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    30 January 2022, Volume 56 Issue 1 Previous Issue    Next Issue
    Preparation and Characterization of Corn Straw Based Activated Carbon by Phosphoric Acid Activation
    Ruting XU, Xincheng LU, Wei XU, Ao WANG, Kang SUN
    2022, 56 (1):  1-6.  doi: 10.3969/j.issn.1673-5854.2022.01.001
    Abstract ( 175 )   HTML ( 455063 )   PDF (504KB) ( 171 )   Save

    Corn straw based activated carbon was prepared from corn straw after formed and torrefied by H3PO4 activation and characterized by N2 adsorption, elemental analysis and FT-IR. The results showed that the optimal conditions were the impregnated ratio of 4∶1, the activation temperature of 400 ℃ and the activation time of 100 min. Under these conditions, the yield of activated carbon was 47.78% and the activated carbon showed excellent adsorption capacity with the iodine adsorption value of 864 mg/g, the methylene blue adsorption of 210 mg/g and the caramel decolorization of 100%. The specific surface area and the total volume of activated carbon reached 1 105 m2/g and 0.745 cm3/g, the micropore volume was 0.287 cm3/g, the mesopore volume was 0.354 cm3/g. Meanwhile, the distribution of pore was concentrated within 5 nm, accounting for 73.56%, and the average pore diameter is 2.697 nm. The FT-IR results showed that the crosslinking reaction was occured between H3PO4 and corn straw during octivation and the activated carbon lost some functional groups of corn straw.

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    Catalytic Characteristics of Metal Ions for Glucose Isomerization and Dehydration
    Yongzhao ZHANG, Jiajia JI, Yang WANG, Hongwei LI, Songhui LIU, Wende WANG
    2022, 56 (1):  7-12.  doi: 10.3969/j.issn.1673-5854.2022.01.002
    Abstract ( 94 )   HTML ( 54328 )   PDF (556KB) ( 147 )   Save

    The catalytic characteristics of metal ions for glucose isomerization and dehydration were investigated with metal chloride as catalyst. The influences of metal ion category, content and temperature on reaction process were studied. The reaction kinetic model was applied to correlate experimental data to analyze catalytic characteristics quantitatively. The process of glucose to HMF was a tandem reaction, and the kinetic model based on this mechanism could simulate the reaction accurately. Ni2+, Cr3+ and Sn4+ possessed good catalytic activity for glucose conversion, among which the catalyst activity of Sn4+ was the highest, and that of Ni2+ was the lowest. The kinetic constant of side reaction of Sn4+ was about 20 times of that of Ni2+. For Ni2+, reaction rate of glucose isomerization and side reaction increased, yet the catalytic activity for fructose dehydration to HMF was negligible with the increasing of Ni2+ content. Increasing of Cr3+ could enhance reaction rate of glucose isomerization significantly, and almost had no effect on other reactions. With the increasing of Sn4+ content, reaction rate of all steps increased, yet the intensity of side reaction would decrease. The influence of temperature on reaction constants followed the Arrhenius model. Higher temperature was beneficial to the side reaction, fructose dehydration and glucose isomerization respectively, when Ni2+, Cr3+ and Sn4+ were used, respectively.

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    Effect of Aerobic Biological Pretreatment Time on Hydrolytic Acidification of Corn Straw
    Xiyue LI, Hongbo WANG, Yuxiao ZHAO, Dongliang HUA, Ning WANG
    2022, 56 (1):  13-22.  doi: 10.3969/j.issn.1673-5854.2022.01.003
    Abstract ( 69 )   HTML ( 62332 )   PDF (6146KB) ( 153 )   Save

    Corn straw was used as raw material for aerobic biological pretreatment by a complex bacterial system and then inoculated with anaerobic sludge for anaerobic fermentation. The influence of pretreatment time on anaerobic fermentation was investigated, and the changes in lignocellulose structure and content, key enzyme activities, microbial diversity and anaerobic acidification fermentation yield were determined. The results showed that with the extension of pretreatment time, the structure of corn straw was gradually destroyed, the activity of lignin peroxidase, the key enzyme for lignin degradation, gradually decreased, and the activities of xylanase and cellulase gradually increased and were up to 0.879 U/mg and 0.0257 U/mg. Actinomyces, Bacillus and Aspergillus were the dominant bacterium groups in the aerobic biological pretreatment of straw. The best acid production from anaerobic fermentation of corn straw was achieved by aerobic biological pretreatment for 2 d. The yield of ethanol and volatile fatty acids was 249.3 mg/g, 46.73% higher than that of untreated. The yield of ethanol and volatile fatty acids was 138.2 mg/g after 5 d of aerobic pretreatment, which was 18.66% lower than that of the untreated corn straw. The reason for the decrease of volatile fatty acids production from anaerobic fermentation due to extended aerobic pretreatment time was the excessive degradation of hemicellulose and cellulose. The pretreatment method of anaerobic fermentation of corn straw using aerobic biological pretreatment with complex microbial system as the purpose of energy and resource utilization should strictly control the pretreatment time to avoid the decrease of product yield caused by excessive degradation of cellulose and hemicellulose.

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    Application of Rubber Seed Oil-based UV-curable Resins in Casting Stereoscopic Impressions
    Fei ZHANG, Yun HU, Jiatong LIU, Yonghong ZHOU, Chengguo LIU
    2022, 56 (1):  23-29.  doi: 10.3969/j.issn.1673-5854.2022.01.004
    Abstract ( 68 )   HTML ( 20693 )   PDF (9279KB) ( 52 )   Save

    Using rubber seed oil (RSO) as raw material, hydroxylated rubber seed oil was firstly prepared, and then it was reacted with isophorone diisocyanate and pentaerythritol triacrylate to obtain rubber seed oil-based polyurethane acrylate oligomers (RSO-PUA). The obtained oligomers were then blended with different types of thinners hydroxyethyl methacrylate (HEMA) and 1, 6-hexanediol diacrylate (HDDA) to form UV-curable resins. Then, the ultimate properties of the resultant materials in casting stereoscopic impressions were investigated and compared with the traditional stereoscopic impression casting materials (silicone casting material and impression compound). The experimental results showed that when the amount of HEMA was 20% and the amount of HDDA was 30%, the obtained RSO-PUA showed the best performance in casting stereoscopic impressions. The casting stereoscopic impressions with rubber seed oil-based UV-curable resins had the following properties, easy manipulation, fast curing time, controllable, viscosity, obtained complete, vivid and sharpness impression casts, qualified for inspection and identification. However, the casts prepared from silicone casting material and impression compound had some shortcomings, such as feature defect, bubble generation and incomplete impression reflection.

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    Summary of Corrosion Characteristics and Inhibition Methods of Biomass Fluidized Bed
    Haodong FAN, Dongwang ZHANG, Bin ZHAO, Man ZHANG, Yan JIN
    2022, 56 (1):  30-36.  doi: 10.3969/j.issn.1673-5854.2022.01.005
    Abstract ( 61 )   HTML ( 16823 )   PDF (1435KB) ( 174 )   Save

    Biomass fuel has the characteristics of high moisture, volatile, alkali metal content and low calorific value, which makes it more suitable for fluidized bed combustion. However, the alkali metal and Cl elements volatilized in the combustion process will threaten the safe and economic operation of fluidized bed boiler at a certain temperature. For example, the volatilization of Cl element is easy to lead to the corrosion of heating surface. The corrosion types can be divided into gas phase corrosion, liquid phase corrosion and solid phase corrosion. The corrosion degree is mainly affected by fuel composition and temperature. Through literature reading, this paper expounded the mechanism of corrosion of biomass circulating fluidized bed boiler, pointed out the corrosion phenomenon of actual boiler and engineering countermeasures according to engineering practice, and summarized that the prevention of corrosion could mabe breakthroughs in biomass fuel pretreatment, increasing secondary air ducts near the dense phase zone of the furnace, changing the layout of the superheater heating surface, adding specific additives and selecting the material of the heating surface. The conclusions were expected to provide guidance for the high reliability operation of biomass circulating fluidized bed boiler.

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    Research Progress in Applications of Amphiphilic Algal Polysaccharides in Emulsification and Dispersion
    Shanyong WANG, Haisong QI, Zhouyang XIANG
    2022, 56 (1):  37-46.  doi: 10.3969/j.issn.1673-5854.2022.01.006
    Abstract ( 87 )   HTML ( 31676 )   PDF (1283KB) ( 91 )   Save

    Algal polysaccharide is a natural gel polysaccharide with great application potentials in emulsification and dispersion. Its hydrophilic and hydrophobic functional groups endow it with natural amphiphilicity, which could improve the interface compatibility between heterogeneous phases. Furthermore, the algal polysaccharide with a natural gel network structure could greatly improve the stability of the sol-gel system by effectively preventing the re-aggregation between the dispersed phases in the system. This paper introduced the chemical compositions, structures and properties of algal polysaccharides, including alginate, fucoidan, carrageenan, agar, ulvan, etc. Their amphiphilic structures were originated from the functional groups on sugar units including hydrophilic groups such as carboxyls and sulfates and hydrophobic groups such as methoxyls, acetyls and proteins. The effects of the amphiphilic structures on molecular configuration, surface activity and rheological properties of algal polysaccharides and further on their applications in emulsification and dispersion were summarized. At the same time, the researches on enhancing amphiphilic properties of algal polysaccharides by physical or chemical methods were introduced. The research progress of the applications of algal polysaccharide derivatives in emulsification and dispersion was summarized. Finally, the direction of enhancing the interfacial adsorption activity of algal polysaccharides was prospected.

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    Research Progress and Dynamic State of Plant Oil-based Pressure-sensitive Adhesives
    Wei LIU, Zhong WANG, Zhongkai WANG
    2022, 56 (1):  47-56.  doi: 10.3969/j.issn.1673-5854.2022.01.007
    Abstract ( 114 )   HTML ( 44201 )   PDF (3129KB) ( 140 )   Save

    Using natural and renewable plant oils as raw materials to prepare pressure-sensitive adhesives is an effective way to solve the current resource shortage and environmental problems of petroleum-based pressure-sensitive adhesives, it is also one of the hotspots in academic research and application development. The author reviewed the research progress of plant oil-based pressure-sensitive adhesives by domestic and foreign researchers in recent years. And the adhesives were classified according to the types of plant oil-based polymers (epoxy resin, acrylic resin, fatty acid derivatives, polyester and polyurethane, etc.), and the design ideas and modification methods of these research were emphatically summarized. On this basis, the development of new plant oil monomer structure and copolymerization with functional monomer were discussed, so as to provide a feasible theory and reference for the design and development of new bio-based pressure sensitive adhesive materials.

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    Research Advance on Adjustment of Pore Structure of Plant-based Activated Carbon
    Meijuan ZHONG, Xing′e LIU, Lili SHANG, Genlin TIAN, Shumin YANG, Jianfeng MA
    2022, 56 (1):  57-66.  doi: 10.3969/j.issn.1673-5854.2022.01.008
    Abstract ( 86 )   HTML ( 66145 )   PDF (570KB) ( 121 )   Save

    The proportion of plant-based activated carbon used in the field of environmental protection is increasing year by year due to its characteristics such as wide sources, price moderate, short preparation cycle, mature process, large specific surface area, developed pore structure, low content of hybrid elements, and excellent thermal and chemical stability. The main components of plant are cellulose, hemicelluloses and lignin. In the present work, the effect of these three components on the pore formation of biochar and activated carbon was reviewed. In addition, the pore forming mechanism and characteristics of the formed pores of the physical activation, chemical activation (KOH activation, H3PO4 activation and ZnCl2 activation), catalytic activation and self-activation process were contrasted and summarized. Finally, the future research direction of plant-based activated carbon pore regulation was proposed based on the problems in previous research work.

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    Current Situation of Cellulose Based Superhydrophobic Materials
    Xiaowang LI, Yudong LI, Xin WANG, Jiazuo ZHOU, Xiaohan SUN, Yusen ZHAO, Chengyu WANG
    2022, 56 (1):  67-74.  doi: 10.3969/j.issn.1673-5854.2022.01.009
    Abstract ( 127 )   HTML ( 35931 )   PDF (4334KB) ( 172 )   Save

    In recent years, the application field of superhydrophobic materials has become more and more extensive, and the requirements on mechanical strength, wear resistance, light transmissibility, reuse and other properties of super hydrophobic materials have become higher and higher, and the requirements on green environmental protection of raw materials have been increasing day by day. Biomass materials have many kinds and large volume, which occupy the do minant position of renewable resources. Cellulose, as the downstream fine products of biomass materials, has entered the field of vision of researchers with its advantages of green environmental protection, large reserves and flexible application. This paper briefly indicates the development history, characteristic, and application of superhydrophobic materials and cellulose, the application of superhydrophobic modification methods such as hydrothermal method, chemical deposition method, atom transfer radical polymerization and sol-gel method (cellulose/SiO2 super-hydrophobic materials and cellulose aerogel) in the preparation of cellulose based superhydrophobic materials was emphatically analyzed. Finally, the future development of cellulosic superhydrophobic materials was prospected.

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