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Table of Content
15 August 2023, Volume 42 Issue 8
    Consideration on research content and method of polymer product engineering
    LI Bogeng, LUO Yingwu, LIU Pingwei
    2023, 42(8):  3905-3909.  doi:10.16085/j.issn.1000-6613.2023-0595
    Abstract ( 50 )   HTML ( 0)   PDF (887KB) ( 32 )  
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    The structure of polymer products has obvious multi-level and polydispersity. The performance is also very rich. In this article, it was suggested that the rational design based on quantitative relationship between structure and performance and the precise manufacturing of product structures should be taken as the core research content and innovative development approach of the polymer product engineering. In order to accurately describe the relationship between polymer structure and performance, the database construction of polymer and polymer informatics derived therefrom, especially the application of artificial intelligence technology, should be paid more attention in the future. For more precise manufacturing of polymer structures, in the future, attention should be paid to the CNC manufacturing of molecules in the polymerization process. At the same time, the soft measurement technology for polymerization process should be continuously innovated and developed to improve the scope, accuracy and speed of the online detection of structure during the manufacturing process of polymer products. The article also pointed out that attention should be paid to the in-situ alloying and compounding methods of polymers in the reactor and the application research of reactive extrusion on molecular modification, group conversion, chain extension, cross-linking, alloying and compounding of polymers, so as to fully leverage their advantages in the precise manufacturing of multiphase and multi-component polymer products.

    AI-driven innovative design of chemicals in practice and perspective
    WU Zhenghao, ZHOU Tianhang, LAN Xingying, XU Chunming
    2023, 42(8):  3910-3916.  doi:10.16085/j.issn.1000-6613.2023-0811
    Abstract ( 76 )   HTML ( 19)   PDF (1558KB) ( 53 )  
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    It has long been a grand goal for researchers and industry professionals in the chemical engineering community to revolutionize the paradigm of chemical product development and shorten the time from product discovery to application. However, chemical product design is a complex process involving multiple components, scales, and physical fields. It is difficult for existing experimental research models to reveal the relevant physical and chemical mechanisms in depth and efficiently. Therefore, it is necessary to use multi-scale computer simulation technology to predict the properties of chemical products by coupling multi-scale simulation methods starting from the chemical structure at the micro-molecular level. Along with the increasing computing power, "artificial intelligence (AI)-driven" approaches are becoming a significant promise in the pursuit of this objective, where AI is being organically integrated with established multi-scale simulation techniques for efficient and high-fidelity modeling framework with potential for transformative impact on chemical design. For instance, machine learning models trained on high-fidelity multi-scale simulation data can accelerate the prediction of chemical structure-property relationship by orders of magnitude. However, the chemical industry, particularly, the development of new chemical products, presents many unique challenges. The crude application of AI to existing problems and data to construct some predictive models can hardly break the existing bottlenecks fundamentally. Hence, it is imperative to consider how we can integrate AI techniques more effectively and comprehensively with innovative chemical product design. We envision this can be achieved through, e.g., using AI to optimize existing physics-based simulation techniques and efficiently explore hundreds of millions of design parameters to find the best design solutions. Here we discuss the recent development of AI-driven chemical innovation design from three aspects: multi-scale simulation, material design framework, and scientific software development, with an emphasis on the important role of AI technology in achieving the innovation pathway of chemical products. At last, we present our perspective on the current efforts to embrace AI techniques in the engineering of novel chemical product, with the goal of providing a strong foundation to support the advancement of domestic chemical industry.

    Group recognition hydrogenation: From concept to application
    MAO Shanjun, WANG Zhe, WANG Yong
    2023, 42(8):  3917-3922.  doi:10.16085/j.issn.1000-6613.2023-0802
    Abstract ( 38 )   HTML ( 7)   PDF (3344KB) ( 58 )  
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    Catalytic hydrogenation plays a vital role in the production of both bulk and fine chemicals. In cases where multiple reducible functional groups are present in the reactants, selective hydrogenation of specific groups is required to produce high-value chemicals. Due to the lack of in-depth understanding of the interaction between the active sites of catalysts and functional groups, achieving targeted hydrogenation conversion remains highly challenging. Some catalysts sacrifice activity for relatively higher selectivity. To address this issue, a new concept called "group recognition hydrogenation" has been proposed, providing a different perspective for the rational design of hydrogenation catalysts. The new concept aims to achieve targeted activation or recognition response of catalysts towards the target functional groups, while demanding that the enhancement of reaction selectivity does not come at the expense of activity. This paper reviewed several strategies to achieve this goal. Firstly, regulation can be achieved from the energy space by adjusting the orbital symmetry and energy level matching between the catalyst active sites and the target functional groups. Secondly, control can also be achieved from the physical space, such as by adjusting the catalyst's geometric structure to improve its activity, selectivity, and stability. In addition, regulating the reaction microenvironment to achieve group recognition adsorption and activation was another effective option. Catalysts designed based on the "group recognition hydrogenation" concept demonstrated excellent hydrogenation performance in several challenging hydrogenation reactions, showing significant industrial application value. Finally, orthogonal decomposition was employed to decouple electronic and geometric effects, providing a methodological foundation for the quantitative analysis of the above strategies.

    Development and consideration of adiabatic continuous microreaction technology for safe production of nitro compounds
    DENG Jian, WANG Kai, LUO Guangsheng
    2023, 42(8):  3923-3925.  doi:10.16085/j.issn.1000-6613.2023-0286
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    Nitration reaction is a typical fast and strong exothermic reaction, which is an important reaction for the production of energetic chemicals, but also a reaction with frequent safety accidents. Therefore, nitration reaction is a major challenge for the production of energetic chemicals. Compared with foreign nitration technology, China's nitration process and equipment have obvious gaps, and continuous nitration is a bottleneck technology. In order to break through the technical barrier of constant temperature continuous nitration and realize the intrinsically safe nitration, this paper summarized the concept of adiabatic micro reaction continuous nitrification proposed by the micro chemical team of Tsinghua University, and put forward its progress in the research of aromatic compound adiabatic micro reaction nitrification. It was pointed out that the technical innovation mainly involved the evaluation method of micro-reaction process safety system, nitration kinetics, adiabatic reaction technology, construction of micro-chemical system and reconstruction of the entire nitrification process.

    Advanced microporous membranes for efficient separation of same-carbon-number hydrocarbon mixtures: State-of-the-art and challenges
    PAN Yichang, ZHOU Rongfei, XING Weihong
    2023, 42(8):  3926-3942.  doi:10.16085/j.issn.1000-6613.2023-0464
    Abstract ( 25 )   HTML ( 2)   PDF (10719KB) ( 15 )  
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    Separation of hydrocarbon mixtures with the same carbon number by thermal distillation is one of the most energy-consuming processes in the petrochemical industry. The membrane separation technology can realize the reconstruction of membrane technology with low energy consumption due to the advantages of low investment and operating costs, high energy saving and high process integration degree. The advanced microporous membranes represented by zeolite and metal-organic framework materials have better separation performance than traditional polymers membrane, which can improve the permeability and selectivity by one or two orders of magnitude, and show excellent application prospects. This paper reviewed the progress of advanced microporous membranes in improving permeability, separation selectivity and separation process stability. The structure-activity relationship between the separation performance of hydrocarbon with the same carbon number and the microstructure regulation of membrane thickness, pore orientation, framework flexibility and intergranular defects was discussed in detail. The bottleneck problem of area scaling preparation of several zeolite films and MOF films for efficient separation of hydrocarbon with the same carbon number was analyzed, and the key role of homogeneity distributionof crystal seed/nucleation site in advanced microporous film scaling was proposed. Finally, it was expected to further accelerate the development of new advanced microporous membrane materials to cope with the diversified separation system in the petrochemical industry, and to increase the development of membrane technology to match the main process requirements in the petrochemical industry.

    Progress in preparation and application of omniphobic membranes for membrane distillation process
    XU Jie, XIA Longbo, LUO Ping, ZOU Dong, ZHONG Zhaoxiang
    2023, 42(8):  3943-3955.  doi:10.16085/j.issn.1000-6613.2023-0741
    Abstract ( 32 )   HTML ( 4)   PDF (5371KB) ( 20 )  
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    Water shortage has become a global problem. Membrane distillation (MD) is widely used in seawater desalination and high-salt wastewater treatment due to its advantages. However, membrane wetting, membrane contamination and other problems still hinder the large-scale application of MD technology. In recent years, the omniphobic membrane can repel all kinds of liquids, and greatly improve the permeability, pollution resistance and stability of MD. In this work, the basic principles of anti-wetting and anti-pollution of omniphobic membranes are reviewed from the aspects of surface roughness, surface free energy, contact angle and liquid entry pressure, in the framework of membrane distillation application process. The preparation process of omniphobic membrane was summarized from the two basic steps of re-entrant rough surface construction and fluorination, and the potential application fields of omniphobic membrane were summarized. Finally, the challenges and future research directions of omniphobic membranes were discussed. This review had important guides for the structure design, preparation and application of polymer membranes for MD.

    Progress of the development and application of 3D printing catalyst
    WU Haibo, WANG Xilun, FANG Yanxiong, JI Hongbing
    2023, 42(8):  3956-3964.  doi:10.16085/j.issn.1000-6613.2023-0150
    Abstract ( 25 )   HTML ( 1)   PDF (4516KB) ( 19 )  
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    Compared with traditional catalyst preparation techniques, 3D printing has been gathered much attention due to the advantages of low cost, high accuracy and controllable structures. Recent progress of 3D printing technology in catalytic materials was introduced in this paper, including fused deposition modeling, stereo lithography appearance, direct ink writing and selective laser sintering. The catalytic applications of polymer, carbon-based materials, metal and oxide-based materials prepared by 3D printing techniques were reviewed. 3D printing provides a new catalyst preparation way, but there were still shortcomings in the preparation and application, such as slow printing speed, unstable physical and chemical properties of materials, and limited application field. The directions for future development such as expanding material types, optimizing catalyst structures, new printers and surface coating technologies were proposed.

    Research progress in high value chemical recycling of waste polyolefins
    CHANG Yinlong, ZHOU Qimin, WANG Qingyue, WANG Wenjun, LI Bogeng, LIU Pingwei
    2023, 42(8):  3965-3978.  doi:10.16085/j.issn.1000-6613.2023-0556
    Abstract ( 34 )   HTML ( 2)   PDF (3639KB) ( 53 )  
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    Polyolefin plastics account for more than half of the world's plastics and have an extremely long natural degradation time due to their stable hydrocarbon chain structure. The accumulation of plastic waste leads to serious environmental disasters such as "white pollution" and "microplastics". It is of great importance to focus on the chemical up-recycling of polyolefin waste. This paper summarized the characteristics of catalytic recycling of polyolefins including catalytic pyrolysis, hydrocracking and hydrogenolysis. An overview of the mechanism of formation of value-added products (e.g., aromatics, light olefins and lubricants) commonly used catalysts, and the relationship between structure and activity of catalysts in the cracking process was presented. Meanwhile, process intensification methods for producing high-value products were introduced, including intensification of the reaction process based on reactor design and intensification of the separation process based on the design of efficient separation materials. It was expected that controllable low-temperature pyrolysis and high-value recovery of waste polyolefins can be achieved through the development of high-efficiency catalysts and research on intensification technologies in reaction and separation processes.

    Research advances on runaway decomposition of high pressure polyethylene: Reaction mechanism, initiation system and model
    ZHANG Zhichen, ZHU Yunfeng, CHENG Weishu, MA Shoutao, JIANG Jie, SUN Bing, ZHOU Zichen, XU Wei
    2023, 42(8):  3979-3989.  doi:10.16085/j.issn.1000-6613.2023-0739
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    High pressure polyethylene, as known as low density polyethylene (LDPE), is the most widely used plastic products in the world. However, LDPE preparation needs to be carried out under high pressure process, and then ethylene will decompose out of control under adiabatic compression condition with a large risk of ignition and explosion. This paper analyzed the causes of LDPE production accidents at home and abroad in recent years, introduced the high pressure polymerization process of LDPE and discussed the polymerization and decomposition mechanism of LDPE synthesis in detail. The main causes of the runaway decomposition of ethylene caused by initiators and hot spots at high temperature were summarized, and the key parameters as well as limit boundary of the runaway decomposition of ethylene under polymerization conditions were also described carefully. In addition, the mathematical model and development of ethylene decomposition were fully introduced and discussed. Finally, this paper put forward the problems that needed to be solved to deal with the essential safety production of LDPE, and proposed the solution and future development direction to provide thinking for the future safety development of LDPE process and capacity improvement.

    Research progress of polymer inclusion membrane in metal separation and recovery
    WANG Baoying, WANG Huangying, YAN Junying, WANG Yaoming, XU Tongwen
    2023, 42(8):  3990-4004.  doi:10.16085/j.issn.1000-6613.2023-0152
    Abstract ( 27 )   HTML ( 2)   PDF (6488KB) ( 14 )  
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    Polymer inclusion membranes (PIMs) are new type of liquid membranes developed on the basis of supported liquid membranes, which are mainly composed of carrier, base polymer and plasticizer. Due to the advantages of high selectivity, long service life, high stability, flexible design and low cost, PIMs have gradually attracted great attention in the field of metal separation and recovery. In this paper, the composition and preparation methods of PIMs and the research progress of PIMs made of different types of carriers, base polymers and plasticizers in metal separation and recovery in recent years were reviewed, the two transport mechanisms of carrier diffusion and fixed-site jumping in PIMs were discussed, the separation reinforcement methods of PIMs were elaborated, and the main advantages of PIMs coupled with electrodialysis to enhance metal ion separation process were introduced in detail. Finally, several critical issues in the future development of PIMs for metal separation and recovery were summarized, mainly including the research and development of high-performance and low-cost carriers, the deep exploration of membrane microstructure and separation mechanism, and the promotion of the wide application of polymer inclusion membrane-electrodialysis technology, which had guiding significance for accelerating the industrialization process of PIMs.

    Recent progresses in the activity and selectivity improvement of electrocatalytic organic synthesis
    XIANG Yang, HUANG Xun, WEI Zidong
    2023, 42(8):  4005-4014.  doi:10.16085/j.issn.1000-6613.2023-0510
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    Compared with traditional organic synthesis techniques, electrosynthesis has many advantages such as high atom utilization, mild reaction conditions, easy reaction control, and friendly to the environment, and has become a popular research area of organic synthesis in recent years. The electrochemical reaction mainly occurs at the electrode-solution interface, and the mass transfer, adsorption and surface reaction behavior of the reactants at the interface determine the activity and selectivity of the electrochemical reaction. This paper reviewed the latest research progress on improving the activity and selectivity of organic electrosynthesis at different scales, focusing on the strategies of catalyst electronic structure regulation, electrode-solution interface design, reaction and transport coupling. It also proposed the important research directions in the future, including electrochemical organic reaction mechanism, catalyst structure-performance relation, electrosynthesis reactor, and coupling of reaction and separation, which could provide reference for the development of electrocatalytic organic synthesis.

    Research progress on chemical modification of polyether ether ketone for the high bioactivity
    CHEN Junjun, FEI Chang’en, DUAN Jintang, GU Xueping, FENG Lianfang, ZHANG Cailiang
    2023, 42(8):  4015-4028.  doi:10.16085/j.issn.1000-6613.2023-0500
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    Because of its hydrophobicity and biological inertness, polyether ether ketone (PEEK) used as an orthopedic material is difficult to bond with surrounding cells and bone tissues. It is the most effective method to improve cell adhesion, proliferation and osteogenic differentiation on the surface of PEEK materials by introducing biologically active groups into the molecular chain of PEEK. Based on the different introduction positions of functional groups, the chemical modification of PEEK is classified into three types: benzene cyclic modification, ketone modification and copolymerization modification. The principles and characteristics of these different chemical modification methods and their impact on the biological activity of PEEK materials are emphatically reviewed. The benzene cyclic modification mainly involved the introduction of functional groups such as carboxyl groups through strong acid treatment, resulting in the residual sulfur or nitrate compounds that has a certain toxic effect on cells. Ketone group modification used reagents such as amines and sodium borohydride to react with the ketone group and further introduced functional groups through grafting, however, it would destroy the ether-ketone ratio on the main chain of PEEK, affecting its physical and thermal properties. Introducing bioactive functional groups into the side chain of PEEK by copolymerization methods such as electrophilic addition, nucleophilic addition or halogenation-modification can maintain the ether and ketone ratio in the polymer backbone and improve the bioactivity, which has good application prospects. On the basis of chemical modification, studying the synergistic effect of various functional groups and further introducing physical modification to optimize comprehensive performance for different scenarios is the development trend for expanding the application of PEEK in the medical field.

    Practical carbon anodes for sodium-ion batteries: progress and challenge
    YANG Han, ZHANG Yibo, LI Qi, ZHANG Jun, TAO Ying, YANG Quanhong
    2023, 42(8):  4029-4042.  doi:10.16085/j.issn.1000-6613.2023-0640
    Abstract ( 22 )   HTML ( 1)   PDF (7154KB) ( 18 )  
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    With the continuous increase in demand for electrochemical energy storage coupled with factors such as low content, uneven distribution and high cost for lithium resources, sodium-ion batteries (SIBs) have ushered in new development opportunities as a representative of low-cost secondary energy storage batteries. The research and industrialization of SIBs have entered a fast lane of development. Among them, carbon materials with abundant resources and excellent performance stand out and become the primary choice for the anode of SIBs. Here, research progress and storage mechanism of carbon anode materials are introduced with emphasis on the design and practical progress of different types of carbon anodes. Finally, the challenges faced and the main problem needed further attention in the development of carbon anodes for practical SIBs are discussed.

    Strategies for regulating product selectivity of copper-based catalysts in electrochemical CO2 reduction
    WANG Yaogang, HAN Zishan, GAO Jiachen, WANG Xinyu, LI Siqi, YANG Quanhong, WENG Zhe
    2023, 42(8):  4043-4057.  doi:10.16085/j.issn.1000-6613.2023-0397
    Abstract ( 22 )   HTML ( 1)   PDF (9783KB) ( 15 )  
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    Directly converting CO2 into valuable chemicals in aqueous electrolytes using renewable electric energy provides a sustainable strategy for the CO2 utilization. Copper is the only metal catalyst that can efficiently produce C2+ products at appreciable rates. However, the diverse distribution of products (more than 16 types) in the electrocatalytic CO2 reduction reaction (eCO2RR) significantly increases the cost of product separation and weakens the energy conversion efficiency of the system, thus hindering the industrialization of eCO2RR. Therefore, it is of great importance to rationally design copper-based catalysts that exhibit high selectivity toward a specific product. During more than 30 years of development, the research on copper-based catalysts has made great progress. This review provided an overview of the reaction mechanisms, reaction paths and regulation strategies of eCO2RR using copper-based catalysts based on recent studies. The regulation strategies for achieving various products were comprehensively summarized. Finally, challenges and future directions for copper-based catalysts were discussed.

    Recent progress of long-wavelength-light-driven photoswitches
    ZHANG Zhiwei, YANG Weixin, ZHANG Junji
    2023, 42(8):  4058-4075.  doi:10.16085/j.issn.1000-6613.2023-0894
    Abstract ( 21 )   HTML ( 0)   PDF (8895KB) ( 7 )  
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    Photoswitches are chromophores that undergo reversible isomerization between different states upon irradiation with light, allowing a convenient means to spatiotemporally control their influence over the system of interest. However, a significant limitation of classical photoswitches is the requirement to initiate the switching in one or both directions using deleterious UV light with high damage, energy consumption, toxicity, and poor tissue penetration. Red-shifted photoswitches are in high demand and have attracted recent research interest. In this review, we highlight recent progress towards the development of visible- and NIR-activated photoswitches characterized by distinct photoswitches and examine the key photochromic properties, including photoconversion efficiency, isomerization quantum yields, the thermal half-lives of the thermodynamically unstable isomers, and the resistance of the systems to photofatigue in each case. Finally, the opportunities and challenges that visible- and NIR-activated photoswitches may face in future development are prospected.

    Application of special wettability materials for anti-hydrate-nucleation and anti-hydrate-adhesion in oil and gas pipelines
    YIN Xinyu, PI Pihui, WEN Xiufang, QIAN Yu
    2023, 42(8):  4076-4092.  doi:10.16085/j.issn.1000-6613.2023-0291
    Abstract ( 15 )   HTML ( 1)   PDF (6576KB) ( 6 )  
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    Natural gas hydrates are a green fossil energy source, however, during oil and gas extraction and pipeline transportation, the formed hydrates can plug pipeline, posing a serious challenge to the safe storage and transportation of oil and gas pipelines. In this article, we outline the research process and influencing factors of hydrate nucleation and aggregation in different transport systems, and reviews the traditional methods of preventing and managing the nucleation and aggregation of natural gas hydrate and their advantages and drawbacks. Then, the fundamental principles of special wetting materials and their applications in oil and gas related fields were elaborated, and their research progress in inhibiting the nucleation of natural gas hydrates and preventing their adhesion and aggregation to pipe walls was highlighted. The challenges of special wetting materials in various transportation systems in addressing the nucleation and aggregation of natural gas hydrates are discussed, and focused solutions are suggested. Finally, we outlook the future development trend of special wetting materials in the field of preventing hydrate nucleation and aggregation.

    Research status and future trend of sulfur hexafluoride alternatives
    YANG Zhiqiang, ZENG Jijun, MA Yiding, YU Tao, ZHAO Bo, LIU Yingzhe, ZHANG Wei, LYU Jian, LI Xingwen, ZHANG Boya, TANG Nian, LI Li, SUN Dongwei
    2023, 42(8):  4093-4107.  doi:10.16085/j.issn.1000-6613.2023-0724
    Abstract ( 24 )   HTML ( 3)   PDF (3871KB) ( 25 )  
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    Sulfur hexafluoride (SF6) is the most widely used insulation and arc extinguishing medium in the power industry. However, SF6 has a strong global warming potential (GWP=23900), and the environmental problems caused by it have gradually become an important factor restricting the green development of the power grid in China. This paper reviewed the screening history of SF6 substitutes from the view of testing methods and computer-aided methods. The authors also summarized the research progress of perfluoroketone, perfluoroisobutyronitrile, trifluorosulfur nitrogen, hydrofluoroolefin, and other gases in both insulation properties and synthesis mothed. Focus on the core issues in the screening of SF6 alternative gases, the research progress of various predictive methods for the performance of insulating gases was reviewed from the perspectives of physical definition, group contribution, quantitative structure-activity relationship, and machine learning, and authors pointed out that the prediction method that takes into account the calculation efficiency, accuracy, and versatility is the future development trend. Based on the current research status, two methods of high-throughput molecular design and azeotropic gas were proposed, which provided a useful references for the development of novel eco-friendly insulating gases.

    Recent advances of dioxetane-based afterglow system for bio-imaging
    LYU Chengyuan, ZHANG Han, YANG Mingwang, DU Jianjun, FAN Jiangli
    2023, 42(8):  4108-4122.  doi:10.16085/j.issn.1000-6613.2023-0749
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    Afterglow imaging avoids the interference of autofluorescence, dramatically reduces the background signal, and significantly improves the imaging signal-to-noise ratio. Recently, the dioxetane-afterglow system that bases on photo-oxidation reaction has attracted wide attention. This afterglow system has good biocompatibility, improved aqueous and oxygen tolerance capability, and is easily synthesized and modified. Moreover, this form of afterglow can realize the requirements of multifunctional imaging and has a broad application prospect in the disease diagnosis and treatment process. In this review, the luminescence mechanism of the dioxetane-based afterglow system is briefly described, and the construction method of the system is summarized. The recent breakthroughs in surgical navigation, bioactive molecular imaging, diagnosis, and treatment are also listed. Finally, this review summarizes the current research progress of the dioxetane-based afterglow system, analyses the challenges confronted with the clinical application and prospects the development of this system in future.

    Progress and challenges of engineering microorganisms to produce biobased monomers
    GAO Cong, CHEN Chenghu, CHEN Xiulai, LIU Liming
    2023, 42(8):  4123-4135.  doi:10.16085/j.issn.1000-6613.2023-0289
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    Monomers are the basic raw materials used in the synthesis of polymers, which mainly come from fossil fuels. Engineering microorganisms to synthesize monomers has the advantages of mild production conditions, environmental friendliness, and sustainability, which is an important way to achieve green manufacturing in the material industry. With the help of metabolic engineering and synthetic biology parts, microbial manufacturing of various monomers has been realized at present. However, compared with petroleum-based production processes, the production performance of these microbial cell factories is limited. Focusing on the bottleneck problems in engineering microorganisms to synthesize bioplastic monomers, this review summarizes the latest research progress in the metabolic engineering of microorganisms to produce monomers from three aspects: efficient utilization of cheap substrates, improvement of monomer synthesis efficiency, and enhancement of cell environment tolerance, based on specific case studies. At the same time, the current challenges and future direction of the microbial monomer cell factory are discussed.

    Cu facets regulation of Ag/Cu coupled catalysts for electrocatalytic reduction of carbon dioxide
    LIU Yi, FANG Qiang, ZHONG Dazhong, ZHAO Qiang, LI Jinping
    2023, 42(8):  4136-4142.  doi:10.16085/j.issn.1000-6613.2023-0273
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    Electrocatalytic carbon dioxide reduction is an effective method to reduce atmospheric carbon dioxide concentration and mitigate the greenhouse effect. However, electroreduction of CO2 to hydrocarbons or fuels with high-added value and high energy density(C2+ products) remains extremely challenging, which however could be effectively promoted by optimizing the facets of Cu in the Ag/Cu coupled catalysts. Three Ag/Cu coupled catalysts with different Cu facets were obtained by reduction of Ag/Cu2O-(100) with exposed Cu2O-(100) facets, Ag/Cu2O-(111) with exposed Cu2O-(111) facets, and Ag/Cu2O-(100/111) with Cu2O(100) and (111) facets. The CO2 electrochemical reduction performance was evaluated in an H-type electrolytic cell filled with CO2-saturated 0.1 M KHCO3 electrolyte, and the Cu/Ag ratio was controlled as 30∶1. Among them, Ag/Cu-(100/111) catalyst with Cu(100) and Cu(111) facets showed the best performance of reduction CO2 to C2+ productswith aFE of C2+ products above 50% at -1.3V and -1.5V vs. RHE. When the potential was -1.5V vs. RHE, the maximum FE of C2+ products was 57.7% and the partial current density was 8.92mA/cm2.

    Fabrication and performance of Hg2+-responsive smart hydrogel grating detector
    ZHANG Tingting, PAN Dawei, JU Xiaojie, LIU Zhuang, XIE Rui, WANG Wei, CHU Liangyin
    2023, 42(8):  4143-4152.  doi:10.16085/j.issn.1000-6613.2023-0345
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    Highly sensitive and selective detection of Hg2+ in water is of great significance for human health and eco-environmental sustainability. In this work, based on microstructure adjustment and signal conversion via selective and strong chelation between thiourea groups and Hg2+, a Hg2+-responsive smart hydrogel grating was created for ultrasensitive, highly-selective and facile detection of trace Hg2+ in water. In the crosslinked polymeric networks of the hydrogel grating, the thiourea groups can selectively chelate with Hg2+ to induce the height change of the hydrogel grating, thus realizing the signal conversion from concentration change of Hg2+ to intensity change of diffracted light. By integrating the hydrogel grating into an optical detection system to conveniently detect the intensity changes of diffracted light, ultrasensitive and highly-selective detection of Hg2+ with concentration as low as 10-9 mol/L in water can be achieved. This work provided a new strategy for development of convenient and sensitive detection technique for trace Hg2+ in water.

    Separation and purification of salivary acids with adsorption resin
    ZHANG Zhen, LI Dan, CHEN Chen, WU Jinglan, YING Hanjie, QIAO Hao
    2023, 42(8):  4153-4158.  doi:10.16085/j.issn.1000-6613.2022-2052
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    A new adsorbent resin RH-1 was used to recover SA from sialic acid (SA) biotransformation solution. The adsorption equilibrium, adsorption kinetic and dynamic adsorption and desorption processes of SA onto the resin were investigated. The adsorption isotherms of SA at different temperatures were determined. It was observed that the adsorption capacity of SA onto the resin decreased with increase of temperature and the adsorption process was exothermic. The adsorption equilibrium could be described by the Henry adsorption model (R2=0.998). The surface diffusion model could better describe the kinetic behaviour of SA adsorption onto the resin. The fitted surface diffusion coefficient De was 2.19×10-9m2/s, and SA could reach adsorption equilibrium within 10min. Finally, the SA in the conversion solution was recovered by column dynamic method. The breakthrough curves of SA on the resin under different operating conditions were investigated. The yield of SA obtained was ≥99.8% with water as the eluent. In this paper, the separation and recovery of SA can be achieved with water, which provides a new method for the green production of SA.

    Synthesis of highly dispersed Pt/HY catalyst by rapid pyrolysis of platinum precursors and its performance for deep naphthalene hydrogenation
    WANG Lanjiang, LIANG Yu, TANG Qiong, TANG Mingxing, LI Xuekuan, LIU Lei, DONG Jinxiang
    2023, 42(8):  4159-4166.  doi:10.16085/j.issn.1000-6613.2023-0548
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    Decalin has multiple applications as both premium solvent and crucial ingredient in aviation fuel. The synthesis of decalin through deep hydrogenation of coking naphthalene has considerable industrial value. Acetylacetone platinum was used as precursor and deposited into the pores of HY zeolite through physical vapor deposition. A Pt-based catalyst with high dispersion was then obtained by rapidly pyrolyzing the organic ligands at high temperatures. The catalyst's structure and properties were characterized systematically by XRD, N2 adsorption, CO-DRIFT, HRTEM, H2-TPR, and XPS. The Pt particle size on the 0.5Pt/HY catalyst after rapid heat treatment, was small and uniform, unlike that by the traditional high-temperature calcination method. Under mild reaction conditions (H2 3MPa, 100℃, 1h), it exhibited high-efficiency in the deep hydrogenation of naphthalene, with the conversion of naphthalene and the yield of decalin both reaching 99.9%, and a TOF value of 2171h-1. The experimental results indicate that the efficient production of decalin from naphthalene through deep hydrogenation is dependent on two factors: the high dispersion of platinum species in the catalyst and the presence of positively charged platinum species. The research results have certain guiding significance for the preparation of efficient Pt based catalysts for deep hydrogenation of naphthalene.

    Chemical processes and equipment
    Review on computational fluid dynamics (CFD) simulation and advances in pulsating heat pipes
    BU Zhicheng, JIAO Bo, LIN Haihua, SUN Hongyuan
    2023, 42(8):  4167-4181.  doi:10.16085/j.issn.1000-6613.2022-1771
    Abstract ( 18 )   HTML ( 1)   PDF (6597KB) ( 9 )  
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    The pulsating heat pipe (PHP) realizes efficient heat transfer through latent and sensible heat of the working fluid. Due to the strong reciprocating oscillation of the gas and liquid plug, the flow and heat transfer mechanisms are extremely complex. Computational fluid dynamics (CFD) simulation on PHPs can provide important information, such as gas-liquid interface shape, flow pattern transition, oscillating pressure drops, etc. Thus, the published CFD simulations on PHPs are reviewed in this paper. The main formulas, numerical simulation methods, advantages and limitations are introduced, and the available simulation research and conclusions are summarized. The analysis reveals some issues to be solved: there is no definite theoretical basis for the choosing of evaporation and condensation coefficients in phase change model; an agreement on the determination of pipe diameter in two-dimensional model has not been reached; the particle fluid of gas-liquid-solid three-phase flow is simplified into the homogeneous fluid. Based on the above problems, further research directions for using CFD to simulate PHPs are proposed.

    Performance and control system of gas engine heat pump based on waste heat recovery
    LYU Jie, HUANG Chong, FENG Ziping, HU Yafei, SONG Wenji
    2023, 42(8):  4182-4192.  doi:10.16085/j.issn.1000-6613.2022-1776
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    Gas engine-driven heat pump (GHP) has the advantages of strong environmental adaptability, high efficiency and low electricity consumption. It can solve the problems of low primary energy utilization, waste of resources and environmental pollution. Current research focuses on the operational characteristics of GHP systems, while neglecting design of the control system. A control system is very important to ensure efficient and stable operation of GHP systems. In this study, an embedded control system was proposed to monitor gas engine driven heat pump cold-hot water equipment (GHPW). The design principles and methods of the core control modules were described in detail. The operational performance of experimental system was tested by experiments. Experimental results indicated that the control system could monitor the experimental system accurately and stably, and rapid cooling/heating and precise temperature control could be realized. Through double closed-loop control of the main controller on engine speed and evaporator superheat, the stability and accuracy of the outlet water temperature could be achieved. When the ambient temperature was low, heating capacity of GHP systems was better than that of EHP systems due to recovery of engine waste heat. As the ambient temperature rises from -20℃ to 7℃, heating capacity of the experimental system gradually improved from 52.94kW to 105.87kW, and primary energy ratio (PER) of the system steadily increased from 0.819 to 1.489. The recovery of engine waste heat improved heating capacity and PER of the experimental system.

    Influence of surface microstructure on arrayed microjet flow boiling heat transfer
    ZHANG Chao, YANG Peng, LIU Guanglin, ZHAO Wei, YANG Xufei, ZHANG Wei, YU Bo
    2023, 42(8):  4193-4203.  doi:10.16085/j.issn.1000-6613.2022-1807
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    Compared with single-phase microjet heat transfer, arrayed microjet boiling combines two highly efficient heat transfer modes of distributed microjet convection and liquid/vapor phase change, which has an important application prospect in the field of high heat flux electronic cooling. A novel arrayed microjet flow boiling heat transfer system, which consisted of microjet-column array on the top cover and micropillar array on the base copper plate, was presented and fabricated. With ethanol as the working fluid, an experimental investigation was conducted in order to disclose the influence of inlet subcooling, the Reynolds number and heat flux on the microjet-column array boiling heat transfer. Furthermore, Ni/graphene micro/nano composite structures were prepared on the micropillar surfaces with electric brush plating method. However, the Ni/graphene microstructures was found to deteriorate heat transfer because of the combined effects of the additional thermal resistance induced by the Ni transition layer and the suppression of bubble detachment caused by the mushroom-like micropillar array structures. In order to overcome the above disadvantages, laser etching was used to cut part of the Ni transition layer and mushroom-like microstructures on the micropillar array. After being treated by laser etching, it was found that the microjet-column array boiling heat transfer was obviously enhanced and the maximum heat transfer coefficient was 30787.0W/(m2∙K), which is increased by 140.7% and 119.8%, respectively, compared with the Ni/graphene covered micropillar surface and the bare micropillar surface. It can be concluded that the effect of micro/nano composite structures on microjet array boiling heat transfer depends their surface morphology and fabrication method, and the laser etching is more suitable than the electric brush plating for the boiling heat transfer enhancement purpose. This work provides a scientific guidance for the design, fabrication and operation for the arrayed microjet boiling heat transfer enhancement with microstructures.

    Waste heat recovery performance of an air-source gas engine-driven heat pump system in multi-heating operation modes
    HU Yafei, FENG Ziping, TIAN Jiayao, SONG Wenji
    2023, 42(8):  4204-4211.  doi:10.16085/j.issn.1000-6613.2022-1815
    Abstract ( 19 )   HTML ( 1)   PDF (1794KB) ( 8 )  
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    Gas engine-driven heat pump, abbreviated as GHP, is an efficient natural gas distributed energy system, which can significantly improve the shortcomings of air-source heat pump's large-scale attenuation of heating capacity by recovering the engine waste heat at low ambient air temperature in winter. An air-source GHP experimental setup was designed based on open scroll compressors with R410A. The changes in the parameters of heating performance were obtained for different heating modes (mode-1 to mode-4) under two ambient air temperatures Tamb (7℃ and -15℃). The results illustrated that the heating performance of the GHP system can be significantly improved by waste heat recovery (mode-2 to mode-4) compared with no waste heat recovery (mode-1). This showed that mode-4 was a better heating mode for the GHP system. In the experiments of mode-4, when the Tamb were 7℃ and -15℃, the values of primary energy ratio were 1.552 and 0.983, respectively. Meanwhile, the ratios of recovered waste heat to total waste heat (Rrec,res) were 50.63% and 64.15%, respectively, and the recovered waste heat accounted for 28.97% and 36.58% of the total heating capacity, respectively, implying that the effect of waste heat recovery in the GHP system was excellent. Compared with the values of Rrec,res and Rrec,h in the rated heating operation mode, the waste heat recovered in the heating mode with an ultra-low ambient air temperature accounted for a smaller proportion of the total waste heat of the engine, but the recovered waste heat accounted for a higher percentage of the total heating capacity.

    Analysis of flow and heat transfer characteristics in porous media reservoir
    WANG Jiansheng, ZHANG Huipeng, LIU Xueling, FU Yuguo, ZHU Jianxiao
    2023, 42(8):  4212-4220.  doi:10.16085/j.issn.1000-6613.2022-1833
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    Focusing on the problem of high requirements for site selection and groundwater pollution in aquifer energy storage, the construction of artificially filled underground reservoir for energy storage was proposed, and the local flow and heat transfer characteristics in underground reservoir were studied. The conjugate heat transfer model was used to simulate the flow and heat transfer in three kinds of porous media filled with non-uniform particle structure, dodecahedral gradient opening structure and icosahedral gradient opening structure, respectively. The effect of porous media structure on flow and heat transfer characteristics were compared and analyzed. The results indicated that comprehensive heat transfer performance in underground reservoir can be improved by selecting the appropriate filling structure. Among three kinds of porous media, the comprehensive heat transfer efficiency of dodecahedral gradient porous media was the highest. The average Nusselt number of porous media filled with non-uniform particle structure was the largest, but at the same time, the unit pressure drop and friction coefficient were also the largest. With the change of Reynolds number, the Nusselt number of dodecahedral gradient opening structure and icosahedral gradient opening structure intersected. The Nusselt number of icosahedral gradient porous media was larger when Reynolds number was smaller, and the Nusselt number of dodecahedral gradient porous media was larger when Reynolds number was larger.

    Energy processes and technology
    Research progress on vehicle liquid hydrogen cylinder design
    GUO Jin, ZHANG Geng, CHEN Guohua, ZHU Ming, TAN Yue, LI Wei, XIA Li, HU Kun
    2023, 42(8):  4221-4229.  doi:10.16085/j.issn.1000-6613.2022-1764
    Abstract ( 15 )   HTML ( 0)   PDF (504KB) ( 9 )  
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    Under the dual pressure of energy consumption and environmental pollution, new energy generation and hydrogen energy have attracted much attention. Hydrogen fuel cell vehicle is the most widely used terminal application scenario of hydrogen energy. The on-board liquid hydrogen cylinder is widely regarded as an important type of fuel tank for fuel cell vehicles in the next stage due to its high density and lightweight. The safety and reliability of on-board liquid hydrogen cylinder are the key problems at present. In view of the complex operating environment and high accident hazards of hydrogen fuel cell vehicles, the essential safety, high efficiency and energy saving of vehicles are very important. However, the design method of on-board liquid hydrogen cylinders is not perfect, and there are failure risks such as brittle material breakage, fatigue failure and vacuum loss. In this paper, the key design links of vehicle-mounted hydrogen storage bottles are discussed from the aspects of material selection, model selection, design and testing. The historical development and related research progress are reviewed on ductile brittle transition of liquid hydrogen cylinder material, and performances of vehicle-mounted liquid hydrogen cylinders, including static and dynamic analysis, using process and the fatigue life, thermal insulation performance after loss of vacuum, pressurization design and boosting heat transfer. The research trend of on-board liquid hydrogen cylinder is forecasted. Finally, the key technology of on-board liquid hydrogen cylinder design is summarized and prospected.

    Experimental analysis of condensation heat transfer and synergistic desulfurization
    WANG Yungang, JIAO Jian, DENG Shifeng, ZHAO Qinxin, SHAO Huaishuang
    2023, 42(8):  4230-4237.  doi:10.16085/j.issn.1000-6613.2022-1769
    Abstract ( 16 )   HTML ( 0)   PDF (3225KB) ( 5 )  
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    Exhaust from oil-fired and gas-fired boilers contains a large amount of water vapor, and direct emissions will not only result in the waste of resources and energy, but also the formation of white smoke, causing visual pollution and partial haze. Condensation heat transfer technology can effectively recover the waste heat of the exhaust gas and synergistically remove some pollutants. A hot-state experiment for natural gas combustion was designed. It was built to research on the characteristics of condensation heat transfer and decontamination for two heat exchangers with horizontal tubes. The influence of the excess air coefficient and the feed water temperature on the condensation heat transfer was analyzed, and two non-dimensional correlation formulae for the water vapor condensation ratio of 2205 stainless steel/PTFE heat exchangers were fitted. In addition, based on the established SO3/H2SO4 atomization evaporation experimental system, the condensation removal rule of SO3/H2SO4 under different working conditions was further analyzed. The results showed that the condensation rate of 2205 heat exchanger was 19.53%—85.57%, and the maximum condensation heat transfer coefficient was 250.68W/(m2·K). The condensation rate of fluorine plastic heat exchanger was 4.92%—42.04%, and the maximum condensation heat transfer coefficient was 131.09W/(m2·K). At the same time, the condensation removal rate of SO3/H2SO4 increased with the increase of the water supply temperature, and decreased with the increase of the concentration of SO3/H2SO4. However, the absolute condensation amount of H2SO4 increased within a certain period of time, and the maximum condensation removal rate of SO3/H2SO4 reached more than 18%.

    Performance of series stack of non-aqueous nano slurry thermally regenerative flow batteries
    LI Dong, WANG Qianqian, ZHANG Liang, LI Jun, FU Qian, ZHU Xun, LIAO Qiang
    2023, 42(8):  4238-4246.  doi:10.16085/j.issn.1000-6613.2022-1820
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    Thermally regenerative batteries (TRBs) have great development and application prospects in low temperature waste heat recovery and comprehensive utilization of electricity. The application of non-aqueous solvents improves the open-circuit voltage, energy density and thermal efficiency of TRBs. However, the internal resistance of TRBs is relatively large, and few research is for practical applications. Therefore, a compact TRB reactor and a series stack reactor were constructed by using copper-acetonitrile non-aqueous system. The effect of electrode spacing on the performance of a single cell and the effects of liquid supply mode, number of sub cells, circuit connection mode and electrolyte flow rate on the performance of the stack were studied. The results showed that single cell performance was significantly improved by constructing the compact structure, and the parallel supply liquid mode enhanced the mass transfer and the uniformity of the sub-cells, so that the reactor gave high output power. Meanwhile, the open-circuit voltage and the maximum output power of the series reactor increased linearly with the increase of the number of sub-cells. Therefore, it is necessary to select appropriate sub-battery number and circuit connection mode to meet the practical power supply requirements of working voltage and current. Increasing the electrolyte flow rate is helpful to strengthen the material transfer and the maximum output power of the series stack increases first and then remains unchanged with the increase of electrolyte flow rate.

    Industrial catalysis
    Research progress on catalysts for photocatalytic CO2 and CH4 reforming
    HUANG Yufei, LI Ziyi, HUANG Yangqiang, JIN Bo, LUO Xiao, LIANG Zhiwu
    2023, 42(8):  4247-4263.  doi:10.16085/j.issn.1000-6613.2022-1785
    Abstract ( 29 )   HTML ( 2)   PDF (10377KB) ( 16 )  
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    Solar-driven conversion of CO2 and CH4 to syngas is a very promising technology for producing renewable fuels. However, solar-driven CH4 reforming catalysts suffer from low conversion efficiency, fast photogenerated electron-hole complexation rate and poor catalyst stability. This paper briefly describes the possible mechanisms of photocatalytic CO2 and CH4 reforming, including the adsorption of CO2 and CH4, the migration of photogenerated electrons and holes and the desorption of products. The research progress of precious metal catalysts, non-precious metal catalysts and carbon-nitrogen compounds for the photocatalytic CO2 and CH4 reforming is highlighted, and the advantages and shortcomings of these catalysts are also summarized. Finally, this paper discusses the possible development directions in the field of photocatalytic conversion of CO2 and CH4 to syngas, i.e. the development and design of efficient photocatalysts to improve the reaction efficiency, catalytic mechanism investigation by density functional theory (DFT) and advanced characterization techniques.

    Efficient catalytic performance of CuO-CeO2/TiO2 for CO oxidation at low-temperature
    LI Runlei, WANG Ziyan, WANG Zhimiao, LI Fang, XUE Wei, ZHAO Xinqiang, WANG Yanji
    2023, 42(8):  4264-4274.  doi:10.16085/j.issn.1000-6613.2022-1832
    Abstract ( 28 )   HTML ( 3)   PDF (4631KB) ( 26 )  
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    CuO-CeO2/TiO2 catalyst was prepared by incipient impregnation method and then used for CO oxidation at low temperature. The effects of calcination temperature, Cu-Ce loading and Ce/Cu molar ratio on the catalytic performance of CuO-CeO2/TiO2 were investigated. The catalyst was characterized by XRD, N2 isothermal adsorption-desorption, XPS and H2-TPR. When nCe/nCu was 1.6, and Cu-Ce loading was 30%, the catalyst calcined at 500℃ showed the best catalytic activity. When GHSV was 24000mL/(g·h), CO can be completely oxidized on the catalyst at 90℃. It was found that the high content of Ce3+, Cu+ and adsorbed oxygen on the surface of CuO-CeO2 /TiO2 catalyst was favorable to catalyze CO oxidation. The preparation conditions could affect the catalyst activity by regulating the content of Ce3+, Cu+ and adsorbed oxygen on the catalyst surface. Among them, calcination temperature, Cu-Ce loading and nCe/nCu would influence the contents of Cu+ and adsorbed oxygen on CuO-CeO2/TiO2 surface, while Cu-Ce loading has greatly impact on the Ce3+ content on catalyst surface.

    Preparation of NiCoP/rGO/NF electrocatalyst by eletroless plating for efficient hydrogen evolution reaction
    ZHANG Yajuan, XU Hui, HU Bei, SHI Xingwei
    2023, 42(8):  4275-4282.  doi:10.16085/j.issn.1000-6613.2022-1846
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    Electrochemical water splitting is an important green hydrogen technology. The development of efficient and cost-effective electrocatalyst is the focus of current research. A novel hydrogen evolution reaction (HER) electrocatalyst NiCoP/rGO/NF was constructed by electroless plating on nickel foam substrate that was loaded with three-dimensional reduced graphene oxide (rGO). The electrocatalysis performance of NiCoP/NF and that with the introduction of rGO (NiCoP/rGO/NF) was compared. The test results of the three-electrode system showed that, in 1mol/L KOH electrolyte and under the current density of 10mA/cm2, the NiCoP/rGO/NF electrode gave the highest overpotential of 98mV. The remarkable performance of NiCoP/rGO/NF electrode in HER might be the comprehensive result of fast reaction kinetics, large electrochemical active specific surface area (ECSA) and small reaction resistance (Rct) as indicated by the Tafel, cyclic voltammetry (CV) and impedance (EIS) analysis. The structure characterization confirmed that NiCoP was deposited uniformly on the surface of rGO and NF, and the three-dimensional network structure formed by rGO increased the catalyst surface area and exposed rich active edges. The formation of the Ni—P/Co—P bond in NiCoP/rGO/NF was key of HER performance improvement.

    Synthesis and hydrocracking performance of Y molecular sieves with different crystal sizes
    WANG Xiaohan, ZHOU Yasong, YU Zhiqing, WEI Qiang, SUN Jinxiao, JIANG Peng
    2023, 42(8):  4283-4295.  doi:10.16085/j.issn.1000-6613.2022-2071
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    Y molecular sieves of high n(SiO2)/n(Al2O3) ratio were prepared by the seeding method, and then different crystal size(515mn、317nm、220nm) Y molecular sieves were synthesized by changing the aging temperature of the seeding gel. The prepared Y molecular sieves with different crystal sizes and amorphous silica-alumina were mixed as supports, and the loaded NiW/(Y+ASA) hydrocracking catalysts were prepared by the incipient impregnation method. The physicochemical properties of the Y molecular sieves with different crystal sizes and corresponding catalysts were analyzed by scanning electron morphology(SEM), X-ray diffraction(XRD), N2 sorption-desorption, and NH3 temperature-programmed desorption(NH3-TPD). The active metals morphology, dispersion, and sulfation of the catalysts were characterized by H2 temperature-programmed reduction (H2-TPR), transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), and other characterization methods. The results showed that the external specific surface area and pore size increased with the decrease of Y molecular sieves grain size. Meanwhile, as the n(SiO2)/n(Al2O3) ratio increases, the weak and medium acid acidity decreases, and the number of acid decreases. The results of hydrocracking of n-hexadecane showed that the reduction of Y molecular sieve crystal size was beneficial to improve the yield and selectivity of the middle distillate products (C8—C12). Since the small crystal size of Y molecular sieve can reduce the residence time of reactant molecules in the pore channel and improve the accessibility to the active phase on the catalyst surface, over cracking can be avoided and higher yields of middle distillates can be obtained. Therefore, the highest yield of C8—C12 products was obtained for the Y zeolite catalyst NiW/(Y3+ASA) with a crystal size of 220nm.

    Materials science and technology
    Research progress on element doped biomass carbon materials for electrochemical energy storage
    WANG Shuaiqing, YANG Siwen, LI Na, SUN Zhanying, AN Haoran
    2023, 42(8):  4296-4306.  doi:10.16085/j.issn.1000-6613.2022-1797
    Abstract ( 28 )   HTML ( 1)   PDF (2059KB) ( 19 )  
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    In order to achieve emissions peak and carbon neutrality, the development of new biomass carbon materials and their application in the field of electrochemical energy storage has been attracted extensive attention. Among various methods, element doping can solve the problems of low specific capacity and poor stability, and provide a simple and effective method and strategy to optimized and improve the electrochemical properties of biomass carbon materials. In this review, the precursors of doped biomass carbon materials were introduced from three aspects: plant-based, animal-based and microbial-based. The elemental doped biomass carbon materials were classified as single-element doped and multi-elements co-doped according to the number of doped elements. The applications of elemental doped biomass carbon materials in electrochemical energy storage devices (supercapacitors,lithium-ion batteries, sodium-ion batteries and lithium-sulfur batteries) were reviewed, and the effects of their chemical composition and microstructure on electrochemical performance were analyzed. Finally, the future development and commercialization prospects of element doped biomass carbon materials were prospected. The regulation of types and contents of doped elements, the optimization of preparation methods and processes and the activation of biomass self-doped properties were future development directions and urgent problems to be solved.

    Optimization of thermochemical energy storage reactor based on calcium and magnesium binary salt hydrates
    YE Zhendong, LIU Han, LYU Jing, ZHANG Yaning, LIU Hongzhi
    2023, 42(8):  4307-4314.  doi:10.16085/j.issn.1000-6613.2022-1763
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    Thermochemical energy storage material of salt hydrate has high energy storage density, and the regeneration temperature is consistent with the temperature of solar collectors. It can be used to improve the utilization of solar energy. The optimization of thermochemical energy storage reactor based on salt hydrate is important for the thermal energy storage system. In this study, a two-dimensional numerical model of the packed bed reactor of Wakkanai Siliceous Shale (WSS) + MgCl2/2CaCl2 was established. The effects of the content of calcium and magnesium binary salt hydrate, particle size and the height of packed bed on the heat release process of packed bed were analyzed. The numerical simulation results showed that the outlet air temperature increased with the decrease of the particle size. The decay rate of the outlet air temperature decreased with the increase of the calcium-magnesium binary salt content, increased with the decrease of the particle size and decreased with incresing height of the packed bed. The large salt hydrate content and small particle size were conducive to get high heating power and energy storage density of the packed bed. When the height of the packed bed prolonged, the heat release power increased, while the energy storage density decreased. When the particle size of WSS20 was 2mm, the height of the packed bed reactor was 10cm, the energy storage density can reach 0.985GJ/m3, which was almost 4 times that of water.

    Anti-scale and anti-corrosion properties of PDA/PTFE superhydrophobic coating on metal surface
    WANG Xin, WANG Bingbing, YANG Wei, XU Zhiming
    2023, 42(8):  4315-4321.  doi:10.16085/j.issn.1000-6613.2022-1765
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    Superhydrophobic coatings have very wide applications, but the fabrication of stable superhydrophobic coatings on metal surface has the challenge. In order to improve the stability of the coating, a stable polydopamine (PDA) intermediate coating was fabricated on the stainless-steel surface by simple immersion method, and then the polytetrafluoroethylene (PTFE) superhydrophobic coating was prepared on the surface modified by PDA by the electrophoretic deposition method. The field emission scanning electron microscope, contact angle tester and electrochemical workstation were adopted to analyze the performance of the PDA/PTFE coating. The surface of the prepared PDA/PTFE coating presented a bump structure. With the increase of electrodeposition preparation time and water content in solution, the water contact angle of the coating surface increased first and then decreased. The maximum water contact angle was 160.2°±1.3° and the surface energy of coating was 5.57mN/m. The test of tape stripping and sandpaper wear showed that the prepared PDA/PTFE coating was very stable. The fouling deposition test indicated that the scale inhibiting rate of the coating surface was 64.71%, 72.22% and 81.25% in comparison with the untreated stainless steel after immersion in supersaturated CaCO3 solution at 50℃, 70℃ and 90℃ for 12 hours, respectively. Electrochemical test results showed that PDA/PTFE superhydrophobic coating had better corrosion resistance with the corrosion inhibition rate of 95.1% compared with the pure stainless steel.

    Research progress of phase change materials and their application systems for cool storage
    TANG Lei, ZENG Desen, LING Ziye, ZHANG Zhengguo, FANG Xiaoming
    2023, 42(8):  4322-4339.  doi:10.16085/j.issn.1000-6613.2022-1777
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    Phase change cold storage technology uses the heat absorption or release of phase change materials to store and apply energy, which plays a role in the precise control of temperature, the reduction of energy consumption and the energy load transfer. In this paper, the phase change materials with a phase change temperature below 25℃ for different application scenarios were summarized. The applications of phase-change cold storage materials, such as the food and medical cold chain logistics, the building air-conditioning, the data center emergency cooling, and the phase-change textiles for human thermal management and medical care were introduced. The thermal properties of phase change materials and the advantages and disadvantages for various applications were discussed. It was pointed out that the poor heat transfer performance of ordinary materials can be improved by enhancing the thermal conductivity and heat transfer structure of the phase change cold storage system. Moreover, the research prospects of phase change thermal storage technology, from the preparation of composite phase change materials to the system design optimization and application expansion, were proposed.

    Application of coal-based graphene quantum dots in supercapacitors
    ZHANG Yaojie, ZHANG Chuanxiang, SUN Yue, ZENG Huihui, JIA Jianbo, JIANG Zhendong
    2023, 42(8):  4340-4350.  doi:10.16085/j.issn.1000-6613.2022-1791
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    In order to solve the problems of excessive use of potassium hydroxide (KOH) and unreasonable pore structure distribution in the preparation of coal-based activated carbon, Taxi anthracite was used as carbon source to oxidize graphene quantum dots by potassium ferrate and hydrogen peroxide, and then mixed with KOH to prepare coal-based graphene quantum dots activated carbon. The results showed that this method could reduce the amount of KOH (making the alkali-carbon ratio less than 1), and the activation mechanism of the alkali-carbon ratio to graphene quantum dots was similar to that of coal. When the amount of KOH was small (alkali-carbon ratio with 0.25), only pore-forming effect was observed. After increasing the dosage (alkali-carbon ratio with 0.5), KOH had not only the pore-forming effect, but also the pore-expanding effect. The excess KOH (alkali carbon ratio with 0.75) was mainly focus on pore-expanding effect. With the increase of alkali-carbon ratio, the specific surface area and total pore volume of activated carbon also increased, and the micropore rate gradually decreased, while the mesoporous rate and the average pore size increased. When the alkali-carbon ratio was 0.75, the activation effect was the best. The specific surface area of GQDAC-0.75 was 1207.3m2/g, the micropore rate was 39.5%, and the mesoporous rate was 51.8%. Thanks to its unique hierarchical pore structure of "macropore-mesopore-micropore", GQDAC-0.75 showed the optimal electrochemical performance with specific capacitance of 243.6F/g at 0.5A/g current density. When the current density increased to 10A/g, the specific capacitance of GQDAC-0.75 was maintained at 202.2F/g. Even the current density continued to increase to 100A/g, the specific capacitance was still 179.5F/g, and the specific capacitance could remain 191.6F/g at the current density of 20A/g after 10000 cycles with a 98.1% retention rate, which indicated the excellent rate performance and cycle performance.

    Biochemical and pharmaceutical engineering
    Degradation of naphthalene by degrading bacteria isolated from coking contaminated sites
    YANG Jing, LI Bo, LI Wenjun, LIU Xiaona, TANG Liuyuan, LIU Yue, QIAN Tianwei
    2023, 42(8):  4351-4361.  doi:10.16085/j.issn.1000-6613.2022-1742
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    To isolate high effective naphthalene degradation bacteria, a strain AO-4, which could use naphthalene as the sole carbon source by gradient screening and enrichment culture, was obtained from the coking contaminated soil. According to the morphology and 16S rDNA gene sequence, it was identified as Pseudomonas aeruginosa. It was verified by PCR that the strain had naphthalene dioxygenase gene (nahAC) and catechol 2,3-dioxygenase gene (nahH), so the possible degradation pathway of naphthalene might be salicylic acid pathway. In the analysis of the degradation characteristics of the strain, it was found that the degradation rate of naphthalene (400mg/L) by strain AO-4 reached 97.67% in 24h. During the degradation process, the growth and dehydrogenase activity of the bacteria were positively correlated with the degradation rate of naphthalene. The effects of temperature, pH, initial naphthalene concentration and bacterial population on the degradation of naphthalene by the strain were explored. The results showed that the optimum degradation temperature was 30℃ and pH was 5.0—7.0. Within a certain range, the degradation efficiency of the strain increased with the increase of naphthalene concentration and bacterial population. The broad-spectra property experiments of PAHs degradation showed that strain AO-4 could not only degrade naphthalene effectively, but also could degrade other PAHs fluorene, phenanthrene, anthracene and pyrene in single and mixed systems. The above research results can provide technical support for the bioremediation of PAHs-contaminated sites.

    Preparation and characterization of a novel polylactic acid/chitosan/graphene oxide/aspirin drug-loaded biomimetic composite scaffold
    LIU Shuqiong, WU Fangfang, LIU Ruilai, XU Zhenyi
    2023, 42(8):  4362-4371.  doi:10.16085/j.issn.1000-6613.2022-1772
    Abstract ( 18 )   HTML ( 0)   PDF (4989KB) ( 8 )  
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    The biomimetic structure of scaffolds alone has certain limitations on regulating cell behavior and bone tissue regeneration, so the combination of biomimetic scaffolds and nano-drug delivery has become an effective solution. A serial of 3D porous PLA/CS/GO/ASA biomimetic composite scaffolds with different ASA contents were successfully prepared by phase separation method. The addition of ASA destroyed the formation of PLA spherulite structure but had little effect on the structure of biomimetic micro-nano fiber. With the increasing of ASA, the hydrophilicity of drug-loaded scaffolds was improved in the experimental range, but the porosity showed a trend of decreasing first and then increasing, all of which were more than 80%. The hemolysis rate and platelet adhesion experiments showed that the scaffold material with good blood compatibility could be obtained by controlling the ASA content below 5%. Thecell proliferation experiments in vitro showed that the prepared drug-loaded scaffolds had cytocompatibility. Low ASA content could promote the proliferation of MC3T3-E1 cells, and high ASA content had a certain inhibitory effect on MC3T3-E1 cells. The sustained release experiments showed that the PLA/CS/GO/ASA drug-loading biomimetic composite scaffold had good sustained release performance.

    Fine chemicals
    A new method for observation of microstructure of waxy crude oil and its emulsion system
    ZHAO Jian, ZHUO Zewen, DONG Hang, GAO Wenjian
    2023, 42(8):  4372-4384.  doi:10.16085/j.issn.1000-6613.2022-1821
    Abstract ( 21 )   HTML ( 0)   PDF (14204KB) ( 11 )  
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    Based on the rheological-in-situ microscopic synchronous measurement technique and the improved composite light source, a new method for observing the microstructure of waxy crude oil and its emulsion system was established. The actual observation results showed that the number of wax crystals observed by the newly constructed microscopic observation method was 70% higher than that observed by polarizing microscope, and had higher accuracy in identifying small size wax crystals compared with conventional polarizing microscopic observation results. The number of wax crystals in the range of 1—3μm was 150% more, and the fractal dimension of wax crystals in the range of 1—2μm was 15% higher. The newly constructed microscopic observation method had a more prominent observation advantage for the dense wax crystals formed under the deterioration of the initial cooling temperature. In addition, the deterioration identified by the new observation method and the difference between the edge spacing of wax crystals at the optimal initial cooling temperature were larger, which was about twice that of the conventional microscopic observation results. It can better reflect the wax crystal structure at different initial cooling temperatures. The correlation with crude oil rheology was also more significant. The microscopic morphology of wax crystals under dynamic shearing conditions was significantly affected by the flow field. With the increase of shear rate, the synergy between the morphology and arrangement of wax crystals and the flow field increased. Compared with offline observation, the correlation between the wax crystal micromorphology and crude oil rheology obtained by in-situ microscopic observation was more significant, which was more beneficial to explain the rheological mechanism of waxy crude oil from the microscopic scale. The new observation method can realize the simultaneous observation of wax crystals and emulsified water droplets in crude oil emulsion, and had better identification quality in identifying their interaction and aggregation structures.

    Resources and environmental engineering
    Research progress of manganese-loaded biochar preparation and its application in environmental remediation
    JIANG Jing, CHEN Xiaoyu, ZHANG Ruiyan, SHENG Guangyao
    2023, 42(8):  4385-4397.  doi:10.16085/j.issn.1000-6613.2022-1746
    Abstract ( 18 )   HTML ( 0)   PDF (1816KB) ( 10 )  
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    Biochar is a promising adsorbent due to its wide source of raw materials, low preparation cost and large specific surface area, and is an important direction for the resource utilization of solid waste, but its low adsorption capacity limits its practical application in environmental remediation. The modification of biochar by different methods can optimize its physicochemical properties and thus enhance its ability to remove pollutants. In recent years, the preparation of Mn-loaded biochar by various methods has shown great potential for environmental remediation. This paper summarized the preparation of Mn-loaded biochar and its application in the removal of organic pollutants and heavy metals in the environment, and briefly discussed its application in environmental remediation such as advanced oxidation process, sludge treatment, low temperature selective catalytic reduction of nitrogen oxides and recycling. In light of the current research status, possible future research directions for the preparation, application and post-application impacts of manganese loaded biochar were proposed, with a view to providing references for the wider application of manganese loaded biochar in environmental remediation.

    Research progress on highly efficient demulsifiers for complex crude oil emulsions and their applications
    WU Ya, ZHAO Dan, FANG Rongmiao, LI Jingyao, CHANG Nana, DU Chunbao, WANG Wenzhen, SHI Jun
    2023, 42(8):  4398-4413.  doi:10.16085/j.issn.1000-6613.2022-1754
    Abstract ( 31 )   HTML ( 0)   PDF (6607KB) ( 18 )  
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    In petroleum production, a large number of W/O, O/W or multiple emulsified emulsions are usually produced, resulting in greatly reduced production efficiency and serious environmental problems. The demulsifiers used in production have low demulsification efficiency, high cost, poor universality and insufficient safety. There is still more attention to develop efficient, universal, green and safe demulsifiers. Based on the analysis of the characteristics and stability mechanism of crude oil emulsion, the research progress of demulsifiers for different crude oil lotion were summarized. It mainly included polymer demulsifiers, biomass based demulsifiers, ionic liquid demulsifiers and nano material demulsifiers. Finally, the development of efficient demulsifiers and the future development trend of demulsification technology were put forward. It laid a foundation for the demulsification technology application of W/O, O/W or complex crude oil emulsions.

    Research progress on the application of micro/nano bubbles in anaerobic digestion
    XI Yonglan, WANG Chengcheng, YE Xiaomei, LIU Yang, JIA Zhaoyan, CAO Chunhui, HAN Ting, ZHANG Yingpeng, TIAN Yu
    2023, 42(8):  4414-4423.  doi:10.16085/j.issn.1000-6613.2022-1762
    Abstract ( 25 )   HTML ( 0)   PDF (1670KB) ( 12 )  
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    Research on micro/nano bubbles (MNBs) have attracted much attention due to their wide application fields and good application prospects. In the field of anaerobic digestion (AD), the high gas transfer efficiency, ROS generation, high zeta potential, high surface charge, and inherent micro-aeration capability (air or O2-MNBs) of MNBs can improve the performance of AD processes, improving the rate-limiting steps (hydrolysis and methanogenesis), which provide new directions for the improvement of AD processes. In recent years, more and more studies have used different MNBs in AD in different ways. These studies mainly focus on using nanobubble-rich nanobubble water to improve AD reactor performance, while the research on the application of microbubbles in AD is relatively small. Considering that both nanobubbles and microbubbles have the potential to improve AD, this study reviewed the characteristics, preparation methods and equipment of MNBs, as well as their research status and possible mechanism in AD, and discussed possible future application directions, which aims to provide a reference for further research on using MNBs to enhance AD.

    Application and prospect of algal-bacterial symbiosis technology in zero liquid discharge of industrial wastewater
    ZHENG Mengqi, WANG Chengye, WANG Yan, WANG Wei, YUAN Shoujun, HU Zhenhu, HE Chunhua, WANG Jie, MEI Hong
    2023, 42(8):  4424-4431.  doi:10.16085/j.issn.1000-6613.2022-1778
    Abstract ( 19 )   HTML ( 0)   PDF (1088KB) ( 15 )  
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    Due to amounts of toxic organics and nitrogen and phosphorus nutrients, industrial wastewater is the key source of black-odor water and eutrophic water, and thus zero liquid discharge has become the inevitable course to sustainable industrial development. With the advantages of organic degradation and simultaneous carbon, nitrogen and phosphorus fixation, increasing researcher is located to algal-bacterial symbiosis technology for zero liquid discharge. In this paper, the mechanism and key influencing factors of algal-bacterial symbiosis technology for removing organics, nitrogen and phosphorus from industrial wastewater were reviewed. Meanwhile, the biodegradation characteristics and difficulties of algal-bacterial symbiosis technology were discussed in terms of dyeing wastewater, pharmaceutical wastewater and petrochemical wastewater. Besides, excessive environmental factors and high concentration of toxic organics in industrial wastewater stressed the transformation of microalgae trophic modes, and induced strong reaction of oxidative stress of microorganisms, thus inhibiting their growth and metabolism and also reducing the efficiency of wastewater treatment. Therefore, this paper proposed the prospect: the application of algal-bacterial symbiosis technology in industrial wastewater treatment should reduce reaction of oxidative stress and enhance the coupling of algal-bacterial metabolism advantages by pretreatment process and the enhancement of bacteria algae symbiosis mechanism. Finally, the directional transformation of biomass could be achieved by exploring the regulation strategy of environmental factors.

    Application prospect, challenge and development of ammonia energy storage in new power system
    YANG Pengwei, YU Linzhu, WANG Fangfang, JIANG Haoxuan, ZHAO Guangjin, LI Qi, DU Mingzhe, MA Shuangchen
    2023, 42(8):  4432-4446.  doi:10.16085/j.issn.1000-6613.2022-1817
    Abstract ( 26 )   HTML ( 2)   PDF (2325KB) ( 15 )  
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    Energy storage technology and its industrial application are of great significance to the construction of new power systems. In the process of upgrading and transforming the traditional power system to the new power system, the proportion of wind energy, solar energy and other new energy power generation continues to increase, but its volatility and intermittence restrict the high-level consumption of new energy, resulting in a sharp increase in the demand for flexible regulation resources in the power system. Ammonia has the advantages of large-scale, cross-seasonal and cross-regional storage. Accelerating the development of ammonia energy industry and the application of ammonia energy storage in new power systems is a strategic choice to achieve the "double carbon" goal and ensure national energy security. This paper compares the characteristics of ammonia energy storage and other energy storage systems, including the similarities, advantages and disadvantages of ammonia energy storage, hydrogen energy storage, methanol energy storage and other chemical energy storage, focuses on the existing ammonia energy storage technology, ammonia storage and transportation methods and low concentration ammonia separation technology at home and abroad, and expounds the application value of ammonia energy storage in the power supply side, power grid side and user side. Finally, the challenges faced by the application of ammonia energy storage in the new power system are pointed out and its future development is prospected.

    Resource utilization of coal gasification slag
    ZHANG Lihong, JIN Yaoru, CHENG Fangqin
    2023, 42(8):  4447-4457.  doi:10.16085/j.issn.1000-6613.2022-1845
    Abstract ( 30 )   HTML ( 3)   PDF (2124KB) ( 24 )  
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    Coal gasification technology has developed rapidly as a clean utilization technology, but a large amount of coal gasification slag has been produced at the same time. With the sources and hazards, the basic properties, the prepared materials (mesoporous materials, activated carbon, composite materials) and the application of coal gasification slag (in the field of waste gas and wastewater treatment, construction and building materials, agriculture) involved, this article reviews the research status, analyzes the existing problems and forecasts application prospects. Coal gasification slag is rich in carbon, aluminum and silicon, with large specific surface area and relatively developed pore structure. Then it can be used to prepare high-value products. However, the waste liquid generated during the preparation process needs to be urgently treated and disposed of. The remaining aluminum, silicon and carbon-containing residues also need to be recycled. Although the research on coal gasification slag has achieved good results, most are still in the stage of laboratory research or experimental promotion, and cannot achieve large-scale utilization. In this paper, it is suggested that developing resource utilization technology of coal gasification slag with simple process, strong feasibility and economic benefits, the synergistic utilization of aluminum, silicon and carbon resources should be realized on the basis of hierarchical utilization, and large-scale utilization should be achieved on the ground of full utilization.

    Experimental comparation on anti-scaling and anti-wetting ability of hydrophilic and hydrophobic modified membranes
    LI Xuejia, LI Peng, LI Zhixia, JIN Dunshang, GUO Qiang, SONG Xufeng, SONG Peng, PENG Yuelian
    2023, 42(8):  4458-4464.  doi:10.16085/j.issn.1000-6613.2022-1738
    Abstract ( 19 )   HTML ( 0)   PDF (3433KB) ( 8 )  
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    Membrane distillation processes are less affected by water with high salinity, including high saline water from mines. However, membrane scaling and wetting have restricted their industrial applications. In this work, we compared two types of commercial flat hydrophobic membranes, i.e., polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), with their composite membranes. The composite membranes were prepared with hydrophilic and hydrophobic surface modification, namely PVA-PAA/PTFE and Teflon/PVDF. The effects of membrane scaling and wetting on the prepared membranes were systematically investigated using the concentrated saturated calcium sulfate (CaSO4) solution in direct contact membrane distillation (DCMD). We analyzed their membrane scaling and wetting mechanisms and presented their potential application and optimal membrane structure for high-saline mine water. Our experimental results indicated that the scaling on the membrane surface was the main influencing factor in the concentration process of the CaSO4 solution in DCMD. Although the microstructures of the bare and modified membranes differed, their anti-scaling abilities were similar. Compared to the other prepared membranes, the Teflon/PVDF composite membrane exhibited superior anti-scaling performance given its slip characteristics. On the other hand, the PVA-PAA/PTFE composite membrane exhibited marginal improvement in anti-scaling ability despite its dense hydrophilic surface.