. Dengtaixiaomu and Duocengloudamu. These lacquer trees account for 32.2 thousand hm2. In addition, the physical and chemical indexes were tested, for example, urushiol content and application quality such as adhesion, impact strength, rigid, temperature resistance, oil resistance, 30% H2SO4 resistance, 30% NaOH resistance, 30% NaCl resistance, steam and boiled water resistance. The results showed that the quality of Yanggangdamu lacquer and Yanggangxiaomu lacquer was fine, whose urushiol content reached up to 76.88% and 75.13%, respectively. And their physical and chemical indexes exceeded national standard.
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    Research Progress of Modification and Application of Raw Lacquer
    SUN Xiang-ling, WU Guo-min, KONG Zhen-wu
    2014, 48 (2):  41-47.  doi: 10.3969/j.issn.1673-5854.2014.02.008
    Abstract ( 868 )   PDF (1866KB) ( 818 )   Save
    Several modification ways of raw lacquer and the application progress at home and abroad in the field of coatings, catalysts, adsorption materials and chemical sensors were summarized, with the aim of offering reference for the effective use of raw lacquer.
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    Technological Process, Application Progress, Market Status and Industrial Policy of Environmental Plasticizer Tributyl Citrate
    SU Hui-bo
    2014, 48 (2):  48-53.  doi: 10.3969/j.issn.1673-5854.2014.02.009
    Abstract ( 883 )   PDF (1511KB) ( 682 )   Save
    Physical and chemical property, plasticizing effect, manufacturing technology, catalyst selection, application fields, international and domestic market, relevant policies and regulations, industrial standards, industrial status and development trends of tributyl citrate were summarized and analyzed in this paper. To promote the sustainable development of domestic citrate plasticizer industry, the author also made several proposals at the end of this paper.
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