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Table of Content
05 January 2021, Volume 72 Issue 1
    Reviews and monographs
    Research progress on improving the tumor-targeting of photosensitizers in photodynamic therapy
    YANG Yuxin, ZHAO Xueze, FAN Jiangli, PENG Xiaojun
    2021, 72(1):  1-13.  doi:10.11949/0438-1157.20201047
    Abstract ( 718 )   HTML ( 37)   PDF (1238KB) ( 755 )  
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    Due to the advantages of minimal invasiveness, high temporal and spatial selectivity, and repeated application without drug resistance, photodynamic therapy is considered to be a promising new cancer treatment method. However, traditional photosensitizers possess poor tumor targeting ability and always result in non-specific photodamage to adjacent normal tissues, which greatly limits its clinical application. Constructing the targeting photosensitizers or activatable photosensitizers is an effective way to improve the tumor selectivity of photosensitizers. This paper summarizes the current research progress of targeting photosensitizers and activatable photosensitizers, and gives the prospection of the challenges in future.

    Advancements in adsorption separation of Xe/Kr noble gases
    CHEN Rundao, ZHENG Fang, GUO Lidong, YANG Qiwei, ZHANG Zhiguo, YANG Yiwen, REN Qilong, BAO Zongbi
    2021, 72(1):  14-26.  doi:10.11949/0438-1157.20200863
    Abstract ( 1047 )   HTML ( 37)   PDF (4451KB) ( 611 )  
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    The efficient capture and separation of noble gas Xe/Kr is one of the important separation processes in the gas industry, nuclear environment monitoring, and spent fuel treatment. Xenon and krypton have similar molecular size and polarizability, thus the industrial Xe/Kr separation relies on the energy-intensive cryogenic distillation based on minor difference in boiling point. Adsorption separation is a promising alternative technology. The novel solid porous materials with structural diversity and designability, represented by metal-organic frameworks (MOFs), show great potential in the Xe/Kr adsorption application. The minor difference between xenon and krypton can be accurately discriminated by adjusting the polar pore surface chemistry and pore aperture of MOF materials. In this review, recent advancement in the novel adsorbents for the adsorption separation of xenon and krypton were summarized. The effect of pore surface polarity, pore structure, framework flexibility on the Xe/Kr separation performance were discussed. The current challenges and perspective of MOF materials for Xe/Kr separation were pointed out.

    Application of genetic algorithm in the global structure optimization of catalytic system
    SHI Xiangcheng, ZHAO Zhijian, GONG Jinlong
    2021, 72(1):  27-41.  doi:10.11949/0438-1157.20201037
    Abstract ( 842 )   HTML ( 22)   PDF (3159KB) ( 829 )  
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    Genetic algorithm is widely used to search for the global minimum structure that is important for analyzing the catalyst structure, the mechanism of heterogeneous catalytic reaction, and actual reaction pathway. By performing crossover, mutation and selection, genetic algorithm reflects the process of natural selection where the fittest individuals are selected for reproduction to explore the potential energy surface. As an unbiased optimization algorithm, the optimization process of genetic algorithm does not depend on the input structure and has strong global search capabilities. This review summarizes the recent progress of the design and application of genetic algorithm, as a global structure optimizer, in the catalytic system. Starting with introducing the standard genetic algorithm framework for global structure optimization, this review also includes the advanced framework developed by introducing parallel computing and machine learning technique. Finally, some examples about the reported application of genetic algorithm in catalytic structure optimization are presented, such as the optimization of metallic clusters, supported catalysts, etc. This review might provide a significant insight into the further improvement of genetic algorithm and the wider application in catalytic system.

    Controllable fabrication of functional microparticle materials from microfluidic droplet templates
    SU Yaoyao, LI Pingfan, WANG Wei, JU Xiaojie, XIE Rui, LIU Zhuang, CHU Liangyin
    2021, 72(1):  42-60.  doi:10.11949/0438-1157.20201099
    Abstract ( 442 )   HTML ( 61)   PDF (10326KB) ( 237 )  
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    Functional microparticle materials have a wide range of applications in many fields due to their advantages of miniaturization and multi-functionality. As a new technical platform for materials fabrication, microfluidic technique shows unique creativity and superiority for controllable fabrication of functional microparticles. This review summarizes recent progress on controllable fabrication of diverse functional microparticles from microfluidic droplet templates, for use in fields such as chemical engineering, pharmaceuticals, energy storage, and environment. The rational design and controllable fabrication of functional microparticles, including porous spherical microparticles, compartmental spherical microparticles, and diverse nonspherical microparticles, by designing the structure and composition of microfluidic emulsion droplets are introduced. Strategies for the microparticles to achieve unique functions based on coupling of their microstructures and chemical compositions are discussed. Prospects on the future development of microfluidics for controllable fabrication of novel functional microparticles are provided.

    Recent advances in solid-state lithium metal batteries: the role of external pressure and internal stress
    NAN Haoxiong, ZHAO Chenzi, YUAN Hong, LU Yang, SHEN Xin, ZHU Gaolong, LIU Quanbing, HUANG Jiaqi, ZHANG Qiang
    2021, 72(1):  61-70.  doi:10.11949/0438-1157.20201201
    Abstract ( 914 )   HTML ( 27)   PDF (1246KB) ( 701 )  
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    The solid-state lithium metal battery has the advantages of high theoretical energy density and high safety, and is a very promising next-generation energy storage system. However, the limited solid–solid contact retards the migration of Li ions between solid electrolytes and electrodes. Consequently, applying external pressure is an effective route to enhance interfacial contacts and extend battery cycle life. At the same time, the internal stresses generated with the volume changes of electrodes during cycling will also hugely influence the interfacial contacts. In this paper, the mechanisms of external pressure and internal stresses on electrodes and electrolytes are reviewed by introducing two basic physical contact models and analyzing the physical properties of sulfide, oxide, polymer electrolytes and lithium metal anodes. Finally, the roles of external pressure and internal stresses in all-solid-state Li metal batteries are summarized and prospected.

    Preparation and research progress of amphiphobic membrane for air purification
    ZHU Xiao, FENG Shasha, ZHONG Zhaoxiang, XING Weihong
    2021, 72(1):  71-85.  doi:10.11949/0438-1157.20201356
    Abstract ( 456 )   HTML ( 5)   PDF (5347KB) ( 313 )  
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    Industrial flue gas usually contains a large number of oily aerosols, which may lead to serious plug for the traditional oleophilic filters. When facing the complex flue gas system with high humidity and oily aerosol, the amphiphobic membrane material has the advantages of high separation efficiency, strong pollution resistance and easy cleanin. This paper systematically summarizes the preparation methods of air purification amphiphobic membrane. The formation and control mechanisms of foulants on the surface of the membrane are elaborated through analyzing the microscope interaction between the oily aerosols and the membrane surfaces. Finally, the development prospect of amphiphobic membranes in air purification field is analyzed and discussed.

    Synthesis and structure control of horizontally aligned carbon nanotubes: progress and perspectives
    SHI Xiaofei, JIANG Qinyuan, LI Run, CUI Yiming, LIU Qingxiong, WEI Fei, ZHANG Rufan
    2021, 72(1):  86-115.  doi:10.11949/0438-1157.20200992
    Abstract ( 770 )   HTML ( 26)   PDF (28500KB) ( 682 )  
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    The horizontal array of carbon nanotubes refers to a type of carbon nanotubes grown on a flat substrate and arranged parallel to the substrate. Compared with other types of CNTs, HACNT arrays have much fewer defects and superior mechanical, electrical and thermal properties, and therefore have great application prospects in various frontier fields such as microelectronics, super fibers and aerospace. In these cases, defect concentrations, chirality distributions, semiconducting purities and number densities of HACNT arrays are strictly required to meet the demand. Hence, efficient structure control and mass production of HACNT arrays are crucial to the realization of ideal properties and the corresponding application. In the past near thirty years, researchers have made great progress in the structure-controlled growth of HACNT arrays, while many challenges still exist. The progress in structure control, mass production and advanced application of HACNT arrays are reviewed. The significant challenges and development directions for the synthesis and application of HACNT arrays are also discussed.

    A review on kinetics and reactor concept design of propylene epoxidation using H2 and O2
    DU Wei, ZHANG Zhihua, DUAN Xuezhi, ZHOU Xinggui
    2021, 72(1):  116-131.  doi:10.11949/0438-1157.20201247
    Abstract ( 526 )   HTML ( 23)   PDF (3348KB) ( 343 )  
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    Propylene oxide (PO) ranks among the 35 chemicals with the highest production capacity in the world, and is the second largest propylene derivative after polypropylene. It is mainly used to produce polyether polyols, polyurethanes, etc. Compared with traditional PO production technology such as the chlorohydrin, co-oxidation and HPPO method, using H2 and O2 to oxidize propylene for PO production (HOPO) has the advantages of environmental friendliness, simple process and good economic efficiency. It is the ideal technology for PO production. In this review, the reaction kinetics of the propylene epoxidation using H2 and O2 reaction are highlighted, including the main and side reaction kinetics and deactivation models. The reactor concept design based on safe operation is summarized. The existing problems of HOPO reaction are analyzed and possible research focus is remarked from the aspects of side reaction pathways, deactivation kinetics and kinetics on catalyst pellet.

    Research progress of high temperature proton exchange membranes
    LI Hui, YANG Zhengjin, XU Tongwen
    2021, 72(1):  132-142.  doi:10.11949/0438-1157.20201073
    Abstract ( 773 )   HTML ( 29)   PDF (2521KB) ( 451 )  
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    High temperature proton exchange membrane fuel cells (HT-PEMFCs) have become one of the most important research directions in the energy field because of their good catalyst CO tolerance, high energy conversion rate, and simple hydrothermal management. High temperature proton exchange membranes (HTPEMs) are the most critical component. In this paper, we reviewed current research progress of HTPEM based on proton carriers at high temperature, including water, phosphoric acid and imidazole molecules. It appears that HTPEMs based on phosphoric acid doping perform the best. There are also a few issues that need to be addressed. Future directions concerning the development of HTPEMs were also outlined.

    Progresses in the preparation of micro-scale process-enhanced crystalline particles
    SHENG Lei, LI Peiyu, NIU Yuchao, HE Gaohong, JIANG Xiaobin
    2021, 72(1):  143-157.  doi:10.11949/0438-1157.20201051
    Abstract ( 434 )   HTML ( 12)   PDF (4362KB) ( 300 )  
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    Crystal particle preparation technology has an irreplaceable role in the fields of chemical engineering, medicine, electronics, biology and so on. The improvement of this technology has always attracted people's attention. In recent years, with the rapid development of chemical process intensification and micro-chemical technology, micro-scale process intensification methods have been widely used in crystal particles preparation and become the research frontier of high-end particle preparation. This article reviews the research progresses of micro-scale enhanced process for particle preparation: focusing on microfluidic module, the principle of microstructure mixer, microfluidic technology to improving micro-mixing efficiency, and its application in nanoparticles drug crystallization and other fields are briefly described. On the micro-force fields, the structure design and visualization study of rotating packed bed, the acoustic cavitation effect represented by ultrasonic field and the application of external force field to the preparation of ultrafine nanoparticles and continuous drug crystallization process are introduced. Further, in view of the micro-scale intensified mass transfer process based on membrane technology, the enhanced mass transfer process of the microporous membrane and the effect of crystal “adhesion-growth-detachment” are analyzed. At the same time, the key structural and process parameters that affect the dispersion mass transfer enhancement process of microporous membrane are explored. The surface renewal mechanism of dense membrane liquid layer to enhance mass transfer and multi-stage membrane operating system that controls preparation of crystalline particles were discussed systematically. Finally, we outline the development trend of crystal particle preparation technology with enhanced mass transfer via microscale processes.

    Research progress of Hofmann rearrangement reaction
    HUANG Jinpei, HUANG Dan, WANG Fajun, XU Jianhong
    2021, 72(1):  158-166.  doi:10.11949/0438-1157.20200890
    Abstract ( 1598 )   HTML ( 43)   PDF (1084KB) ( 862 )  
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    Hoffman rearrangement reaction is an important method for preparing primary amines and their derivatives, and has a wide range of applications in the fields of drug synthesis and functional material preparation. At present, the traditional Hofmann rearrangement processes involved liquid bromine and batch reactors encounter lots of problems in large-scale production, such as low reaction efficiency, complex operation and poor safety. To solve these problems, scientific and engineering researchers have made a lot of efforts, and a large number of studies about optimization of reaction conditions and process intensification have been reported. Through the optimization of reaction conditions, many mild and highly selective reaction reagents have been developed, which provide more choices for the reaction scheme design of different amide substrates. The emergence of novel reaction process intensification technologies such as microwave assistance, electrochemistry and micro-reactors has created favorable conditions for the realization of high-efficiency and environmentally friendly Hofmann rearrangement reaction. This review focuses on the latest research progress of Hofmann rearrangement reaction in the optimization of reaction conditions and process intensification. On this basis, the future research direction of this reaction was prospected.

    Research progress of MOF-based composites for gas adsorption and separation
    LI Jianhui, LAN Tianhao, CHEN Yang, YANG Jiangfeng, LI Libo, LI Jinping
    2021, 72(1):  167-179.  doi:10.11949/0438-1157.20200925
    Abstract ( 1148 )   HTML ( 58)   PDF (7364KB) ( 550 )  
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    As a new type of porous material, metal-organic frameworks (MOFs) have the advantages of high porosity, large specific surface area, adjustable pore size, and diverse structures. In recent years, it has shown broad application prospects in the field of gas adsorption and separation. Nevertheless, MOFs still have some drawbacks such as poor structural stability that restrict their further industrial applications. Fabrication of multifunctional MOF-based composite materials will significantly enhance their structural stability and maintain their separation performance. This review summarized the preparation methods of MOF-based composites. The materials were used to build MOF-based composites including carbon-based materials, ionic liquids, MOFs, molecular sieve and so on. Their recent advances in gas adsorption and separation field were analyzed and the future research of this direction was prospected.

    Research progress of ammonia borane hydrolytic hydrogen production
    WANG Yutong, PAN Lun, ZHANG Xiangwen, ZOU Jijun
    2021, 72(1):  180-191.  doi:10.11949/0438-1157.20200976
    Abstract ( 855 )   HTML ( 43)   PDF (4344KB) ( 477 )  
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    Hydrogen energy is an important clean energy to replace traditional fossil energy. However, achieving high-quality and dense storage of hydrogen energy and rapid release under mild conditions is still a major bottleneck. Ammonia borane, with a high hydrogen content of 19.6%(mass), that can release hydrogen under mild condition, is an exordinary hydrogen storage material. However, ammonia borane is relatively stable in water, so the development of catalyst is very important. The research on hydrolyzing catalyst of ammonia borane mainly focuses on metal, metal compound and photocatalyst. In this paper, the research methods of ammonia borane hydrolysis for hydrogen production are introduced in practice, and the steps and mechanism of ammonia borane hydrolysis are reviewed theoretically. Noble metals have intrinsic ammonia borane catalytic activity and the design of noble metal catalysts should focus on reducing particle size to avoid agglomeration. Specific strategies include the addition of surfactants and loads on skeleton and atomic dispersion. Due to the different electronegativity between metals, metal alloys will have their own charge migration. Such unbalance charge can effectively adsorb the different hydrogen on ammonia borane and promote the dissociation. Metal compounds have also become the focus of research and development due to their unique electronic properties. Photocatalysis can drive semiconductor or plasma materials to generate electrons and holes and promote charge transfer, so it is also an effective measure to improve hydrolysis efficiency. This paper describes the process of hydrogen production, introduces the method of positive regulation of reaction, and puts forward the design strategy of catalyst in the future.

    Progress in lead ion detection technologies based on 18-crown-6
    LIU Yuqiong, LI Yao, JU Xiaojie, XIE Rui, WANG Wei, LIU Zhuang, CHU Liangyin
    2021, 72(1):  192-204.  doi:10.11949/0438-1157.20201161
    Abstract ( 371 )   HTML ( 5)   PDF (2942KB) ( 171 )  
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    Lead is a heavy metal pollutant that has serious harm to the environment and the human body. Research on lead ion (Pb2+) detection technology has important practical significance. In recent years, based on the Pb2+ recognition properties of 18-crown-6 units, a series of smart polymeric materials have been designed to detect Pb2+. In this paper, recent research progress in Pb2+ detection technologies based on 18-crown-6 is reviewed, and detection technologies based on smart membranes, smart optical elements, smart microchips and smart microcapsules are mainly introduced. Finally, the perspectives and challenges of these Pb2+ detection technologies are discussed, which provides valuable information and guidance for the further development and application of Pb2+ detection technologies based on 18-crown-6.

    Advances in the synthesis of chiral amines by biocatalytic C—N bond formation
    CHENG Yaqi, WU Jing, LIU Liming, SONG Wei
    2021, 72(1):  205-215.  doi:10.11949/0438-1157.20201075
    Abstract ( 566 )   HTML ( 10)   PDF (2491KB) ( 387 )  
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    Biocatalytic C—N bond formation is mainly used to synthesize chiral amines, which are widely used in the preparation of foods, fine chemicals and pharmaceutical intermediates. Enzymatic production of chiral amines is characterized by high enantioselectivity, conversion and space-time yield. This review mainly introduces three ways of C—N bond formation, which are reductive amination reaction, hydrogen amination reaction and transamination reaction. The related enzymes were summarized according to different reaction types.

    Biocatalysis C—C bonding reaction and its application
    QI Na, SONG Wei, LIU Liming, WU Jing
    2021, 72(1):  216-228.  doi:10.11949/0438-1157.20201098
    Abstract ( 751 )   HTML ( 12)   PDF (2541KB) ( 325 )  
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    The CC bond formation reaction is the key reaction to construct the carbon skeleton of organic molecules in organic synthesis. This review presents the key enzymes that catalyze C—C bond formation reactions such as Aldol, Acyloin condensation, Stetter, Pictet-Spengler, etc., and the application progress of those enzymes in the synthesis fine chemicals such as β-hydroxy-α-amino, α-hydroxyketone, 1,4-diketone, β-carboline and tetrahydroisoquinoline in recent years. In addition, this manuscript also describes the application prospects of biocatalysis C—C bond formation reactions to expand the application scope of biocatalysis in chemical production.

    Research progress of chemiluminescence probes based on adamantane-dioxetane
    JIANG Long, WANG Kaijie, KONG Qing, LU Sheng, CHEN Xiaoqiang
    2021, 72(1):  229-246.  doi:10.11949/0438-1157.20201090
    Abstract ( 733 )   HTML ( 27)   PDF (5868KB) ( 355 )  
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    Chemiluminescence is released by its chemical reaction instead of light energy excitation to generate optical signals, which has the advantages of low background, no autofluorescence interference and high sensitivity. In recent years, chemiluminescence imaging technology, especially dioxetane chemiluminescence probe in biological imaging, has been developed rapidly. Glow-type adamantane-dioxetane chemiluminescence have been widely used for ion detection (fluoride ions), specific identification of bioactive species (reactive oxygen species, active sulfur species), biomarker enzymes (β-galactosidase, nitroreductase, cathepsin B, etc.) and the development of chemiluminescence materials. This article summarizes the research progress of adamantane-dioxetane chemiluminescence in the above four aspects in recent years, and prospects the research direction in this field.

    Study on application and mechanism of ionic liquids in biomass dissolution and separation
    ZHAO Jinzheng, ZHOU Guohui, LIU Xiaomin
    2021, 72(1):  247-258.  doi:10.11949/0438-1157.20201065
    Abstract ( 488 )   HTML ( 13)   PDF (1394KB) ( 220 )  
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    Biomass is one of the most abundant renewable resources in nature. To convert biomass into high value-added chemical products, biomass pretreatment must be carried out. Chemical, physical and biological methods are used to disrupt the interactions between cell wall components, making biomass easier to degrade. Ionic liquids have drawn widespread attention in many fields due to their excellent physical and chemical properties. Many ionic liquids have shown good effects in biomass pretreatment. In this paper, recent researches on ionic liquids as lignocellulose solvent systems are discussed, with focuses on the mechanism of molecular level interaction between ionic liquids and lignocellulose. The effects of ion types and hydrogen bonds are also discussed. This paper also gives the development prospect of ionic liquid as biomass solvent.

    Research progress of semiconductor materials for photocatalytic low concentration nitrogen oxides
    ZHANG Guping, WANG Beibei, ZHOU Zhou, CHEN Dongyun, LU Jianmei
    2021, 72(1):  259-275.  doi:10.11949/0438-1157.20201018
    Abstract ( 595 )   HTML ( 12)   PDF (3893KB) ( 189 )  
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    Nitrogen oxides (NOx) are a type of harmful air pollutants that can cause serious environmental problems such as acid rain, haze, and photochemical smog. At present, how to effectively remove the low concentration of NOx in the air (ppb level: one part per billion) is a research hotspot and difficulty. The semiconductor photocatalytic oxidation method can oxidize low concentration NOx in the air into non-toxic nitrate, which is one of the economic and effective purification technologies. This review article mainly focuses on three types of semiconductor photocatalytic materials, such as titanium dioxide (TiO2), carbon nitride (g-C3N4) and Bi-based semiconductors, and provides a brief overview of their research on the photocatalytic removal of low-concentration NOx in recent years. Meanwhile, various representative works introduce the modification strategies of noble metal deposition, element doping, semiconductor combination and surface vacancy defect engineering to improve the photocatalytic performance of semiconductor materials in removing low concentrations NOx. In order to provide ideas for the rational design and preparation of high-performance semiconductor photocatalysts and the exploration of catalytic mechanisms, the future development of semiconductor materials in photocatalytic low concentration NOx is finally prospected.

    Recent progress on extractive desulfurization of fuel oils through reactions based on ionic liquids as solvents and catalysts
    WU Peiwen, XUN Suhang, JIANG Wei, LI Huaming, ZHU Wenshuai
    2021, 72(1):  276-291.  doi:10.11949/0438-1157.20201131
    Abstract ( 698 )   HTML ( 15)   PDF (2071KB) ( 326 )  
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    With the continuous development of society, the consumption of gasoline and diesel has been increasing year by year. The development of non-hydrodesulfurization methods with excellent removal performance of aromatic sulfides under mild conditions is of great significance to the upgrading of Chinese gasoline and diesel standards. Extractive desulfurization can remove aromatic sulfides in fuel oils at room temperature and normal pressure. Moreover, selective desulfurization can be gained by the design of the extractant structures. This article reviews the current research progress of ionic liquid reaction-type extraction desulfurization method. The principle and mechanism of ionic liquid reaction-type extraction desulfurization method are discussed in detail. Moreover, this review focuses on the effects of ionic liquid, oxidant type, and process intensification separation and recovery of ionic liquids, etc. in ionic liquid reaction-type extraction desulfurization method. This article also analyzes the bottleneck restricting the extensive industrial application of reaction-type extraction desulfurization method.

    Research progress of Pd-based catalysts for DSHP from hydrogen and oxygen
    ZHANG Meijia, WU Dengfeng, XU Haoxiang, CHENG Daojian
    2021, 72(1):  292-303.  doi:10.11949/0438-1157.20201168
    Abstract ( 577 )   HTML ( 11)   PDF (3753KB) ( 430 )  
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    The development of highly active and selective catalysts is the key to the industrial application of direct synthesis of hydrogen peroxide (DSHP) from hydrogen and oxygen. The design, preparation and development of Pd-based catalysts are emphatically reviewed from the perspectives of catalytic mechanism, optimization of active components, morphology and size control, support selection, improvement of preparation method, selection of reaction additive and reaction condition tuning, et al. In addition, the existing optimization strategies for the activity and selectivity of Pd-based catalysts are discussed systematically based on recent investigations. Finally, the research progress of Pd-based catalysts for DSHP is summarized, and the future development prospects are prospected.

    Research progress on electro-sorption technology and fabrication of adsorptive electrode materials
    BIAN Weibai, PAN Jianming
    2021, 72(1):  304-319.  doi:10.11949/0438-1157.20201019
    Abstract ( 574 )   HTML ( 31)   PDF (7292KB) ( 146 )  
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    Due to the technical advantages of eco-friendly cleanliness, simplicity and energy saving, electrosorption technology has important application potential in the fields of seawater desalination and pollutant adsorption treatment. The key of high-efficiency electro-sorption and high adsorption capacity for ions is how to construct adsorption electrode with a high charge capacity. In this paper, the theoretical model of double layer for ions adsorption and storage by electro-sorption technology was introduced based on the principle of electro-sorption technology, and the research progress of electro-sorption technology was summarized as well. Next, the carbon adsorption electrode, metal oxide adsorption electrode and composite adsorption electrode were reviewed from the point of materials fabrication, respectively. It summarized the merits and deficiencies of each kind of electrode materials, and the proposed corresponding solutions for the deficiencies from researchers were also analyzed and summarized. With the goal of high-efficient practical application for electro-sorption technology, it also prospected the design and preparation of electrode materials.

    Research progress of lignans biosynthesis and their microbial production
    WANG Lian, WU Di, ZHOU Jingwen
    2021, 72(1):  320-333.  doi:10.11949/0438-1157.20201089
    Abstract ( 630 )   HTML ( 14)   PDF (1964KB) ( 289 )  
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    Lignans are a class of secondary metabolites distributed in plants, which are formed by the polymerization of two molecules of phenylpropanine derivatives. Lignans have antibacterial, antiviral and antifungal activities, and are widely used in medicine and food. At present, lignans production mainly depends on plant extraction. The commercial application of lignans is limited by the problems of long plant growth period and low content. With the continuous demonstration of lignans biosynthesis pathways and key enzymes, biocatalytic synthesis of lignans has attracted more and more attention. In this review, the biological activity, biosynthesis pathway and microbial production of typical lignans were summarized, which may provide reference for the investigation of microbial synthesis of lignans.

    Recent progress of membrane materials for mono-/di-valent ions separation
    HUANG Qingbo, LIU Gongping, JIN Wanqin
    2021, 72(1):  334-350.  doi:10.11949/0438-1157.20200920
    Abstract ( 693 )   HTML ( 22)   PDF (7077KB) ( 304 )  
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    Mono-/di-valent ion separation membranes play an important role in energy storage and conversion, pollution monitoring and control, and clean industrial processes. This article aims to review the research progress of materials for mono-/di-valent ions separation membranes in recent years. It focused on the current status of polymeric membranes, mixed-matrix membranes and novel membranes such as metal-organic frameworks and two-dimensional-materials for mono-/di-valent ions separation; the effect of fabrication methods such as interfacial polymerization, layer-by-layer, deposition and blending on the membrane structures and separation performance; the main challenges and future research directions of mono-/di-valent ions separation membranes.

    Metabolic engineering of Yarrowia lipolytica to produce fatty acids and their derivatives
    WANG Kaifeng, WANG Jinpeng, WEI Ping, JI Xiaojun
    2021, 72(1):  351-365.  doi:10.11949/0438-1157.20201043
    Abstract ( 872 )   HTML ( 24)   PDF (2186KB) ( 570 )  
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    Microbial-derived fatty acids and their derivatives are widely used in the fields of energy, materials and nutritional chemicals, and can be used to produce aviation fuels, polymers, plasticizers, lubricants and food additives. Yarrowia lipolytica is one of the well-studied oleaginous yeasts, which has the potential of producing various fatty acids and their derivatives. In this paper, the development of genetic manipulation tools of Yarrowia lipolytica is firstly summarized, and the progress of engineering Yarrowia lipolytica to produce fatty acids and their derivatives using the metabolic engineering and the emerging synthetic biology tools is then reviewed. Finally, the trends of constructing Yarrowia lipolytica cell factory to produce these products are prospected.

    Research progress of low-dimensional nanoconfined ionic liquids
    WANG Chenlu, WANG Yanlei, ZHAO Qiu, LYU Yumiao, HUO Feng, HE Hongyan
    2021, 72(1):  366-383.  doi:10.11949/0438-1157.20201146
    Abstract ( 628 )   HTML ( 10)   PDF (3676KB) ( 586 )  
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    When ionic liquids are confined in low-dimensional (LD) nano-spaces, the thermal motion of molecules will be greatly limited, resulting in significant differences in the structures and properties compared with three-dimensional bulk ionic liquids. At the same time, the external conditions such as electric fields, magnetic fields and temperatures, as well as factors like the size of the confined nano-space, the physicochemical properties and geometric morphology of the confined surface could also greatly affect the structures and physicochemical properties of LD nanoconfined ionic liquids. In this paper, based on the latest research progress of LD nanoconfined ionic liquids, the experimental and theoretical methods suitable for LD nanoconfined ionic liquids systems are introduced. The dynamic regulation mechanism of LD nano-spaces on the structures and hydrogen bonding networks of confined ionic liquids is also summarized. Moreover, the thermodynamic properties, physicochemical properties and structural phase transition of different LD nanoconfined ionic liquids systems are discussed. Furthermore, the applications of LD nanoconfined ionic liquids systems in gas separation, confined catalysis and energy storage of supercapacitors are combed. Finally, the prospects and challenges of LD nanoconfined ionic liquids are discussed.

    Progress of metal macrocyclic compound-based oxygen reduction electrocatalysts
    GUO Jianing, XIANG Zhonghua
    2021, 72(1):  384-397.  doi:10.11949/0438-1157.20201256
    Abstract ( 323 )   HTML ( 11)   PDF (2568KB) ( 312 )  
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    As a key reaction of the fuel cell, the oxygen reduction reaction (ORR) on the cathode electrode has slow reaction kinetics, and a large amount of expensive platinum-based electrocatalysts are needed to improve the reaction kinetics. However, the high price, scarcity and poor durability of platinum seriously hinder the widespread application of fuel cell system in practice. Therefore, developing low cost and high activity non-precious metal oxygen reduction reaction catalysts is one of the key ways to realize the commercial application of fuel cells. Macrocyclic compound-based catalysts are considered as potential substitutes for platinum-based materials due to their unique coordination structure and highly conjugated chemical properties. Here, we summarize the development and research achievements of metal macrocyclic compound-based oxygen reduction catalysts in recent years, emphatically discuss the design and preparation of metal macrocyclic compound-based oxygen reduction catalysts, and outline the challenges and future development direction of metal macrocyclic compound-based oxygen reduction catalysts.

    Latest development of ultrathin two-dimensional materials for photocatalytic and electrocatalytic CO2 reduction
    REN Jing, TAN Ling, ZHAO Yufei, SONG Yufei
    2021, 72(1):  398-424.  doi:10.11949/0438-1157.20201297
    Abstract ( 575 )   HTML ( 21)   PDF (9325KB) ( 260 )  
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    Energy shortage and environmental pollution are huge challenges for all mankind. The over-dependence on fossil fuels has led to a sharp increase in CO2 emissions. How to transform excessive greenhouse gases into fuels or other high-value chemicals through clean means has become a global research topic. Over the past few decades, solar and electrochemical approaches to reducing carbon dioxide have proved to be as both clean and effective methods to reduce the global carbon footprint and realize the efficient utilization of fossil resources. In recent years, the excellent performance of ultrathin two-dimensional materials (such as hydrotalcite, oxide, perovskite, etc.) in the field of catalysis has attracted a lot of attention. The electronic structure of two-dimensional materials is more adjustable and can be modified on its surface, which provides more opportunities for them to play a role in more catalytic reactions. This article summarizes the frontier progress of ultra-thin two-dimensional related materials in photocatalysis, photothermal/photovoltaic/photovoltaic-electrocatalysis, and electrocatalytic reduction of CO2 in recent years, and summarizes their modulation rules, which will provide reference for the design of high-efficiency optical and electrocatalysts in the future.

    Progress in academic and application researches on polyoxymethylene dimethyl ethers
    WEI Ran, ZHENG Yanyan, LIU Fang, WANG Tiefeng
    2021, 72(1):  425-439.  doi:10.11949/0438-1157.20201189
    Abstract ( 928 )   HTML ( 14)   PDF (1693KB) ( 469 )  
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    Polymethoxy dimethyl ether (PODEn) has the characteristics of high cetane number, high oxygen content, good volatility, no sulfur and aromatic hydrocarbons, and is considered to be the most promising diesel blending component. When blended with diesel or wide distillation fuel, PODEn can improve engine efficiency and reduce soot emission, contributing to environmental protection and energy conservation. PODEn are derived from coal or biomass, which conforms to the characteristics of energy structure in China. The development of PODEn industry has been a new branch of coal chemical industry in China. The synthesis and application of PODEnhave been widely studied in recent years due to its characteristics mentioned above. This paper reviews the synthesis and application of PODEn. The reaction kinetics, mechanism and product distribution of PODEn synthesis are discussed in detail, followed by an introduction to the industrialization status of PODEn. The above studies provide guidance for further research on PODEn.

    Review on synthesis of polyether-co-polyester from copolymerization of epoxides and lactones
    GAO Hongjuan,REN Weimin
    2021, 72(1):  440-451.  doi:10.11949/0438-1157.20200944
    Abstract ( 486 )   HTML ( 10)   PDF (1093KB) ( 238 )  
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    As a high-performance, multi-purpose biodegradable material, aliphatic polyester is considered to be one of the attractive alternatives to petroleum-based polymers. However, they often suffer from drawbacks, such as hydrophobicity and brittleness due to their single structure nature, which limits its application in biomedical and pharmaceutical industries. Thus, the modification of polyester is of great theoretical significance and practical application, of which one efficient way is to incorporate the aliphatic polyethers segments into the main chain of polyesters. Herein, this review aims to describe the synthesis of polyester-polyether copolymers by the copolymerization of lactones and epoxides, including random, block, and alternating copolymers.

    Research progress on micro-scale internal liquid-liquid mass transfer and reaction process enhancement
    LI Guangxiao,LIU Sai'er,SU Yuanhai
    2021, 72(1):  452-467.  doi:10.11949/0438-1157.20201114
    Abstract ( 644 )   HTML ( 23)   PDF (12910KB) ( 314 )  
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    Micro-chemical technology has been widely used as an efficient process intensification technology. This paper starts with the coupling mechanism among hydrodynamics, transport and reaction, and reviews the latest progress and development of research on characteristics of hydrodynamics and mass transfer for liquid-liquid systems at microscale, various types of microreactors with mass transfer process intensification, its evaluation criteria, and relevant applications on synthesis of chemicalsand materials. Finally, future development of microchemical technology regarding liquid-liquid two-phase systems is envisaged.

    Design and construction of exoelectrogens by synthetic biology
    ZHAO Zhenyao, ZHANG Baocai, LI Feng, SONG Hao
    2021, 72(1):  468-482.  doi:10.11949/0438-1157.20201100
    Abstract ( 453 )   HTML ( 10)   PDF (2495KB) ( 346 )  
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    Bioelectrocatalysis systems are widely used in a wide range of applications. However, industrial applications of exoelectrogens remain elusive because of narrow available substrate spectrum, weak of ingested and metabolic intensity, poor capacity of intracellular electron, low regeneration efficiency of electron, and small electron flux. This review summarizes the mechanisms of intracellular electron generation and extracellular electron transfer of exoelectrogens based on the metabolic and electron transfer pathway of conversing chemical energy to electrical energy, and then systematically reviews the recent research on enhancing substrate intake, strengthening intracellular electron generation and accelerating extracellular electron transform in exoelectrogens with synthetic biology strategy in last five year. And the future design and construction of high-efficiency electricity-producing cells are prospected.

    Advancement in two-phase flow of annular centrifugal extractor
    YANG Xiaoyong, DAI Jian, WANG Bingjie, YAN Shenglin, YANG Hang, BAI Zhishan, PENG Chong
    2021, 72(1):  483-494.  doi:10.11949/0438-1157.20201126
    Abstract ( 657 )   HTML ( 7)   PDF (3834KB) ( 186 )  
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    The annular centrifugal extractor(ACE) is a high-performance extraction equipment that integrates liquid-liquid mixing and liquid-liquid separation. It is widely used in nuclear industry, chemical environmental protection, non-ferrous metallurgy, biomedicine and other fields. The excellent hydraulics and mass transfer characteristics of the ACE are due to its internal flow characteristics, including Taylor vortex flow in the annulus region and centrifugal flow in the rotor. According to the structure and flow characteristics in the annular centrifugal extractor, the advances in the gas-liquid interface, bubble flow, liquid-liquid flow pattern and droplet flow in the annular, as well as the gas-liquid interface in the rotor were summarized, respectively. Also, the influences of structure optimization, such as helical baffles of annular, curved radial vane of rotor etc., on flow characteristics, mixing or separation performance were summarized. In the future, the mechanism of dispersion and coalescence of droplets in the process of centrifugal extraction, the three-phase flow test and simulation, and the design method of modeling would be the emphasis of ACE research.

    Research advances on nickel extraction technology from nickel sulfide ore
    RAO Fu, MA En, ZHENG Xiaohong, ZHANG Xihua, LYU Weiguang, YAO Peifan, SUN Zhi
    2021, 72(1):  495-507.  doi:10.11949/0438-1157.20201091
    Abstract ( 630 )   HTML ( 13)   PDF (2265KB) ( 707 )  
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    As a strategic metal, nickel is widely used in many industrial fields such as stainless steel, special metal alloys, and rechargeable batteries. Recently, with rapid development of new energy vehicles and ever-obviously tendency of “cobalt-free nickel-rich” in cathode materials for lithium-ion batteries, the demand for nickel is more and more increasing. However, the external dependence of nickel in China is as high as 86%, which deteriorated the supply-demand of nickel. Faced by the bottlenecks including difficulty of mining and enrichment of nickel sulfide ores, lower recycling rate, and higher environmental risk existed in the traditional smelting methods of nickel, this research systematically reviewed the research advances on nickel extraction from nickel sulfide ores globally based on the analysis of mineralogical properties. Finally, considering recycling rate of nickel, chemicals and energy consumption, and environmental risks, suggestions on further research and development of nickel extraction technologies are put forwarded. In addition, the development tendency for nickel extraction technologies from nickel sulfide ores is discussed.

    Thermodynamics
    Nonequilibrium thermodynamic modeling and prediction of the effect of polymer excipients on aspirin crystallization kinetics
    JI Yuanhui, CHEN Qiao, WENG Jingyun
    2021, 72(1):  508-520.  doi:10.11949/0438-1157.20201192
    Abstract ( 419 )   HTML ( 9)   PDF (1812KB) ( 150 )  
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    Exploring the mechanism of the influence of polymer excipients on the crystallization of insoluble drugs is the key to guide the design of amorphous solid dispersion formulations and the selection of excipients in the preparation. The effects of different factors (temperature, stirring rate, polymer concentration, molecular weight and polymer type) on the growth kinetics of aspirin crystal were studied. Firstly, the chemical potential gradient model based on three different crystal growth mechanisms and the UNIQUAC activity coefficient model were used to describe and predict the crystallization kinetics of aspirin under different conditions. The effects of different factors on the growth constant kt and crystallization driving force ?μ of aspirin were studied. The results showed that the crystal growth rate of aspirin decreased with the increase of crystallization temperature and polymer concentration, but increased with the increase of stirring rate. Polyvinylpyrrolidone (PVP K25) and hydroxypropyl methyl cellulose (HPMC E3) significantly inhibited the crystal growth of aspirin. The crystal growth of aspirin in HPMC E3 aqueous solution belongs to two-dimensional nucleation mechanism, while the crystal growth in pure water and PEGs aqueous solution belongs to adhesion growth mechanism. The chemical potential gradient model used in this paper can well predict the crystallization kinetics of aspirin at different temperatures and stirring speeds, which can effectively reduce the manpower, material and financial resources required for the experiment. This study can provide theoretical basis for the selection of polymers in the preparation of solid dispersions.

    Fluid dynamics and transport phenomena
    Simulation of scale-up effect of particle residence time distribution characteristics in continuously operated dense-phase fluidized beds
    LAN Bin, XU Ji, LIU Zhicheng, WANG Junwu
    2021, 72(1):  521-533.  doi:10.11949/0438-1157.20201004
    Abstract ( 515 )   HTML ( 6)   PDF (1147KB) ( 322 )  
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    Scale-up of fluidized bed is a great challenge in chemical engineering. In order to explore the particle flow behavior and residence time distribution characteristics of the continuously operated polydisperse fluidized bed during the scale-up process, a large-scale parallel GPU-based coarse-grained CFD-DEM method coupled with a polydisperse and non-spherical particle drag model was used. Long-term particle residence time simulations were carried out in a continuously operated three-dimensional fluidized bed. Through the simulation of fluidized beds of different sizes (lengths), it is found that the mean residence time (MRT) of particles of different sizes has a linear relationship with the length of the fluidized bed. This relationship can be used to predict the particle MRT of larger fluidized beds. As the length of the fluidized bed increases, the difference in MRT of particles with different sizes becomes larger, indicating that the increase in the length of the fluidized bed has a certain ability to regulate the residence time of particles with different sizes.

    Catalysis, kinetics and reactors
    Preparation of NiZnCe composite oxide and its catalytic performance for dehydrogenation of n-butane
    WANG Lian, WAN Chao, CHENG Dangguo, CHEN Fengqiu, ZHAN Xiaoli
    2021, 72(1):  534-542.  doi:10.11949/0438-1157.20201041
    Abstract ( 328 )   HTML ( 5)   PDF (1552KB) ( 153 )  
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    The nickel zinc cerium (NiZnCe) composite oxide catalyst was prepared by the sol-gel method, and the effects of Zn and Ce content in the NiZnCe composite oxide catalyst on the performance of n-butane oxidative dehydrogenation were investigated. The research results showed that the conversion rate and olefin selectivity of NiZn0.5Ce0.3 catalyst were higher. A series of characterization methods, such as H2-TPR, XPS and TPRO, were used to reveal the influence of different steps of the oxygen movement cycle in the catalyst on the performance of the catalyst. The results showed that the introduction of Ce element had a greater impact on the oxygen mobility of the catalyst, and the catalyst performance was positively correlated with the oxygen capacity (the amount of oxygen in the catalyst participating in the reaction). In addition, the interaction between Ni and Ce led to an increase in the cation valence and acceptable electron capacity of Ni. Active Ni became easier to adsorb active oxygen species, and the cyclic reciprocating reaction between metal and oxygen was more active.

    Study of solvent effect on the dissolution, size, structure and catalytic hydrogenation of nitrile butadiene rubber
    GE Bingqing, YIN Yixuan, WANG Yaxi, ZHANG Hongwei, YUAN Pei
    2021, 72(1):  543-554.  doi:10.11949/0438-1157.20201045
    Abstract ( 1182 )   HTML ( 29)   PDF (3523KB) ( 641 )  
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    Nitrile butadiene rubber (NBR) is an important synthetic rubber made by copolymerization of butadiene and acrylonitrile. The hydrogenated nitrile rubber (HNBR), made by selective hydrogenation of NBR, not only maintains the original oil resistance and wear resistance, but also greatly improves its weather resistance and ozone resistance properties, which is widely used in weapon parts, aerospace seals and other fields. It is a key hot topic for the chemical modification of unsaturated polymers. In this paper, we systematically investigated the influence of solvent properties on the dissolution behavior, size distribution molecular structure of NBR and catalytic performance in solvent by using nanometer particle size analyzer, ubbelohde viscometer and Fourier transform infrared spectroscopy combined with density functional theory (DFT). The results show that strong electrophilic solvents cannot dissolve NBR, but electron donating solvents and some weak electrophilic solvents can dissolve NBR well. Especially in ketone solvents, NBR has small particle size with narrow distribution. DFT calculations reveal that compared with the gas atmosphere, the bond lengths of CC double bonds in NBR segment has increased in all solvents, and show an increasing trend as the polarity of the solvent increases. The dipole moment of NBR also increases with the increase of solvent polarity. Especially in ketone solvents, the highest occupied molecular orbital (HOMO) of NBR molecule moves from the edge to the inside of the molecule under the strong solvent effect, indicating that it may have a positive influence on the CC double bond inside the chain segment. The hydrogenation results show that the hydrogenation activity of NBR in the electron donating solvents is higher than that in weak electrophilic solvents, but no matter which solvent is selected, the hydrogenation selectivity to CC double bonds of NBR is 100%. This study provides a theoretical basis for the selection of solvents in the NBR heterogeneous solution hydrogenation system.

    Separation engineering
    Fine adjustment of elliptical windows of ZIFs and performances of adsorptive separation of furfural/5-hydroxymethylfurfural
    ZHAO Yu, SHI Qi, DONG Jinxiang
    2021, 72(1):  555-568.  doi:10.11949/0438-1157.20201071
    Abstract ( 359 )   HTML ( 6)   PDF (2891KB) ( 109 )  
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    In the process of refining furan compounds through biomass catalysis, a mixture of low concentration furfural (Fur) and 5-hydroxymethylfurfural (5-HMF) aqueous solution is usually obtained. Based on the fact that both Fur and 5-HMF are elliptical molecules, the sieving separation of Fur and 5-HMF can be achieved by designing and adjusting the elliptical windows of the adsorbents. In this paper, we used divalent cobalt salts and three imidazole ligands with gradually increasing alkyl substituent groups (2-ethylimidazole/2-eIm, 2-propylimidazole/2-pIm and 2-butylimidazole/2-bIm) to synthesize three ANA topology ZIFs materials with gradually decreasing elliptical windows: ANA-[Co(eIm)2], ANA-[Co(pIm)2] and ANA-[Co(bIm)2]. Firstly, the crystal structures of these three ZIFs were analyzed, and basic characterizations such as PXRD, water vapor adsorption, N2 adsorption and desorption, and SEM were performed, and then batch adsorption and dynamic column adsorption were used to study the adsorptive separation performance of the three materials for Fur and 5-HMF. The results of batch adsorption, single-component dynamic column adsorption and general rate model simulation calculations show that: narrow and elliptical window of ANA-[Co(pIm)2] is close to the Fur molecular size, but smaller than 5-HMF, so that Fur molecular can be adsorbed into the elliptical windows, while 5-HMF molecular is hardly adsorbed and cannot pass through. Furthermore, the adsorption capacity of ANA-[Co(pIm)2] for Fur in the binary-component Fur/5-HMF (5%/5%,mass ratio) dynamic column adsorption is 91.7 mg·g-1, and 5-HMF is not adsorbed. Therefore, by changing the imidazole ligand substituent groups, the size of the elliptical windows of ZIFs was finely adjusted, and the steric hindrance effect of the elliptical windows of ZIFs was used to achieve the sieve separation of Fur and 5-HMF.

    Preparation and stability study of TMCS modified MFI zeolite for ethanol/water separation
    PENG Li, WU Zhengqi, WANG Boxuan, WANG Xing, GU Xuehong
    2021, 72(1):  569-577.  doi:10.11949/0438-1157.20201083
    Abstract ( 497 )   HTML ( 8)   PDF (3214KB) ( 144 )  
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    Trimethylchlorosilane (TMCS) was used as the modification source to modify the surface of MFI zeolite membranes. The effect of TMCS concentration and modification time on the performance of MFI zeolite membranes in the separation of ethanol/water mixtures was systematically investigated. Biofuel ethanol is a kind of renewable fuel resource with the characteristics of low carbon and sulfur-free. Pervaporation is considered as a most promising energy-efficient process for ethanol extraction from the fermentation broth containing dilute alcohol. Pure-silica MFI zeolite membrane, also called silicalite-1 membrane, possesses uniform pore size of 0.55 nm and desirable hydrophobicity with the potential to achieve large flux and high separation factor for ethanol over water. However, the significant performance degradation of MFI zeolite membranes in ethanol/water mixture separation is an obstacle to industrial their application. Based on the literature investigation and our previous work, we found that the stability of membrane during pervaporation was affected by the silicon defects in MFI zeolite membranes formed under alkaline synthetic conditions. Herein, we present the Si—OH eliminated MFI membranes by a simple Trimethylchlorosilane (TMCS) modification, which can effectively prevent the chemical reaction between Si—OH groups and components, endowing the long-term pervaporation stability for the ethanol/water mixture. The effects of TMCS content and modification time on the separation performances of membranes were studied, and the obtained membranes were characterized by SEM, XRD,29Si NMR, FT-IR and contact angle measurement. The results show that the surface Si—OH groups can be effectively reduced after the modification, and obtained membranes showed improved hydrophobicity and separation stability. With the increase of silane content and modification time, the obtained MFI zeolite membranes showed decreased initial pervaporation performance but better stability. The zeolite membrane prepared with TMCS content of 0.4%(mass) and the reaction time of 2 h had the best separation performance and also showed a long-term stability for the separation of 5%(mass) ethanol/water mixture at 60℃. During the 90 h pervaporation process, the permeation flux slightly decreased from 1.83 kg·m-2·h-1 to 1.61 kg·m-2·h-1, and the separation factor decreased from 27 to 20. For the unmodified MFI zeolite membrane, however, the permeation flux dramatically decreased from 3.46 kg·m-2·h-1 to 0.6 kg·m-2·h-1, and the separation factor decreased from 30 to 3. This study showed that, the surface organic modification can be an effective method to improve the hydrophobicity and separation stability of MFI zeolite membrane.

    Preparation of nanofiltration membrane for separation of mixed monovalent salts
    LIU Ning, CHU Changhui, WANG Qian, SUN Shipeng
    2021, 72(1):  578-588.  doi:10.11949/0438-1157.20200955
    Abstract ( 375 )   HTML ( 5)   PDF (1782KB) ( 194 )  
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    This paper aims to develop new nanofiltration membranes that achieve high selectivity of CH3COO- and Cl-, which is difficult to separate in pigment and other wastewater. Guided by the separation mechanism between the apparent activation energy and dehydration, 3,5-diaminobenzoic acid (DMA) was utilized to adjust the pore size, surface charge and other properties of a thin film composite (TFC) nanofiltration membrane. XPS results show that DMA participates in the interfacial polymerization reaction to form a loose selective layer; Zeta potential shows that the surface of the film is negatively charged. By tuning the pH, operating pressure, and other conditions, the optimized membrane [0.6%(mass) DMA-TFC] was obtained with the water flux 44% higher than that of the unmodified composite membrane, and the separation ratio of CH3COO- and Cl- reached 15.0. This work provides a theoretical and practical basis for the design and preparation of nanofiltration membranes for similar ion separation. It shows great application prospects in the fields of water treatment such as pigment wastewater and material separation.

    Energy and environmental engineering
    Study on performance of polyethersulfone-polyvinylpyrrolidone high temperature polymer electrolyte membrane and fuel cell stack
    ZHANG Jin, GUO Zhibin, ZHANG Jujia, WANG Haining, XIANG Yan, JIANG San Ping, LU Shanfu
    2021, 72(1):  589-596.  doi:10.11949/0438-1157.20200962
    Abstract ( 513 )   HTML ( 18)   PDF (1153KB) ( 214 )  
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    High temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on phosphoric acid doped polybenzimidazole (PA/PBI) membrane express high stability and outstanding performance. However, the high price and complex fabrication procedures of PBI substantially hinder the commercial application of PBI in HT-PEMFCs. This study aims to accelerate the commercial application of polyether sulfone-polyvinyl pyrrolidone (PES-PVP) membrane in HT-PEMFCs. The achievement of PES-PVP membrane with width of 40 cm proves feasibility for scale-up production of the PES-PVP membrane. After PA doping, the membrane obtains PA uptake of 4.9 PA per repeat unit of PVP and the high proton conductivity of 85 mS·cm-1 at 180℃. In addition, the PA/PES-PVP membrane fuel cell with active area of 165 cm2 shows power output of 0.19 W·cm-2@0.6 V at 150℃ under H2/air atmosphere. That is comparative to the power output of commercial PA/PBI membrane fuel cells under the same test conditions. Furthermore, the fuel cell shows exceptional durability up to 3000 h under 150℃. In addition, the fuel cell stack containing 3 cells with active area of 200 cm2 shows outstanding stability during start-up/shut down cycles, while the fuel cell stack with 20 cells shows peak power output of 1.15 kW under the same test conditions. Overall, the PA/PES-PVP composite membranes with low cost show excellent performance in HT-PEMFCs, which have promising application for the commercialization of domestic HT-PEMFCs. This research work provides a research foundation for the localization of key materials and stacks for high-temperature polymer electrolyte membrane fuel cells.

    Material science and engineering, nanotechnology
    Fabrication of serum albumin-copper phthalocyanine nanoparticles for mitochondria-targeted phototherapy
    YU Fuqiang, DU Jianjun, LU Yang, MA He, FAN Jiangli, SUN Wen, LONG Saran, PENG Xiaojun
    2021, 72(1):  597-608.  doi:10.11949/0438-1157.20201078
    Abstract ( 419 )   HTML ( 12)   PDF (4701KB) ( 249 )  
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    Copper phthalocyanine is a kind of dye with excellent photophysical properties and good photothermal stability, and it has a wide range of applications in the fields of printing and dyeing, solar cells, sensors and so on. Serum albumin, as the main transport protein in the blood, is often used for loading and transporting small molecules and drugs. In this work, LGS-CuPC-BSA nanoparticles (NPs) were constructed by self-assemble of bovine serum albumin (BSA) and copper phthalocyanine dyes (LGS-CuPc), which works as an integrated reagent for photodynamic and photothermal therapy. Under illumination at 671 nm (800 mW·cm-2), the reactive oxygen species yield of LGS-CuPc-BSA NPs reached 23.3%, and the photothermal conversion efficiency was 36.8%. Compared with LGS-CuPc, LGS-CuPc-BSA nanoparticles showed low cytotoxicity, good biocompatibility and mitochondrial localization in tumor cells. LGS-CuPc-BSA nanoparticles significantly promoted cell apoptosis in vitro, realizing the combination therapy of photothermal and photodynamic therapy.

    Synthesis and performance improvement mechanism of high-efficiency B doped LiNi0.5Co0.2Mn0.3O2 cathode materials for Li-ion batteries
    ZHU Huawei, YU Haifeng, JIANG Qianqian, YANG Zhaofeng, JIANG Hao, LI Chunzhong
    2021, 72(1):  609-618.  doi:10.11949/0438-1157.20200836
    Abstract ( 486 )   HTML ( 18)   PDF (6964KB) ( 168 )  
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    High-efficiency doping of strong-bonding energy heteroatoms is an effective strategy to stabilize high-voltage LiNi0.5Co0.2Mn0.3O2 (NCM) ternary cathode materials and improve their electrochemical performance. Herein, a strategy with boron-containing precursor surface enrichment and diffusion-reinforcement by high-temperature calcination is proposed to construct high-efficiency B-doped LiNi0.5Co0.2Mn0.3O2 cathode material (NCM-B). The high B—O bond energy (809 kJ·mol-1) greatly inhibits the evolution of oxygen atoms, hence steadying the oxygen ion framework. Moreover, the LiO2-B2O3 coating layer with high Li+ conductivity can stabilize the electrode-electrolyte interface. Compared with pure NCM, the NCM-B exhibits a high reversible capacity of 193.7 mA·h·g-1 within 3.0—4.5 V and delivers a superior high-rate performance of 120 mA·h·g-1 at 10 C (only 78.2 mA·h·g-1 for NCM). Furthermore, the capacity retention after 100 cycles at 1 C can be improved from 73% to 90%. The present surface-enrichment and diffusion-reinforcement strategy is expected to realize high-efficiency doping of other cathode materials.

    One-step fabrication of biocompatible oil-core microcapsules with controlled release
    SHI Pan, YAN Xiaoxiao, WANG Xingzheng, FENG Leyun, CHEN Dong
    2021, 72(1):  619-627.  doi:10.11949/0438-1157.20201000
    Abstract ( 420 )   HTML ( 11)   PDF (4194KB) ( 205 )  
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    One-step controlled preparation of biocompatible oil-core microcapsules is of great significance for the industrial fabrication of microcapsules and their applications. In this paper, biocompatible oil-core microcapsules with uniform and controllable size are successfully prepared via a one-step method using microfluidic devices. This method uses concentrically-aligned glass capillaries to prepare microfluidic devices. The inner oil phase is sheared into oil droplets by the outer hydrogel phase, which is then pulled off the orifice of the microfluidic device by gravity, forming oil-core microcapsules. The shells of the microcapsules are then cross-linked to form a stable hierarchical structure. The influences of microfluidic device design, inner phase and outer phase flow rates on the number of oil cores, microcapsules diameter and shell thickness are systematically investigated. As an ideal carrier for active substances, biocompatible oil-core microcapsules can achieve rapid release triggered by pH changes and slow release of wall thickness adjustment, laying the foundation for their practical applications.