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    30 September 2022, Volume 56 Issue 5 Previous Issue   
    Research Report
    Composition Change and Performance Decay Characteristics of Engine Lubricant During the Utilization
    Ruting XU, Jian ZHAO, Kang SUN, Xincheng LU, Yanping ZHANG, Jianchun JIANG
    2022, 56 (5):  1-7.  doi: 10.3969/j.issn.1673-5854.2022.05.001
    Abstract ( 2 )   HTML ( 2 )   PDF (501KB) ( 4 )   Save

    Taking the fully synthetic engine lubricant as the research object, the performance and composition changes were studied and its decay characteristics was also explored after 10 000 km running of real vehicle. The results showed that the kinematic viscosity of lubricant decreased by 23.84%. Meanwhile, the total acid value and n-pentane insoluble matter increased up to 3.53 mg/g and 0.268%, respectively, and the contents of wear elements(i.e, Fe and Al) and pollutant element(i.e, Si) increased from < 1, < 1, 2 μg/g to 11, 20, 20 μg/g, respectively. During the decay process of lubricant, the decomposition and polymerization reactions of poly α olefin(PAO) made the composition of lubricant complicated, while the decomposition process was dominated by the decomposition reaction of molecular chain fracture that led to the decrease of kinematic viscosity. In addition, the reaction of oxidation and nitration also occurred, and the ketones, polycyclic aromatic hydrocarbons, amines and acids were generated with the additives consumption, which led to the deepening color and increasing total acid value. The change of lubricant molecular weight distribution indicated that both decomposition and polymerization reactions occured during the decay process, while the chain-breaking decomposition reaction was dominated.

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    Preparation and Adsorption of Fe3+ Using Sulfamic Acid Modified Sodium Alginate
    Yue WANG, Jun YANG, Wei QIU, Yani GUO
    2022, 56 (5):  8-14.  doi: 10.3969/j.issn.1673-5854.2022.05.002
    Abstract ( 2 )   HTML ( 1 )   PDF (3029KB) ( 2 )   Save

    Coating adsorbent materials on drainage facilities could effectively prevent chemical clogging of tailings dams. In this study, a sulfamic acid-modified sodium alginate adsorbent(MSA) was prepared using sodium alginate(SA) as the matrix, sodium periodate as the oxidant, and sulfamic acid as the modified material. The structure was characterized by Fourier transform infrared spectroscopy and scanning electron microscope, and the adsorption behavior of MSA on Fe3+ was also studied. The results showed that MSA was prepared successfully by introducing —NHSO3H into alginic acid dialdehyde(ADA). Molecular size and molecular chain gap of MSA increased after adsorbing Fe3+. The optimal conditions for the adsorption of Fe3+ by MSA were that the initial mass concentration of Fe3+ was 200 mg/L, the pH value was 2, the adsorption time was 240 min, and the adsorption temperature was 25 ℃. Under these conditions, the maximum Fe3+ adsorption capacity of MSA was 151 mg/g. The adsorption process conformed to the pseudo-second-order kinetic model and Langmuir adsorption isotherm, and adsorption of Fe3+ by MSA was a monolayer chemical adsorption. Adsorption thermodynamic analysis showed that the adsorption process was a spontaneous process, and the increase of temperature was not conducive to the progress of the adsorption reaction.

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    Nitrogen-doped Modification and Electrochemical Properties of Lignin-based Activated Carbon
    Qi GUO, Wei XU, Junli LIU
    2022, 56 (5):  15-22.  doi: 10.3969/j.issn.1673-5854.2022.05.003
    Abstract ( 3 )   HTML ( 1 )   PDF (782KB) ( 4 )   Save

    Nitrogen-doped activated carbon(NAC) was prepared by synchronous doping method using phosphoric acid lignin-based activated carbon(LAC) as raw material, melamine as nitrogen source and KOH as activator. The structure and composition of the modified activated carbon were characterized by BET, XRD, Raman spectroscopy and XPS characterization. The electrochemical performance of the modified activated carbon as the electrode material of supercapacitor in several electrolytes with different properties was tested by electrochemical characterization, and the influence mechanism of the electrolyte on the electrochemical performance of electrode material was preliminatively explored. The results indicated that the modified activated carbon has abundant pore structure, with specific surface area of 2 332 m2/g, micropore volume of 1.37 cm3/g, middle pore volume of 0.74 cm3/g, average pore size of 2.79 nm, and nitrogen content of 7.5%, of which graphite-like nitrogen(N-Q) structure content of 34.6%. The rich pore structure and nitrogen content greatly improved the electrochemical performance of activated carbon, and it exhibited high specific capacitance in the aqueous electrolyte. The maximum specific capacitance was 424 F/g at the current density of 1 A/g. In organic electrolyte, its specific capacitance was only 87 F/g at a current density of 1 A/g, while it had higher energy density owing to the wider operating voltage window(0-2.5 V). The results showed that the performance of activated carbon electrode material in aqueous electrolyte was mainly determined by the hydration ion radius of electrolyte, while the performance in organic electrolyte was mainly affected by the viscosity of electrolyte.

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    A Preliminary Study of the Degassing Pretreatment Effect on the Specific Surface Area and Pore Volume of Woody Activated Carbon
    Mingzhe MA, Kang SUN, Hao SUN, Yanping ZHANG, Guanfeng LIN, An'guo WEI
    2022, 56 (5):  23-29.  doi: 10.3969/j.issn.1673-5854.2022.05.004
    Abstract ( 2 )   HTML ( 1 )   PDF (691KB) ( 2 )   Save

    Before determining the specific surface area and pore volume of woody activated carbon, the activated carbon was pre-treated with degassing, and the effect of pre-treatment conditions(desorption temperature and desorption time) on the specific surface area and pore volume of activated carbon was investigated. The obtained results were compared with those measured under the recommended conditions of the instrument. The results showed that the desorption temperature and time had little influence on the specific surface area and pore volume of physical activated carbon. It was owing to the preparation temperature of physical activated carbon was high few functional groups, the structure was mainly microporous, the adsorption type was mainly physical adsorption, and the adsorption and desorption speeds were fast. The optimum pretreatment condition of physical activated carbon was desorbed at a temperature of 150 ℃ for 3 hours. Compared with the pretreatment conditions of 350 ℃ and 24 hours recommended in the instruction manual of ASAP 2460, pretreatment time was significantly shortened, the power consumption was reduced, and the detection efficiency was improved. The degassing temperature and time had a great influence on the specific surface area and micro-pore of chemical wood activated carbon, and the suitable pretreatment condition was 300 ℃ for 12 h. The main reason was that the preparation temperature of activated carbon by phosphoric acid method was relatively low, and there were many heteroatoms and the surface chemical groups. Physical and chemical adsorption were easy to occur simultaneously, which required higher temperature and longer time for degassing. When the degassing temperature was too high, the adsorbate in the pores would be carbonized to form carbonaceous particles that blocked the pores. At the same time, part of the physical adsorption would be converted into chemical adsorption at a higher activation energy, which would reduce the analysis results.

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    Effect of Peroxyformic Acid Pretreatment on Enzymatic Hydrolysis and Fermentation Efficiency of Sugarcane Bagasse
    Ning LI, Fanyang MENG, Haiyan YANG, Zhengjun SHI, Ping ZHAO, Jing YANG
    2022, 56 (5):  30-36.  doi: 10.3969/j.issn.1673-5854.2022.05.005
    Abstract ( 2 )   HTML ( 2 )   PDF (617KB) ( 2 )   Save

    Sugarcane Bagasse(SCB) was used as raw material for enzymatic hydrolysis after pretreatd by peroxyformic acid(PAP). Ethanol was produced by fermentation with hydrolysate, and the effect of hydrogen peroxide(HPP) concentration on the efficiency of enzymatic hydrolysis and ethanol fermentation of SCB was investigated. The results showed that the delignification percentage of pretreated bagasse(PAP-SCB-1) reached 84.30% during PAP pretreatment of SCB when the volume ratio of HPP to formic acid(FAP) was 1∶1. Using the cellulase dosage of 10 FPIU/g(based on the mass of pretreated sugarcane bagasse), the glucose yield of PAP-SCB-1 after 72 h hydrolysis was 98.21%, which was 9.84 and 12.98 times higher than that of pretreated bagasse with hydrogen peroxide(HPP-SCB, glucose yield 9.11%) and formic acid(FAP-SCB, glucose yield 7.06%), respectively. The ethanol yield was 84.06% with the enzymatic hydrolysate fermentation for 24 h, which was higher than that of HPP-SCB(76.20%) and FAP-SCB(75.15%). The chemical composition, specific surface area and crystallinity of the materials before and after pretreatment were measured. The results showed that the lignin in bagasse could be significantly removed after pretreatment with PAP, and the lignin content was reduced from 21.27% without pretreatment to less than 10%. The specific surface area and crystallinity of PAP-SCB-1 were increased up to 13.01 m2/g and 54.18%, which were 10.66(11.39) and 1.11(1.15) times higher than those of FAP-SCB(HPP-SCB).

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    Thermal Behavior and Kinetic Analysis for Co-pyrolysis of Camellia oleifera Shell and Polypropylene
    Xingli DENG, Shaojian JIANG, Zhihong XIAO, Changzhu LI, Xudong LIU, Ying LI
    2022, 56 (5):  37-42.  doi: 10.3969/j.issn.1673-5854.2022.05.006
    Abstract ( 2 )   HTML ( 1 )   PDF (537KB) ( 4 )   Save

    To study the effects of mixing ratio on the co-pyrolysis thermal behavior and kinetic parameters of Camellia oleifera shell(CS) and polypropylene(PP), CS and PP were mixed at different mass ratios(3∶7, 5∶5 and 7∶3) to carry out thermogravimetric experiment and kinetic analysis from 50 to 800 ℃ with the heating rates of 5, 10, 15 and 20 ℃/min. The result of thermogravimetric experiment indicated that the co-pyrolysis of mixed samples could be divided into two stages. When the temperature was lower than 352 ℃, the pyrolysis of CS played a leading role in the pyrolysis of mixed samples and PP promoted the pyrolysis of CS. When the temperature was higher than 352 ℃, the pyrolysis of PP dominated the pyrolysis of mixed samples and the pyrolysis of CS played an inhibitory role. The results of kinetic analysis showed that the FWO method was suitable for the kinetic analysis of pyrolysis and co-pyrolysis of CS and PP, and the average apparent activation energy of the mixed samples with a mass ratio of 3∶7 between CS and PP was the lowest(217.04 kJ/mol), which was 54.3% lower than that of CS pyrolysis alone(474.94 kJ/mol).

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    Evaluation and Product Analysis of Large-scale Continuous Biomass Carbonization Equipment
    Biao MA, Ru LI
    2022, 56 (5):  43-50.  doi: 10.3969/j.issn.1673-5854.2022.05.007
    Abstract ( 1 )   HTML ( 1 )   PDF (2646KB) ( 2 )   Save

    At present, there were some problems existing in the large-scale production of domestic agricultural straw waste biomass pyrolysis carbonization equipment, such as unstable operation, low straw carbonization yield and difficult recovery, etc. Using rice husk and corn straw molding particles as raw materials, the situation of long-time continuous carbonization in this large-scale continuous biomass carbonization equipment was studied, and the applicability and stability of this equipment were analyzed systematically. The equipment was composed of a carbonization unit, a gas separation unit, and a biochar discharge unit. The carbonization unit adopted a double-layer sleeve structure, where the inner layer was a carbonization chamber and the outer layer was a gas heating chamber. The high calorific value biomass gas produced by biomass carbonization was recovered and then combustion-heated to realize the continuous operation of pyrolysis carbonization process. The results showed that the design of the biomass carbonization equipment was reasonable, which could satisfy the carbonization of different raw materials and realize the continuous and stable carbonization of rice husk and corn stalk particles for a long time. The carbonization capacity could reach 490 kg/h. When the carbonization temperature was controlled at around 500 ℃, the yield of biochar was more than 37%. After pyrolysis, the solid, liquid, and gas phases were completely separated, and the gas was recycled.

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    Technical Study and Kinetic Analysis of the Treatment of Refined Soybean Oil Wastewater by Trichosporon fermentans
    Song WU
    2022, 56 (5):  51-57.  doi: 10.3969/j.issn.1673-5854.2022.05.008
    Abstract ( 3 )   HTML ( 2 )   PDF (584KB) ( 4 )   Save

    The treatment of the refined soybean oil wastewater by Trichosporon fermentans was optimized by orthogonal test in a 5 L stirred reactor. By the range analysis, the optimal conditions for biological treatment of refined soybean oil wastewater were temperature of 28 ℃, rotating speed of 300 r/min, air intake of 2 L/min, and inoculation amount of 10%. After 36 h operation under these conditions, the removals of COD and oil content of the refined soybean oil wastewater were 97.31% and 89.09%, and the biomass and lipid content reached 9.27 g/L and 51.9%, respectively. The Monod, Tessier, and Moser models were applied to study the biomass growth of Trichosporon fermentans and the pollutant degradation of the refined soybean oil wastewater, and it was found that the Tessier model was more suitable for studying the growth of microorganisms than those of the Monod and Moser models. The kinetic equations for the biomass growth of Trichosporon fermentans were established, and the corresponding parameters were obtained and applied to assess the design and operation of a bioreactor for the treatment of oily wastewater.

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    Effect of Heavy Turpentine's Middle Distillate on the Rectification of Longifolene
    Xingyue TANG, Jihua GUAN, Mi QIU, Shunzhong LU, Yan CHEN, Guoliang XU
    2022, 56 (5):  58-62.  doi: 10.3969/j.issn.1673-5854.2022.05.009
    Abstract ( 1 )   HTML ( 1 )   PDF (500KB) ( 2 )   Save

    In order to reduce the influence of middle distillate on the rectification of high-purity longifolene in real production, the mass fraction of middle distillate in the process of isolating longifolene from heavy turpentine was monitored, and the relative density and refractive index of the product were measured. The experimental results showed that longipinene and (+)-longicyclene existed in the whole process of longifolene rectification, and the effect of longipinene was significantly higher than that of (+)-longicyclene. Under the operating pressure of -0.1 MPa, the tower kettle temperature of 150 ℃, and the reflux ratio of 1∶7, the distillation of heavy turpentine was carried out. In this process, the influence of the middle distillate on the longifolene rectification could be minimized by adjusting the reflux ratio or lowering the temperature of the column kettle. When the d20 of the top distillate was between 0.926 0 and 0.926 3 and the reflux ratio was adjusted to 10∶1(or the temperature of the tower reduced to 140-150 ℃ when the mass fraction of longifolene in the overhead distillate exceeded 30%), or the temperature of the tower increased to 150 ℃ when the d20 of overhead distillate was greater than 0.933 5, more than 90% longifolene could be obtained, and the total mass fractions of longipinene and(+)-longicyclene was less than 1.5%.

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    Review Comment
    Research Progress of Rhamnolipid Production from Waste Carbon Resources
    Shixun LIU, Haojie LIU, Jie ZHOU, Ning XU, Fengxue XIN, Weiliang DONG, Min JIANG
    2022, 56 (5):  63-71.  doi: 10.3969/j.issn.1673-5854.2022.05.010
    Abstract ( 3 )   HTML ( 1 )   PDF (1096KB) ( 3 )   Save

    Rhamnolipid(RL) was a kind of glycosolipid biosurfactant synthesized by microorganism with excellent surface activity, physical and chemical properties, and broad application prospect. Pseudomonas aeruginosa was the main strain for RL production, which could produce RL by fermentation with a variety of water-soluble carbon sources or hydrophobic carbon sources as substrates. At present, waste and pollution caused by waste carbon resources(WCR) were increasingly serious, based on the characteristics of RL and the substrate preference of producing strain, the production of RL from waste carbon resources had great development potential. In this paper, the research progress of RL production using waste oils(ioly wastewater, food processing waste oil and kitchen waste iol), sugary waste(sugar-containing food processing by-products, sugar-containing fruit and vegetable waste and lignocellulose) and waste plastics was introduced. The effects of different substrates and producing strains for RL yield were mainly highlighted. By analyzing the current status of WCR utilization, it was found that various species, low classification degree, and unbiodegradable ingredients were the main factors restricting the further development of RL production using WCR as substrates, and the future development direction of RL production based on WCR was also pointed out.

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    Research Progress of Carbon-based Catalysts Applied in Thermal Conversion Process
    Xiaopeng SHI, Zhongfeng ZHANG, Xiaoru WANG, Pan LI, Shuqi FANG, Chun CHANG
    2022, 56 (5):  72-78.  doi: 10.3969/j.issn.1673-5854.2022.05.011
    Abstract ( 3 )   HTML ( 2 )   PDF (599KB) ( 4 )   Save

    Biochar had the advantages of environmental friendliness, wide sources, and low cost. It was widely used as catalyst and catalyst carrier in thermal conversion processes, while there were problems such as easy coking and inactivation and the unclear directional regulation mechanism of product. In this paper, the research progress on the application of biomass char-based catalysts for thermal conversion processes was reviewed, and the research status of preparation and modification(heteroatom doping and metal loading) schemes of biomass char-based catalysts were introduced. The application of char-based catalysts was discussed from five aspects: conventional catalytic pyrolysis, microwave-assisted pyrolysis, tar removal, esterification synthesis of transportation fuels, and hydrothermal liquefaction. Exploring the deep catalytic mechanism of catalysts and construct multistage char-based catalysts with multi-stage pore structure for targeted production of high-value chemicals were a future research direction as the future research directions.

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