Please wait a minute...
Table of Content
10 May 2023, Volume 42 Issue 5
    Invited review
    Carbon footprint assessment technology and its application in key industries
    LIU Hanxiao, WU Liming, LIN Qingyang, ZHOU Ye, LUO Xiang, GUI Zhijun, LIU Xiaowei, SHAN Sike, ZHU Qianlin, LU Shijian
    2023, 42(5):  2201-2218.  doi:10.16085/j.issn.1000-6613.2022-1501
    Abstract ( 11 )   HTML ( 2)   PDF (1524KB) ( 3 )  
    Figures and Tables | References | Related Articles | Metrics

    As our country’s carbon footprint research is started late, the establishment of a thorough carbon footprint assessment system is an inevitable choice for us to effectively cope with complex international relations and increasingly fierce international low-carbon economic competition, scientifically promote and guide the development of green and low-carbon transformation, and orderly achieve the “double carbon” goal. Based on domestic and foreign literature research, the carbon footprint concept, carbon footprint assessment methods, carbon footprint assessment standards, carbon footprint assessment boundary division and data acquisition were reviewed and analyzed systematically. Although the academic definition of carbon footprint was not yet completely unified, more people tended to elaborate it from the perspective of the whole life cycle. In this paper, the concept of carbon footprint of industrial products was supplemented and improved from the perspectives of the “whole life cycle” and “whole process”. Compared with the input-output analysis method (IOA), the life cycle assessment method (LCA) was relatively leading in development, had certain advantages in universality, systematization and quantification, and expanded the product system in time and space, but it still needed to be further improved in the terms of the truncation error control, data quality assurance and unification of standard system, etc. PAS2050, GHG Protocol and ISO14067 were currently the most widely used whole life cycle carbon footprint assessment standards. However, more detailed, precise and clear Product Category Rules (PCR) were needed for specific product categories. Based on the above research summary and the analysis of the application progress of carbon footprint assessment technology in key industrial emission control industry such as electric power, steel, cement, petroleum and chemical industry, the problems existing in the current research and the challenges facing the development of our country's carbon footprint assessment technology were proposed: ①The localization carbon emission database of the whole life cycle and whole process of multiple fields had yet to be improved; ②A high-precision, standardized and internationally recognized carbon footprint assessment methodology had yet to be built; and ③The research on the combination of carbon footprint and quantitative assessment of carbon emission reduction was not in-depth enough, and there were few landmark demonstration projects that supported the implementation of carbon footprints for low-carbon solutions. In the future, it was necessary to further explore the combination of carbon footprint assessment technology with carbon emissions accounting and carbon trading research, combine product carbon footprint with product carbon labeling and Environmental Product Declaration (EPD), and give full play to the role of carbon footprint assessment technology in promoting scientific and orderly carbon reduction, guiding green and low-carbon consumption, and responding to trade barriers, etc. This paper could provide a reference for promoting the establishment of a comprehensive, scientific, accurate and standardized carbon footprint assessment system in China.

    Chemical processes and equipment
    Research progress of cyclone-enhanced separation based on disperse phase rearrangement at the inlet
    SONG Minhang, ZHAO Lixin, XU Baorui, LIU Lin, ZHANG Shuang
    2023, 42(5):  2219-2232.  doi:10.16085/j.issn.1000-6613.2022-1382
    Abstract ( 9 )   HTML ( 1)   PDF (5137KB) ( 3 )  
    Figures and Tables | References | Related Articles | Metrics

    With the rapid progress of industrialization, cyclone separators suitable for separating multiphase immiscible media have been widely used in key industries such as petrochemical and environmental protection. In order to improve the separation efficiency of the dispersed phase in the whole particle size range, a variety of cyclone separation enhancement technologies have emerged. Among them, the efficiency enhancement technology of rearranging the dispersed phase at the inlet of hydrocyclone has shown important application value and promotion prospects, owing to the advantages of low manufacturing and operating cost, easy implementation, and obvious enhancement effect. This paper focuses on the efficiency enhancement technology for the rearrangement of the dispersed phase at the inlet segment. The efficiency enhancement principle of dispersed phase rearrangement based on inertial force and centrifugal force fields, the rearrangement structure types, and the enhancement technologies and research results applied to the dispersed-phase rearrangement in liquid-liquid, solid-liquid, and gas-solid were systematically analyzed. On this basis, the technical route of disperse-phase rearrangement was summarized and the research prospects were also carried out from the following three aspects: the organization and construction of multiple liquid flows after rearranging the dispersed phase, the selection of swirl field injection positions for promoting cooperative and efficient separation of multiple streams, and the enhancement of agglomeration growth and/or inertial collisions during disperse phase movement. The relevant analysis and conclusions aim to guide the separation enhancement and optimization design of hydrocyclones, and to improve the separation efficiency.

    Research progress on simulated moving bed separation process and its optimization methods
    LING Shan, LIU Juming, ZHANG Qiancheng, LI Yan
    2023, 42(5):  2233-2244.  doi:10.16085/j.issn.1000-6613.2022-1321
    Abstract ( 9 )   HTML ( 0)   PDF (1825KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    The simulated moving bed technology has the advantages of high yield, high purity and process continuity, which makes it applicable for multi-component system and complicated system containing components with similar properties. However, the process design and optimization are always the important and challenging works for its research and application. In this paper, the separation mechanism and various modifications of simulated moving bed were firstly introduced, and then the widely used sequential simulated moving bed technology was emphatically described due to its unique separation mode and superior performance. Based on this background, diverse optimization methods and research progress of simulated moving bed area were summarized and analyzed. At first, the conventional triangle theory was investigated and its important applications and limitations were summarized. Furthermore, several optimization methods, such as sequence quadratic programming algorithm, standing wave design, separation volume analysis and multi-objective optimization method based on NSGA-Ⅱ algorithm were reviewed, respectively. The literature analysis revealed that in addition to multi-objective optimization, both the basic triangle theory and other optimization methods showed many limitations in parameter selection and experiment design. The multi-objective optimization method was proved to perform better and suitable for most simulated moving bed modes, which would have great development potential and application prospects in the future.

    Energy saving optimization of cyclohexane three-effect distillation in cyclohexanone production
    WANG Dong, YU Pinhua, CHEN Bin, XIAO Ang, CHEN Feng, JIANG Yangyang
    2023, 42(5):  2245-2251.  doi:10.16085/j.issn.1000-6613.2022-1252
    Abstract ( 7 )   HTML ( 0)   PDF (898KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    According to the process characteristics of a 60kt/a cyclohexanone unit, the whole process calculation model of three-effect distillation of cyclohexane oxidation product separation system was established by using Aspen plus simulation software and NRTL physical property method, and the data were optimized. Taking the cyclohexanone and cyclohexanol content of overhead distillates of 1st alkane tower, 2nd alkane tower, 3rd alkane tower and the amount of hot/cold cyclohexane sent out as constraints, the variables such as reflux of each distillation tower, reflux ratio of 1st alkane tower and 2nd alkane tower, reflux of alkane 3rd tower and steam consumption were optimized, and the optimized process parameters were applied to the energy-saving optimization of actual production units. The results showed that the steam consumption can be reduced from 5.53kg/s to 3.9kg/s theoretically under the condition of 8.02kg/s total reflux of 1st alkane tower and 2nd alkane tower, 0.67 reflux ratio of 1st alkane tower and 2nd alkane tower, and 17.93kg/s reflux of 3rd alkane tower. The actual optimization results showed that 0.28kg/s steam could be reduced and the annual operation cost could be reduced by about 1.44 million yuan.

    Super-quadric discrete element method investigation of mixing behaviors of cylindrical particles in a rotating drum
    LU Xingfu, DAI Bo, YANG Shiliang
    2023, 42(5):  2252-2261.  doi:10.16085/j.issn.1000-6613.2022-1373
    Abstract ( 6 )   HTML ( 0)   PDF (4373KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    The cylindrical particles were characterized by a super-quadric model under the discrete element method (DEM) framework and the effects of aspect ratio (AR) and rotating speed on the mixing and diffusion characteristics of cylindrical particles in a rotating drum were studied. The results showed that enlarging AR increased the inter-locking and packing effects, leading to a higher elevation height and steeper inclination angle of free surface. Three mixing mechanisms were illuminated in the rotating drum: ①macro-scale convection mixing induced by particle internal circulation; ②meso-scale shear mixing induced by active-passive layers relative motion; ③micro-scale diffusion mixing induced by particle diffusion. Under the given operating parameters, cylindrical particles with the AR of 2 had the largest time-averaged mixing index while cylindrical particles with the AR of 4 had the smallest time-averaged mixing index. The primary factor influencing the mixing rate was rotating speed. Increasing the rotating speed enhanced the kinematic of cylindrical particles, and slightly increased the axial diffusion coefficients. The axis of cylindrical particles in the active layer tended to have the orientation in the range of 0°—30° while cylindrical particles in the drum preferred to be perpendicular to the drum axis. Computational costs for the cylindrical particles using the super-quadric model were higher than that for the spherical particles and increasing the AR increased computational costs.

    Separation of lysozyme from egg white by electrodialysis with ultrafiltration membrane(EDUF) process
    SUN Luqin, LU Huixia, WANG Jianyou
    2023, 42(5):  2262-2271.  doi:10.16085/j.issn.1000-6613.2022-1293
    Abstract ( 8 )   HTML ( 1)   PDF (2398KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Lysozyme (LYZ) is a natural active protein with stable chemical properties, non-toxic and antibacterial function. Lysozyme with high purity and high activity has great value in the fields of food and medicine. In this paper, a novel electrodialysis with ultrafiltration membrane (EDUF) technology was used to directly separate LYZ from egg white based on the difference in charge and molecular weight between ovalbumin (OVA) and LYZ under specific pH conditions. The effects of ultrafiltration membrane material and the solution flow rates in feed and recovery compartments on the separation performance of EDUF were investigated. Results showed that the recovery rate and purity of LYZ could respectively reached 21.05% and 100% by using PVDF100Ⅰmembrane when the operating voltage was 5.0V and the solution flow rates in feed and recovery compartments were both 50mL/min. The final transport rate of LYZ was 0.21g/(m2·h) and energy consumption per unit product was 2.30kW·h/g under the tested conditions. This study demonstrates that EDUF, as an unique electro-driven membrane separation technology, has remarkable characteristics with its high selectivity. EDUF technology has good application prospects in the field of high-efficient separation of active proteins.

    The influence of the wall on the mesoscale drag force in a gas-solid downer
    YUAN Shouzheng, CHEN Xiao, JIANG Ming, YU Yaxiong, ZHOU Qiang
    2023, 42(5):  2272-2281.  doi:10.16085/j.issn.1000-6613.2022-1268
    Abstract ( 6 )   HTML ( 0)   PDF (1931KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    The construction of traditional mesoscale drag models is usually based on fine-grid simulation databases in full-periodic domains, without considering the effect of the wall. The wall conditions in a real fluidized bed reactor can affect the inhomogeneous structure in near-wall regions, which further affects the drag force on particles in these regions. Therefore, it’s necessary to study the wall effect influence on the mesoscale drag model. By comparing the radial profile of the relative error for mesoscale drag correction coefficient in the quasi-two-dimensional full-periodic system and downers with different bed widths, the regression phenomenon of the mesoscale drag force toward the full-periodic system drag force in the periodic downer fluidized bed was explored. Here, the mesoscale drag correction coefficient was the ratio between the mesoscale drag coefficient and the corresponding microscopic drag coefficient. The influence factors of the radial profiles for mesoscale drag correction coefficient were analyzed. The results showed that the ratio of the distance affected by boundary walls to the entire bed width changes little under different bed widths, and the relative error for drag coefficient was affected by factors such as solid holdup, solid holdup gradient, solid shear rate and granular temperature distribution. The formula of drag coefficient relative error with respect to the radial position was developed. The influence of the filter scale on the drag coefficient relative error was discussed. The study also showed that the wall effect was not implicitly included in drag modes with markers such as gas-solid slip velocity and pressure gradient of the gas phase. Therefore the developed formula was also suitable for correcting these models when the wall effect was considered.

    Effect of groove width on pool boiling heat transfer characteristics in 3D printing groove structure
    LIU Houli, GU Zhonghao, YANG Kang, ZHANG Li
    2023, 42(5):  2282-2288.  doi:10.16085/j.issn.1000-6613.2022-1211
    Abstract ( 4 )   HTML ( 0)   PDF (2301KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Surface microstructure is an important means to enhance boiling heat transfer, and it is significant to study the influence of microstructure size on boiling heat transfer characteristics. In this paper, selective laser melting (SLM) technology was used to fabricate channel structure samples with different widths, and the experimental study of pool boiling heat transfer characteristics under atmospheric pressure was carried out. The results showed that compared with the smooth copper surface, the heat transfer coefficient (HTC) and critical heat flux (CHF) of the groove structure with the groove length of 2.3mm and the groove width of 0.5—2.3mm were significantly improved. CHF of channel structure first increased and then decreased with the increase of channel width, and HTC decreases with the increase of channel width. CHF reached a maximum of 331.5W/cm2 at a channel width of 0.9mm, which was 3 times that of a smooth copper surface, and the HTC was 1.7 times that of the smooth surface. Smaller channel widths increased the heat transfer area of the specimen, limited the bubble departure diameter, and then increased the bubble separation frequency, which was a key factor for HTC enhancement. The gas-liquid flow resistance limitation and hydrodynamic instability in the channel were the key control factors for CHF enhancement in channel structure.

    Influence mechanism of skeleton structure of foamed SiC corrugated structured packing on the mass transfer performance
    CHEN Weiliang, GAO Xin, LI Hong, LI Xingang
    2023, 42(5):  2289-2297.  doi:10.16085/j.issn.1000-6613.2022-1213
    Abstract ( 5 )   HTML ( 0)   PDF (2681KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    Mass transfer performance and operating pressure drop of six structured corrugation foam packing (SCFP) were evaluated and compared using a ϕ100mm×2000mm packing performance test column with ethanol/n-propanol as the model system. The column was operated under atmospheric pressure and total reflux conditions. The results showed that the two types of packing had excellent mass transfer performance within the gas phase load measured by the experiment, and the theoretical plate was at least 5 pieces per meter. The SiC-SCFP displayed a better mass transfer performance than Si-SiC-SCFP. With the increase of porosity, the mass transfer performance of Si-SiC-SCFP decreased, while the performance of Si-SCFP was improved. The increase of compression ratio was beneficial to the mass transfer performance of Si-SCFP. In terms of pressure drop performance, the operating pressure drop of the six packings all increased with the gas phase load, but there was little difference between them. At the same time, the liquid flow on the surface of the SCFP packing sheet was conducted, and the wetting area and transverse wetting length of liquid on different packing surfaces were compared. The packing sheet with higher mass transfer efficiency had better liquid wetting effect on the surface, with larger wetting area and longer transverse wetting length.

    Study on optimization limits of dehydration and desalination pretreatment of hydrogenated coal tar
    ZHANG Lele, QIAN Yundong, ZHU Huatong, FENG Silong, YANG Xiuna, YU Ying, YANG Qiang, LU Hao
    2023, 42(5):  2298-2305.  doi:10.16085/j.issn.1000-6613.2022-1244
    Abstract ( 6 )   HTML ( 0)   PDF (3454KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Pretreatment of coal tar by dehydration and desalination is the key to ensure the lasting operation of the subsequent hydrogenation reaction and the safety of the equipment. However, the special properties and the complex composition of coal tar lead to the bad performance and the difficulty of regulation in the current pretreatment system. Based on the pretreatment process of a large coal tar hydrogenation unit, the two key factors of the dehydration effect and the desalination effect were studied. Firstly, the dehydration and desalination limits of non-thermophysical separation were analyzed. Moreover, the pilot test of the combination of a fiber coalescence separator and an enhanced sedimentation device was conducted to obtain the separation limit of coalescence and sedimentation and evaluate the influence of salt washer series and water injection rate. Under the optimal conditions of 6% water injection rate, three-stage salt washers in series, 0.003m/s superficial velocity of the fiber coalescence and the settling residence time of more than 60min, the water content of coal tar was reduced to 3.1% and the salt content was reduced to 2.81mg/kg, both of which were close to the theoretical separation limit. The results would provide a new idea for the process design and operational optimization of the pretreatment unit.

    Effects of built-in tube bundle arrangements on solid particle flow characteristics in heat exchangers
    QI Chenglu, ZHANG Zhongliang, WANG Mingchao, LI Yaopeng, GONG Xiaohui, SUN Peng, ZHENG Bin
    2023, 42(5):  2306-2314.  doi:10.16085/j.issn.1000-6613.2022-1383
    Abstract ( 17 )   HTML ( 0)   PDF (1851KB) ( 4 )  
    Figures and Tables | References | Related Articles | Metrics

    The horizontal heat exchange tube bundle is an important factor affecting the flow uniformity of solid particles in the heat exchanger. The discrete element method was used to construct the flow calculation model of the built-in horizontal tube bundle solid particle heat exchanger. Effects of tube bundle arrangements and horizontal tube distance on the flow of solid particles in the heat exchanger were studied. The results showed that the uniformity of particle flow through the staggered tube bundle was better than that of the in-line tube bundle. The particle flow non-uniformity number of the staggered tube bundle was 0.00721, which was 42.3% lower than that of the in-line tube bundle. The standard deviation of particle residence time of the staggered tube bundle was 0.029, which was 39.1% less than that of the in-line tube bundle. With the decrease of the horizontal heat exchange tubes distance, the degree of deformation of the particle layer and the fluctuation of residence time would increase if the particles passed through the staggered tube bundles. And at the same time, the uniformity of particle flow deteriorated significantly. The particle flow non-uniformity number increased from 0.00721 to 0.00996, an increase of 38.1%. The increase from 0.029 to 0.039 was the standard deviation of particle residence time, which increased by 33.8%. The difference in particle velocity in the shear zones was enlarged, and the average particle velocity gradient increased from 5.97×10-4s-1 to 7.85×10-4s-1, an increase of 31.4%.

    Analysis of convective heat transfer and thermo-economic performance of Al2O3-CuO/water hybrid nanofluids
    GUO Wenjie, ZHAI Yuling, CHEN Wenzhe, SHEN Xin, XING Ming
    2023, 42(5):  2315-2324.  doi:10.16085/j.issn.1000-6613.2022-1222
    Abstract ( 7 )   HTML ( 0)   PDF (2704KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    To investigate the single-phase heat transfer performance of hybrid nanofluid in a tube, the flow and heat transfer characteristics of Al2O3-CuO/water (W) hybrid nanofluid and its corresponding mono nanofluid were comparatively investigated under Reynold number of 1040—7086 and volume fraction of 0.02%, respectively. The results indicated that the addition of particles led to the advancement of Reynolds number range in the transition zone. Compared with deionized water, the maximum Nu enhancement of Al2O3/W and Al2O3-CuO/W nanofluids was 32.09% and 38.38% under laminar region (1040<Re<1891), respectively, however, the heat transfer performance of CuO/W nanofluids was worse than that of water. The reason was that the forward driving force of CuO/W nanofluid was not sufficient to overcome the self-weight and it was easy to deposit on the inner wall of the tube. In the turbulent flow region (4073<Re<7806), the heat transfer performance of all studied nanofluids was more remarkable than that of water in the combination of strong forward driving force and the rotation of fluid molecules themselves. The Al2O3-CuO/W hybrid nanofluids had the optimum heat transfer performance under turbulent flow region. Considering the comprehensive heat transfer performance and economic factor, the most suitable nanofluids were Al2O3/W and Al2O3-CuO/W nanofluids for practical application under the laminar and turbulent flow regions, respectively.

    Energy processes and technology
    Analysis of the influence of heating transformation on the performance of thermal power unit
    WANG Zijie, LU Shuyin, ZHAO Ziliang, WANG Ning, GU Yujiong
    2023, 42(5):  2325-2331.  doi:10.16085/j.issn.1000-6613.2022-1390
    Abstract ( 21 )   HTML ( 7)   PDF (2286KB) ( 4 )  
    Figures and Tables | References | Related Articles | Metrics

    To solve the problem of energy consumption increase caused by the operation load exceeding the design range after unit heating or heating cascade utilization transformation, a new energy consumption evaluation method for heating transformation was proposed in this paper. Taking a 600MW unit in China as an example, the thermodynamic model of the unit was established using Ebsilon software, and the correctness of the model was verified. The distribution law of heat rate and output energy of the unit under different heating transformation parameters and thermoelectric loads were analyzed using the heat rate as the unit performance evaluation index. Then the concepts of heating economic benchmark line and heating economic operation area were proposed. The results showed that the minimum heating extraction pressure of the unit had an obvious influence on the generating power of the low-pressure cylinder of the unit. With the increase of the minimum heating extraction pressure, the scope of the heating economic baseline gradually moved to the right, and the scope of the heating economic operation area was gradually reduced. When the unit load was located on the left side of the heating economic baseline, the unit heating energy consumption increased. when the unit load was located on the right side of the heating economic baseline (heating economic operation area), the unit heating energy consumption decreased. Therefore, the actual operation process of the unit after heating and heating cascade utilization transformation was not necessarily energy-saving, and the transformation parameters should be reasonably selected according to the load range of the unit.

    Performance evaluation of the multiple layer latent heat thermal energy storage unit combined with nanoparticle for heat transfer enhancement
    ZHANG Chenyu, WANG Ning, XU Hongtao, LUO Zhuqing
    2023, 42(5):  2332-2342.  doi:10.16085/j.issn.1000-6613.142022-1366
    Abstract ( 7 )   HTML ( 0)   PDF (2268KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Using latent heat thermal energy storage (LHTES) system can alleviate the mismatch between the energy supply and demand. In this paper, a vertical shell and tube LHTES unit was designed, and multiple layer phase change materials (PCMs) with melting temperatures of 35℃, 42℃, and 50℃ were filled. The nanoparticle of Al2O3 was added in PCM and heat transfer fluid for heat transfer enhancement. The thermal energy and exergy performance of the multiple LHTES unit were compared with the single layer unit. The thermal energy and exergy density evaluation criteria that comprehensively considered the volume of the composite PCM and the heat storage time were proposed. The effects of different nanoparticle volume fractions (1%, 3%, 5%, 7%, 9%, and 11%) on the performance of the multiple LHTES unit were analyzed. The results showed that compared to the single layer unit with a melting temperature of 50℃ of composite PCM, the heat storage time of the multiple LHTES unit was reduced by 29.81% under the same condition. Moreover, the multiple LHTES unit simultaneously presented higher thermal energy and exergy storage amounts. When the volume fraction of nanoparticles increased from 1% to 11%, the heat storage rate of the multiple LHTES unit could be improved by 21.31%, the thermal energy storage density increased by 15.61%, and the thermal exergy density decreased after reaching the maximum value of 3086J/(m3·s) at the volume fraction of the nanoparticle of 7%. Considering the volume of composite PCM, heat storage time, and total thermal energy and exergy storage amounts, the multiple LHTES unit presented the best performance with a nanoparticle volume fraction of 7%. Compared with the nanoparticle volume fraction of 1%, the thermal energy and exergy storage densities increased by 11.57% and 12.96%, respectively. This paper provided a theoretical reference for the application and optimization of multiple LHTES systems.

    Effect of raw material composition on the development of semicoke mesophase structure
    XU Xian, CUI Louwei, LIU Jie, SHI Junhe, ZHU Yonghong, LIU Jiaojiao, LIU Tao, ZHENG Hua’an, LI Dong
    2023, 42(5):  2343-2352.  doi:10.16085/j.issn.1000-6613.2022-1276
    Abstract ( 6 )   HTML ( 0)   PDF (3498KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Semicoke with different microstructures was prepared from medium and low temperature coal tar full distillate hydrogenation tail oil (FHT) and >350℃ medium and low temperature coal tar pitch (CTP). The composition and structure of the raw materials were characterized by means of elemental analysis, 1H NMR spectroscopy, Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry, and the influence of the raw material composition on the development of the mesophase structure was studied. The results showed that: FHT contained 25.94% naphthenic and the side chain of aromatic ring was dominated by naphthenic structure, while CTP contained 3.92% naphthenic and the side chain of aromatic ring was dominated by short alkyl groups. The content of oxygen-containing heterocyclic compounds in FHT was lower than that in CTP. Thermal polymerization experiments showed that the raw material (FHT) with high content of naphthenic structure and low content of oxygen-containing heterocyclic compounds was beneficial to reduce the carbonization reaction activity and viscosity of the reaction system, and promote the orderly development of the mesophase. Polarizing microscope, scanning electron microscope and X-ray diffraction were used to analyze the microstructure and crystallite parameters of the semicoke. The results showed that CTP had high oxygen content and QI content, which was easy to form mosaic structure, distorted crystallite arrangement, and poor orientation. On the other hand, FHT was rich in naphthenic structure and low in oxygen content, and the aromatic hydrocarbon sheet molecules were easier to stack in an orderly manner to form a fine fiber structure, and the internal carbon crystallites were arranged more regularly, making it easier to graphitize. In addition, the optical structure of the semicoke was quantitatively analyzed by fiber software, and it was found that the fiber structure content of the semi-coke prepared by FHT was 79.84%, while that of the semi-coke prepared by CTP was 22.18%.

    Industrial catalysis
    Oxygen evolution cocatalyst enhancing the photoanode performances for photoelectrochemical water splitting
    FU Shurong, WANG Lina, WANG Dongwei, LIU Rui, ZHANG Xiaohui, MA Zhanwei
    2023, 42(5):  2353-2370.  doi:10.16085/j.issn.1000-6613.2022-1322
    Abstract ( 6 )   HTML ( 0)   PDF (4077KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    Hydrogen is recognized as the ideal “carbon neutrality” energy carrier due to its remarkable properties including high heat value, low density, storable and no carbon emission. Photoelectrochemical water splitting offers the most promising approach to convert solar energy into green hydrogen fuels. However, the sluggish surface oxygen evolution reaction on the photoanode greatly restricted the photoconversion efficiency. Introducing oxygen evolution cocatalyst on the photoanode has been proven to be a feasible strategy for promoting the charge separation, reducing the overpotential, and providing more active sites for water oxidation. Therefore, this review discusses the origin and types of cocatalyst on the photoanode surface, the influence of its micro-nano structure, and the interfacial construction strategy on water oxidation activity, and photoelectrochemical water splitting performance. Firstly, it introduces the types of cocatalyst and summarizes the roles of cocatalyst, the effect of different cocatalysts on the charge separation, transfer and stability of photoelectrode. Moreover, the influencing factors of cocatalyst on photoelectrochemical water splitting are compared and analyzed including size effect, surface defect and fluorination. Furthermore, the interface modulation strategies between cocatalyst and semiconductor are discussed such as the carrier transport channel, hole storage layer, and interface chemical bond. Finally, it discusses the focused problems and prospects the future research direction of the oxygen evolution cocatalyst. It is believed that the photoelectrochemical water splitting performance can be improved by regulating the crystal structure, cluster, single-atom and interface chemical bonding of the oxygen evolution cocatalyst. Moreover, carbonyl metal is suggested as a unique precursor for constructing oxygen evolution cocatalyst.

    Progress in alkylation of gasoline with molecular sieve catalyst for benzene reduction
    WANG Zijian, KE Ming, SONG Zhaozheng, LI Jiahan, TONG Yanbing, SUN Jinru
    2023, 42(5):  2371-2389.  doi:10.16085/j.issn.1000-6613.2022-1204
    Abstract ( 5 )   HTML ( 0)   PDF (4253KB) ( 3 )  
    Figures and Tables | References | Related Articles | Metrics

    With the increasing awareness of environmental protection, the limitation of benzene content in gasoline is becoming more and more stringent. Benzene reduction technologies of gasoline mainly include saturation by hydrogenation, distillation, etherification and alkylation, among which alkylation technology has obvious advantages in improving the octane number and yield of gasoline. The process and reaction mechanism of alkylation with methanol and light hydrocarbons as alkylation reagents, which are widely used at present, are reviewed. The structure and characteristics of typical molecular sieves ZSM-5, MCM-22 and Beta, and their catalytic alkylation characteristics are analyzed in detail. It is pointed out that methanol, when used as an alkylation reagent, needs higher reaction temperature than the light hydrocarbons with high carbon number, but has less influence on the distillation range of gasoline. When light hydrocarbon is used as alkylation reagent, the activation temperature decreases with the increase of carbon number, but it has a great impact on the distillation range of gasoline, and the deactivation of molecular sieves would take place by their promotion of olefin polymerization at low temperature. At present, the application of the three kinds of molecular sieves is difficult to balance the benzene conversion, gasoline distillation range and energy consumption. The development of molecular sieves with suitable pore size, the preparation of composite molecular sieves and hierarchical porous molecular sieves are expected to solve this problem.

    Progress on heterogeneous catalysts for cyclopropanation of diazo compounds
    YUE Xin, LI Chunying, SUN Dao’an, LI Jiangwei, DU Yongmei, MA Hui, LYU Jian
    2023, 42(5):  2390-2401.  doi:10.16085/j.issn.1000-6613.2022-1307
    Abstract ( 19 )   HTML ( 1)   PDF (1965KB) ( 9 )  
    Figures and Tables | References | Related Articles | Metrics

    Heterogeneous cyclopropanation catalysts are classified as metal catalysts, metal-supported catalysts, complex-immobilized catalysts, and MOF-based catalysts. Research progress on the reactive components, supports, immobilization methods and action principles of heterogeneous cyclopropanation catalysts is reviewed in detail. Metal-supported catalysts are easy to prepare and have relatively high activity, selectivity but the stereoselectivity is low, therefore they show better application in fuel-synthesis than medical or pesticide. To improve the stability and expand the reactive components of metal-supported catalysts is the development tendency. Complex-immobilized catalysts have good activity and stereoselectivity with wide adjustability of structure and performance. Nevertheless, optimizing immobilization methods such as using covalent bonding and enhancing synergistic action between supports and ligands by optimizing pore structure and surface group are quite important to promote the catalyst stability and immobilizing strength. MOF-based catalysts exhibit unique properties in cyclopropanation reactions, and the catalytic performance can be improved by defect-engineering (mechanical grind, ligand doping, heat treatment, etc.) which should balance the activity and stability. Furthermore, designing chiral ligands for new MOF-based catalysts to enhance the stereoselectivity is also the important research direction.

    Research progress of low temperature catalytic oxidation of VOCs by metal oxides
    WANG Keju, ZHAO Cheng, HU Xiaomei, YUN Junge, WEI Ninghan, JIANG Xueying, ZOU Yun, CHEN Zhihang
    2023, 42(5):  2402-2412.  doi:10.16085/j.issn.1000-6613.2022-1312
    Abstract ( 6 )   HTML ( 0)   PDF (1046KB) ( 3 )  
    Figures and Tables | References | Related Articles | Metrics

    Metal oxide catalysts with strong oxidation activity and high resistance are hot research topics in catalytic removal of volatile organic compounds (VOCs). In this paper, the effects of preparation factors such as composition ratio, morphology, calcination temperature, preparation method and carrier on catalytic VOCs oxidation activity and carbon dioxide selectivity was compared and analyzed from the perspectives of oxygen vacancies, active oxygen species, structure and crystalline surface. The poisoning mechanism of water vapor, nitrogen oxides and sulfur dioxide during the oxidation reactions in the actual working conditions was elaborated. The action mechanism of oxygen vacancies, lattice oxygen and surface adsorbed oxygen explored in depth by DFT calculations was prospected, and some key factors such as active component dispersion, high active crystalline surface ratio and oxygen vacancy strength can be considered in the optimization of catalysts. This review has provided scientific reference for the research and development of related catalytic systems.

    Characteristics of calcium and magnesium deactivation and regeneration of waste incineration SCR catalyst
    HE Chuan, WU Guoxun, LI Ang, ZHANG Fajie, BIAN Zijun, LU Chengzheng, WANG Lipeng, ZHAO Min
    2023, 42(5):  2413-2420.  doi:10.16085/j.issn.1000-6613.2022-1392
    Abstract ( 6 )   HTML ( 0)   PDF (1430KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    The deactivation characteristics of Ca and Mg of selective catalytic reduction (SCR) denitration catalyst were studied on the catalyst from a domestic waste incineration power plant, and the activity recovery method and mechanism of the waste catalyst were discussed. The denitration performance of new catalyst, deactivated catalyst and regenerated catalyst samples was compared and tested. Scanning electron microscopy (SEM), N2 adsorption-desorption and X-ray fluorescence spectroscopy (XRF) were used to characterize the surface structure and chemical composition of the catalyst samples. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the chemical changes between the deactivated and regenerated catalysts, while NH3 temperature programmed desorption (NH3-TPD) and H2 temperature programmed reduction (H2-TPR) were used to study the acid site changes and redox characteristics of the catalysts. The results showed that due to the deactivation of Ca and Mg, the denitration performance of the deactivated catalyst decreased significantly, and the denitration efficiency in the temperature range of 300—350℃ decreased from more than 95% of the new catalyst to about 80%. However, the denitration capacity was significantly restored by using the method of “EDTA cleaning + active material loading”, and the denitration efficiency of RegCat could be restored to the level of new catalyst in the temperature range of 300—350℃. Ca and Mg formed sulfate on the surface of the catalyst, and consumed a large amount of surface active oxygen, so as to lower the activity of the catalyst. In addition, Ca would also deposit on the catalyst surface in the form of CaO, causing physical deactivation of the catalyst. After the activity recovery, the harmful substances such as Ca, Mg and S on the catalyst surface were effectively removed, and the acid sites and oxidation properties of the catalyst surface were significantly restored.

    CO xco-methanation over a Ni-based catalyst supported on CeO2-Al2O3 composite
    MA Yuan, XIAO Qingyue, YUE Junrong, CUI Yanbin, LIU Jiao, XU Guangwen
    2023, 42(5):  2421-2428.  doi:10.16085/j.issn.1000-6613.2022-1260
    Abstract ( 7 )   HTML ( 0)   PDF (1383KB) ( 3 )  
    Figures and Tables | References | Related Articles | Metrics

    Ni/Al2O3, Ni/CeO2 and Ni/CeO2-Al2O3 catalysts were prepared by impregnation-precipitation method and applied for CO xco-methanation with different ratios of CO/CO2. It was found that the conversion of CO to CH4 was higher over Ni/Al2O3 than thatover Ni/CeO2, while CO2 methanation gave reverse order. Adopting Ni/CeO2-Al2O3 as CO xco-methanation catalyst improved the CO conversion without lessening CO2 conversion. BET, XRD, TPR, TPD and in-situ FTIR characterizations showed that the surface area and dispersion degree of metallic nickel decreased after CeO2 was dopped in Al2O3. However, the CO2 adsorption and activation capacity were increased, because the rich oxygen vacancies on CeO2 would increase the basic sites on the support which activated CO2 to monodentate carbonate, and then be hydrogenated to methane quickly. Limited by the CO2 adsorption capacity and the activity of the medium product-bidentate carbonate, the CO2 conversion over Ni/Al2O3 catalyst was lower than that over Ni/CeO2-Al2O3 catalyst while CO conversion was unaffected during CO xco-methanation.

    Materials science and technology
    Research progress on detection of Cr(Ⅵ) by electrochemically modified electrode
    CHEN Shaohua, WANG Yihua, HU Qiangfei, HU Kun, CHEN Li’ai, LI Jie
    2023, 42(5):  2429-2438.  doi:10.16085/j.issn.1000-6613.2022-1354
    Abstract ( 8 )   HTML ( 0)   PDF (2050KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    With the increasing demand for hexavalent chromium ions detection, electrochemical detection has been widely concerned because of its advantages of high efficiency and economy. This review presented the application of different electroactive layer modified electrodes for the detection of Cr(), comparing the detection effect of different modified electrode materials for Cr() and their respective advantages and disadvantages including inorganic nanomaterials (nano-carbon materials, nano-metals and metal oxides), and organic polymers and organic molecular composites. This review summarized the behavioral mechanisms of different modified electrodes in the detection of Cr(), which were divided into four main categories detection mechanisms: including electrostatic adsorption mechanism of lignin-poly(propylene oxide) copolymer, formation of complexes between nitrogen heterocrown and HCrO4- impeding electron transfer, Cr6+ induced disulfide bond formation causing rGO channel resistance changes and detection of pp-junction interface potential barriers as a driving factor. Finally, prospects were given for the optimal design of the modified electrodes, the improvement of their selectivity, stability and interference immunity, and the enhancement of the detection capability of bare glassy carbon electrodes.

    Development of thermally stable fiber-based air filter materials
    CHEN Mingxing, WANG Xinya, ZHANG Wei, XIAO Changfa
    2023, 42(5):  2439-2453.  doi:10.16085/j.issn.1000-6613.2022-1195
    Abstract ( 8 )   HTML ( 0)   PDF (1802KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    The hot flue gas from the industry is one of the main factors that cause air pollution. Therefore, the purification of hot flue gas is important for the environment and humankind. The fiber-based air filters have attracted much attention in the field of air purification due to its larger specific surface area and higher porosity. However, most fiber materials cannot withstand such high temperatures. In view of this, this paper reviewed the development of thermally stable fiber-based air filters in recent years. The main topics were focused on the raw materials (organic fibers, inorganic fibers) which can be used in the preparation of thermally stable air filters, preparation technologies (needle punching, spun lace, melt-blown, electrospinning, centrifugal spinning, air jet spinning, etc.) and multifunctional modification (denitration, desulfuration, and VOCs removal, etc.) of thermally stable fiber-based air filters. The shortcomings of thermally stable fiber-based air filters were discussed from the preparation to application. The development of thermally stable fibers, preparation technologies and multi-functionalization would be the key points for thermally stable fiber-based air filters. It was expected that thermally stable fiber-based air filters would gain more applications in the future.

    Research progress on intercrystalline defects control and remediation technologies for zeolite membranes
    REN Zhongyuan, HE Jinlong, YUAN Qing
    2023, 42(5):  2454-2463.  doi:10.16085/j.issn.1000-6613.2022-1848
    Abstract ( 6 )   HTML ( 0)   PDF (1687KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Zeolite membranes have been used in pervaporation, membrane distillation, gas separation, etc. due to their high efficiency, energy-saving and stability. However, the intercrystalline defects of zeolite layer seriously reduce the separation performance, which hinders the further application of zeolite membranes. In this paper, the latest researches on the defects control and repair were reviewed and classified as “control during synthesis” or “remediation after synthesis”. In “control during synthesis” section, the factors that caused intercrystalline defects in the process of zeolite layer formation were summarized, including supports properties, zeolite seed properties, seeding method, secondary growth parameters and template-removal method. In “remediation after synthesis” section, necessary modification/blocking technologies were introduced since intercrystalline defects still existed after improved preparation. The general idea about defect elimination was to improve the intergrowth of zeolite crystals, reduce thermally induced cracking and develop more accurate, efficient and energy-saving remediation technology. In the future, to meet higher industrialization requirements, it will be necessary to integrate the defect control and remediation technologies during the whole preparation process, and develop membrane technologies with low cost, low energy consumption and short process.

    Biosynthesis and EOR application of magnetic Fe3O4 NPs
    LIU Yulong, YAO Junhu, SHU Chuangchuang, SHE Yuehui
    2023, 42(5):  2464-2474.  doi:10.16085/j.issn.1000-6613.2022-1246
    Abstract ( 6 )   HTML ( 0)   PDF (2847KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Nano Fe3O4 has attracted extensive attention in the field of petroleum development in recent years due to its unique properties, such as superparamagnetism, small size, low toxicity, and easy separation under external magnetic fields. This paper reviews the biosynthesis and enhanced oil recovery (EOR) application of magnetic Fe3O4 NPs. First, the biosynthesis of magnetite by microorganisms, plant extracts and animals is introduced. Microbial synthesis mainly includes two processes: adsorption of metal ions and reduction mineralization. The synthesis by plant extracts depends on water-soluble metabolites, such as polyphenols, alkaloid and citric acid. Magnetite is also found in animals, which use it to sense the earth’s magnetic field to determine direction. Then, the EOR mechanism and application of Fe3O4 NPs are described. Fe3O4 NPs can form stable emulsion by wrapping oil droplets, reduce interfacial tension, change wettability, improve wave efficiency by improving the viscosity of displacement fluid and reducing the viscosity of heavy oil, and generate separation pressure with wedge structure. Under this mechanism, EOR applications of magnetic Fe3O4 are summarized. Magnetic Fe3O4 NPs is environmentally friendly and has a good application effect in EOR, which has a broad development prospect.

    Recent advances in preparation and application of floating photocatalysts in water treatment
    ZHANG Ning, WU Haibin, LI Yu, LI Jianfeng, CHENG Fangqin
    2023, 42(5):  2475-2485.  doi:10.16085/j.issn.1000-6613.2022-1273
    Abstract ( 6 )   HTML ( 0)   PDF (2079KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Photocatalysis with floating photocatalysts is one of the promising advanced oxidation technologies in water treatment field, which can overcome the recovery problem of nanoparticles. This method relies on the high-efficiency photocatalysts and could be driven by green energy such as sunlight. Pollutants can be efficiently in-situ degraded under the synergistic effects of adsorption and photocatalysis. In this paper, the lightweight construction strategies, morphological structures and pros and cons are summarized from the point of support styles. The advantages and disadvantages of typical composites preparation methods are analyzed and compared, and the applications of floating photocatalysts of different categories in the water treatment field are presented. By summarizing the problems of floating photocatalysts in practical applications, we point out that future research and development of floating photocatalysts should focus on the eco-friendly carriers and the stability of composites. Multifunctional floating photocatalysts as well as coupling technologies can be applied for promoting the large-scale application of high-efficiency photocatalysts in water treatment.

    Recent advances in bionic surfaces for fog collection
    LI Xue, WANG Yanjun, WANG Yuchao, TAO Shengyang
    2023, 42(5):  2486-2503.  doi:10.16085/j.issn.1000-6613.2022-2100
    Abstract ( 6 )   HTML ( 0)   PDF (6904KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Herein, the two theoretical stages of fog collection were described. With the controllable biomimetic structure and surface properties (wettability), developed materials can show a significant efficiency on fog collection. The important research progress of biomimetic surfaces for fog collection in recent years was reviewed and the development of functional materials following the different bio-inspired strategies was discussed. Functional structures and surfaces such as spider silk spindle knots, cactus cone spines, Stenocara beetle hydrophilic/hydrophobic surfaces and the smooth surface of nepenthes were mainly introduced. In an overview of the recent progress in the development of bionic functional materials, the preparation process mainly started from simple functional structure/surface properties, combined with the understanding of the water mass transfer process, and finally realized the reconfiguration of the structure and surface properties (wettability). Biomimetic materials based on spider silk spindle knots and cone spines of cacti were designed to modulate biomimetic functional structures. The results showed that achieving structural modulation enhanced droplet transport and fog collection efficiency. The modulation of surface properties (wettability) was achieved to mimic the Stenocara hydrophilic/hydrophobic surface as well as the smooth surface of nepenthes, enhancing droplet capture. The multifunctional materials formed by coupling of different functions were introduced and the efficiency of fog collection by bionic materials in recent years was summarized. Finally, an outlook on the practical application and future development prospects of bionic materials were provided, pointing out that simplifying material preparation and improving water collection efficiency were still bottlenecks in the actual development process and indicating the development direction of bionic materials.

    Recent advances in crystal plane regulation of zinc metal anodes for intrinsically safe aqueous zinc-ion batteries
    ZHANG Zhicheng, HAN Daliang, FAN Dinghui, TAO Ying, WENG Zhe, YANG Quanhong
    2023, 42(5):  2504-2515.  doi:10.16085/j.issn.1000-6613.2022-1278
    Abstract ( 6 )   HTML ( 0)   PDF (7533KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Aqueous zinc-ion batteries (AZIBs) are considered a promising electrochemical energy storage technology due to their merits of good environmental friendliness, low cost and intrinsically high safety. The zinc dendrite growth caused by the uneven deposition of zinc ions will eventually lead to internal short-circuit of the battery, which severely limits the cycle life of AZIBs and thus hinders their industrialization. Construction of (002) plane preferentially oriented zinc anodes is considered an effective strategy to inhibit the dendrite growth and thus to improve the Coulombic efficiency of zinc anodes. Reviewing the recent research on zinc anodes, this review first overviewed the electrode process of zinc metal anodes and the factors that affected the morphology of zinc deposition. Strategies and the corresponding mechanisms for achieving (002) plane preferentially oriented zinc anodes were then emphatically summarized from the aspects of substrate design, coating design and electrolyte optimization. At last, challenges and future directions for research on (002) plane preferentially oriented zinc anodes were highlighted, especially pointing out that the evaluation of the optimizing strategies for zinc anodes should be made under practical working conditions.

    Research progress on enzyme immobilization on porous framework materials
    MAO Menglei, MENG Lingding, GAO Rui, MENG Zihui, LIU Wenfang
    2023, 42(5):  2516-2535.  doi:10.16085/j.issn.1000-6613.2022-1299
    Abstract ( 8 )   HTML ( 0)   PDF (3932KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Metal-organic framework materials (MOFs) and covalent organic framework materials (COFs) are excellent carriers for enzyme immobilization because of their porous properties, large specific surface area, controllable structure, adjustable pore, designed framework and easy functionalization. In this paper, the structure, properties and functionalization methods of MOFs and COFs were briefly introduced, and following that, the latest research progresses of the two materials in the field of enzyme immobilization were reviewed and compared. MOFs and COFs have one-, two- and three- dimensional structures, among which three-dimensional and a small amount of two-dimensional structures show porosity. For MOFs, the functional groups can be introduced to the surface of the support by various methods including pre-modification, in-situ modification and post-synthetic modification, and enzyme can be immobilized by encapsulation, pore diffusion or surface attachment, so that a large variety of enzymes have been attempted to immobilize on them. For COFs, the functional groups were mainly introduced through post-synthesis modification and enzymes were immobilized by pore diffusion or surface attachment method. Finally, it was pointed out that MOFs had poor water or acid-base stability, the preparation conditions of COFs were harsh, and the reusability of the immobilized enzymes on MOFs and COFs was not satisfying. We should explore more effective modification strategies to improve the stability of MOFs, develop safer preparation methods of COFs, and improve reusability of the immobilized enzymes in the future.

    Hydrothermal carbonization of the lignocellulosic biomass and application of the hydro-char
    WANG Xue, XU Qiyong, ZHANG Chao
    2023, 42(5):  2536-2545.  doi:10.16085/j.issn.1000-6613.2022-1223
    Abstract ( 6 )   HTML ( 0)   PDF (1347KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    Hydrothermal carbonization (HTC) is an efficient way to convert the lignocellulosic biomass to high-value added products. The wide variety of lignocellulosic biomass has complex physiochemical structures, resulting in complicated reactions including hydrolysis, degradation, and polymerization during HTC at different conditions. Characteristics of the hydro-char, such as morphology, pore structure, and the surface functional groups distribution are determined not only by the structure of the raw materials but also the hydrothermal reaction conditions, and directly affect the application of hydro-char. Lignin carbonization requires higher hydrothermal strength than cellulose and hemicellulose. In addition, the resulted hydro-char has a higher degree of graphitization and stability. It could be used as electrical and high temperature resistant materials. Compared to lignin, cellulose and hemicellulose can form porous structure more easily. In the meanwhile, they are rich in hydroxyl groups, the prepared hydro-char has abundant oxygen-containing functional groups, which is beneficial to the electrostatic adsorption and ion exchange. The generated biochar can be applied to the fields of environmental treatment. The hydrothermal temperature mainly affects the degree of carbonization and the yield of hydro-char, while the reaction time affects the morphology of the hydro-char obviously. The properties of hydro-char can be regulated by modification to expand its application. In this paper, the relationship among the composition of raw materials, HTC conditions and the structural characters of hydrothermal products were reviewed; the mechanism of carbonization process was deeply analyzed; the modification methods of hydro-char were discussed; the application of hydro-char in different fields was summarized; and the further development directions of HTC were proposed to provide a reference for the research of biomass-based hydro-char.

    Recent progress of synthesis technology and gas barrier research of poly(butylene succinate)
    LYU Xuedong, LUO Faliang, LIN Haitao, SONG Danqing, LIU Yi, NIU Ruixue, ZHENG Liuchun
    2023, 42(5):  2546-2554.  doi:10.16085/j.issn.1000-6613.2022-1380
    Abstract ( 7 )   HTML ( 0)   PDF (1108KB) ( 3 )  
    Figures and Tables | References | Related Articles | Metrics

    Biodegradable polymers are one of the important materials to thoroughly solve the white pollution problem of plastics. Poly(butylene succinate) (PBS) has excellent combined properties and has been developed as an important biodegradable polymer material. This paper elaborated recent progress of synthesis technology, and systematically introduced the advantages and disadvantages of different synthesis technologies including direct esterification, transesterification, acid anhydride and chain extension. As an important property of PBS to be applied as a food packaging material, the gas barrier properties and its principles were systematically summarized and the progress in the modification of barrier properties was reviewed. Finally, the future research and development direction of PBS was analyzed, and the future research direction of PBS production technology should be high performance, low cost and green process.

    Research progress on the synthesis of excellent impact and transparency polyesters with high glass transition temperature
    DAI Hang, GAO Ruixue, LI Yiguo, ZHU Jin, WANG Jinggang
    2023, 42(5):  2555-2565.  doi:10.16085/j.issn.1000-6613.2022-2069
    Abstract ( 5 )   HTML ( 0)   PDF (1422KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    The polyesters with high glass transition temperature (Tg), excellent impact resistance and transparent were used in many fields, such as machine in kitchen and automobile manufacturing. However, the development of high thermal resistance polyesters also faces some problems, such as the monomers derived from petroleum, the insufficient Tg and only single variety. In this work, the petroleum and bio-based polyesters were introduced based on the different rigid diacids or diols monomers. For petroleum based polyesters, they were synthesized from 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. For bio-based polyesters, they were synthesized mainly from 2,5-furandicarboxylic acid, diacid derived from lignin, camphoric acid and L-tartaric acid, galactosyl acid, betulinol and alien sugar alcohol. In the future, the high glass transition temperature, excellent impact resistance and transparent polyesters derived from 2,5-furandicarboxylic acid or isosorbide would be successful mostly in commerce. The main development direction of high Tg and impact resistant transparent polyester in the future research could be focused on the monomers from renewable materials, higher heat resistance temperature and excellent toughness.

    Research progress on graphitic carbon nitride based materials for supercapacitor
    CHEN Fei, LIU Chengbao, CHEN Feng, QIAN Junchao, QIU Yongbin, MENG Xianrong, CHEN Zhigang
    2023, 42(5):  2566-2576.  doi:10.16085/j.issn.1000-6613.2022-1277
    Abstract ( 6 )   HTML ( 0)   PDF (5016KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Supercapacitors have attracted great attention in the field of energy storage due to their advantages of high-power density, fast storage efficiency, fast discharge speed and long cycle life, etc. Electrode materials are the key factor of supercapacitor to improve their performance. As an excellent electrode material for supercapacitors, g-C3N4 with high nitrogen content, abundant active sites and good stability is favored by researchers. In this paper, the structural characteristics and energy storage mechanism of g-C3N4 based electrode materials for supercapacitor were reviewed, and the performance improvement strategies of the composites were elaborated. Finally, the application research progress of g-C3N4 based supercapacitor electrode materials was summarized. It was indicated that g-C3N4 based materials had excellent application prospects for supercapacitor use.

    Preparation of quaternized/sulfonated chitosan and its anti-biofilm activity
    WANG Lin, XIN Meihua, LI Mingchun, CHEN Qi, MAO Yangfan
    2023, 42(5):  2577-2585.  doi:10.16085/j.issn.1000-6613.2022-1790
    Abstract ( 7 )   HTML ( 0)   PDF (1803KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    N-(2-hydroxypropyl trimethylammonium chloride) chitosan (HTCC), N,N,N-trimethyl chitosan (TMC) and N-(sodium 2-hydroxypropylsulfonate) chitosan (HSCS) were synthesized and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectra and elemental analysis. The antibacterial activity and anti-biofilm activity of quaternized chitosan with different structures (HTCC and TMC), and quaternized chitosan and sulfonated chitosan with similar structures (HTCC and HSCS) were compared. The experimental results showed that the antibacterial rate and biofilm removal rate of chitosan quaternary ammonium salt obtained by direct quaternization of chitosan (TMC) were better than those obtained by grafting quaternization of chitosan (HTCC). The antibacterial activity and antibiofilm activity of quaternized chitosan (HTCC) were better than those of sulfonated chitosan (HSCS). The antibacterial rates of TMC at 0.5mg/mL against E.coli and S.aureus were 93.0% and 100%, respectively. The biofilm inhibition rates of TMC at a half of minimal inhibitory concentration against E.coli and S.aureus were 51.4% and 41.5%, respectively. The biofilm removal rates of E.coli by TMC, HTCC and HSCS at 2.5mg/mL were 49.1%, 48.6% and 21.2%, respectively, and the biofilm removal rates of S.aureus were 85.1%, 82.7% and 81.8%, respectively.

    Response surface analysis and optimization of membrane permeation vaporization by Silicalite-1 molecular sieve
    ZHAO Yao, ZHOU Zhihui, WU Hongdan, HU Chuanzhi, ZHANG Guochun, WU Ruipeng
    2023, 42(5):  2586-2594.  doi:10.16085/j.issn.1000-6613.2022-1345
    Abstract ( 6 )   HTML ( 0)   PDF (4066KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    The pervaporation separation of low concentration ethanol/water solutions by Silicalite-1 molecular sieve membranes was studied. The effects of seed concentration, crystallization temperature and crystallization time on the pervaporation separation performance of Silicalite-1 molecular sieve membrane were investigated by single factor experiment. Response surface analysis (RSM) was used to study the effects of feed liquid temperature, ethanol concentration and vacuum pressure on the separation coefficient and permeate flux. The results of single factor experiments showed that the Silicalite-1 molecular sieve membrane prepared under the conditions of seed concentration 0.3%, crystallization temperature 175℃ and crystallization time 7h exhibited the preferable pervaporation separation of ethanol aqueous solutions. According to the RSM results,the separation coefficient and permeate flux were significantly affected by feed liquid temperature, feed liquid ratio, and vacuum pressure. A polynomial model was established according to RSM results and the optimal conditions of the model prediction were verified by experiments. At feed temperature of 70℃, ethanol concentration of 3.49%, and vacuum pressure of 7.82kPa, the deviations of the actual separation coefficient and permeate flux from the predicted values were less than 5.46% and 7.39%, respectively.

    Preparation and properties of fly ash based phase change energy storage materials
    XU Yuzhen, JIANG Dahua, LIU Jingtao, CHEN Pu
    2023, 42(5):  2595-2605.  doi:10.16085/j.issn.1000-6613.2022-1236
    Abstract ( 7 )   HTML ( 0)   PDF (2738KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    Fly ash (FA) is a solid waste discharged from coal-fired power plants. It can serve as carrier of phase change material (PCM) due to the large specific surface area and good adsorption activity and solve the leakage problem in phase change process effectively. In this paper, a novel CA-OD/FA shape-stabilized phase change material (SSPCM) was prepared via vacuum adsorption method, where a CA-OD binary eutectic system was selected as PCM to store thermal energy, FA was employed as supporting material for preventing the leakage of CA-OD at melting state. The preparation factors of SSPCM were analyzed by single factor and diffusion-exudation circle experiments, including mass fraction of PCM, adsorption temperature, adsorption vacuum and adsorption duration. The structures and thermal properties of the SSPCM were investigated by scanning electronic microscope (SEM), Fourier transformation infrared spectroscope (FTIR), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermal gravimetric analyzer (TG). The SEM results indicated that PCM was evenly filled on the surface and pores of FA. The FTIR and XRD results demonstrated that there was no chemical reaction and no new substances occurred among the three materials. The DSC results revealed that the phase change temperature and latent heat of SSPCM were 27.44℃ and 37.18J/g, respectively, which was conductive to adjust the indoor temperature and was used as building energy storage material. The TG results suggested that the SSPCM would not decompose below 117.45℃ and had excellent thermal stability. The SSPCM still had good thermal reliability and chemical stability after 500 cycles of heat absorption and release. It was considered suitable for the application field of building energy conservation and thermal recovery.

    Structural characteristics and mechanism of GO prepared via improved Hummers method based on segmental sampling
    ZHANG Haoyue, LI Chunli, XU Bo, LI Xiaohe, TONG Ling, QIU Guangming
    2023, 42(5):  2606-2615.  doi:10.16085/j.issn.1000-6613.2022-1275
    Abstract ( 7 )   HTML ( 0)   PDF (3309KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    The research on the regulation and mechanism of graphene oxide (GO) preparation is of great significance for its properties and functional modification. In this paper, the synthesis Hummers method was used to prepare GO, and the segmented sampling method was employed to extract the intermediates of the main stages. SEM, Raman spectroscopy, XRD, FTIR, XPS and other detection methods were used to characterize and analyze the micromorphology, structure and composition of the products at each stage to explore the preparation mechanism of GO. TEM was used to characterize and observe the morphology of the final prepared GO to explore the influence rule of each stage reaction on GO preparation and to realize the regulation of GO oxidation degree and structure. The results displayed that in the mixed system of concentrated H2SO4/KMnO4, the intercalation and oxidation of graphite could not be carried out by using a single concentrated H2SO4, while KMnO4 was the necessary condition for graphite oxidation. In the oxidation phase, a large number of oxygen-containing functional groups was formed, leading to further expansion of graphite layer spacing. In the GO-1 to GO-5 stage, the C/O ratio of graphite oxide decreased from 7.23 to 2.03 and the laminar spacing of graphite oxide increased from 0.344nm to 0.815nm. The research results provided distinct data and theoretical support for further modification and application of GO products.

    Fine chemicals
    Separation of boron isotopes by collagen fibers-immobilized black wattle tannin
    PANG Nanjiong, WANG Xiaoling, LIAO Xuepin, SHI Bi
    2023, 42(5):  2616-2625.  doi:10.16085/j.issn.1000-6613.2022-1282
    Abstract ( 4 )   HTML ( 0)   PDF (3295KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Glutaraldehyde was used as a cross-linking agent to immobilize black wattle tannin (BWT) on the surface of collagen fibers (CF) to obtain a new type of boron isotope separation resin (CF-BWT). Using FTIR, XPS, SEM and 11B MAS NMR, the elemental composition, morphology, structure and adsorption mechanism of CF-BWT to boron were explored. The results showed that the equilibrium adsorption capacity of CF-BWT could reach 1.9mg/g when the pH was 8.0 and the initial concentration of boron was 110mg/L. The adsorption isotherms of CF-BWT to boron could be described by the Langmuir equation and the adsorption capacity increased with the increase of temperature. The adsorption kinetics could also be described by the pseudo-second-order kinetic model, and the equilibrium adsorption capacities calculated by the model were close to the experimental value. Furthermore, the boron-tannin active exchange interface formed by the tannin immobilized on the surface of CF-BWT promoted the isotope exchange reaction of 10B and 11B, thereby enriching 10B on the surface of CF-BWT and realizing the separation of 10B and 11B. The corresponding single stage separation factor could reach 1.17 at pH=7.0. When the initial boron isotope ratio (10B/11B) was 0.2180, the column of CF-BWT was used for the separation of 10B and 11B. The results showed that the boron isotope ratio (10B/11B) was 0.2149 at the penetration section and high up to 0.2234 at the elution section, suggesting effective separation of 10B and 11B.

    Preparation of mandarin oil microcapsules and its product quality evaluation
    SUN Yanchenhao, WANG Wei, LI Yizhe, ZHU Yanni, LIU Xuewu, ZHANG Dawei
    2023, 42(5):  2626-2637.  doi:10.16085/j.issn.1000-6613.2022-1347
    Abstract ( 7 )   HTML ( 1)   PDF (2523KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    Mandarin oil is characterized by easy volatilization and oxidization, which is difficult for long-term storage. Spray drying and freeze-drying methods were adopted in this work to encapsulate the mandarin oil in order to prolong its shelf life and enrich its application scope. Microcapsules qualities, such as encapsulation efficiency and product microstructure, were evaluated. Optimal operating conditions of spray drying were air inlet temperature 194˚C, feed flow rate 90.2mL/min, and feed solid content 34.7%. Operating conditions of freeze-drying were freezing temperature -30˚C, chamber pressure 30Pa, and radiation temperature 30˚C. Encapsulation efficiencies of products prepared by spray drying and freeze-drying were 90.17% and 82.48%, respectively, under the present conditions. The products by spray drying were fine and sphere-like with dense microcapsule walls, while the products by freeze-drying were irregular and platelet-shaped but with lower moisture content and better fluidity. Both products exhibited certain heat resistances, which could reduce the heat-induced loss of core materials in storage and application. In general, the spray drying method was more suitable than the freeze-drying method for the preparation of mandarin oil microcapsules.

    Design and synthesis of hydrogenated dimeric acid ethylene glycol ether esters as highly-efficient plasticizers for PVC
    HUANG Nengkun, WANG Ziwen, WANG Wengeng, WANG Xuefeng, TAN Jihuai, ZHU Xinbao
    2023, 42(5):  2638-2646.  doi:10.16085/j.issn.1000-6613.2022-1251
    Abstract ( 7 )   HTML ( 0)   PDF (2558KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    Novel hydrogenated dimeric acid alcohol ether esters (HDA-2n, n=1, 2, 3, 4) with different number of ethoxy functional units were synthesized from hydrogenated dimeric acid and ethylene glycol ether (ethylene glycol methyl ether, diethylene glycol methyl ether, triethylene glycol methyl ether, tetraethylene glycol methyl ether) via the direct esterification. The structures of resulting products were determined by 1H NMR, 13C NMR and FTIR, respectively. Also, the microstructure, mechanical, thermal stability, migration resistance as well as the volatilization resistance of PVC plasticized by HDA-2n were investigated. The results indicated that the plasticization of HDA-2n increased along with the increase of the number of oxethyl units. Compared with the PVC samples plasticized by dioctyl phthalate (DOP), the elongation at break and tensile strength of the products plasticized by hydrogenated dimeric acid (tetraethylene glycol methyl ether) ester (HDA-8) with the largest number of oxethyl units increased by 125% and 11.29MPa, respectively. Meanwhile, the migration in n-hexane and the volatility (70℃) of PVC/HAD-8 decreased by 14.25% and 5.29%, respectively, while the initial thermal decomposition temperature (T5%) increased by 27.2℃.

    Preparation and properties of heat resistant emulsion thickener for fracturing
    ZHOU Yafeng, YANG Jiang, MA Cheng, LIU Hailing
    2023, 42(5):  2647-2654.  doi:10.16085/j.issn.1000-6613.2022-1371
    Abstract ( 6 )   HTML ( 0)   PDF (1414KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    In order to develop the heat-resistant hydrophobic polymer fracturing fluid system, in this paper, hydrophobic monomer octadecyl methacrylate was introduced into acrylamide acrylic acid AMPS to improve the temperature resistance of thickeners, and the polymer thickeners PAS was synthesized. The experimental results showed that the preparation conditions of modified polymer were as follows: monomer accounted for 30% of the total mass, emulsifier accounted for 10% of the oil phase, hydrophilic lipophilic balance (HLB) was 6, initiator accounted for 0.2% of the total mass of monomer, and oil water ratio was 1∶2. Its viscosity-average molecular weight was 450×104g/mol. The viscosity of the polymer at 1.5% concentration remained at 80mPa·s after shearing for 1.5h at 120℃ and 170s-1. The polymer had good temperature resistance and shear recovery performance. Its particle size distribution was 500—1200nm. When the amount of potassium persulfate as gel breaker was 0.03%, the viscosity could be reduced to 5mPa·s at 90℃, reaching glue breaking.

    Resources and environmental engineering
    Recent advances on catalytic co-pyrolysis of biomass and plastic
    WANG Zhiwei, GUO Shuaihua, WU Mengge, CHEN Yan, ZHAO Junting, LI Hui, LEI Tingzhou
    2023, 42(5):  2655-2665.  doi:10.16085/j.issn.1000-6613.2022-1316
    Abstract ( 8 )   HTML ( 0)   PDF (1271KB) ( 4 )  
    Figures and Tables | References | Related Articles | Metrics

    Biomass is the only renewable carbon source, and its efficient utilization is the link to solve energy and environmental problems. In recent years, waste of plastic products based on fossil energy has increased rapidly because of their huge consumption. However, plastic is difficult to degrade naturally, thus posing a serious threat to the environment. The catalytic co-pyrolysis technology of biomass and plastic can obtain more selective products, and improve the yield and quality of products, which is an important direction for large-scale utilization of biomass and plastic. From the perspective of efficient conversion of biomass and plastic, recent advances on catalytic co-pyrolysis of biomass and plastic were summarized in the paper. Mechanism of co-pyrolysis of biomass and plastic, and advances of the co-pyrolysis with different types of catalyst, such as ZSM-5-based catalyst, transition metal-based catalyst, alkali/alkaline earth metal catalyst, and multi-catalysts, were reviewed. Catalytic co-pyrolysis with in-situ and non-in-situ mode were compared. Prospects for the primary technology and future development direction of catalytic co-pyrolysis of biomass and plastic were pursued, which may provide technical references and research ideas for the efficient synergistic conversion of biomass and plastic.

    Progress on evaluation methods for toxic leaching of heavy metals from MSW incineration fly ash
    LI Weihua, WU Yinkai, SUN Yingjie, YIN Junquan, XIN Mingxue, ZHAO Youjie
    2023, 42(5):  2666-2677.  doi:10.16085/j.issn.1000-6613.2022-1314
    Abstract ( 7 )   HTML ( 0)   PDF (1226KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    Municipal solid waste incineration (MSWI) fly ash is a large amount of hazardous waste, and its proper treatment is the focus of pollution control in the whole process of waste incineration. It is particularly important to select appropriate heavy metal toxicity leaching evaluation methods for fly ash pollution control. In this review, the commonly used evaluation methods for toxic leaching of heavy metals in fly ash at home and abroad were systematically summarized. The differences of experimental parameters/conditions and application background of relevant evaluation methods were compared. The application and limitations of the mainstream simulation scenario methods were emphatically analyzed, and the problems existing in the current toxic leaching evaluation methods were analyzed, and some guiding suggestions were given for researchers and managers to select appropriate toxic leaching methods. It was pointed out that in order to realize the fine management of fly ash, the content of the method should be updated in time according to the changes of society, environment, and science and technology. Especially, the multidimensional nature of environmental conditions (such as the diversification of the disposal environment) should be considered in the method. At the same time, based on the actual needs (such as the long-term stability of the occurrence of pollutants, etc.), the evaluation method for the toxicity of heavy metals in fly ash should be explored according to China’s national conditions and local conditions.

    Research progress of Anammox bio-electrochemical coupling wastewater treatment system
    LI Huahua, LI Yihang, JIN Beichen, LI Longxin, CHENG Shao’an
    2023, 42(5):  2678-2690.  doi:10.16085/j.issn.1000-6613.2022-1369
    Abstract ( 10 )   HTML ( 0)   PDF (1078KB) ( 4 )  
    Figures and Tables | References | Related Articles | Metrics

    In recent years, the Anammox bio-electrochemical coupling wastewater treatment system (Anammox-BES), a promising wastewater denitrification technology, combines the benefits of pollutant removal with energy recovery. This article summarized the main types and reaction mechanisms of the Anammox-BES. The main factors affecting Anammox-BES were reviewed, including electrode materials, electrode potential, temperature, pH, dissolved oxygen, organic matter and inoculum. Finally, the research status of Anammox-BES was outlined, and its denitrification performance and energy consumption were compared to those of the conventional Anammox process. Numerous studies indicated that the denitrification processes in Anammox-BES involved the anammox, nitrification, denitrification, and microbial power generation. However, the Anammox-BES has not been widely applied in actual wastewater treatment due to the multiple influencing factors and poor energy recovery rate. Therefore, it is important to develop technical measures to increase the power-generating capacity of anammox bacteria to achieve denitrification of wastewater and recover the chemical energy contained in ammonium. For the present Anammox-BES, it is essential to develop anode materials with high conductivity, biocompatibility and specific surface area, and further optimize the operating conditions to improve the denitrification and electricity generation performance and stability of the system.

    Research progress in directed bioconversion of lactic acid and acetic acid from wood lignocellulosic wastes
    HUANG Yue, ZHAO Lixin, YAO Zonglu, YU Jiadong, LI Zaixing, SHEN Ruixia, AN Kemeng, HUANG Yali
    2023, 42(5):  2691-2701.  doi:10.16085/j.issn.1000-6613.2023-0055
    Abstract ( 8 )   HTML ( 1)   PDF (1662KB) ( 3 )  
    Figures and Tables | References | Related Articles | Metrics

    Anaerobic fermentation technology is one of the critical ways of resource recycling to treat wood lignocellulosic wastes such as straw and cow manure. Lactic acid and acetic acid are essential intermediate products of anaerobic fermentation, and significant precursor substances for the production of biogas, medium chain fatty acids and additional energy chemical products. However, the collaborative production efficiency of directed biotransformation is not elevated, and the mechanism of collaborative production of lactic acid and acetic acid from wood lignocellulosic waste still needs to be further explored. Based on the analysis of the metabolic pathway mechanism of acid production, this paper sorted out the characteristics of simultaneous fermentation and stepwise fermentation in collaborative production of lactic acid and acetic acid and summarized the key factors affecting the efficiency of biological transformation in acid production. It was found that the wood lignocellulosic waste had a favorable synergic acid production effect under high solid content of 15%—20%, inoculation of 20%—40% active substances and appropriate process parameters [pH=5.0, moderate temperature and moderate organic load 5—10kgVS/(m3·d)]. In addition,we explored the promoting effect of physicochemical and bio strengthening coupling means on lignocellulosic degradation and target products, which provided a theoretical basis for the development of key technologies for the collaborative production of lactic acid and acetic acid by bioconversion, and the promotion of high-value conversion and utilization of wood lignocellulosic waste such as straw.

    Research progress of positive electrode material recycling technology for retired lithium batteries
    WANG Hao, HUO Jinda, QU Guorui, YANG Jiaqi, ZHOU Shiwei, LI Bo, WEI Yonggang
    2023, 42(5):  2702-2716.  doi:10.16085/j.issn.1000-6613.2022-1239
    Abstract ( 7 )   HTML ( 0)   PDF (1256KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    The rapid development of the new energy vehicle industry drives the increasing consumption of lithium-ion batteries, which directly leads to the serious shortage of cobalt, lithium, nickel and other energy metals used in the production of battery materials. In the future, the output of retired lithium-ion batteries will increase exponentially. The resource recycling can not only alleviate the shortage of battery materials, but also solve the damage caused by the accumulation of spent batteries. In this paper, the latest research status of discharge pretreatment and two hydrometallurgy and pyrometallurgy resource recovery technologies of retired lithium-ion battery were reviewed, and the future development trend was discussed. On the basis of the existing pyrometallurgy recycle process, a new method was proposed to recover valuable metals by using high-temperature melting smelting slag to treat waste lithium ion batteries. By adding suitable chlorination agent to transform lithium from slag into high-temperature volatile LiCl, a new idea of enrichment and efficient recovery of lithium from dust was realized, and the technical defect of secondary extraction of lithium from slag by traditional fire process was solved.

    Parameter optimization of jet aeration in catalytic ozonation system and analysis of stage oxidation of phenol
    ZHU Hao, LIU Hanfei, GAO Yuan, BAI Rongrong, NI Songbo, HUANG Yiping, LI Qingtong, LI Xiaodong, HAN Weiqing
    2023, 42(5):  2717-2723.  doi:10.16085/j.issn.1000-6613.2022-1266
    Abstract ( 8 )   HTML ( 0)   PDF (1765KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    As a typical phenolic compound, phenol showed the characteristics of high content and wide range of toxicity in phenol-containing wastewater. Mastering effective method of phenol treatment will provide technical support for the efficient treatment of phenol-containing wastewater. By analyzing the catalytic performance of five ozone catalysts, type A catalyst was selected as the preferred catalyst in ozone jet aeration system. The key operating parameters of the system were optimized. The results showed that the jet aeration system based on type A catalyst presented the good pollutants removal performance with an average COD removal efficiency of 56.7% when the circulating water velocity, wastewater pH and initial concentration of pollutant were 1400L/h, 8 and 148mg/L, respectively. The stage oxidation of phenol at different time nodes was investigated using three-dimensional fluorescence spectra, GC-MS and aerobic respiratory inhibition rate as evaluation indexes. By comprehensive analysis of the evaluation indexes, it was found that Ex/Em was (300~350nm)/(420~460nm) region in the three-dimensional fluorescence spectrum might be an indicator of high removal efficiency and low aerobic respiratory inhibition at the reaction time of 60min.

    Preparation of yolk-shell mesoporous magnetic carbon microspheres and its efficient adsorption of erythromycin
    LIU Nian, CHEN Kui, WU Bin, JI Lijun, WU Yanyang, HAN Jinling
    2023, 42(5):  2724-2732.  doi:10.16085/j.issn.1000-6613.2022-1230
    Abstract ( 4 )   HTML ( 0)   PDF (2313KB) ( 1 )  
    Figures and Tables | References | Related Articles | Metrics

    With Fe3O4 nanoparticles prepared by solvothermal method as magnetic cores, tetraethyl orthosilicate as the pore-forming precursor, and resorcinol-formaldehyde resin as the carbon source, yolk-shell mesoporous magnetic carbon microspheres (abbreviated as Fe3O4@C) were prepared by one-step method, and used as adsorbent to remove erythromycin from water. It was characterized by TEM, XRD, FTIR, BET and VSM. The results demonstrated that the prepared Fe3O4@C core-shell had a large cavity, with specific surface area of 444m2/g and average pore diameter of 7.7nm, and exhibits superparamagnetic properties. The adsorption equilibrium and rate of Fe3O4@C to erythromycin were studied by batch experiments, and the optimal operating conditions were determined. The results indicated that the adsorption capacity of Fe3O4@C for erythromycin was 210mg/g under the optimized conditions of adsorbent dosage of 1.0g/L, initial erythromycin concentration of 300mg/L and pH of 10. The adsorption process of Fe3O4@C to erythromycin was spontaneous, endothermic and irreversible, following pseudo-second-order kinetics and Langmuir isotherm models. After three cycles of regeneration, the adsorption capacity of Fe3O4@C still remained above 86% of the initial adsorption capacity.

    Effect of H2S gaseous substrate on sludge bioleaching treatment efficiency
    CHANG Zhankun, ZHANG Chi, SU Bingqin, ZHANG Congzheng, WANG Jian, QUAN Xiaohui
    2023, 42(5):  2733-2743.  doi:10.16085/j.issn.1000-6613.2022-1348
    Abstract ( 9 )   HTML ( 0)   PDF (2943KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    H2S was used as the partially alternative nutrient substrate for sludge bioleaching, and the effects of H2S load on bioleaching treatment efficiency and community diversity were studied. The changes of pH, ORP, heavy metal removal rate and CST were examined, and the community diversity was analyzed. The results showed that H2S load of 50mL/L with gas flow of 2mL/min could significantly accelerate the bioleaching process, improve the decline rate of pH and maintain a higher oxidation-reduction potential in the sludge system. The addition of H2S improved dewaterability with CST shortened by 35.8s, had significant effects on heavy metal leaching with the removal rate of Ni, Pb, and Cr increasing by 18.35%, 21.22%, and 13.07% respectively, and promoted the conversion of various heavy metal forms to the easily soluble state. The SEM results showed that H2S promoted the reproduction of dominant microflora and made the sludge particles larger and compact. High-throughput sequencing showed that the addition of H2S gaseous substrate strengthened the efficiency of sludge bioleaching treatment, accelerated the trend reducing the number of species, microflora abundance and community diversity in the sludge system, and promoted Proteobacteria as the dominant phylum and Acidithiobacillu as the dominant genus.

    Promotion technology of aerobic compost ripening
    MA Jingwen, NIU Jiayu, LI Xiufen
    2023, 42(5):  2744-2750.  doi:10.16085/j.issn.1000-6613.2022-1391
    Abstract ( 8 )   HTML ( 0)   PDF (986KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    Aerobic composting technology has become one of the important ways to return waste crop straw to the field. With the increasing popularity of rare earth agricultural use, it is of academic significance to study the effect of rare earth elements on the composting process and compost quality of waste straw. The results showed that lanthanum, a rare earth element, was beneficial to improve the metabolic activity of Bacillus thermophiles GX5 and other indigenous microorganisms in the piles, promote the degradation and transformation of lignocellulose, and improve the compost maturity. When lanthanum was present in the composting system with addition of Bacillus thermophilus GX5, the pile temperature increased to 70.3℃ on the third day and maintained above 55℃ for 5 days. The dehydrogenase activity of the pile was 11.02U/g. The enzyme activities of cellulose degrading enzyme, lignin peroxidase and laccase were 4.55U/g, 2.82U/g and 0.21U/g, respectively. During the maturity stage, the degradation rates of hemicellulose, cellulose and lignin reached 47.6%, 40.6% and 31.1%, the E4/E6 value was 3.24, the nitrification index was 1.87, and the seed germination index was 221.80%. The compost quality met the relevant standards of organic fertilizer in China (such as NY/T 525—2021).

    Chemical industry park
    Vulnerability assessment of storage tanks based on Monte Carlo simulation and dynamic event tree
    ZHAO Jingbin, WANG Yanfu, WANG Tao, MA Weikai, WANG Chen
    2023, 42(5):  2751-2759.  doi:10.16085/j.issn.1000-6613.2022-1376
    Abstract ( 4 )   HTML ( 0)   PDF (1309KB) ( 2 )  
    Figures and Tables | References | Related Articles | Metrics

    The leakage event is the main cause of domino accident in chemical tank farm. With the increase of leakage time, there are many possible scenarios for its subsequent evolution, and the vulnerability of affected tanks in each scenario is also different. In order to comprehensively analyze the vulnerability of chemical storage tanks after leakage event, a dynamic vulnerability assessment method based on Monte Carlo simulation and dynamic event tree was proposed in this paper. In this method, the ignition probability, synergistic effect and other factors were considered, and the failure probability of storage tanks was calculated by Probit model. The dynamic vulnerability under fire and explosion accident scenarios was obtained by Monte Carlo simulation. The dynamic event tree was used to combine the occurrence probability of each accident scenario and the corresponding vulnerability change according to the time series, so as to comprehensively describe the subsequent evolution scenario of the leakage event, and obtain the total vulnerability of the fire and explosion scenarios. The feasibility of this method was verified by two cases. The results showed that this method could dynamically predict and assess the vulnerability of chemical storage tanks.