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Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Research progress in modification of layered oxide cathode materials for sodium-ion batteries Miaomiao LI Xiangyun QIU Yanxin YIN Tao ZHANG Zuoqiang DAI The Chinese Journal of Process Engineering    2023, 23 (6): 799-813.   DOI: 10.12034/j.issn.1009-606X.222296 Abstract （359）   HTML （91）    PDF （47402KB）（360）       Knowledge map    Save Sodium-ion batteries (SIBs) have been regarded as the major candidate technologies for large-scale energy storage applications due to the rich abundance of Na sources, low cost and safety. And the development of cathode materials also determines the final performances and commercialization. Layered oxide cathode materials have the advantages of high specific capacity, simple structure and good stability. It is one of the most promising sodium cathode materials at present. However, such materials are still faced with irreversible changes in the electrochemical process, unstable storage in air and poor interface stability, which seriously restricts the development of commercialization of SIBs. In order to solve these problems of materials, researchers modified and optimized them. Accordingly, the modification measures of ion doping, surface coating, nanostructure design and P/O mixing and other related modification measures of sodium electric layered oxide cathode materials, which provides a basis for the modification research of sodium electric layered oxide cathode materials are reviewed in this review. Besides, the future development trend of layered oxides is prospected. Related Articles | Metrics Select Research progress on liquid bridge fracture in field of micro-nano technology Zhaofei ZHU Yalong CHU Xianming GAO The Chinese Journal of Process Engineering    2023, 23 (6): 814-825.   DOI: 10.12034/j.issn.1009-606X.222287 Abstract （216）   HTML （10）    PDF （4290KB）（183）       Knowledge map    Save Affected by the scale effect, the morphological characteristics of liquid bridges at the microscale determine the changes in liquid bridge forces that are area-related. Liquid bridge forces have an important impact on the formation and fracture of liquid bridges. The liquid bridge fracture mechanism based on liquid bridge morphology is the theoretical basis of biology, chemistry, materials, micro-nano technology, and many other research fields. At present, the study of liquid bridge fracture is an interdisciplinary discipline involving mathematics, fluid mechanics, interface chemistry, materials science, and other disciplines, however there is few review of the research progress focusing on liquid bridge fracture based on liquid bridge morphology. This review mainly summarizes the fracture theoretical models and experimental methods of axisymmetric liquid bridges, non-axisymmetric liquid bridges, and non-Newtonian liquid bridges. It mainly introduces the weak nonlinear behavior of the fluid generated during the tensile and rupture of the liquid bridge under equilibrium or steady state caused by the forced hydraulic bridge. The influences of key factors such as liquid volume, viscosity, surface tension, wettability, roughness of the solid surface, fracture speed, and liquid bridge morphology on the fracture location or liquid distribution rate of the liquid bridge are systematically described. The experimental methods for quantitatively studying the use of different key parameters affecting liquid bridge fracture are analyzed. The structural characteristics of different experimental apparatus and their advantages and disadvantages are compared and discussed. Furthermore, the innovative and high-value research direction of the research is summarized and proposed, which may be used in future research. Finally, the research frontier trends of liquid bridge fracture in the field of micro-nano technology prospected, and it is pointed out that the future research focused on issues including a more comprehensive hydraulic bridge fracture model, the fracture mechanism, and multi-parameter control method of the liquid bridge. Related Articles | Metrics Select Research progress of core monomer separation and purification technology for bio-based materials Kun WANG Xiuling JI Kun LIN Yuhong HUANG The Chinese Journal of Process Engineering    2023, 23 (8): 1137-1149.   DOI: 10.12034/j.issn.1009-606X.222314 Abstract （201）   HTML （8）    PDF （2738KB）（113）       Knowledge map    Save The production of petrochemical-based materials consumes large amounts of non-renewable resources and cause a certain degree of pollution to the environment. The performance of bio-based materials produced by renewable resources can be comparable to that of petrochemical based materials, which is in line with the development concept of green, low-carbon and environmental protection, and provides strong technical support for the realization of the goal of carbon peaking and carbon neutrality. In recent years, with the domestic and international policies tilted to the bio-based materials industry, bio-based materials have become a new material for domestic and international development, providing a good opportunity for the development of bio-based materials industry. The core monomer of bio-based materials produced by biological method has the advantages of mild production conditions, low price, and green environmental protection. But the complex composition within the fermentation broth as well as the low concentration of monomers and the difficulty of separation have seriously restricted the development of the whole industry of bio-based materials. The production of bio-based materials requires high-purity monomers, and a small amount of impurities affect the appearance and performance of bio-based materials. The existing research and application of separation of core monomers of bio-based materials has developed the process of obtaining high purity separation and purification of core monomers of bio-based materials by taking full advantage of chemical separation technology. This review briefly introduces the current status of the production of bio-based materials, reviews the research progress of several widely used separation and purification technologies for core monomers of bio-based materials in recent years, analyzes the advantages and disadvantages of current separation technologies. Finally providing an outlook on the development trend of separation and purification technologies for core monomers of bio-based materials. Related Articles | Metrics Select Research progress on desulfurization technology for blast furnace gas Xindong WANG Tingyu ZHU Yuran LI The Chinese Journal of Process Engineering    2023, 23 (7): 1003-1012.   DOI: 10.12034/j.issn.1009-606X.222334 Abstract （190）   HTML （8）    PDF （1011KB）（122）       Knowledge map    Save The desulfurization technology for blast furnace gas as a source of emission reduction technology is of great significance to promoting ultra-low emission for the whole process in the iron-steel industry. The sulfur-containing components in the blast furnace gas are mainly organic sulfur, coexisting with other complex components. This work discusses the emission limits of sulfur-containing components in various occurrence forms (SO2, H2S, and S), and analyzes their transformation relationship through the mass balance of sulfur. The bottleneck of desulfurization technology for blast furnace gas is to remove the carbonyl sulfur (COS). The aluminum-based catalyst and carbon-based catalyst used for COS catalytic hydrolysis are analyzed in detail, in which γ-Al2O3 is both a carrier and an active component, and activated carbon has the functions of catalyst and adsorbent. The effect mechanism of the complex components O2, and Cl- on the deactivation of hydrolysis catalyst is further elucidated due to the formation of deposition products. For the gaseous H2S formed after the COS hydrolysis, the two kinds of wet removal technology, mainly including the chemical absorption method and catalytic oxidation method, are compared in the reaction mechanism, desulfurizer and product. The difference among the zinc oxide, iron oxide, and activated carbon adsorbent used in the dry removal technology is also concretely elaborated in the reaction mechanism, sulfur capacity, and temperature adaptability. In view of the integrated adsorption of organic sulfur and inorganic sulfur, molecular sieve adsorbent is briefly described in the selective adsorption principle and regeneration process. The "hydrolysis+wet", "hydrolysis+dry", and integrated removal processes have been explored and applied currently, which are preliminarily evaluated. Finally, it is pointed out that the research and development of desulfurization technology focus on how to improve the activity of the hydrolysis catalyst and reduce the influence of complex components in blast furnace gas on catalyst activity and improve the applicability of the technology. Related Articles | Metrics Select Research progress in the preparation of porous biomass carbon materials and their applications in supercapacitors Xuemin ZHANG Guanyu HE Shaoqi YIN Tingting HUANG Jinping LI Jian ZHENG The Chinese Journal of Process Engineering    2024, 24 (2): 127-138.   DOI: 10.12034/j.issn.1009-606X.223036 Abstract （182）   HTML （14）    PDF （1013KB）（112）       Knowledge map    Save The biomass carbon material is a kind of green and renewable energy material. Its efficient utilization is of great significance for the sustainable development of the energy environment and the green and low-carbon transition of energy. Biomass carbon materials are widely used in energy storage and conversion, catalysis, adsorption, and many other fields due to their porous nature, abundant functional groups, large specific surface area, excellent electrochemical performance, low cost, and renewable. However, the properties of biomass carbon materials are not only closely related to the microstructure, but also the heteroatom doping has an important impact on the structure and electrochemical properties of biomass carbon materials. The accurate structure regulation of biomass carbon materials is an effective way to improve their electrochemical performance. In this work, the preparation methods of biomass carbon materials and their applications in supercapacitors are comprehensively reviewed, and the relationship between the structure and properties of porous carbon materials is discussed. On this basis, the influence mechanism and rules of different conditions, and different preparation processes (such as material selection, material treatment, and activation mode) on the structure characteristics of biomass carbon materials are analyzed. In this review, the mechanism and rules of the influence of the structure characteristics on the electrochemical properties of porous biomass carbon materials are described in detail, and the preparation process and performance regulation of porous biomass carbon materials need to be perfected and improved. Finally, the main development directions of preparation technology and electrochemical properties of porous biomass carbon materials in the future are pointed out. Related Articles | Metrics Select Research progress of lithium polysulfide capture in lithium-sulfur batteries Tingting HU Haijian LIU Yunyi CHEN Lingli LIU Chun'ai DAI Yongsheng HAN The Chinese Journal of Process Engineering    2023, 23 (9): 1231-1243.   DOI: 10.12034/j.issn.1009-606X.222413 Abstract （177）   HTML （17）    PDF （6063KB）（179）       Knowledge map    Save Lithium-sulfur battery has an ultra-high theoretical specific capacity (1675 mAh/g) and theoretical specific energy (2600 Wh/kg), which is far higher than commercial secondary batteries. In addition, the sulfur element is rich in the earth, and its price is cheap, the extraction process is environmentally friendly. Therefore, a lithium-sulfur battery is considered as an ideal energy storage unit for the future energy storage system. However, the lithium polysulfide intermediates generated in the charging and discharging process are easily soluble in the electrolyte, resulting in a loss of active materials and an increase in the electrolyte viscosity. In addition, the dissolved lithium polysulfide is inclined to migrate between positive and negative electrodes, and reacts with the lithium negative electrode, causing irreversible loss of active substance sulfur, greatly reducing the battery life and safety. This phenomenon is called the shuttle effect, which hinders the commercialization process of lithium-sulfur batteries. In recent years, researchers have attempted to solve this problem through physical adsorption, chemical action, and external field constraint, and achieved impressive progress. This work summarizes the research progress of capturing lithium polysulfide, and compares the characteristics of each approach and its impact on the electrochemical performance of lithium-sulfur batteries. Whether it is the physical constraint of the porous structure of carbon materials, the chemical interaction between the carrier materials and lithium polysulfide, or the adsorption of electric and magnetic fields on lithium polysulfide, lithium polysulfide is fixed on the positive side and to inhibit its dissolution and diffusion to the negative electrode. Capturing lithium polysulfide by external magnetic field, internal magnetic field induced by magnetic particles, and internal electric field generated by spontaneous polarization of ferroelectric materials is also highlighted. Finally, the challenges in capturing lithium polysulfide and the possible solution are prospected. Related Articles | Metrics Select Key technologies and advances of positron emission particle tracking Kun LI Liyun WU Ping CHEN Yan HAN The Chinese Journal of Process Engineering    2024, 24 (4): 381-390.   DOI: 10.12034/j.issn.1009-606X.223266 Abstract （163）   HTML （2）    PDF （2513KB）（81）       Knowledge map    Save Measuring multiphase flow parameters and the understanding of multiphase flow mechanisms are of great importance value for the design, operation, and optimization of industrial process devices. Due to the inherent multiscale nature of multiphase flow, its flow field often has great complexity, which makes our understanding of its flow process relatively limited. There are still many key issues that need to be explored in the mechanism of multiphase flow. Positron emission particle tracing (PEPT) is a new undisturbed and non-destructive imaging method for complex multiphase flows in industrial processes. γ photon detection is used to perform 3D dynamic imaging of radioactive labeled tracer particles. Due to γ photons have high penetration and are not affected by electromagnetic fields, making PEPT a unique advantage in detecting non-transparent and complex industrial multiphase flows. Currently, it is mainly used for measuring multiphase flow phenomena and extracting system physical parameters in industrial fields such as chemical, food, and pharmaceutical industries. However, the difficulties in preparing miniaturized tracer particles and the poor localization effect of multiple tracer particles at the same time seriously hinder the further application and promotion of PEPT technology. In this work, basic principles of PEPT technology are firstly briefly introduced, then the key technologies and research progress of PEPT are discussed from the aspects of tracer particles, algorithms, hardware systems and data processing in applications. The existing problems and potential development directions are pointed out. Finally, the development and application of PEPT is summarized and prospected. Related Articles | Metrics Select Research process of multivesicular liposomes Xing FAN Hua YUE Xiaojun WANG The Chinese Journal of Process Engineering    2023, 23 (10): 1371-1380.   DOI: 10.12034/j.issn.1009-606X.222431 Abstract （161）   HTML （11）    PDF （2032KB）（83）       Knowledge map    Save Since 1983, multivesicular liposomes (MVLs), as a member of the liposome family, have been of interest in the biomaterials and medical fields. MVLs have multiple aqueous compartments separated by phospholipid bilayers and an internal aqueous phase of up to 90%. They also have the advantages of reducing the number of injections, extending the duration of drug action, and improving patient compliance. So far, most of the MVLs reported in the literature are above 10 μm in size and have made good progress mainly in the encapsulation of analgesic drugs. This review provides an overview of the preparation methods, characterization methods, and drug release mechanisms of MVLs that have been reported in the literature in the last decade. There are relatively several methods for preparing MVLs, including the double emulsification method, spray atomization technique, and electroforming method. Currently, the main characterization methods used for MVLs are optical/fluorescent confocal imaging, scanning electron microscopy imaging, determination of particle size distribution, entrapment efficiency, and determination of zeta potential. Because of the large volume of the internal aqueous phase of MVLs and the high hydrophilic drug encapsulation rate of the internal vesicles, the individual vesicles gradually rupture and the hydrophilic drug gradually gets released during in vitro release, with a three-phase release pattern of sustained release. This review also summarizes the current status of clinical studies and types of commercialized products. At present, the application of MVLs regarding analgesics has reached stages II-IV, and three commercialized formulations have entered the clinic with satisfactory results. Moreover, this review summarizes the current progress in applied research, mainly in the delivery of anticancer drugs, analgesic drugs, and protein peptides. Last but not least, the challenge and prospects regarding small-sized MVLs, diverse biomedical applications, and scale-up strategies are proposed. Related Articles | Metrics Select Research progress of flotation activator for complex copper oxide minerals Haoxiang WANG Peilun SHEN Jinpeng CAI Xiaodong JIA Rong PENG Dianwen LIU The Chinese Journal of Process Engineering    2023, 23 (10): 1381-1389.   DOI: 10.12034/j.issn.1009-606X.222336 Abstract （145）   HTML （10）    PDF （5380KB）（108）       Knowledge map    Save Copper is widely used in industry because of its excellent physical and chemical properties.At present, with the depletion of copper sulfide resources, the development and utilization of copper oxide resources has gradually become the focus of research. As an important source of copper metal extraction, the key to efficient recovery of copper oxide ore is the activation process. However, the existing copper oxide resources have the characteristics of high oxidation rate, complex mineral composition and easy sludge, which makes the beneficiation more difficult. The classical sulfidization-xanthate flotation method can't meet the current requirements of complex copper oxide ore resource separation. In addition, the mechanism of activator acting on mineral surface and the unclear explanation of crystal structure of activated products restrict the development of the theory and method of copper oxide ore separation to some extent. In recent years, a variety of new activators or combination activators have been reported in reference for the complex and difficult-to-beneficiated copper oxide resources. Scholars have made a deeper research and elaboration on the activation mechanism of copper oxide ore based on the existing activation theory, and put forward a variety of effective and practical new theories and methods, which have solved the problem of complex copper oxide ore beneficiation to some extent. In this review, by combing the development of activator for copper oxide ore in recent years, the application and activation mechanism of new activator and new activation method are summarized, aiming at enriching the theoretical system of efficient flotation of copper oxide ore and providing reference for production practice. Related Articles | Metrics Select A review on current status and carbon accounting of recycling and reusing of spent power batteries Zhiying LAI Wenbin LAI Chuyuan LIN Lingjun HE Hui LIN Fuyu XIAO Qingrong QIAN Jixiang ZHANG Qinghua CHEN Lingxing ZENG The Chinese Journal of Process Engineering    2024, 24 (2): 139-150.   DOI: 10.12034/j.issn.1009-606X.223195 Abstract （120）   HTML （4）    PDF （3821KB）（71）       Knowledge map    Save The booming development of the new energy vehicle industry has ed a significant rise in the amount of end-of-life power batteries, which in turn generates a huge amount of solid waste. Reuse of retired power batteries through laddering utilization and recycling can not only realize the resourceful reuse of valuable metals but also reduce carbon emissions and production costs. As an important part of developing the circular economy and promoting the intensive use of resources, the recycling and the resource utilization of power batteries are of great significance to the implementation of the carbon peaking and carbon neutrality strategy and the promotion of the construction of ecological civilization. Currently, a substantial body of literature and information pertaining to retired batteries has been extensively disseminated across the pertinent domains. Consequently, it is imperative to consolidate the pivotal insights within the industry to furnish industry professionals with a comprehensive point of reference. Overall, based on the current situation of the industry, the main purpose of this review is to discuss the environmental and economic impacts of the different recycling and reusing methods for retired batteries from the perspectives of the recycling process. By analyzing the current situation of recycling and summarizing the progress of research, an accounting method for carbon emissions from decommissioned power batteries is proposed, and then it is pointed out the necessity and feasibility of recycling. The aim of this review is to provide new insights into building waste-free cities and achieving carbon peaking and carbon neutrality target. It is hoped that the battery recycling industry will be able to realize healthy and orderly development in the future under the macro-control of the country, combined with efficient and eco-friendly retired battery recycling technology and relevant standards and norms. Related Articles | Metrics Select Research progress on preparation of magnetic activated carbon and its application in water treatment Qianyu WANG Yuming ZHANG Yanbin CUI The Chinese Journal of Process Engineering    2024, 24 (3): 259-272.   DOI: 10.12034/j.issn.1009-606X.223228 Abstract （119）   HTML （6）    PDF （2257KB）（109）       Knowledge map    Save Activated carbon (AC) has the characteristics of high specific surface area, porosity, abundant surface functional groups and chemical stability, and these advantages make it a widely used adsorbent in water treatment. After being exhausted (saturated adsorption contaminants), the spent AC needs to be separated from aquatic systems and regenerated which is conductive to materials recycling. However, it is difficult to efficiently separate the powder AC saturated adsorption contaminants from aquatic systems by traditional separation methods (gravitational sedimentation, centrifugation, filtration, and flotation), and the disadvantages for these methods root in many aspects including time-consuming, high-cost, and low separation efficiency. These limit the wide application of activated carbon in the field of water treatment to some extent. Magnetic modification treatment on AC can provide a magnetic activated carbon (MAC) which possesses better performances reflecting in higher adsorption capacity, and can be easier, rapid and efficient separation through external magnetic fields. At the same time, MAC has good catalytic activity, which is useful for enhancing the capability of advanced oxidation process to efficiently degrade organic pollutants in aquatic systems. Therefore, MAC has broad application prospects in the field of water treatment. This work mainly introduces the preparation methods (co-precipitation method, thermochemical method, and mechanical milling method), microstructure and physicochemical properties (specific surface area, pore structure, magnetism, crystal and chemical structure, surface charge) of MAC. The research progress of MAC in wastewater treatment in recent years is reviewed, consisting of organic pollutant removal, heavy metal removal and other applications. The adsorption characteristics (adsorption isotherms and adsorption dynamics) and corresponding influencing factors (adsorption temperature, solution pH, and coexisting ions) are summarized in details. And the regeneration methods of AC are investigated comprehensively. In the end, the development and prospect of the application of MAC in water treatment are also discussed. Related Articles | Metrics Select Progress on resource utilization and second utilization of chloride removal products from Friedel's salt precipitation method Yun GU Peng CHU Dongdong GE Shouqiang HUANG Min JIANG Hongying LÜ Wenxin ZHANG Yangyang LÜ Yang LÜ Yaheng ZHANG The Chinese Journal of Process Engineering    2024, 24 (2): 151-161.   DOI: 10.12034/j.issn.1009-606X.223122 Abstract （114）   HTML （4）    PDF （1474KB）（76）       Knowledge map    Save The high concentration of Cl- in wastewater can seriously corrode industrial equipment, and also pollute the water environment. A series of technologies for removing Cl- from wastewater have been reported, such as membrane separation, concentration, evaporation crystallization, chemical precipitation, adsorption, ion exchange, electrolysis, oxidation, and solvent extraction. Among them, chemical precipitation has significant advantages in equipment investment and operability, Friedel's salt precipitation method of Cl- removal has been intensively studied because of the wide source and low price of raw materials, compared with other methods using silver, copper, or bismuth. After the Cl- removal, a large quantity of chemical sludge is produced, which mainly contains Friedel's salt (3CaO?Al2O3?CaCl2?10H2O), katoite [Ca3Al2(OH)12], and calcium hydroxide, etc. Due to the complex components and the tight binding of Cl- in the interlayer spacing of Friedel's salt, the resultant sludge is difficult to recycle. To promote the application of Friedel's salt precipitation method, it is very important to utilize its Cl- removal products, especially Friedel's salt, as a resource. Based on the introduction of the compositional and structural characteristics of Friedel's salt, this work highlights the advantages of Friedel's salt precipitation method, which cannot only remove Cl-, but also obtain Friedel's salt, by comparing other preparation methods. According to the aluminum and calcium components of Friedel's salt and its layered bimetallic hydroxide structure, effective resource utilization can be carried out, including the removal of various heavy metal cations (i.e., Cu2+, Cd2+, Co2+, Zn2+, and Pb2+) and oxygenated anion complexes [i.e., Sb(OH)6-, AsO43-, SeO42-, and CrO42-], and the preparation of polyaluminum chloride coagulants and as sludge dewatering regulators, etc. These uses have broad application prospects, providing reference and exploration direction for the further development of Friedel's salt precipitation method. Related Articles | Metrics Select Research progress on depression mechanism of chitosan and its derivatives during flotation Pengpeng ZHANG Cheng YANG Hongming LONG Xiangpeng GAO Mingyang LI The Chinese Journal of Process Engineering    2023, 23 (8): 1150-1160.   DOI: 10.12034/j.issn.1009-606X.222217 Abstract （108）   HTML （3）    PDF （4306KB）（87）       Knowledge map    Save As one of the most effective methods for low-grade ore separation, flotation has the advantages of obvious sorting effect on fine-grained ores and high separation efficiency. It is crucial to use reasonable and eco-friendly depressants in order to improve the flotation separation effect. As a new type of organic depressant, chitosan is widely used in mineral flotation due to its outstanding physical and chemical properties, environmental protection and easy preparation. Many chitosan derivatives also have excellent depression capabilities. In this work, the research progress of chitosan and its derivatives in flotation experiments of various minerals in recent years is reviewed. Firstly, the main adsorption methods of chitosan and its various novel derivatives as flotation depressants on mineral surfaces are introduced. Then, the depression mechanism and the main factors affecting the depression effect are summarized. Discussion and potential future research directions of chitosan derivatives depressants are also included. Although the research on chitosan and its derivative depressants is becoming more and more mature, the main depression mechanism is still not detailed enough. With the advancement of various detection methods, how to improve the depression effect and further clarify the related groups and main depression mechanisms will be a major focus of future research on chitosan derivatives depressants. Related Articles | Metrics Select Research progress of coalbed methane combustion deoxidation technology Feiqiong ZHANG Xuefeng YIN Jianan HU Wei HE Jing WANG Pengfei DAI Zichen WANG Na ZHANG The Chinese Journal of Process Engineering    2023, 23 (7): 1013-1023.   DOI: 10.12034/j.issn.1009-606X.222299 Abstract （106）   HTML （1）    PDF （790KB）（62）       Knowledge map    Save Coal bed methane (CBM) is a kind of unconventional natural gas energy that is mostly made of methane and is held as an adsorbed substance in coal seams. It has received a lot of attention both domestically and internationally due to its benefits of plentiful reserves and clean combustion. China has the third largest CBM deposits in the world, and the exploitation of CBM is expanding due to the increased interest in CBM in recent years, although the utilization rate is consistently low. The fundamental cause is a lack of effective low-concentration CBM utilization, where oxygen is essential to limiting safe CBM utilization. Deoxygenation is a requirement for safe utilization since low-concentration coalbed methane poses an explosion danger due to the presence of oxygen. This work introduces the basic principle and characteristics of combustion deoxidation, including the coke combustion method, catalytic combustion method, and chemical looping combustion method, with emphasis on carbon material, catalyst, oxygen carrier analysis of the current research status. In particular, the new technology of chemical looping combustion is discussed and analyzed. The findings demonstrate that the coke combustion process has a better deoxidation effect but has the shortcoming of high deoxidation temperature (650~1000℃), the key of current research is to improve the performance of carbon material and effectively control the reaction temperature. Methane will be consumed during catalytic combustion deoxidation, and the catalyst is easily poisoned and rendered inactive, the key to this technique is to investigate and develop a powerful catalyst, and this technique is not suitable for treating low-concentration CBM deoxidation. For the chemical looping combustion deoxidation method, the oxygen carrier material is inexpensive and simple to get, the reaction temperature is low, and this method can retain the maximum amount of methane. The thorough comparison reveals that deoxygenating low-concentration coalbed methane is more effectively accomplished using the chemical looping combustion approach. Related Articles | Metrics Select Research progress of metal-organic framework material modified MFC air cathode to improve the electric performance Jinrong LU Linde REN Hua LIU The Chinese Journal of Process Engineering    2023, 23 (8): 1161-1172.   DOI: 10.12034/j.issn.1009-606X.222339 Abstract （96）   HTML （2）    PDF （29624KB）（49）       Knowledge map    Save Microbial fuel cell (MFC), a new type of clean energy production equipment, can generate electricity while decomposing organic matter in wastewater. Facing the emergence of energy crisis, the reasonably designed MFC equipment can alleviate the current energy crisis, the generation of this new energy is green and sustainable. The conversion rate of energy is an important factor that affect the wide application of MFC, so improving the power production performance of MFC has attracted a lot of attention from scholars. Air-cathode MFC is an MFC configuration that uses oxygen as an electron acceptor to complete current transfer, that is the most promising type of MFC, but it is also accompanied by the problem of low activity of cathodic oxygen reduction reaction (ORR). Precious metal catalysts have never been able to meet the needs of practical applications, and cost-effective metal-organic framework (MOF) materials have been studied as ORR catalysts for many years. Therefore, MOF materials suitable for MFC air-cathode can be prepared as cathode catalysts to improve their power production performance through rational design. This work reviews the recent research progress of MOF and its derivatives as catalysts for modifying MFC air-cathode to improve their electricity production performance. The principles of MFC and the natural advantages of MOF materials as ORR electrocatalysts are introduced, and the latest applications of three types of materials, namely, simple MOF, MOF composites, and MOF derivatives, as MFC air-cathode catalysts are highlighted, leading to a variety of different research directions of MOF and its derivatives as MFC air-cathode catalysts. Finally, the challenges and future prospects of MOF and its derivatives in modifying MFC air-cathode to improve their power production performance are elucidated. The intention is to summarize the shortcomings exposed by MOF in modifying MFC air-cathode and provide new research ideas for the future application of MOF materials in MFC cathodes in order to promote the practical application of MFC. Related Articles | Metrics Select Research progress on multi-objective comprehensive evaluation of urban wastewater treatment processes Han CUI Yuting WANG Huajie LI Di ZHANG Longyi LÜ Zhijun REN Zhi SUN Pengfei WANG Xiaoyang LIU Li SUN Guangming ZHANG Wenfang GAO The Chinese Journal of Process Engineering    2024, 24 (1): 1-16.   DOI: 10.12034/j.issn.1009-606X.223037 Abstract （93）   HTML （6）    PDF （4095KB）（108）       Knowledge map    Save With the rapid development of the wastewater treatment industry, various treatment technologies emerge in endlessly, which have largely solved the pollution problem and caused environmental impacts. In order to select more efficient wastewater treatment technologies, various evaluation methods have been applied in the wastewater treatment industry under the background of carbon peaking and carbon neutralization. This review summarizes the current research situation of environmental and economic impact evaluation which are widely used in urban wastewater treatment plant (WWTP) and proposes the "5E" assessment system based on the existing research. At present, the assessment system mainly focuses on the environmental impact assessment based on life cycle assessment, focusing on the impact of eutrophication potential, global warming potential, and energy consumption on traditional and unconventional wastewater treatment technologies in WWTP. Economic evaluation is mainly divided into cost and benefit evaluation. Through the analysis of cost and profit in economic evaluation, the energy cost is very important in each treatment process, where the recovery and utilization of biogas can effectively improve the profit. In addition, carbon footprint assessment and organic contaminants toxicity evaluation have gradually become the research hotspot. In each part of this article, the evaluation of technology in wastewater treatment process is mentioned. At last, the "5E" assessment system (i. e., comprehensive environmental impact assessment, economic evaluation, carbon footprint evaluation, organic contaminants toxicity evaluation, and technology evaluation) is proposed to effectively solve the multi-objective comprehensive assessment problem of the urban WWTP. This research can support the sustainable development of the wastewater treatment industry and the realization of carbon peaking and carbon neutralization targets. Related Articles | Metrics Select Research status and prospect of flash boiling spray Jian GAO Run HONG Wenlong DONG Nian XU Huaqiang CHU The Chinese Journal of Process Engineering    2024, 24 (3): 273-283.   DOI: 10.12034/j.issn.1009-606X.223157 Abstract （76）   HTML （5）    PDF （1493KB）（59）       Knowledge map    Save The rapid boiling that occurs when high-temperature fuel is injected into a low-pressure environment is called flash boiling, reasonable use of flash boiling phenomenon can effectively improve the atomization effect of fuel spray and improve engine efficiency. The research on the flash boiling phenomenon can be traced back to more than 60 years ago. With the development of the research on the flash boiling spray, the focus of the spray-related research has gradually shifted to the spray collapse. The related theories of flash boiling spray are summarized in this review, and some visualization techniques commonly used in the observation of flash boiling spray are briefly introduced. The influence of different fuel characteristics on the flash-boiling spray is illustrated by comparing different fuel characteristics. The characteristics of flash boiling spray of multi-component fuel are summarized. The superheat index which can be used to measure the flash boiling spray of multi-component fuel are introduced. The collapse mechanism of non-flash boiling spray and flash boiling spray and the influencing factors of spray collapse are studied by comparing the research status of non-flash boiling spray and flash boiling spray. It is generally considered that the collapse mechanism of non-flash-boiling spray is jet-induced collapse, and flash-boiling spray seriously affects the experimental observation because of too many droplets. Therefore, the understanding of the collapse mechanism of the flash boiling spray is numerous but not certain. In addition, according to the above summary, several feasible research directions are put forward for the spray research: effect of different fuel properties on flash boiling spray, study of parameters to measure the degree of superheat of multi-component fuels, the study on the collapse mechanism of the flash-boiling spray and the study on the suppression of the collapse of the flash-boiling spray. Related Articles | Metrics Select Recent progress of heterogeneous catalysts towards selective catalytic reduction of NO by CO under oxygen-rich conditions Yaqi LIU Yan LIU Ke WU Liwen XING Dianxing LIAN Mohaoyang CHEN Jianjun JI Yongjun JI The Chinese Journal of Process Engineering    2024, 24 (3): 284-296.   DOI: 10.12034/j.issn.1009-606X.223136 Abstract （70）   HTML （3）    PDF （3784KB）（33）       Knowledge map    Save Nitrogen oxides (NOx), as one of the predominant atmospheric pollutants mainly derived from automobile exhaust and industrial waste gas, have played the role of an inevitable precursor that led to acid rain, photochemical smog, and other environmental contamination issues. In addition to atmospheric pollution, the growing emissions of NOx pollutants also give rise to a serious threat to agricultural production and human health. Thus, it is of urgent need to develop feasible NOx abatement strategies. Selective catalytic reduction of NO by CO (CO-SCR) is a very promising denitrification technology that can simultaneously remove harmful gases of NO and CO, making it one of the most ideal solutions for flue gas treatment. To promote its industrial applications, CO-SCR should have a low operating temperature ranging from 150℃ to 250℃ and superior resistance to oxygen poison. Therefore, there is an urgent need to develop efficient CO-SCR catalysts used under oxygen-rich conditions for abating severe environmental pollution problems. This work provides a comprehensive review of the research progress and latest research findings of CO-SCR under oxygen-containing conditions. The research advances of Pd, Ir, Rh, Mn, and Co-based heterogeneous catalysts were introduced, and the effects of active components, promoters, and supports on the catalytic performance of CO-SCR are described in detail. In this section, the preparation method, doping modification, and reaction conditions are analyzed. Meanwhile, the impact of O2, H2O, and SO2 on the catalytic activity of CO-SCR is discussed, in which the inhibition mechanism of O2 is summarized. Finally, the challenges and future developments of CO-SCR under oxygen-rich conditions are summarized and the corresponding coping solutions are proposed. We hope this review can provide an in-depth understanding and useful guidance for the rational design of efficient heterogeneous catalysts for the CO-SCR reaction in practical applications. Related Articles | Metrics