Table of Content

30 May 2023, Volume 57 Issue 3 Previous Issue   

Invited Paper

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Research Progress on Manufacturing Technology of New Fibrous Veneer High Performance Wood Scrimber Minghui GUO, Hao ZHONG, Hao ZHANG 2023, 57 (3):  1-7.  doi: 10.3969/j.issn.1673-5854.2023.03.001 Abstract ( 13 )   HTML ( 2 )   PDF (1874KB) ( 8 )   Save This paper expounded the origin and development of wood scrimber, and our country proposed new type of fibrous veneer high-performance wood scrimber manufacturing technology specific links research progress was summarized. In the rolling and loosening stage of the raw wood, the physical and mechanical properties of the wood scrimber were enhanced with the increase of dispersion degree. In the fibrous veneer modification stage, the modified treatment improved the fire prevention and mildew resistance of the wood scrimber, giving the wood scrimber versatility. In the gumming stage, the differences in mechanical strength and function of wood scrimber of different tree species under different soaking method and impregnation amount were summarized. The influence of the paving method and equipment on the strength and dimensional stability of wood scrimber was analyzed. The advantages and disadvantages of hot pressing method and cold pressing as well as hot curing in the pressing stage are summarized. Finally, based on the defects of wood scrimber and the high value-added utilization cases of existing wood materials, some new ideas were raised improving the strength of wood scrimber and expanding their application. Figures and Tables | References | Related Articles | Metrics

Research Report

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Preparation and Performance of Regenerated Cellulose/Polyvinyl Alcohol/Chitosan/TiO2 Antibacterial Composite Film Qunli ZHANG, Ge XIAN, Linlin CUI 2023, 57 (3):  8-14.  doi: 10.3969/j.issn.1673-5854.2023.03.002 Abstract ( 11 )   HTML ( 1 )   PDF (4518KB) ( 9 )   Save Using microcrystalline cellulose(MCC) and polyvinyl alcohol(PVA) as raw materials, 1-butyl-3-methylimidazole chloride as solvent system, the regenerated cellulose(RGC)/PVA base film was prepared by dissolving and regenerating MCC and blending with PVA. The antibacterial composite film of RGC/PVA/CS/TiO2 was prepared by coating chitosan(CS) and titanium dioxide(TiO2) blend solution. The morphology and structure of the composite film were characterized by fourier transform infrared spectrometer, X-ray diffraction and scanning electron microscope, and the thermology, mechanical, optical, barrier and antibacterial properties were tested and analyzed. The results showed that CS and TiO2 were successfully compounded on the cellulose based film. The thermal decomposition of RGC/PVA/CS/TiO2 composite film was mainly composed of the decomposition of CS-TiO2 coating layer and RGC/PVA base film. Compared with the regenerated cellulose film, when the mass fraction of TiO2 was 0.2%, the tensile strength of the RGC/PVA/CS/TiO2 composite film increased by 39.28%, the elongation at break increased by 51.66%, light transmittance remained at 88.72%, oxygen transmittance decreased by 47.77% and had a good inhibitory effect on Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Figures and Tables | References | Related Articles | Metrics

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Storage Stability of Olive Oil Microencapsulated by Ultrasonic-spray Drying Caihong ZHANG, Lixin HUANG, Pujun XIE, Yejun DENG 2023, 57 (3):  15-22.  doi: 10.3969/j.issn.1673-5854.2023.03.003 Abstract ( 9 )   HTML ( 1 )   PDF (950KB) ( 8 )   Save Olive oil was microencapsulated by ultrasonic spray drying method to investigate the influence of inlet air temperature on water and encapsulation efficiency of olive oil microcapsules. And then the storage stability of microencapsulated olive oil microencapsulation was also evaluated. The results of the ultrasonic-spray microencapsulation of olive oil showed that the surface color of the olive oil microencapsulation was deepened, some olive oil was dissolved out and the encapsulation efficiency of olive oil was reduced owing to the higher inlet temperature. However, the too low inlet temperature leaded to the higher moisture content of the olive oil microencapsulation. The optimization of olive oil microencapsulation by ultrasonic spray drying conditions was obtained, which was the inlet temperature of 180 ℃ and feed rate of 6 r/min. The encapsulation efficiency of olive oil microcapsules prepared under this conditions reached 98.2%. The stability was studied after olive oil microencapsulation stored under the different conditions of illumination, temperature and humidity for 30 days. The results shown that the peroxide value and acid value of microencapsulated olive oil under light were 1/5 and 1/3 of that of unencapsulated olive oil, respectively. Under dark condition, the peroxide value and acid value of microencapsulated olive oil were about 2/3 of that of unencapsulated olive oil. Owing to the increase of temperature, the peroxide value of unencapsulated olive oil was doubled, and the maximum acid value increased by 77.8%, while the peroxide value of microencapsulated olive oil increased by only 15%, and the maximum acid value increased by 40.5%. The peroxide value and acid value of encapsulated olive oil were lower than those of unpacked olive oil, indicating that the microencapsulation delayed oxidation of olive oil and improved the storage stability of olive oil. Figures and Tables | References | Related Articles | Metrics

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Energy Saving Optimization of Total Comminution Fermentation Process of Aged Rice Based on Exergy Analysis Mengting LIU, Yuanyuan CHEN, Hong LIU, Yixin LI, Qingrui ZHANG 2023, 57 (3):  23-30.  doi: 10.3969/j.issn.1673-5854.2023.03.004 Abstract ( 10 )   HTML ( 0 )   PDF (2355KB) ( 7 )   Save Based on Aspen Plus, a total comminution fermentation process of aged rice with a capacity of 4 hundred thousand tons per year was designed and established. Exergy analysis method was used to study the thermodynamic properties of the process, and the source of exergy loss was clarified and optimized. The results showed that exergy loss was 106 477.62 kW before optimization, and the exergy loss was 79 108.84 kW after optimization. Meanwhile, the exergy loss was reduced by 27 368.78 kW and the exergy efficiency increased by 5.97% after optimization. The total energy consumption of 1 ton fuel ethanol production was 1 424.69 MJ, the raw material consumption was 4.25 ton, and the consumptions of water and wastewater were 2.9 and 0.37 ton, respectively. On the basis of meeting the demand of steam consumption in the production process, the power generation was 15.03 MW, and the system consumption was 12.9 MW. Through the economic analysis of the processes before and after optimization, the optimized process had better economy. The cost of public works decreased by 52.76%, the total cost decreased by 49.73 yuan per ton and the annual net profit increased by 2.85% after process optimization. Figures and Tables | References | Related Articles | Metrics

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Effects of Typical Pretreatments on Sugar Production by Enzymatic Hydrolysis and Structural Changes of Licorice Root Residue Mengjia LIU, Gaojie WEI, Chenxi YU, Jianmin XING, Xinyu LIU, Maohua YANG 2023, 57 (3):  31-38.  doi: 10.3969/j.issn.1673-5854.2023.03.005 Abstract ( 7 )   HTML ( 0 )   PDF (3421KB) ( 8 )   Save Four typical pretreatment methods of dilute acid, hydrothermal treatment, ionic liquid and steam blasting were used to treat licorice residue. The effects of different pretreatment methods on sugar production and structure of licorice residue were compared by high performance liquid chromatography, scanning electron microscope, fourier transform infrared spectrometer and X-ray diffraction analysis. The results showed that ionic liquid pretreatment had obvious effect on cellulose in licorice residue, and the contents of glucose, xylose and xylodisaccharide in the enzymatic hydrolysate were the highest, and the enzymolysis rate reached 77.08%±2.12%, which was 2.05 times than that of untreated enzymatic hydrolysis rate. Hydrothermal pretreatment had obvious effects on hemicellulose licorice residue, and the contents of xylose, arabinose and xylodisaccharide in the pretreatment solution were the highest. The enzymatic hydrolysis efficiency of hemicellulum was the highest, reaching 82.37%±1.13%, which was 8.90 times than that of untreated enzymolysis. Steam blasting pretreatment had obvious effect on licorice residue lignin, and the glucose yield in the pretreatment solution was the highest. The structural analysis results were consistent with the component analysis results. Compared with other pretreatment, the lignocellulose structure of licorice residue was effectively broken in the ionic liquid pretreatment process, which was more conducive to the further high-value utilization of licorice residue. Figures and Tables | References | Related Articles | Metrics

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Prediction Hybrid Model for Biogas Production in Cattle Manure Anaerobic Fermentation Established by Mechanism and Data-driven Tingting ZHAO, Shipin YANG, Lijuan LI, Xingyu PAN, Yu CHEN 2023, 57 (3):  39-48.  doi: 10.3969/j.issn.1673-5854.2023.03.006 Abstract ( 10 )   HTML ( 0 )   PDF (1102KB) ( 9 )   Save As a mass and energy transfer process involving microorganisms, the complexity, time variability and severe nonlinearity of anaerobic fermentation process greatly reduced the accuracy and practicability of the prediction models established on pure mechanism or pure data. In order to solve this problem, taking the methane production process of cow dung fermentation as the research object, a hybrid model for predicting gas production by anaerobic fermentation was proposed. Firstly, the clear kinetic equations of hydrolysis, acidification hydrogen production and acetic acid production were established, and then the data-driven model of methane production and liquid-gas mass transfer process was constructed combined with Random Forest Regression(RFR). And the Sparrow Search Algorithm(SSA) was used to optimally estimate the super parameters of RFR algorithm. Finally, two sub-models, the kinetic model of the fermentation mechanism and the random forest regression model, were cascaded to form a hybrid model for the whole process of anaerobic fermentation biogas production prediction.The hybrid model was used to simulate the anaerobic digestion experiment of cow manure. The results showed that the methane production rate using the hybrid model simulation was in good agreement with the experimental data, and the prediction accuracy of the mechanism and data-driven mixed model(SSA-RFR-ADM) was close to the prediction accuracy of the complex pure mechanism model. The mean squared error of the model prediction was 0.003 035. The proposed hybrid model effectively overcame the limitation of single model, and could be used as a proxy model of complex pure mechanism model, providing correct theoretical guidance for practical anaerobic fermentation methane production process. Figures and Tables | References | Related Articles | Metrics

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Kinetic Characteristics of Yak Dung Under Steam Atmosphere Zi'ang NI, Zhufu FU, Yuan XUE 2023, 57 (3):  49-55.  doi: 10.3969/j.issn.1673-5854.2023.03.007 Abstract ( 8 )   HTML ( 2 )   PDF (656KB) ( 7 )   Save The thermal weight loss characteristics of yak dung under water vapor atmosphere was investigated via the thermogravimetric analysis. The Flynn-Wall-Ozawa method, master plot method/Kissinger method and continuous coupling method of distributed activation energy model(DAEM) were used to analyze the reaction mechanism and calculate kinetic parameters of the pyrolysis process. The results showed that yak dung steam gasification process was mainly divided into two stages, namely the pyrolysis reaction stage and the gas-solid reaction stage. The steam could slightly inhibit the pyrolysis reaction and significantly promote the gas-solid reaction. The kinetic analysis demonstrated that the reaction order mechanism model(the reaction-orders of the pyrolysis stage and the gas-solid reaction stage were 2.40 and 1.17, respectively) had good adaptability to the kinetic process of yak dung steam gasification. The activation energies of the hemicellulose, cellulose and lignin in pyrolysis stage were 169.32, 185.76 and 219.52 kJ/mol, respectively. The activation energies of the pyrolysis carbon condensation reaction and the steam gas-solid reaction in the gas-solid reaction stage were 275.59 and 312.44 kJ/mol, respectively. Figures and Tables | References | Related Articles | Metrics

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Preparation and Properties of Sunflower Stalk-based Phosphorus Doped Porous Carbon by One-step Pyrolysis Method Yanyan LIU, Yuhan ZHANG, Guilong WANG, Qihua XIA, Kang SUN, Guanfeng LIN 2023, 57 (3):  56-60.  doi: 10.3969/j.issn.1673-5854.2023.03.008 Abstract ( 9 )   HTML ( 1 )   PDF (1477KB) ( 9 )   Save Phosphorus doped porous carbon was prepared by one-step pyrolysis using sunflower straw as carbon source and phytic acid as phosphorus dopant and active agent. The effect of impregnation ratio, activation temperature and holding time on the yield and iodine adsorption value of phosphorus-doped porous carbon was discussed. The pore structure, surface chemical properties and binding state of doped porous carbon were analyzed by automatic specific surface area analyzer and X-ray photoelectron spectroscopy. The results showed that with the increases of impregnation ratio, activation temperature and holding time, the iodine adsorption value of sunflower stalk-based phosphorus doped porous carbon increased first and then decreased. The activation of phytic acid was conducive to the increase of specific surface area and pore volume of porous carbon. Phytic acid was used as a phosphorus source to achieve phosphorus doping of porous carbon, and the binding types of phosphorus were C—PO3、C—P—O、C3—PO、C—P＝O and C—P. Under the optimum conditions, when the impregnation ratio was 2, activation temperature was 900 ℃ and the holding time was 2 h, the specific surface area, total pore volume and iodine adsorption value of phosphorus-doped porous carbon were 992.7 m2/g, 1.33 cm3/g and 1 099.8 mg/g, respectively. Figures and Tables | References | Related Articles | Metrics

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Optimization of Preparation Process of Locust Carbon as Electrical Double-layer Electrode Using Response Surface Methodology Fanzhu KONG, Lijuan GAO, Yingjie SU, Kaichuang ZHAO, Cheng QIAN 2023, 57 (3):  61-65.  doi: 10.3969/j.issn.1673-5854.2023.03.009 Abstract ( 8 )   HTML ( 2 )   PDF (1242KB) ( 11 )   Save Using Robinia pseudoacacia branches as raw materials, the activation process of activated carbon with double-layer electrode was optimized by response surface method using water vapor activation method and the mass specific capacitance at current density of 1A/g as the index. The electrochemical properties of the prepared double-layer electrode Robinia pseudoacacia carbon were studied by constant current charge/discharge, cyclic voltammetry curve and AC impedance methods. The experimental results showed that the best process for preparing the double-layer electrode Robinia pseudoacacia charcoal was that the activation temperature of 1 g charcoal was 674.85 ℃, the activation time was 82.42 min, the water vapor flow rate was 0.92 g/min, and the specific capacitance predicted by the model was 133.2 F/g. The significance of the activation conditions on the specific capacitance of activated carbon was: activation temperature>water vapor flow rate>activation time. The double-layer electrode prepared under the optimized conditions had low resistance and strong conductivity. Its pore structure was conducive to the migration of ions on the electrode surface, and maintains good double-layer characteristics and magnification performance in the range of 10-50 mV/s. Figures and Tables | References | Related Articles | Metrics

Review Comment

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Research Progress on Determination Methods of Plant Indigo Extract Danyang LIU, Chengzhang WANG 2023, 57 (3):  66-72.  doi: 10.3969/j.issn.1673-5854.2023.03.010 Abstract ( 11 )   HTML ( 1 )   PDF (724KB) ( 8 )   Save Taking plant indigo extract as the research object, the research progress and trend of the detection methods for the main effective components at home and abroad were reviewed. The main components and their functions of plant indigo extract such as indigo and indirubin were summarized. The analytical examination methods of indigo extract were reviewed, mainly including high performance liquid chromatography, thin layer chromatography, thin layer scanning, dual wavelength spectrophotometry, titration analysis, gas chromatography-mass spectrometry and the combination of multiple detection methods. The application of high performance liquid chromatography(selection of chromatographic column, mobile phase, detection wavelength and evaluation parameters) was emphatically analyzed. At the same time, the problems existed in the present analysis methods were analyzed, and the future development trends of the indigo extract analysis and detection were predicted. Figures and Tables | References | Related Articles | Metrics