Separation of olefins/paraffins with the same carbon number is currently one of the most energy-consuming processes in the petrochemical industry. The development of new, low-energy propylene/propane separation processes is considered to be one of the seven chemical separation technologies that can change the world. Gas separation membrane technology is considered to be an alternative technology for replacing conventional cryogenic distillation to separate propylene/propane mixture due to its high efficiency, energy-saving and environmental-friendliness. The effective pore diameter of the metal-organic framework material ZIF-8 is just between the molecular dynamic diameters of propylene and propane, which can achieve efficient separation of propylene/propane. Among various membrane materials, ZIF-8 exhibits the best separation performance for propylene/propane mixture. This review systematically summarized the both preparation method and development process of ZIF-8 membrane for propylene/propane separation. The regulation of ZIF-8 membrane microstructure, especially the repair of membrane defects and the control of ZIF-8 framework flexibility, was discussed. The influence of the process parameters on the propylene/propane separation performance of ZIF-8 membrane was also discussed. The problems and future development of ZIF-8 membrane in large-scale preparation and potential industrial separation of propylene/propane were proposed.

This reviews introduces various types of adsorption materials for air and water pollution treatment, and elaborates the latest research progress on "enhanced enrichment/catalytic degradation" integrated composites in environmental governance. Through comparison, although the adsorption materials are cheap, stable and easy to operate, and it has good adsorption performance for waste water and exhaust gas, and the adsorption capacity can be further improved by certain modification methods. However, it has been limited due to the low adsorption capacity, extremely easy to saturate, frequent material replacement, and easy to cause secondary pollution after adsorption saturation. Catalytic technology is the catalytic oxidation of these pollutants into small inorganic molecules such as CO₂ and H₂O, which is cheap, no secondary pollution, high purification rate, and low energy consumption. Combining adsorption with catalytic technology, it can be found that the addition of adsorption materials has successfully improved the catalytic efficiency of the catalyst, which can solve the disadvantages of adsorption technology while retaining the advantages of catalytic technology. It is one of the most promising methods to deal with these pollutants.

In order to maximize the utilization value of various components in coal-based liquids, the research progress of highly efficient extraction and separation of complex components from coal-based liquids by ionic liquids and deep eutectic solvents is reviewed. Firstly, the properties and classification of ionic liquids and deep eutectic solvents are briefly introduced. Secondly, according to the target compounds, the extractive separation are divided into four aspects: phenol extraction from coal-based liquids, extractive desulfurization of fuel oils, extractive denitrification of fuel oils, and the separation of aromatics and aliphatic hydrocarbons. The analysis shows that ionic liquids and deep eutectic solvents have good phenol extraction effect for actual coal-based liquids, and can separate most phenolic compounds. When fuel oils are extracted and desulfurized, ionic liquids and deep eutectic solvents are also effective for actual coal-based liquids, but the desulfurization rate is not high for one time operation and it takes 3 to 5 repeated extractions to obtain the desired results. The denitrification efficiency is not high and this is because the basic and non-basic nitrogen-containing compounds in the fuel oils are difficult to be extracted and separated by the same ionic liquid or deep eutectic solvent at one time. Most ionic liquids and eutectic solvents do not achieve the ideal partition coefficients and selectivity when separating aromatics and aliphatic hydrocarbons, and cannot be used for separation of aromatics and aliphatic hydrocarbons from coal-based liquids. Differences in intermolecular interactions such as hydrogen bonding, π-π, CH-π, and Van Der Waals etc. are the main reasons for the different separation of typical components in coal-based liquids by ionic liquids or deep eutectic solvents. Therefore, the key to separate the actual coal-based liquids by ionic liquids and deep eutectic solvents is their rational molecular design so as to improve the extraction rate and selectivity based on the target compounds, which will inevitably promote the industrialization process of high-valued separation of coal-based liquids.

Vanadium flow battery (VFB) has received increasing attention in large-scale energy storage due to their attractive merits of large storage capacity, adjustable power and capacity, and no cross-contamination of redox-active materials. Commercialized perfluorosulfonic acid membranes are limited in VFB application due to the high cost and low ion selectivity. Therefore, nonperfluorinated polymer membranes have been comprehensively researched. So far, alternative membranes are facing challenges in an intrinsic trade-off between ion transport and selectivity. Meanwhile, the chemical stability of alternative membrane in strongly acidic and oxidizing condition for VFBs is also a challenge. It is the key to achieving high ion-selective transport and high stability to optimize ion-selective transport channels in the membrane on basic of the structure-performance relationship. The ion-selective transport channels based on traditional hydrophilic groups, size sieving effects and non-traditional hydrophilic groups were discussed, respectively. The current progress and problems of membrane were comprehensively overviewed, and the research directions of construction of ion-selective transport channels in membranes were pointed out for large-scale VFB application.

Nanofiltration (NF) technology has been widely applied in the fields of wastewater treatment, seawater desalination, as well as separation and purification in industry because of its high separation efficiency, low operating pressure, and environmental-friendly characters. Polyamide (PA) membranes prepared via interfacial polymerization (IP) are the most commonly used in nanofiltration. However, the reaction rate of IP process is too fast to control. Thus, it is still an urgent issue to effectively regulate the IP process to optimize the selective layer structures of nanofiltration membranes (NFM), which could further enhance the perm-selectivity of the NFM to meet the required performance from different applications. This paper summarized the progress in optimization of perm-selectivity performance of NFM including novel PA NFM, PA/nanomaterials mixed matrix membranes and ultrathin PA NFM from the viewpoint of controlling monomers diffusion during IP process. Then, the structure tuning methods on selective layers to improve the perm-selectivity performance of NFM was discussed. Furthermore, the challenges in large-scale preparation of PA-based NFM with good stability and controllability were pointed out. Finally, the perspectives on the promising methods for tuning microstructures and polymerization process of NFM were provided.

Anion exchange membranes (AEM) have a good potential to be used in alkaline fuel cells and all-vanadium flow batteries, but their conductivity and stability currently can not meet the high power and durability requirements of the devices; in particular, there exists a serious trade-off between the membrane’s conductivity and stability. Recent literature (including our own work) shows that incorporating proper free volume or micropores in the AEM can help resolve this issue because free volume and micropores can reduce the resistance of ion transport, making ion conductivity less dependent on ion exchange capacity so that the conductivity and robustness of membrane can be better balanced. In this review, we make a brief overview on such literature and highlight the main research progress on free volume tuning and micropore construction in AEMs. Free volume can be tuned by the incorporation of bent and twisted chain units and bulky side groups in the membrane structure, and by the use of ladder polymer or polymer of intrinsic microporosity for AEM fabrication; new methods for micropore creation in AEMs include side-chain hydrolysis and cyclodextrin-assisted templating. We also analyze the effects of free volume and microporous structure on the ionic conductivity, stability and device performance of the resulting AEMs.

The unique supramolecular structure and dynamic properties of polyrotaxane have attracted great attention from scientists. It also has important application potential in membrane field, and there have been a series of reports. This paper introduced the development of molecular machine, membrane separation technology, the classification and fabrication of PR-based membranes. The latest background and application progress of PR-based membranes in membrane fields were also presented, including antifouling property, adsorption, ionic conduction, oil/water separation and so on. The separation performance and mechanism of PR-based membranes were discussed. The function of the dynamic structure in membrane and membrane separation were also discussed. The combination of PR and polymers membrane was beneficial for the improvement of membrane properties such as hydrophilicity, water flux, rejection rate antifouling property, adsorption performance, conductivity and mechanical performance. At the end, the challenges and future prospective of PR in membrane field were proposed.

Polyamide (PA) thin-film composite (TFC) membrane prepared via interfacial polymerization (IP) has been extensively used in water treatment due to its advantages of high permeability, high separation selectivity and good chemical stability. The separation performance of PA TFC membrane is mainly determined by the physical structure and chemical properties of the PA skin layer, which can be improved by regulating and optimizing the IP process. Hence, this review focused on the relationship between the physicochemical properties of the PA layer and the separation performance of the TFC membrane, and summarized the research progress on IP-based membrane preparation from three aspects: modification of membrane substrate, regulation of monomers reaction process and post-treatment of PA layer. By analyzing the influence of monomer mass transfer on the IP reaction as well as the relationship between membrane structure and performance, the regulation mechanisms and methods of the IP process to prepare PA TFC membranes were summarized, which provided fundamental theories and perspectives for further improvement of the separation performance of PA TFC membrane.

Membrane distillation technology has shown great potential in desalination owing to its advantages such as high theoretical salt rejection rate, mild operating conditions and low sensitivity to feed salt concentration. In recent years, growing attention has been paid on using graphene for membrane distillation desalination. First, the introduction and membrane materials of membrane distillation technology were outlined in this paper. Next, the hydrophobicity of graphene and preparation methods of hydrophobic graphene membrane were introduced, followed by a detailed review of three kinds of hydrophobic graphene-based membranes (i.e., graphene mixed matrix membranes, graphene composite membranes, and pure graphene membranes) for membrane distillation. Finally, current challenges and future research directions of hydrophobic graphene for membrane distillation desalination were prospected.

Petroleum and chemical industries yielded various oil-water mixtures by accident or on schedule，which might affect processing stabilization or seriously contaminate environment. Therefore, oil-water separation technologies with high efficiency and low running cost are urgently demanded. In comparison to the usually-used industrial methods (floatation, centrifugation, coagulation, etc), micro-porous membrane technology could achieve oil-water separation through selective permeation of oil or water, and the attached advantages included easy operation, high efficiency, low cost, etc. However, the separation efficiency and processing capability of microporous membranes for oil and water mixtures were mainly determined by membrane surface properties (wetting ability) and microscopic structures (permeation channels’ size effect). Oil-water separation principle was firstly introduced based on micro-porous membrane technology via surface wetting and size screening mechanism; then the recent advances on membrane surface properties and microscopic structures were reviewed; finally, the critical problems existing in industrial membrane-based oil-water separation were pointed out in brief, and perspective about the further research on membrane surface properties and microscopic structures was given. This review might afford some theoretical foundations to the researchers around micro-porous membrane technology for oil-water separation.

The pressure-driven thin film composite (TFC) membranes have been widely applied in the field of water treatment due to their high separation efficiency and low-energy consumption.The development and performance improvement of TFC membranes can be optimized for polyamide (PA) separation layer and microporous substrate. Among them, microporous substrate has an important influence on the structure and separation performance of PA layer formed by interface polymerization (IP). In this paper, the recent progress in the substrates of NF/RO TFC membranes is reviewed. Firstly,two kinds of microporous substrates (conventional phase transformed microporous substrate and electrospinned microporous substrate) are introduced. Then, the effects of the phase-inversion substrates on the IP process are summarized. The substrates modification methods (polymer blending, nanomaterial doping, surface modification, etc.) are reviewed. Finally, development directions and challenges in covalent organic frameworks (COFs) interlayer surface modified microporous substrates for high-performance pressure-driven TFC membranes are tentatively discussed.

Molecularly imprinted membrane (MIM) can combine molecular imprinting technology with membrane separation, thus which has exhibited high specific ability of molecular recognition and great potential in separation engineering. In this paper, the basic principle of molecular imprinting technology and the structures of MIM were summarized, and the mass transfer mechanism, including “retard”effect and “gate” effect, recent research progress and applications were also described. Moreover, the challenge of MIM was critically discussed. Finally, the development trends of MIM in future were evaluated.

Transparent and flexible gas barrier materials have wide application prospects in electronic device packaging, food and drug preservation and so on. This article reviews the research and development progress of layered double hydroxides (LDHs)-based gas barrier thin film materials from the aspects of structural design, preparation methods and performance enhancement. The design of the interaction between the guest and the host is the key to the improvement of material properties. Firstly, the host LDH nanosheet has an adjustable aspect ratio, which is an ideal filling material for enhancing the gas barrier property. Secondly, the variety of polymer guest gives unique mechanical, optical and electrochemical, properties to LDH/polymer gas barrier films, providing wide space for the practical application of the barrier materials, and the adjustment of physical and chemical properties of polymer matrix can improve the barrier performance. Furthermore, adjusting the interaction between LDHs and polymers can reduce the free volume between the host and the guest, which further improves the gas barrier properties. At the same time, the ordered 2D structure giving the LDHs nanosheets a high degree of orientation can extend the diffusion path of gas molecules and improve the non-permeability of thin film materials. Finally, it is proposed that the performance enhancement of LDHs-based gas barrier film materials will become a new direction for the development of high-performance gas barrier materials.

Owing to its complex structure, polymorphism and multiple ionization sites, pharmaceutical pollutants can not be completely removed from water. Therefore, it is of vital importance to find an efficient adsorbent to minimize the serious potential harms to human health and environment. Metal-organic frameworks (MOFs) have exhibited excellent performance in liquid adsorption and separation thank to their high specific surface/porosity, structure/chemical tunability, and designability. This review briefly summarizes the recent research progress of the applications of MOFs, functionalized MOFs and MOF-derived carbon materials in adsorption removal of trace antibiotics and other pharmaceutical pollutants from water. For the specific pharmaceutical molecules, the adsorption capacity can be effectively improved by introducing specific functional groups and other substances (such as multi-walled carbon nanotubes and magnetic Fe₃O₄). The interactions between MOFs and pharmaceutical molecules were discussed in detail, including electrostatic interaction, hydrogen bond, π-π interaction. Combined with the research progress in our group, a concise conclusion and outlook are outlined for the adsorption removal of pharmaceutical pollutants using MOFs, including the targeted screening and design of MOFs with excellent adsorption performances using advanced computational methods, as well as the comprehensive consideration of adsorption kinetic.

Lithium and its compounds are not only a kind of green energy materials but also important strategic materials. It has important applications in related industries and the demand for it is drastically growing. There are huge reserves of lithium resources in seawater and salt lake brine. In order to meet the strong market demand, it is of great economic value and strategic significance to separate and extract lithium resources from them. Due to low lithium ion concentration, complex composition and high ratio of magnesium-lithium in salt-lake brine, selectivity adsorption is very important for the lithium extraction. In this paper, the structure characteristics and Li⁺-adsorption mechanism based on manganese ionic sieve, titanium ionic sieve, and organic crown ether with its derivatives were analyzed, respectively. The situation of composite adsorption materials preparation was summarized. It also reviewed the properties of composite adsorption materials based on above selective adsorption units and pointed out the existing problems. Finally, it prospected the preparation and application of selective adsorption materials with high selectivity and high adsorption capacity in the future.

Gaseous light hydrocarbons (C₁—C₃), such as methane, ethylene and propylene, are widely used as clean fuels and bulk chemical products, which occupy important position in the national economy. However, their separation and purification processes are very energy-consumption. As the third generation of new porous materials, metal-organic frameworks (MOFs) have shown great potential in the field of light hydrocarbon separation in recent years. In this paper, the current situation and mechanisms of MOFs in the adsorptive separation of light hydrocarbons were reviewed. According to the separation requirements of different light hydrocarbon mixtures, the adsorption and separation performance of MOF materials were regulated through precise pore size control, ligand functional modification, adsorption sites construction, and adjustment of the "opening pressure" of flexible MOFs. Finally, based on the key problems in the industrial light hydrocarbon separation process, the separation mechanism of MOFs material was analyzed, and the structural stability and separation process matching of MOFs were prospected.

Metal-organic framework is one kind of novel porous material with self-assembly of metal center and organic ligand. Adsorption and separation is one of the important usages of metal-organic framework. This paper introduced the ways to design and synthesize functionalized metal-organic framework with goal-directed based on metal-organic framework as porous platform, and the role of functionalized metal-organic frameworks in the separation of carbon dioxide from nitrogen and methane, as well as alkane from olefin, and the separation and purification of low-carbon alkanes and other small molecules gas. The results showed that the functionalized metal-organic framework had higher separation selectivity than the unmodified metal-organic framework in the separation of carbon dioxide, olefins, alkanes and other small gas molecules due to the existence of active sites from functional groups. The goal-directed of functionalized metal-organic framework makes it have a broader application prospect in the field of chemical separation. At present, the difficulty in mass production of material synthesis limited the popularity of functionalized metal-organic frameworks in chemical separation. With the continuous simplification of synthesis methods, the functionalized metal-organic frameworks would be widely used in chemical separation.

This paper reviews the characteristics of adsorption desulfurization technology which has attracted more attention owing to its mild operating conditions, energy saving, unchanged fuel quality and low cost. The research progress and the selective removal mechanism of refractory thiophene sulfides in fuel by porous adsorption materials in recent years are reviewed, to deal with the issue of deep removal of thiophene and its derivatives. The research status of different porous adsorbents, such as molecular sieves, metal organic frameworks, porous carbon materials, and composite materials, is mainly analyzed. The adsorption mechanism and modification methods involving the advantages and disadvantages of various adsorption materials are discussed. This paper points out that molecular sieves are the most dominant adsorption materials due to their excellent thermal stability, high specific surface area, regular pore structure, low cost and ease of industrialization. Future research should focus on elucidating the adsorption mechanism, improving the convenience of synthesis, adsorption desulfurization performance, and regeneration ability, with a view to laying a foundation for the research and development of new high-efficiency, good selectivity, and easily regenerating adsorbents in a more comprehensive and systematic manner.

Adsorptive desulfurization (ADS) has been considered as one of the most promising non-hydrodesulfurization technologies due to its low operating cost and mild operating conditions. Adsorption desulfurization selectively adsorbs organosulfur compounds from fuel under mid conditions, and the efficient porous adsorbent is the core. In this review, the research progresses on various types of desulfurization adsorbents and their adsorption mechanisms are summarized. Based on the adsorption mechanisms including physical adsorption, chemical adsorption and reaction-adsorption coupling, the ADS adsorbents are classified and discussed in terms of adsorption selectivity, thermodynamic, and kinetics, etc. The perspectives on the challenges, such as the strong competitive adsorption of fuel components in real diesel, and the future directions to be further explored in adsorptive desulfurization of fuels are given.

Combined trapezoid spray tray (CTST) is a novel spray tray with a unique trapezoid spatial structure and excellent characteristics. In gas-liquid co-current contact, the CTST has a lot of advantages, such as high capacity, efficiency and operation flexibility, low pressure drop, excellent anti-blockage performance, and foaming resistance. Such excellent characteristics are the results of multiphase coupling between the tray and its nearby gas-liquid flow field. This paper introduces the characteristics of the CTST, such as structure, pressure drop, and liquid holding capacity, and reviews the performance and mechanism of the gas-liquid flow field near the tray. In addition, it summarizes the optimization directions of CTST and typical application examples of the CTST in recent years. Because the CTST can increase the separation efficiency and processing capacity of the columns without the need of changing the column diameter, it can increase the production with the minimal investment, so that it has been successfully applied in many countries and regions around the world. Among them, over 4000 sets of columns have been successfully operated in more than 500 enterprises in China, covering various industries of petrochemical, PVA, pharmaceutical, chlor-alkali, PTA, benzene refining/ maleic anhydride, chemical fertilizer. Despite all this, the study of its mechanism is still far from completeness, which is of great significance for improving CTST as well as the high-efficiency tray technology.

The selective heating characteristic of microwave irradiation field has great effect on the relative volatility of binary mixture, which can be applied to develop novel separation technology based on the dielectric property difference of the compositions, which will promote process intensification of unit operations in chemical engineering. The progress of microwave-enhanced separation in chemical engineering was summarized while the unique interaction between microwave field and various chemicals was illustrated to emphasize microwave-induced enhancement of distillation separation for the mixture of polar and nonpolar components. In view of the key problems that need to be solved in the practical application of microwave-induced separation technology, the research progress of the author's research group on the mechanism of microwave-induced separation, separation device, structure design of microwave cavity and process model were reviewed. Ultimately, several suggestions were proposed accordingly for the existing problems of microwave technology in the field of chemical separation process intensification for the sake of the further research of dielectric-based separation in chemical engineering.

Solvent extraction columns are widely used in a range of industries including chemical, petrochemical, biological, pharmaceutical and environmental engineering due to its high-volume efficiency, small footprint, fine sealability and environmentally friendly features. This work reviews the progress of solvent extraction column from the following aspects: the model progress of hydrodynamic, axial dispersion and mass transfer for conventional extraction columns (pulsed extraction columns, rotating disc contactors and Kühni columns, etc.), and the effects of surface tension, mass transfer direction and scale-up on the models; the application of computational fluid dynamics (CFD) to solvent extraction column including single droplet and single-phase simulation , the liquid-liquid two-phase simulation, energy input simulation and the population balance model (PBM) coupling with the CFD simulation; some novel extraction columns including the tradition columns with new internals and multiple-fields intensification for mass transfer enhancement. The combination of effective experimental method, accurate empirical model and robust theoretical calculation will become a reliable method and direction for the research of solvent extraction column.

Lithium and its derivatives have wide application prospects, leading to an increasing demand of lithium resource. Therefore, it is of great significance to develop a method that can extract lithium from (concentrated) seawater/brine with high reserves of low-grade lithium. In recent years, electrochemical lithium extraction technology has become a research focus due to its high selectivity, low energy consumption, and environmental friendliness. This paper reviewed the progress on the selection and preparation of electrode materials for lithium adsorption and the construction of electrode systems in electrochemical lithium extraction technology. In the selection and preparation of lithium adsorption electrode materials, LiFePO₄, LiMn₂O₄ and LiNi_1/3Co_1/3Mn_1/3O₂ with high lithium selectivity were developed gradually. In the construction of the electrode structure system, the system with counter electrode of AgCl, ZnCl₂ and polypyrrole, which have the anion reversible exchange performance, can avoid side reactions and reduce energy consumption for lithium extraction. The “rocking chair” system without other counter electrode materials can reduce the cost of the electrode and improve the efficiency of lithium extraction. Furthermore, the current shortcomings of electrochemical lithium extraction technology were pointed out, and its development and application could be promoted by the researches on the electrode material preparation, lithium extraction process optimization and equipment design in future.

Owing to the development of clean coal power generation technology and the improvement of requirements for environmental protection, high-temperature gas-solid separation technology has made important progress. This paper explains in the aspect of high-temperature filter materials, after four periods of exploration, which includes early metal porous materials, homogeneous ceramic porous materials, fiber-reinforced ceramic composite materials, metal alloys and intermetallic compound porous materials, high-temperature gas filter elements in various forms have been gradually formed, such as ceramic powder, ceramic fiber, metal powder, metal fiber and wire mesh, meanwhile, the catalytic filter composite elements have also been gradually applied in engineering in recent years. Moreover, important technological advances have been achieved in the dust layer structure on the surface of high-temperature filter elements, pulse cleaning cycle regeneration, high-temperature filter structure design and real-time operation optimization. At present, hot-gas filtration technology and equipment have been extensively applied in coal gasification, catalytic cracking, metallurgy and waste incineration treatment. With the applicable temperature range of 260～650℃ and the pressure range from atmospheric pressure to 6.0MPa, the hot-gas filtration technology can effectively remove the particles with a size of more than 1μm, the filtration efficiency is more than 99.9%, and the content of the particles in the purified gas is less than 5mg/m³. It is pointed that with the national economic transformation and the improvement of requirements for environmental protection and emission, hot-gas filtration technology will have a wider application in the fields of product quality upgrading, high-temperature waste heat utilization and particulate matter emission control.

Desalting is a key processing step for oilfields or refineries to meet the desired crude oil quality requirement. Dilution-water addition and mixing play an important role in crude oil electric desalting system which directly affects desalting efficiency and operation energy consumption. Given the fact that the essence of dilution-water addition and mixing can be formulated as an oil-water mixing problem under the condition of specific continuous flow, state-of-the-art of dilution-water addition and mixing technology was illustrated systematically from the aspects of evaluation method, mixing mechanism, dilution-water addition and mixing equipment. Based on brief introduction of multiple-scale oil-water mixing concept on dilution-water addition and mixing in engineering practice, classification and summary about five representative categories of oil-mixing mechanisms were completed, including mechanical agitation, pipeline throttling, inline fixed internals cutting, jet impingement and electro-dispersion. Furthermore, structures and working principles of five corresponding categories of dilution-water addition and mixing equipment including pipeline multi-stage mechanical agitator, mixing valve, inline static mixer, jet impingement mixer and electro-dynamic mixer were introduced, as well as their own performances were analyzed. Generally speaking, the research of oil-water mixing mechanism had not been developed along with dilution-water addition and mixing equipment as yet, thus it was advised, based on intersecting and complex concept, to strengthen the research of jet impingement oil-water mixing mechanism and the development of corresponding technology and equipment as soon as possible, and in the meanwhile to expand the application range of efficient mixing unit process furthermore.

With the increasing attention to pipeline safety, reducing cost, and increasing efficiency, pigging robot operation has become an indispensable operation procedure for oil and gas pipelines all over the world, and the pigging speed is one of the key parameters to be controlled. The best pigging effect can be reached when it is within a reasonable range (1—5m/s for crude oil pipelines and 2—7m/s for natural gas pipelines). Based on the research on the mathematical model of pigging, this paper firstly discusses the different passive control methods, which is flexible and widely used. Accurate calculation of pig speed under different inlet conditions is the key to controlling pig speed in a reasonable range. Then different active control methods are studied. The result shows that: the core of bypass pig speed control is the optimization of bypass rate, it depends on the accurate calculation of pressure drop coefficient, friction between bowl and tube wall. The establishment of a simple and reliable friction engineering model will further promote the application of bypass pigging technology. Finally, this paper reviews and looks forward to the intelligent speed control technology of pig, and points out that the development of stable and reliable domestic intelligent speed control technology is the key research direction in the future.

The gas separation employing thermal transpiration effect is a novel method different from traditional gas separation methods in terms of mechanism and application mode. A novel modular gas separation system composed of thermal-transpiration-effect-based gas separation unites in series was proposed. A mathematical model with corresponding algorithms was established to describe the gas separation process and optimal design for the proposed system. On this basis, this type of system was designed to separate hydrogen from the coke oven gas with the corresponding structural arrangements, parts and operating parameters determined. Its parts can be manufactured and assembled by existing technologies. Purity of hydrogen obtained from the system was >99% when six gas separation units were set in series. Energy consumption of the system was 45.41kJ/m³ when separation purity was satisfied. The system conforms to the principle of energy cascade utilization since it can be directly driven by low-grade heat, which makes it competitive from the viewpoint of energy utilization. The emerging gas separation technology based on thermal transpiration effect is worth studying deeply and trying in practice due to its distinct characteristics.

Lavoisier framework MIL-53(Al) was incorporated into the polyether block amide (PEBA-2533) to prepare PEBA/MIL-53(Al) hybrid membranes with different loadings and to be used for pervaporation separation of aniline from water. X-ray diffraction results confirmed that MIL-53(Al) was successfully synthesized. The results of scanning electron microscopy and laser particle size analysis showed that the particle size of MIL-53(Al) was in the nano-scale range. The hybrid membranes were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and water contact angle. The swelling behavior and separation performance of the hybrid membranes were also investigated. The results indicated that the hybrid membranes demonstrated good thermal stability. When the mass fraction of MIL-53(Al) was less than 20%, MIL-53(Al) was evenly dispersed in the polymer phase, and agglomeration occured when the loading amount continued to increase. The crystallinity of hybrid membranes decreased with the increase of MIL-53(Al) loading. The introduction of MIL-53(Al) enhanced the hydrophobicity and swelling of the hybrid membranes. When the feed temperature was 60 ℃, the downstream pressure was 400 Pa and the mass fraction of aniline was 3.6%, the hybrid membrane (M-20) with MIL-53(Al) mass fraction of 20% exhibited the best comprehensive separation performance. The permeation flux reached to 2.15 kg/(m²·h) and the separation factor was high as 264. The long-term test results for 12 days showed that the separation performance of the hybrid membranes had no significant change and can meet the requirements of pervaporation application.

Fluid catalytic cracking (FCC) naphtha is the main blending source of motor gasoline in China, but its sulfur content is always much higher than that of vehicle gasoline quality standards. Therefore, reducing sulfur content efficiently is the key to the refining treatment of FCC naphtha. The clean production technology of FCC naphtha was summarized in this paper from the following three aspects: selective hydrodesulfurization technologies (Prime-G⁺, SCANfining, CD Tech, RSDS, OCT-M and DSO), selective hydrodesulfurization coupled octane number recovery technologies (RIDOS and GARDES) and adsorption desulfurization technology (S-Zorb). The principle, features and applications of those technologies were introduced. The contradiction between deep desulfurization and octane number maintenance as well as olefin saturation was pointed out. The researches on the process modification, operating conditions optimization and new catalysts development should be carried out in the future.

Self-humidifying is of great significance for the practical application of proton exchange membrane fuel cells (PEMFC). From the perspectives of electrode component and structure modification, this paper introduces some important progress and development trends of PEMFC self-humidifying studies in recent years. Firstly, the development of PEMFC self-humidifying based on the modification of the catalytic layer is introduced, and the importance of developing a hygroscopic catalyst to achieve an efficient self-humidifying catalytic layer is pointed out. Secondly, the research progress of PEMFC self-humidifying based on gas diffusion layer modification and electrode structure improvement is introduced. The advantages and disadvantages of the two methods are analyzed, and the future development direction is discussed. Finally, in view of the problems in the existing self-humidifying process, we provide some suggestions on its future research directions and priorities, i.e. the research and development of hygroscopic catalyst and the combinations of various methods.

The high temperature proton exchange membrane fuel cell (HT-PEMFC) has the advantages of strong resistance to CO poisoning, simple water and heat management, and high energy utilization. However, the high temperature and acid environment also makes it face the problem of insufficient durability. In response to this problem, this article generally summarized the physical and chemical characteristics of common materials for the proton exchange membranes, gas diffusion electrodes, bipolar plates, and seals in HT-PEMFC, and systematically summarized the research progress on the mechanism, hazards, influencing factors and corresponding mitigation strategies of those components performance degradation in recent years. Finally, the future development of HT-PEMFC was prospected. Developing high-strength lightweight bipolar plates and high-durability seals, optimizing the cost of the stack, and exploring new electrolyte membrane systems were expected to become the focus research directions in this field.

Ethylene is one of the important organic chemical raw materials. With the increasing demand of ethylene and the shortage of petroleum resources, ethane dehydrogenation has become an important approach to increase ethylene production. Ethane dehydrogenation to ethylene has received an increasing attention, and the catalysts applied in this process have been improved gradually. In this review, the recent domestic and overseas research advances of ethane dehydrogenation were introduced, and then researches on catalysts for ethane catalytic dehydrogenation and oxidative dehydrogenation were summarized and compared in detail, especially in the aspect of catalyst preparation methods and their catalytic performances. Catalytic dehydrogenation was an effective way to convert light alkanes to the corresponding olefins with a high olefin selectivity. While the high energy consumption was inevitable due to thermodynamic equilibrium limitations. In contrary, with the introduction of oxidants, oxidative dehydrogenation became exothermic, as a result, coke formation was effectively inhibited and energy consumption was highly reduced. However, it was difficult to control deep oxidative reactions, leading to a low ethylene selectivity. Therefore, the development of an appropriate catalyst for catalytic dehydrogenation to improve the single pass conversion of ethane and reduce energy consumption was the key to ethane dehydrogenation.

It has been proven that the emissions of N₂O and NH₃ are mainly from automobile exhaust. The research progress of N₂O and NH₃ emissions from light gasoline vehicles in last decade is summarized in the paper. The formation mechanism of the two gaseous pollutants in three-way catalysts is described, and the effects of various factors(the types and contents of noble metals, carrier, different gas composition and concentration, aging condition, different vehicle and test conditions, reaction temperature, et al) on their formation are summarized. It is concluded that N₂O and NH₃ are mainly generated in the cold start phase under rich conditions, and the dissociation of NO plays a key role in the formation of N₂O and NH₃. The factors affecting N₂O and NH₃ generation are interrelated each other, and N₂O and NH₃ emissions increased after catalyst aging. In addition, Rh gives better decomposition of N₂O and NH₃ than Pd and Pt catalyst. The upgrades of engine and strategy of after-treatment system, development of suitable test cycle, optimization of catalyst can further reduce the emission of N₂O and NH₃.

Compared with traditional noble photocatalysts, copper-based catalysts show the advantages of low price, environmental protection, mild reaction conditions and adjustable photocatalytic activity, which have attracted widespread attention from synthetic chemists. This paper briefly described the photocatalytic history of copper-based catalysts, reviewed the research achievements and progress, summarized the independent photocatalytic mechanism and synergistic photocatalytic mechanism of copper-based catalysts. The application of copper(Ⅰ) catalysts in olefin functionalization, carbon-carbon coupling, carbon-hetero coupling and in-situ catalysis was discussed, indicating that copper-based compounds had great application potential in photocatalytic synthesis. Expanding the reaction suitability, exploring the redox capacity and further developing the application of the catalyst in chiral synthesis would be the hotspots in the field.

Ferrous oxalate was used as a novel iron precursor to prepare the iron-based catalysts for Fischer-Tropsch synthesis, and the effects of four preparation methods (cocurrent co-precipitation, positive co-precipitation, precipitation-impregnation K, precipitation-impregnation K, SiO₂) on the crystal structure, physicochemical properties and catalytic properties of the catalysts were investigated. It was found that the preparation method significantly affected the crystal structure and texture properties of the catalyst. The catalyst prepared by co-precipitation had the best crystallinity and reducibility, and the promoter and the active phase was better united, so it exhibited the best activity and stability, and the conversion of CO reached 96.2%. It was also found that the catalyst prepared by the cocurrent co-precipitation method showed higher hydrocarbon product yield and C₂—C₄ olefin selectivity. The carbon number analysis showed that the content of the gasoline components in the liquid phase product obtained by the cocurrent co-precipitation method was as high as 85.8%, and that of C₄—C₁₈ in the C₄₊ heavy hydrocarbon product was as high as 91.0%. The selectivity of the kerosene component in the liquid product by the positive co-precipitation is relatively high, while the liquid phase product by the precipitate-impregnated K contained high amount of diesel components.

CeO₂, Ce-Zr-O (CZ) and Ce-Zr-Al-O (CZA) catalysts were prepared by co-precipitation using salt solution of active components as precursor. A fixed-bed pyrolyzer was used to study the catalytic pyrolysis process and product distribution of tobacco stems in the presence of catalysts. N₂ adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), temperature programmed desorption (NH₃-TPD) and X-ray photolectron spectroscope (XPS) were used to characterize the specific surface area, pore structure, morphology and acidic distribution of the catalyst surface. The results showed that the addition of Al increased the specific surface area, enhanced the weak and medium-strong acid, and decreased the strong acid of the catalyst. The content of nitrogen compounds in the slow pyrolysis product of tobacco stem was the highest, reaching 35.2%, followed by hydrocarbons and phenols. The catalysts inhibited the production of phenols, esters and nitrogen compounds, but the effects on ketones and furans were not obvious. The catalysts significantly promoted the formation of hydrocarbons, reaching 45.24% (CeO₂), 55.35% (CZ) and 52.07% (CZA), respectively. Aromatic hydrocarbons account for the largest proportion of hydrocarbons, of which the content of toluene, xylene, ethylbenzene reached 21.01%, 10.04% and 8.64% in the presence of CZA, CZ and CeO₂, respectively CZA had a very strong ability to resist carbon deposits. After three consecutive uses, the hydrocarbon content in the products was reduced, but it can be completely recovered after regeneration.

The SCR performance and SO₂ resistance of Mn/TiO₂ catalysts doped with Fe, Ce, Ni, Sm and Cu elements synthesized by sol-gel method were investigated, and the physicochemical properties of catalysts were also characterized by XRD and H₂-TPR. The results showed that the particle size and the reducibility were changed by doping elements. The particle size was decreased when Fe and Ni doped while increased when Se, Sm, and Cu doped. The modification of Cu and Ni was beneficial to the enhanced reducibility of catalysts. The SCR results exhibited that the modification of metal elements mainly inhibited the activity at low temperature whereas increased the activity at high temperature except for Cu and Sm. The T₈₀ catalytic temperature window of catalysts after doping the metal elements followed: Fe-Mn/TiO₂＞Ni-Mn/TiO₂＞Ce-Mn/TiO₂≈Mn/TiO₂＞Sm-Mn/TiO₂＞Cu-Mn/TiO₂. Sm-Mn/TiO₂ and Ce-Mn/TiO₂ kept the similar SO₂ resistance with Mn/TiO₂, while samples with Fe, Cu and Ni showed poor SO₂ tolerance. For Fe-Mn/TiO₂ catalyst, the metal active sites were easily poisoned by SO₂, but the activity could be restored by the water washing method. Furthermore, the SO₂ resistance of Fe-Mn/TiO₂ and Ni-Mn/TiO₂ could be improved after the regeneration.

This paper aimed to solve the problem of poor fluidity of HD199, a new PARP (poly ADP-ribose polymerase) inhibitor, and to prepare quality-controllable HD199 capsules with simple and feasible process for phase I clinical studies. The formulation of HD199 capsules was studied by investigating the effects of excipient type and quantity on the powder characters and dissolution profiles. The rest angle of HD199 decreased from 55.5° to 45.6° and the compressibility decreased from 44.4% to 30.7%. Compatibility of raw materials and process reproducibility were also studied. Under various test conditions, the studied excipients had little effect on the stability of HD199, and the change of related substances was similar to that of API. The optimized formulation with good compatibility was as follows: HD199/colloidal silicon dioxide/lactose/magnesium stearate (mass fraction was 1∶0.075∶1.5∶0.025). HD199 capsules, which had high dissolution rate with good reproducibility, were successfully prepared and suitable for scale-up production.

Membrane separation technology has been considered as the most promising one for CO₂ capture due to its low capital cost, low energy consumption and high efficiency. Mixed matrix membranes (MMMs), combining the advantages of organic polymer with inorganic materials, are perceived as one of the effective means to enhance permeability and selectivity simultaneously. Based on the two gas transport mechanisms, this review summarized the progresses in CO₂ separation MMMs in terms of nonporous and porous inorganic filler materials. The roles of fillers in tuning the membrane microstructures were elucidated. The compatibility between the polymer matrix and the inorganic filler was discussed and the corresponding solutions were emphasized. In future, filler structure design, filler dispersion, and structure-properties relationship should continue to be studied, while more attentions should be focused on two-dimensional fillers, microcapsule fillers and facilitated transport.

The sample of sludge-based activated carbon (SAC) with iodine value of 683.40mg/g and yield of 55.5% was prepared by using the dried activated sludge from petrochemical enterprises as carbon source and ZnCl₂ solution as activator. The carbonization condition was 613℃ and 70min. HNO₃, H₂SO₄ and H₂O₂ solutions with different concentrations were used to modify the properties of obtained SAC. Iodine value, BET, Boehm titration, ICP, FT-IR, XRD, SEM and TEM were used to characterize different SAC samples. The results indicated that the BET surface area, pore volume, iodine value of SAC increased obviously after modification of HNO₃ and H₂SO₄, which could enhance the SAC’s adsorption ability efficiently. When the concentrations of HNO₃ and H₂SO₄ were 0.5mol/L and 1.0mol/L, the modification effects to SAC were better than other concentration conditions. Compared to original SAC， the adsorption amounts of toluene increased by 38.80% and 27.19%, respectively and the adsorption penetration time extended. But the modifiers of H₂O₂ solution were not favorable to the modification of SAC. Finally, the regeneration abilities of modified SAC were tested and the modified SAC displayed excellent abilities of recycling utilization.

Aiming at the problem that no difference pipe connection measures cause biochemical system cannot run efficiently in the chemical industry wastewater treatment plant, this study focuses on the subject of the actual chemical wastewater. Put forward a method of S_TOD value based on active sludge oxygen uptake rate(OUR) to evaluate chemical wastewater quality, by this method, wastewater quality can be respectively to three categories of biochemistry, refractory, poisonous fast and accurately. Using S_TOD, luminous bacteria, zebrafish, daphnia magna to evaluate wastewater quality, the correct rates were 100%, 50%, 62.5% and 37.5% respectively, S_TOD value can evaluate wastewater quality more scientifically and reasonably. Thus, a set of classified pipe connection model of wastewater quality is put forward, which realizes the efficient and economic operation of biochemical system of pipe connection, as well as the effective reduction of refractory and toxic substances.

Experiences of pulverized coal combustion with different mineral additives were carried out in a tube furnace. When the mass addition ratio of the four mineral additives ( Kaolin, montmorillonite, attapulgite and limestone ) were 0, 1%, 3% and 5%, the enrichment effects of heavy metals (Pb, Cd, Zn and Cr ) were studied at 900—1300℃. The results indicate that there exists a positive correlation between the addition of additives and the retention rate of each heavy metal, and the addition ratio of 5% is more suitable. The suitable enrichment temperature range of the additives for Pb and Cd is 900—1000℃. The retention rates of Pb and Cd are maintained at approximately 60% in this temperature range. The suitable temperature for Zn enrichment is 900℃. The retention rate of Zn is close to 70% at this temperature. The temperature range for Cr is 1000—1100℃, and the retention rate of Cr can reach 82.1%. When the temperature reaches 1100℃, the coking of coal ash will lead to a decrease in the retention rate of the four heavy metals. When the temperature rises to 1200℃, the retention rate will drop significantly；the additives are almost completely inactivated at 1300℃; and among them, the retention of Pb is only about 25%, the retention of Cd and Zn is reduced to approximately 30%, and the retention of Cr is reduced to 56% or less. Comparing the enrichment effects of the four additives on Pb, Cd, Zn and Cr, Kaolin and attapulgite have better performance, followed by montmorillonite and limestone is the last. This study can provide theoretical and experimental basis for pollution control of heavy metals in coal-fired power plants.

The main component of incineration waste from biomass thermal power plants is plant ash, which has a large output and a small specific gravity. A large amount of ash without treatment will cause environmental pollution problems. The research firstly analyzed the chemical composition of plant ash, determined the fertilizer characteristics of plant ash, and added NH₄H₂PO₄ to make the pH of plant ash reach the relevant national compound fertilizer standard. Polyaspartic acid (30% aqueous solution) was selected as the binder of the compound fertilizer and was applied to the molding and granulation of the plant ash compound fertilizer to increase its compressive strength and fertilizer efficiency. The effects of different drying time, drying temperature, and amount of polyaspartic acid on the compressive strength of plant ash compound fertilizer were studied. By analyzing the plant morphology and physiological indicators, the fertilizer efficiency of plant ash compound fertilizer was studied. The results showed that the optimum drying conditions were 10h and 140℃, polyaspartic acid significantly enhanced the compressive strength of plant ash, and the fertilizer effect was the best when the compound ratio of plant ash to polyaspartic acid was 6g∶1mL. This method solved the problems of interruption of element circulation, environmental pollution of plant ash, the fragility of plant ash compound fertilizer during transportation, and the low efficiency of pure plant ash fertilizer.

With the rapid development of new energy vehicles, the amount of spent lithium iron phosphate (LFP) power batteries increase explosively, and the demand for recycling the spent LFP batteries is very urgent, which however still faces the problem of poor economics of recycling. Due to the high value of the cathode materials in LFP battery, we proposed a new method for preparing battery grade iron phosphate from the spent LFP cathode material by using phosphoric acid, whose key is to remove the impurities such as Al. In this paper, the leaching of aluminum-containing lithium iron phosphate cathode powder was optimized and the process kinetics was studied. The effects of the ratio of acid to material, leaching temperature, liquid-solid ratio and stirring speed on the leaching efficiency of lithium iron phosphate and aluminum, as well as the leaching kinetics in phosphoric acid solution, were also investigated. The results showed that under the optimal conditions of ratio of acid to material 1.1mL/g, temperature 20℃, liquid-solid ratio （5∶1）mL/g, stirring speed 400r/min and reaction time 120min, the leaching efficiency of lithium iron phosphate was above 93%, and the leaching efficiency of aluminum is below 20%. The leaching model was fit to the shrinking core model without solid product layer, yielding an apparent activation energy of 24.62kJ/mol with the liquid film diffusion as the rate limiting step.

In the chemical industry, the voting logic and failure of hazardous gas detection system are very important for the network placement of detectors. In this paper, by introducing the probability of failure on demand (PFD) of the voting system and analyzing the voting logic of the detection system, a method for optimal placement of detectors based on unavailability and voting logic was proposed. The detection time and PFD of each loop in the voting were obtained based on the voting logic analysis, the minimization of total detection time at all levels detectors in each scenario was chosen as optimization goal, which combined the detectors’ number and position constraints to establish mathematical optimization models. Using the monitoring point of each candidate detector as the gene, an optimization program based on genetic algorithm was written to solve the mathematical programming model. By analyzing the scene detection results of each layout scheme, the practicability of the method under different requirements is verified.

Many human-based HAZOP (hazard and operability analysis) results were stored as paper documents. It is difficult to reuse and share the results. At the same time, the computer-aided HAZOP results can only be recognized by the special software. The results are also difficult to reuse and share. For the problem, the HAZOP information standardization framework was proposed. The HAZOP standard information model including the model structure, definitions of the elements and relationships of elements was proposed basing on knowledge ontology and HAZOP international standard IEC 61882. The HAZOP information standardization approach was proposed based on the model. Every HAZOP record was tagged, trained and identified using BiLSTM neural network in the approach. The human-based HAZOP results can be identified and standardized automatically by the approach. The framework was used for HAZOP of an oil synthesis equipment. It was proved that the HAZOP results can be transformed to the standard form automatically using the framework. The HAZOP information can also be reused and shared easily.