In the context of carbon peaking and carbon neutrality, biodiesel is considered to be one of the most promising alternatives to fossil fuels. As a novel heating method, microwave-intensified technology can overcome some disadvantages, such as uneven heating etc., compared with traditional heating. Therefore, it can promote transesterification efficiency significantly and improve biodiesel yield greatly, coupled with different catalytic systems. This review first summarizes the advantages of microwave-assisted intensification of transesterification to prepare biodiesel. Then, the research status of microwave-intensified technology coupled with homogeneous catalysis, heterogeneous catalysis, ionic liquid catalysis as well as enzyme catalysis is especially introduced, and the corresponding pros and cons of each catalytic systems under microwave-intensified technology is analyzed. In terms of the catalytic efficiency and environmental-friend, it is illustrated that microwave-intensified technology coupled with heterogeneous catalysis and enzymatic catalysis is widely used in biodiesel preparation. Finally, some prospects and suggestions are proposed for the research field.

Using fluidized bed to produce polyolefine is one of the core technologies for polyolefin production. By taking the patents related to global polyolefin fluidized bed technology is the research object, the distribution of global polyolefin fluidized bed patent technology was studied from the perspective of global patent application trend, patent technology source and layout in this review. In the meantime, the development trend, main technology distribution and global technology competition pattern of polyolefin fluidized bed technology are analyzed by adopting the methods of text clustering, technical efficacy matrix and cooperative network analysis. The core applicants' key technology are analyzed, so as to provide reference basis for the development of polyolefin fluidized bed technology in China. The results showed that the technology in the field of polyolefin fluidized bed is in a period of technological stability, and the phenomenon of technological monopoly is prominent. The technical strength of United States is strong, while China is a technology importing country and its local strength was relatively week. There is a big gap in technical strength between China and the United States. Technically, the catalyst research is the key direction in the field, and the research around polymerization reactor had gradually become a hot spot. Meanwhile, the condensation process as well as recovery and separation process are relatively lack of attention, which can be the direction of technological breakthrough for domestic enterprises and R & D institutions.

Quench system is a unit of ethylene plant with complex operating conditions and many restricting factors. In this paper, the characteristics of the quench technology were described, and it was emphasized that the composition of cracking gas was very important to the setting of quench process. According to the different effects of raw materials on quench process, the quench process can be divided into three kinds, which were heavy liquid raw material, light liquid raw material and gas raw material (ethane, propane). In this paper, a typical process flow diagram was provided for the quench technology of liquid raw materials, and the heat removal cycle of the quench system of light and heavy liquids was compared and analyzed. The optimization principle of key technical parameters of the quench system was put forward, especially the characteristics and determination methods of the quench technology of light liquid in heat distribution and bottom temperature control of quench oil tower were explained. The quench technology of gas raw material had outstanding characteristics. This paper proposed three kinds of decoking technologies for step by step decoke and purification, and described the combined purification technology of “gas flotating + coalescence” in detail. In this paper, the design and optimization method of quench system were provided, and the application and effect of quench technology of light liquid raw material and ethane gas were also described.

Under the working conditions of flow regulation and fluid excitation, the pump will have a wide range of pressure fluctuation, which is easy to lead to the "instability" of the mechanical seal and affect the safe operation of the pump. By establishing the spiral groove three-dimensional liquid film model, using the Mixture multiphase flow model and the Zwart-Gerber-Belamri cavitation model, the evolution law of boundary pressure fluctuation on the end face cavitation and sealing performance of sealing liquid film is explored. The results showed that there was a phase difference between gas volume fraction fluctuation and pressure fluctuation under the condition of boundary pressure fluctuation. Compared with the pressure fluctuation on the outside diameter side, the pressure fluctuation on the inside diameter side had a greater impact on the end face cavitation. The pressure fluctuation on the outer diameter side had little effect on the sealing performance and had good follow-up, while the pressure fluctuation on the inner diameter side was the opposite. In addition, under the condition of inner diameter side pressure fluctuation, there was a critical pressure that mad the gas phase volume fraction 0, and the critical pressure was related to the fluctuation period. The end face cavitation disappeared, resulting in a sharp change in the sealing performance curve. Based on the research on the influence of boundary pressure fluctuation on liquid film seal, the pump mechanical seal should adopt the form of rotary seal (pressure fluctuation acts on the outer diameter side) to reduce the influence of pressure fluctuation in the pump on the mechanical seal.

Firstly, a new main structure of three-phase decanter centrifuge with adjustable overflow weir plate was proposed, in which radial oil discharge channels and overflow weir plates with adjustable position and size were set up. Secondly, using the computational fluid dynamics software Fluent, based on the Euler-Eulerian multiphase flow model, the numerical simulation of the flow field and separation performance of the three-phase decanter centrifuge was carried out. The three-dimensional flow region model was established, and the meshing and boundary conditions were set. The oil phase and solid phase concentration distribution were analyzed. After that, the experimental process flow chart was determined, and an experimental system platform for oil-water-sand three-phase separation was built. In addition, the three-phase separation experimental system device was established, and the experimental steps were formulated for experimental research and measurement. The respective influence laws on the solid phase recovery rate, oil phase recovery rate, oil loss in filter cake and oil loss in water were studied from the rotating speed of the drum and the treatment capacity. Furthermore, the numerical simulation results were verified experimentally from the aspects of solid-contained of sand outlets, oil-contained of oil outlets, oil-contained of sand outlets, oil-contained mass concentration of water outlets.

Aqueous by-product from Fischer-Tropsch process contains C₁—C₈ alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol) and water (>95%) in which C₂—C₈ alcohols form the minimum-boiling azeotropes with water. The complete separation of alcohol-water mixture is of great importance. However, the process still remains a challenge due to difficulty in separation and huge energy consumption. Therefore, it has been a topic of interest for academia and industry. Noticeably, C₂—C₃ alcohols/water form homogeneous azeotropes whilst C₄—C₈ alcohols/water form highly heterogeneous azeotropes. Based on these characteristics, the two columns-sidestream decanter process was designed to achieve the precise separation of C₁—C₃ alcohols/water mixture, dehydrated C₄—C₈ alcohols mixture and water. C₄—C₈ alcohols/water mixture from the sidestream entered the decanter to break the distillation boundary. Water rich phase returned to the sidestream distillation column, while alcohols rich phase entered stripper column to obtain highly dehydrated C₄—C₈ alcohols mixture. Total annual cost (TAC) targeted steady-state optimization revealed that the two columns-sidestream decanter sequence has a 14.79% reduction in TAC and a 15.96% energy saving compared with the conventional three-column sequence. Furthermore, the control structure of the two columns-sidestream decanter sequence was established. The result of dynamic simulation showed that robust control was achieved with the combination of a concentration controller and a feed-forward ratio control structure. This work provides the design schemes and useful guides for the efficient separation of mixed-alcohol from Fischer-Tropsch aqueous by-product.

CO₂ separation and capture are one of the important ways to achieve the goal of “carbon peak and carbon neutrality”. Conventional CO₂ separation methods are highly energy-consuming in general. CO₂ separation employing waste heat can realize comprehensive utilization of energy so as to reduce energy consumption. Since coal-fired power plants emit lots of CO₂ and are abundant in waste heat resources as well, a thermal-transpiration-effect-based separation system for flue gas from coal-fired power plant was proposed with the establishment of corresponding mathematical model and performance evaluation indicators. The concentration and recovery rate of CO₂ rise as the thermal-transpiration-effect-based separators increased in series, but the improvement of separation effect was not significant when the concentration and recovery rate reached a certain threshold, respectively. After the flue gas from a typical 1000MW coal-fired power plant was processed by the 24 gas separation units in series of the proposed system, the maximum CO₂ concentration and CO₂ recovery rate could approach to 98.89% and 72.53%, respectively. In addition, the system can realize the energy cascade utilization of flue gas with the exergy efficiency of the system of 64.8% and the unit energy consumption of 0.047GJ/tCO₂, which meant the proposed system was potentially energy-saving compared with the traditional CO₂ separation ways. CO₂ separation employing thermal transpiration effect agreed with the current policy orientation of net zero carbon emissions and can provide an innovation for CO₂ separation and capture.

The separation of four-component mixtures containing methanol, water, propylene glycol and dipropylene glycol was studied. A new process using four-product Kaibel dividing wall column (Kaibel column) was proposed in terms of the characteristics of the separation system and separation requirements. The design and energy-saving analysis of Kaibel column were performed by Aspen Plus. Firstly, a three-column distillation (TCD) process and a heat-integrated three-column distillation (HTCD) process were proposed to separate four-component mixtures. Secondly, a simulation for separating four-component mixtures via four-product Kaibel dividing wall column was conducted, and the column design parameters that meet the separation requirements were obtained. Finally, the energy consumption features of Kaibel column were analyzed and compared using an approach based on energy balance and exergy loss analysis. The results showed that compared with the heat-integrated three-column distillation process, Kaibel column didn’t have an advantage in terms of operating costs, but had a significant advantage in terms of equipment investment. It permits separation of a four-component mixture into four pure fractions in a column and the total exergy loss can be reduced by 9.41%.

In order to deal with heat dissipation problems, such as high power, long-distance complex space layout and relative movement of heat sources, a high-performance flexible loop heat pipe (LHP) was designed and manufactured. With ammonia as the working fluid and polytetrafluoroethylene (PTFE) as the capillary wick of LHP, braided stainless steel metal hoses lined with smooth PTFE were coupled in the vapor and liquid lines, respectively. Using a thin film heater as the simulated heat source and the cooling circulating water as the heat sink, the thermal performance of LHP was experimentally tested and evaluated, including the startup, the power increment test, the system thermal resistance and the heat transport capability. The results showed that the LHP exhibited excellent startup characteristics and heat transfer performance, and the response to variable heat load was fast and stable. The LHP could achieve a maximum heat transfer capacity greater than 700W. The system thermal resistance was less than 0.01K/W, and the operating temperature was less than 35℃ under the effective transmission distance of more than 3.97m. To better assess the rationality of the LHP design, the pressure drop of each LHP component during steady state operation was calculated and compared. It was found that the diameter of the vapor line was the main influencing factor, and the reasonable selection of the PTFE hoses caused no significant increase in the system fluid flow resistance virtually, but could provide a good mechanical flexibility.

The LNG separated from syngas by cryogenic liquefaction unit plays an important role in peak regulation, and significantly improves the economic benefits. However, the high energy consumption of cryogenic separation is a big problem in existing industries. In this paper, a cryogenic separation process coupled with lithium bromide absorption refrigeration and organic Rankine cycle was proposed. The waste heat is recovered from original compression refrigeration system, reducing the total refrigeration energy consumption. The compression stage was positively related to energy consumption and available waste heat. In order to minimize the energy consumption of the system, it was necessary to optimize the compression stages and the waste heat utilization system at the same time. The novel process of eight combination of compression stages was optimized by adaptive genetic algorithm. Then the lowest energy consumption was determined by comparing the total energy consumption, performance coefficient and unit energy consumption of each model. The results showed that the total energy consumption was reduced by 34% compared with the original process. The coefficient of performance was increased by 0.07, while the unit energy consumption was reduced by 0.89kW/kg. The economic performance showed that the novel process decreased operating cost by 33% and increased capital cost by 25.5 million. The capital cost can be recovered within one year, indicating the feasibility of novel process in economic.

The larger the scale of heat exchange network, the extreme points in its solution space increase exponentially. The optimization requires not only the algorithm to have strong global optimization ability, but also the high-precision search of local solution space is indispensable. Since random walk algorithm with compulsive evolution (RWCE) is difficult to take into account the local search ability when optimizing large heat exchange networks, it is easy to miss the optimal solution. In order to increase the population size of the algorithm, a parallel double-layer RWCE algorithm was proposed by combining fine search and parallel computing. Based on multi-core parallel technology, the algorithm establishes the basic-search layer and fine-search layer through parallel thread allocation. With the support of parallel computing technology, the global search ability of the algorithm was greatly improved in the basic-search layer. The fine-search layer carried out real-time fine search for the current optimal solution from the basic-search layer, avoiding the phenomenon that the imperfect solution replaced the optimal solution. Finally, through two examples, the results showed that the parallel double-layer RWCE algorithm not only has stronger global search ability, but also has high-precision local search ability, and effectively protects the optimal solution in the optimization process.

Natural gas hydrate has become one of the most promising clean energy sources in the future due to its huge reserves, clean and pollution-free.CO₂ replacement method can realize the safe exploitation of natural gas hydrate and the storage of greenhouse gas. However, the replacement process of CO₂-CH₄ hydrate in porous media is characterized by long reaction period, slow rate and low efficiency, which has become a bottleneck restricting the efficient exploitation of natural gas hydrate. In this paper, the displacement characteristics of CO₂-CH₄ hydrate in porous media system are reviewed, and the displacement mechanism and dynamic process of CO₂-CH₄ hydrate are analyzed. On this basis, the effects of different factors on the efficiency of CO₂-CH₄ hydrate replacement in porous media and their strengthening mechanisms are described in detail, including thermal stimulation, displacement pressure, small molecule gas and chemical additives. Finally, the shortcomings and future development direction of CO₂-CH₄ hydrate replacement enhancement technology in porous media system are pointed out. Further research is needed to understand the strengthening mechanism and dynamic mechanism of CO₂-CH₄ hydrate replacement in porous media.

Proton exchange membrane fuel cell (PEMFC) is a green energy technology with great potential due to its advantages of high efficiency and zero emission. As a reasonable and reliable tool, mathematical models can guide the optimal design of PEMFC by simulating the electrochemical heat and mass transfer process inside PEMFC and study the influence of operating parameters and structural parameters on the performance and lifespan of PEMFC. In this paper, the research models of the PEMFC catalyst layer, gas diffusion layer and flow channel in recent years are reviewed, and the influencing factors and optimization methods of each component modeling are sorted out, which can provide a guideline for the modeling and optimal design of PEMFC. Considering the limitations of the current simulations, the main research directions in the future are the combination of the PEMFC system research and mechanism model, the modeling of catalytic layer microstructure, non-precious metal catalyst, gas diffusion layer degradation, large-area flow channel, and 3D temperature distribution, and the full-scale proton exchange membrane fuel cell model development.

“Emission peak and Carbon neutrality target” brings new challenges to chemical production. Improving energy supply structure and enhancing energy efficiency are ones of the important ways to solve this problem. With the continuous development and improvement of energy conversion technology and energy storage technology, the utilization level and supply stability of renewable energy are further improved. It has obvious advantages in replacing chemical utilities system mainly based on fossil energy, and is considered as the most promising way of energy supply for a new generation of chemical systems. Based on the technology of renewable energy supply, this paper summarizes the application status of renewable energy in new chemical utilities such as heating, cooling, water supply, power supply and multigeneration system, and highlights the important role of renewable energy in energy saving and emission reduction compared with traditional chemical utilities. The matching status, problems and challenges of renewable energy in chemical utilities are discussed, and its future development is forecasted. The paper points out that the renewable energy chemical public engineering will become an important way to solve the dilemma of chemical environmental protection.

Co-pyrolysis technology is an important means to convert a variety of raw materials into clean energy through thermochemical methods. This paper reviewed mainly about the co-pyrolysis technology development status and the research progress of the agricultural biomass resources and plastics such as polypropylene (PP), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyvinyl chloride (PVC), polystyrene (PS) and polyethylene terephthalate (PET), etc, in recent years. The kinetic model and the law of synergy between the components of co-pyrolysis of common agricultural biomass with plastics were analyzed and the co-pyrolysis mechanism of agricultural biomass and plastics was claimed. The influence of temperature, heating rate, residence time, the mixing ratio of raw materials and other factors on co-pyrolysis were concluded. The characteristics and distribution law of co-pyrolysis products of biomass and plastics were analyzed in this paper. In terms of solid products, biochar obtained from co-pyrolysis of biomass and plastics had high calorific value and high porosity, which can be used as cheap absorbent, carbon coating, solid fuel and soil amendment, etc. In terms of liquid products, liquid obtained from co-pyrolysis of biomass and plastics had lower water content, oxygen content, acid content and higher calorific value, and the viscosity coefficient of liquid products can be changed. The liquid can be used as aviation fuel by upgrading. In terms of gas products, syngas obtained from co-pyrolysis of biomass and plastics had higher heating value, which can be used as energy for daily life. Consequently, the advantages and disadvantages of the co-pyrolysis technology of biomass and plastics were summarized and the future development direction of biomass and plastic co-pyrolysis technology was prospected. This paper can provide a theoretical reference for the co-pyrolysis of biomass and plastic to prepare high value-added products, and new methods and new ideas for the treatment of agricultural biomass and agricultural film.

The development of electrolytes for liquid aluminum electrolytic capacitors is mainly focused on the branched polycarboxylic acids and their salts, but the high-temperature stability and low-temperature performance of the electrolytes still need to be improved. To address this shortcoming, three ether-based branched carboxylic acids (EBCS₁, EBCS₂, EBCS₃) that have both skeletal structures and ether groups were prepared, and characterized with NMR and FT-IR spectrum. Then, the electrolyte system was optimized to be 70% ethylene glycol and 10% γ-butyrolactone with an optimal content of EBCS boiled at 140℃, with which an electrical conductivity of 1.8mS/cm and spark voltage greater than 550V were achieved. The assembled capacitors demonstrated excellent performance judging from the resultant capacity, loss, equivalent series resistance, leakage current, low-temperature impedance and high-temperature lifetime, and thus have a good commercialization prospect.

High temperature proton exchange membrane fuel cell (HT-PEMFC) has broad application prospect, but it is limited by the short lifespan. In this paper, the stability of a hundred-watt air-cooled HT-PEMFC stack was studied. The constant current test showed that the voltage decay rate of the single cell in the middle of the stack was 5—10 times that at the two ends. XRD and TEM results showed that the Pt particle size of the single-cell catalyst at different positions varies slightly, while the acid absorption titration of the electrode plate and the ohmic polarization loss analysis showed that the phosphoric acid loss rate of the single-cell catalyst in the middle position was about 2—3 times that at the two ends, causing its internal resistance to be 5—8 times that of the two ends. Meanwhile, the migration of phosphoric acid from the membrane to the electrode resulted in an increase of 41—102mV in the oxygen gain voltage compared to the two ends. To sum up, the excessive loss of phosphoric acid from the single cell in the middle of the stack is the main reason for its short life, which is the result of the uneven temperature distribution inside the stack. Therefore, the key to increase the stack life is to optimize the management of phosphoric acid and heat in the stack.

China’s energy structure determines the coal based methanol production route. The traditional coal-to-methanol process has the problems of low energy efficiency and high energy consumption of CO₂ capture. In order to reduce energy consumption and CO₂ emission, and improve energy efficiency, a new coal-to-methanol process based on chemical looping air separation and hydrogen technology was proposed. The chemical looping air separation technology can replace the cryogenic air separation unit of traditional coal-to-methanol process, and reduce energy consumption to a certain extent. The integration of chemical looping hydrogen production technology can replace the water-gas shift device and greatly reduce the energy consumption of CO₂ capture; moreover, chemical looping hydrogen production technology can also produce hydrogen for adjusting the hydrogen to carbon ratio of syngas. In this paper, the parameters of the core units of the new process were optimized and the whole process was simulated. Based on the simulation, the performance of the new process was analyzed. The results show that the energy consumption of air separation and CO₂ capture is reduced by 41% and 89%, respectively, comparing with the traditional coal-to-methanol process. At the same time, the energy efficiency of the new process is increased by 18% and the CO₂ emission is reduced by 45%.

In the process of removing H₂S from natural gas usng a single MDEA solution, both H₂S and total sulfur content in the output gas always cannot meet the quality requirements of national class II natural gas with the continuous increase of organic sulfur content. After changing the key parameters, the desulfurization effect still could not be improved. Therefore, for the high content of organic sulfur, this paper carried out the research on the compound of MDEA+DIPA, MDEA+DEA, sulfolane+MDEA and sulfolane+DIPA four groups of efficient desulfurizers. By comparing the absorption partial pressure of H₂S and organic sulfur in solution, the better absorption desulfurizer combination was selected as sulfolane+MDEA. Then, the BBD response surface methodology was used according to the different ratio of sulfoxane, MDEA and H₂O as variables, and the optimal ratio of H₂S and total sulfur removal rate was optimized as the objective function. After mixing experiments and composite optimization, the optimal ratio of desulfurizer was obtained as 23.3% sulfoxane+54.6% MDEA+22.1% H₂O. The results of the optimal proportion of desulfurizer after the use of the field device showed that the removal rate of H₂S reached 99.964%, the removal rate of total sulfur was 99.833%, the content of H₂S in the effluent gas was 14.4mg/m³ and the total sulfur content was 78.5mg/m³, which met the national standard of class II gas.

Traditional depressurization method is easy to encounter the slow heat transfer rate of stratum, and thus the system temperature and pressure maintain a phase equilibrium condition for a long period, which seriously prolongs the production time. To solve the slow hydrate decomposition rate in the low temperature area during depressurization, three-dimensional simulation of natural gas hydrate production by inhibitor injection method was carried out to obtain the law of hydrate decomposition and gas production. The effect of inhibitor injection and soaking process on hydrate decomposition was comprehensively analyzed on the basis of temperature and pressure change. The results showed that the inhibitor injection method could significantly speed up the efficiency of hydrate decomposition during injection period, however, large injection volume and multiple-time injection were easy to cause plugging and prolong the production time. Compared with the small-sized experimental device, the inhibitor had been fully migrated in the injection stage due to the long injection time in the pilot-scale experiment, therefore, the soak time should be about 40minutes.

Carbon dioxide hydrate storage has become a research hotspot in the field of carbon sequestration. For this technology, the research on the formation and decomposition characteristics of carbon dioxide hydrate and its influencing factors is the focus and difficulty at present. Therefore, a high-pressure fully transparent double- reactor experimental platform was designed in this paper. Taking high-purity carbon dioxide and deionized water as the research object, the primary and secondary formation/decomposition experiments of carbon dioxide hydrate were carried out under the initial temperature of 17℃and pressure of 7MPa, and the influence of stirring was studied by setting the comparing group. Besides, the experiments were compared with the experiments of methane under the same conditions. The experimental results showed that stirring could promote the formation of carbon dioxide hydrate. At the rotating speed of 400r/min, the induction period could be shortened by 40%, the pressure drop rate could be increased by 15%, more and denser hydrate could be formed, and the decomposition could be delayed. Multiple formation could reduce the induction time of hydrate, but it had little effect on the amount of hydrate. Compared with methane hydrate, the carbon dioxide hydrates were produced in larger quantities and more difficult to decompose. The experimental results were conducive to the marine hydrate storage of carbon dioxide.

The synergistic inhibition of ethylene glycol (MEG) and kinetic inhibitor (KHI) PEO-co-VCap-1 on methane hydrate regeneration in the presence of fine sand was studied in a 500mL high-pressure reactor with pure methane gas. The mass fraction range of MEG and PEO-co-VCap-1 was controlled to be 0—5% and 0—0.5%,respectively. Four inhibitor formulations with different doses were formed, and 12 groups of experiments were carried out. The results show that PEO-co-VCap-1 alone can delay the nucleation stage of hydrate, but it may lead to the disastrous growth of hydrate in a short time. Its combination with MEG can delay hydrate nucleation, effectively reduce the occurrence of catastrophic growth and reduce the risk of pipe blockage in oil and gas pipeline transportation. When the mass fraction of MEG was 5% and the mass fraction of PEO-co-VCap-1 was 0.5%, the synergistic inhibitory effect was very obvious, which could prolong the induction period of methane hydrate to more than 2800 min. The synergistic inhibitory effect of MEG and PEO-co-VCap-1 was similar to that of increasing temperature. This finding shows that if PEO-co-VCap-1 is used together with good synergists such as MEG, it will help kinetic inhibitors to be used in higher undercooling environment, and provide new possibilities for efficiently solving the problem of hydrate prevention and control in oil and gas production under high undercooling conditions.

In recent years, the application of whole-cell biocatalyst in biodiesel production has attracted great attention. Whole-cell catalyst avoids the cumbersome enzyme purification process and saves the preparation cost of the catalyst. Moreover, whole-cell biocatalyst has a long service life. In this study, a strain of Rhizopus oryzae with high lipase production was immobilized and applied. Different immobilization materials were selected and the suitable immobilization conditions were explored. The immobilized Rhizopus oryzae as the whole-cell catalyst was used to catalyze the preparation of biodiesel from Comus wilsoniana fruit oil. The effect of esterification conditions on the yield of biodiesel was discussed. The results showed that the immobilization rate and activity of the immobilized cells were the highest with the loofah sponge as the immobilization material, olive oil as carbon source,and peptone and NaNO₃ as compound nitrogen source. In the reaction system of 10% water content and 12% catalyst dosage, the molar ratio of total alcohol to oil was 4∶1, methanol was added 1∶1 at 0h, 10h, 24h, 40h, respectively, and the yield of methyl ester was more than 94%. After the immobilized whole-cells were reused for 6 times, the transesterification acticity of immobilized cells remained above 80%.

Ethylene is one of the most important industrial raw materials in petrochemical industry, however, the presence of a small amount of acetylene impurities in ethylene products will directly affect the subsequent application of ethylene. Selective catalytic hydrogenation of acetylene is considered to be one of the most effective methods for removing acetylene impurities. In this paper, the research progress of acetylene selective hydrogenation catalysts in recent years is reviewed, including the reaction mechanism, and the effects of active components, promoters, supports and structures on the catalyst performance. In view of the fact that the Pd-based catalysts are still the mainstream catalysts used in industry, the research status and current challenges of Pd-based catalysts are reviewed, and suggestions for the optimization of catalytic performance are proposed. Finally, the development trends to further improve the catalytic performance of acetylene hydrogenation catalysts are summarized, mainly from the aspects of single-atom alloy catalyst, catalyst micro-control, and electrochemical olefin hydrogenation.

To ensure efficient conversion of asphaltenes in residual oil to light fractions under long-term stable operation, it is crucial to use highly-dispersed catalysts that have the activity of oriented catalytic hydrogenation and the ability to restrain coke formation in slurry-phase hydrocracking. Bimetallic dispersed catalyst fabricated by adding promoter metals could effectively reduce the cost and significantly improve the hydrogenation activity. In this paper, the research progress of dispersed bimetallic catalysts in slurry-phase hydrocracking technology are comprehensively reviewed, including the cobalt-molybdenum, nickel-molybdenum, iron-nickel and other bimetallic catalysts, with emphasis on their activities and active phase structures, and the pros and cons of different bimetallic catalysts are analyzed and summarized. As for the future research on dispersed bimetallic catalysts, it is of great significance for the development of high-efficiency catalysts for residual oil by exploring the synergy between metals and the structure of the active phase of the catalysts.

It is of great significance to realize the wide application of non-noble metal catalysts in hydrogenation reaction for industrial catalysis. The new carbon encapsulated non-noble metal catalysts have attracted much attention due to their excellent structural stability and catalytic hydrogenation performance. This paper reviews the recent development of carbon encapsulated non-noble metal catalysts, and the effects of different preparation methods on the carbon encapsulated structure and their advantages and disadvantages are summarized. Furthermore, the performance and stability of carbon encapsulated non-noble metal catalysts in the hydrogenation of nitro-aromatic, carbonyl aromatic hydrocarbons, phenol, quinoline and Fischer-Tropsch synthesis are introduced. At present, the problem to be solved urgently is to realize the controllable adjustment of the size of metal particles and the structure of carbon shell. A future research focus is to further explore economical and feasible preparation methods of carbon encapsulated non-noble metal catalysts whose structure can easily adjusted.

High melt strength polypropylene (HMSPP) is a new kind of polypropylene material with high melt strength, elasticity and strain hardening during melt stretching. In recent years, the research and development of long chain branched (LCB) HMSPP (LCB-HMSPP) has attracted extensive attention in both academia and industry. After preparing LCB-HMSPP via various methods and processes, whether the obtained polymer has long chain branched structure, and the topological structure information such as chemical composition, density and chain length of long chain branch need to be qualitatively or quantitatively verified by various instrumental analysis and characterization methods. The new progress in the analysis and characterization of LCB structures in HMSPP by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹³C NMR), gel permeation chromatography (GPC) and its combined methods, rheology and crystallization behavior characterization, were summarized and reviewed. The advantages, shortcomings and applicability of these methods were introduced and compared. Finally, the future development and application of the analysis and characterization methods of LCB chain structure in LCB-HMSPP were prospected.

Lithium ion battery has high energy density and good cycle performance. It is the most ideal power supply and energy storage system at present. However, due to the immature technology of high-capacity and high-power lithium-ion battery and potential safety hazards, its commercial application has been limited to a great extent. The safety problems of lithium-ion battery mainly include mechanical damage, abnormal charging, gas accumulation and thermal runaway. This paper analyzed the causes of the above risk factors and the suppression methods. Among these methods to enhance battery safety, the use of safety additives was the most economical and effective means, but it was not easy to find a practical additive with high safety performance for the battery without sacrificing other performance in the electrolyte. In the future, multifunctional additives would be the most promising research direction for improving battery performance. This paper briefly analyzed the action mechanism of film-forming additives, flame retardant additives and anti overcharge additives, and prospectd the development direction of related fields.

As a common potentiometric sensor, solid-state ion-selective electrodes (SS-ISEs) have attracted much more attention due to simple structure, low cost, easy miniaturization and wearability, therefore have been widely used in industrial analysis, environmental monitoring, biomedical and related fields. As one of the components of an all-solid-state ion-selective electrode, the solid-state transduction layer plays a crucial role in the performance of the electrode. Carbon-based materials have good ion-electron signal conversion efficiency and chemical stability, are considered as an ideal materials for solid-state transduction layers. This article briefly describes the response mechanism of carbon-based materials in all-solid-state ion-selective electrodes, reviews the research progress of graphene, carbon nanotubes, porous carbon materials and other kinds of carbon-based nano materials as solid-state transconductance layer materials. Finally, we analyze and compare the properties of the above materials such as electrical conductivity, capacitance, specific surface area and hydrophobicity as well as their prospective and future development trends.

Metal-organic framework is a porous crystal material composed of metal ions/clusters and organic ligands with a certain rigid structure connected by coordination bonds. It has many advantages, such as porous, large specific surface area, various structure and easy modification. It is widely used in energy, chemical industry and medicine. Mechanochemical synthesis is a method of chemical reaction induced by mechanical energy. It has been widely concerned in recent years because of its green, short time-consuming, high efficiency, wide application range and few side reactions. Mechanochemical synthesis also shows significant advantages in the preparation of metal organic framework materials. In order to have a comprehensive understanding of the latest development of the mechanochemical synthesis of biomaterials, this paper introduces the classic cases of the preparation of metal-organic frameworks by grinding method. Especially, the synthesis of metal-organic framework for biological and medical applications is introduced. The research progress shows that grinding method, which is green and efficient, provides the possibility for the wide application of metal-organic framework materials in the field of medicine and has a good prospect.

In order to mimic the multifunctional sensing function of skin, a large number of flexible and stretchable sensor arrays have been constructed based on different conduction mechanisms and structural designs. The flexible sensors that can realize multifunctional identification and monitoring of physiological signals related to human health, such as pressure, strain, temperature, humidity and gas, show the great application prospects in the development of wearable artificial intelligence devices. In his paper the latest research achievements in the field of flexible electrochemical sensors with multi-mode monitoring were reviewed. The sensor can detect two stimuli (pressure-strain, pressure/strain-temperature, pressure/strain- humidity, pressure/strain-gas), three stimuli (pressure-strain-temperature, pressure-temperature-humidity, pressure-temperature-gas, etc.) and more than three kinds of stimuli (pressure-strain-temperature-humidity, etc.), which are defined as two-mode sensor, three-mode sensor and multi-mode sensor respectively. This paper focused on the pathway and sensing mechanism of the sensor to achieve multifunctional monitoring. The analysis shows that the methods to achieve multifunctional sensing properties mainly include both structural design and multifunctional material preparation. The flexible multifunctional composites fabricated based on advanced functional materials (including nanometals, nanocarbon and conducting polymers) and flexible matrix materials (such as hydrogels, aerogels and elastic polymers) can effectively reduce the complexity of multi-mode sensors. The characteristics and advantages of different types of functional materials in the fabrication of multifunctional flexible sensors are compared and pointed out to provide implications for the design of multifunctional sensors.

The magnetic mesoporous silica composite material as the enzyme immobilization carrier has excellent enzyme immobilization performance and good magnetic separation performance, and has received extensive attention from academic circles at home and abroad. The surface of the self-made β-FeOOH hollow microspheres was coated with a dense SiO₂ protective layer. Under acidic conditions, β-FeOOH@SiO₂@mesoporous SiO₂ hollow composite microspheres were successfully prepared by using P123 as a template and cetyltrimethylammonium bromide (CTAB) as an auxiliary directing agent. Magnetic β-FeOOH@SiO₂@mesoporous SiO₂ hollow composite microspheres were finally calcined in a reducing atmosphere to obtain Fe₃O₄@SiO₂@mesoporous SiO₂ hollow microspheres. The results showed that the hollow structure of the prepared Fe₃O₄@SiO₂@ mesoporous SiO₂ microspheres was not collapsed and had a regular spherical structure. The mesoporous SiO₂ shell (with a average thickness of about 11nm) was uniformly coated on β-FeOOH@SiO₂ hollow microsphere surface. As the amount of CTAB increases, the most probable pore size of the microspheres decreased from 4.30nm to 3.19nm, the specific surface area increased from 376m²/g to 640m²/g, and the pore volume increased from 0.36cm³/g to 0.56cm³/g. The saturation magnetization of the composite microspheres was 11.3emu/g, and the coercivity was 111.5Oe. The rapid separation of the samples could be achieved under the action of an external magnetic field, and the redispersibility of the samples was good. When the mesoporous pore size was 4.30nm, the amount of laccase immobilized in Fe₃O₄@SiO₂@mesoporous SiO₂ hollow composite microsphere was as high as 234mg/g. The activity of immobilized laccase at different pH and temperature was significantly better than that of free laccase.

Carbon matrix composites are considered to be one of the most promising electrode materials for the wide application of supercapacitors. In this paper, graphene oxide (GO), cobalt nitrate [Co(NO₃)₂] and melamine were used to prepared nitrogen-doped graphene/carbon nanotubes/amorphous carbon (NC) composites which by using the catalytic action of cobalt on pyrolytic carbon source at high temperature, and then NC electrochemical properties were tested. The effects of metal and melamine addition levels on the structure and properties of carbon matrix composites were investigated. It was found that when the addition levels were 0.02mmol and 0.3g, respectively, the prepared materials had large specific surface area (380.5m²/g) and nitrogen content (6.29%). When the current density was 0.5A/g, the material specific capacitance was 137.1F/g, respectively with and when the current density is 5A/g, the specific capacitance was 113.5F/g, and the retention rate was 88.5%, showing excellent rate performance. After 5000 cycles, the capacity retention rate of the material was 104%, indicating good cycle stability. It was attributed to the fact that the three-dimensional structure can accelerate the ion transfer and nitrogen doping during charge and discharge processes, which can improve the material wettability and contribute part of pseudo capacitance, providing theoretical reference for the preparation of electrode materials for supercapacitors.

A series of mesoporous supramolecular polymers (PDP) with abundant CO₂ adsorption sites were constructed through the interfacial assembly of 3,3'-dithiobenzide and p-benzaldehyde at room temperature and ambient pressure. Two kinds of amino-functionalized supramolecular polymers (PDPP and PDPT) were constructed by using imine exchange with polyethylene imine and tetraethylene pentamine. Compared to PDP, the CO₂ adsorption ability of the modified supramolecular polymers was greatly improved. The CO₂ adsorption capacity of PDPT can reach 27.79cm³/g at 80℃. This dynamic imine assembly strategy provided a mild and controllable approach for the development of materials with high CO₂ adsorption performance.

As one of the most widely used power batteries, lithium-ion battery (LIB) plays an important role in electric vehicles and other industries. Temperature is an important factor affecting LIB performance and safety, and thus battery thermal management (BTM) is very important. At present, phase change material (PCM) has become a research hotspot because of high latent heat and no additional power consumption. In this study, the performance of 8 parallel 18650 LIB pack was numerically simulated, and the temperature variation characteristics of LIB was experimentally studied. The LIB heat generation model was established, and the temperature change of single LIB during the discharge process was tested. The influence of thermophysical parameters of composite phase change material (CPCM), such as thermal conductivity, melting point, latent heat and thickness, on the BTM characteristics of LIB pack designed in this paper were studied. The results showed that pure paraffin used in BTM can reduce the maximum battery temperature under 3C discharge by 28.0%. Adding expanded graphite to paraffin can further improve the thermal management performance of CPCM. When the thermal conductivity of CPCM was 2.0W/(m·K), the maximum temperature of battery under 3C discharge can be further reduced by 5.42℃, and the increase of the thermal conductivity of CPCM had little effect on the improvement of thermal management performance. Considering the maximum temperature and temperature uniformity of the battery pack, in order to obtain the best thermal management performance of the lithium-ion battery pack designed in this paper, the thermal conductivity of CPCM should be 2.0W/(m·K), the melting point of CPCM should be between 36—38℃, the latent heat of phase transition was about 212J/g, and the thickness of CPCM was 4mm.

Polymer membrane can play a big role for methanol/dye effluent treatment. For guaranteeing a high performance, enhancing the methanol swelling resistance of membrane is necessary. However, works on organic solvent-resistant membranes for methanol are relatively few. Herein, an active polymer (polyisobutenamine, PIBA) is proposed to be introduced into the separation layer for preparing a novel methanol swelling-resistant polyamide (PA) thin film composite (TFC) membrane. The incorporation of PIBA was confirmed. PIBA increased the membrane surface roughness, active layer thickness and backside compactness of active layer. The methanol swelling resistance of membrane was enhanced obviously by PIBA. The swelling rate dropped from 46.81% to 15.00% when the addition amount of PIBA increased from 0 to 1g/L. Because of this, PA/PIBA TFC membrane exhibited a far higher dye (Safranine T) rejection than PA TFC membrane (99.53% vs. 94.62%). Besides, the PA/PIBA TFC membrane maintained a high flux [84.62L/(m²•h)] and a satisfactory long-term operation stability at an operating pressure of 20bar. Finally, since polyisobutylene (PIB) was also used in previous work to improve the methanol swelling resistance of the membrane, and thus PIBA and PIB were compared. By comparison, PIBA was superior to PIB. This work provided a new avenue for developing a separation membrane for methanol effluent treatment. As a result, PIBA is superior to polyisobutylene. This work provides a novel pathway for developing separation membranes toward methanol effluent treatment.

The cold-adapted lipase, which has become a good candidate for industrial low-temperature processes, plays an important role in the fields of biomass energy, food, leather products and wastewater treatment. In this study, a high-yielding strain, NYNU 19160, was screened from 55 cold-adapted lipase-producing yeast strains preserved in our laboratory. The strain NYNU 19160 was identified as Papiliotrema fonsecae by morphology, physiological characteristics and ITS and 26S rDNA sequence analysis. The properties of the cold-adapted lipase were studied after purification by ammonium sulphate fractionation, dialysis and concentration. Results showed that it belonged to low temperature alkaline lipase. The optimal reaction temperature of the lipase was 20℃, and the optimal reaction pH was 7.5. Cu²⁺ significantly promoted the hydrolysis activity of the enzyme, while Li⁺ showed significant indigenous inhibition. Organic solvents, including acetonitrile, methanol and acetic acid, had a great promotion effect on the enzyme activity, while benzene and n-hexane inhibited the enzyme activity. The enzyme showed strong specificity for p-nitrophenyl butyrate (pNPC₄) substrate.

Using toluene diisocyanate (TDI) and polyethylene glycol (PEG) as monomers, dimethylpropionic acid (DMPA) and phosphorus-boron hybrid prepolymer PBHP as chain extender, FRWPU containing different phosphorus and boron elements was prepared by step polymerization. The paper sizing agent was prepared with ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL) expansion flame retardant system. FRWPU dispersion, FRWPU films, uncoated and coated paper samples were characterized by infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), contact angle determination, X-ray photoelectron spectroscopy (XPS) and vertical combustion test. The results showed that with the increase of PBHP content, the hydrophobicity of the films increased, and the contact angle of FRWPU40 was 85.4°, which was 35.3% higher than that of FRWPU0. At the same time, the maximum thermal decomposition rate of the films decreased, and the residual mass at 800℃ increased from 0 to 7.80%. The maximum thermal decomposition rate of the coated paper samples decreased, the residual quality increased and the average carbonization length decreased. When the PBHP content was 50%, the carbon residue was 27.84%, which was 30.6% higher than FPU0/IFR. The average carbonization length was 5.9cm, 30% lower than that of FPU0/IFR. SEM results indicated that more dense carbon layer was formed on the surface of the coated paper after combustion, and the flame retardant performance was improved.

Polyamide was synthesized by using diethylenetriamine and adipic acid as raw materials and p-toluenesulfonic acid as catalyst. Triethylamine and cationic modifier were added in the reaction of polyamide and epichlorohydrin to obtain modified PAE resin. It was used as paper wet strength agent and performing internal sizing to obtain modified PAE resin sizing paper. The structure and stability of the modified PAE resin were characterized by Fourier transform infrared spectroscopy (FTIR) and solution stability test. The effects of temperature and triethylamine dosage on the content of organochlorine, triethylamine and cationic modification were discussed. The effect of agent dosage on the physical properties of modified PAE resin sized paper was also analyzed. The results showed that when the temperature was 50℃, the amount of triethylamine was 7.4% (relative to the total mass of the reactants) and the amount of cationic modifier was 24.6% (relative to the total mass of the reactants), the organic chlorine content in the modified PAE resin was 0.067% (relative to the total mass of the PAE resin), which was lower than the 0.7% specified by the national standard, and can be placed stably at room temperature. When the amount of modified PAE resin added was 1.6% by mass, the sizing effect in the pulp was the best, the zeta potential in the pulp was -1.2mV, the contact angle of the paper was 63.56°, and the modified PAE resin sizing paper was dry compared with the base paper. Tensile index, wet tensile index, tear index and folding endurance were increased by 41%, 13%, 32.8% and 27%, respectively, and the physical properties of paper were significantly enhanced.

Rare earth metals are regards as the essential strategic resources in China due to the unique roles in high-precision products. The separation and purification of rare earth elements is particularly important in order to satisfy the high purity criterion of products. Membrane separation technology is a highly efficient, low power consuming and environmental-friendly separation method, which can be widely used in extensive fields. In addition, their application in rare earth metal separation can efficiently improve the separation properties and greatly decrease the serious environment pollutions caused by the rare earth separation and its related industries. Hence, the scientific researches on these issues are highly crucial but still facing challenges. In this review, three kinds of membrane separation strategies, including ion imprinted membrane, polymer inclusion membrane and liquid membrane, were systematically introduced. Moreover, the preparation methods and separation properties of membrane materials were summarized, and the characteristics, advantages and disadvantages of subdivision types of membrane technology were discussed and compared. Furthermore, Ion imprinted membrane exhibited the great advantages in separation selectivity, but further improvement of adsorption capacity was highly needed, which was also the research focus of membrane separation technology in the next few years. Polymer inclusion membrane and liquid membrane separation technology showed the great potentials in the rare earth separation using membrane technology in the industrial application because it can flexibly adjust the type and quantity of active sites targeting at rare earth separation according to the type and amount of extractant.

Sulfate reducing bacteria (SRB) method is a potential acid mine drainage (AMD) treatment technology. How to precipitate and separate a variety of heavy metals is the key to engineering application of SRB process. This paper reviews the domestic and foreign research progress of SRB fixation of heavy metals in AMD. It includes the principle of SRB method for removing heavy metals from AMD, the process of SRB method for fractional precipitation of a variety of heavy metals from AMD (separate multistage pH control process and anaerobic baffled reactor process), and the biological mineralization of metal sulfide in anaerobic sludge by SRB process (SRB mediated biological mineralization, influence factors of biological mineralization and the microscopic mechanism of biomineralization process), and the existing problems in this field are analyzed. Finally, the paper prospects the further research and application of SRB method, and it is believed that the regulation of sulfide mineralization in sulfate reduction system, the analysis of mineral-forming phases evolution and microbial community succession process, and the exploration of heavy metal mineralization mechanism in mineralization fixed AMD will be the focus of future research.

Biomass-derived biochar was widely used in environmental fields due to its low cost and environmental friendliness, and had a stimulative effect on achieving carbon peak and neutrality. Due to the doping of N, metal-free N-doped biochar possessed surface alkalinity and multi-adsorption sites, and the performance of pollutants removal was greatly improved. However, little attention had been paid to the green synthesis of N-doped biochar and the doping mechanism. Therefore, this paper summarized the domestic and international production of N-doped biochar and their environmental applications. The methods and N-containing functional groups were articulated. The groups included pyridinic N, pyrrolic N, and graphitic N. Their contents and types were influenced by the pyrolysis process of the N source. N doping mechanism, which was determined by the intermediates of N source decomposition, surface functional groups, and activator in the doping process, was explained. In addition, this paper discussed the environmental applications of N-doped biochar and their reaction mechanism. Based on these, we proposed the research direction of N-doped biochar to provide references for practical applications.

The development of radioactive iodine capture materials with high efficiency and low cost is of great significance for the safe utilization of nuclear energy and the disposal of nuclear waste. In view of the application status which the radioactive iodine capture materials have low adsorption capacity and adsorption rate, and high cost. Green and low-cost lignin has rich active sites such as hydroxyl group and carboxyl group, etc., which will have potential application prospects in iodine capture. Here, the lignin with rich active sites such as hydroxyl group and carboxyl group, etc. was selected as the basic raw materials, N,N-methylene bisacrylamide (MBA) as nitrogen source and crosslinking agent, and 4-vinylbenzyl chloride (VBC) as functional monomer, a series of nitrogen modified lignin based hyper-cross-linked polymers (NLHCPs) were synthesized insitu by the two-step reaction including free radical grafting copolymerization and Friedel-Crafts alkylation, the specific surface areas of these materials was up to 715.8m²/g, and had high nitrogen content (3.95%—4.48%). The adsorption performance of iodine vapor and iodine/n-hexane solution on these NLHCPs were studied, respectively. The results showed that NLHCP-2 had the largest adsorption capacity of iodine vapor (2.5g/g), and the adsorption was mainly chemical adsorption, and the iodine molecule was converted to the polyiodide anion form at the polymer surface. At the same time, the adsorption isotherms of iodine in n-hexane solution on NLHCP-2 was more consistent with Freundlich model, and the maximum equilibrium capacity reached 230.8mg/g. The kinetic curves fitting showed that the adsorption rate was mainly controlled by the diffusion process. In addition, the iodine-loaded NLHCPs can be quickly desorbed in ethanol, and had good cycling performance. This work will provide new ideas for the development of lignin-based porous materials and offer important guidance for green and low-cost radioactive iodine capture.

In order to efficiently remove lignin from lignocellulose, obtain the cellulose-rich substrate and make full use of lignocellulose components, six kinds of ternary deep eutectic solvent (DES) were prepared and synthesized for pretreatment of poplar hydrolysis residue without hemicellulose. The effects of the six DESs on the lignin removal and cellulose retention were studied, and the pretreatment parameters were optimized. The results showed that among the six DESs, triethyl benzyl ammonium chloride-ethylene glycol-ferric chloride (T-EG-Fe) had the best pretreatment effect, with lignin removal rate of 80.46% and cellulose retention rate of 90.81%. The optimal conditions for T-EG-Fe pretreatment of poplar hydrolysis residue were as follows: reaction solid-liquid ratio 1∶15, reaction temperature 130℃, reaction time 5h. Under the optimal conditions, the content of cellulose and lignin in the solid residue was 92.78% and 5.33%, respectively. T-EG-Fe has the potential for lignin separation in the pretreatment process of lignocellulose.

To study the types and sources of organic substances from wastewater generated during the discharge of spent lithium batteries by saline solution, a single-factor optimization method was used to optimize the liquid -liquid extraction pretreatment and the optimal extraction conditions were obtained by investigating the types of extraction agents, pH, and extraction times. Then, a qualitative analysis method for detecting organic substances from discharge wastewater of spent lithium batteries was established using the gas chromatography-mass spectrometry (GC-MS) program with comparative tests of splitting ratio and ramp-up modes, and the detected organic pollutants can be classified and the sources can also be determined. The results showed that the optimal separation effect could be achieved under the following extraction conditions: ethyl acetate as the extraction agent, adjusting the pH of the discharge wastewater to 9.38, centrifugalizing with 8000r/min at 4℃ for 5min, and extracting three times under intermittent mode. Ten types of organic pollutants can be detected from the discharge wastewater by SIM qualitative scanning, among which acid esters, amides and alkanes are more abundant, and those from reaction derivatives and electrolyte additives account for 33.3% and 20%, respectively. The detected organic pollutants mainly include bis(2-ethylhexyl) isophthalate deriving from electrolyte plasticizer; 1,4-cyclohexanedicarboxylic acid dimethyl ester and tris(2-chloroethyl) phosphate from electrolyte solvent effect products; stearyl amide, hexadecanamide, tetradecanamide, 1,4-cyclohexanedimethanol divinyl ether from electrolyte additives; 3,5-di-tert-butylphenol from the raw materials for antioxidant in plastic shell of spent lithium batteries. In view of their toxicity effects to the water environment caused by the detected organic pollutants, it is urgent to further test the concentration of each organic pollutant and reveal their corresponding migration and transformation rules, and establish the list of critical organic pollutants which need to be paid close attention.

The application of reconfigurable technology in battery energy storage systems is one of the effective methods for recycling retired batteries. However, it becomes very difficult to reorganize the battery energy storage system with retired batteries owing to the diverse requirements of the supply side and demand side. Moreover, it is also worthy of noting that the dismantling of retired battery packs is costly and easy to cause environment and safety problems. In order to solve these problems, battery reconfiguration technology is used to reorganize and reuse battery packs with inconsistent voltages to meet the needs of multiple loads. Under the premise of ensuring energy efficiency and system safety, an optimal design method for topology reconfiguration with low topological complexity exchange degree for multiple loads was proposed. By solving a multi-objective optimization model via applying the improved binary crisscross optimization algorithm (BCSO), we obtained an optimal structure that meets the multiple load demands. An example was given to verify the effectiveness of the proposed method. It showed that the design flexibility of the reconfigurable topology of the battery energy system can be improved by adjusting the weights of the multiple objectives.

In order to solve the problems of low hydration activity and long setting time of anhydrite-Ⅱ phosphogypsum, a composite additive was prepared which was composed of β hemihydrate gypsum 6%, sulfuric acid modified steel slag 3%, K₂SO₄ 2% and calcium aluminate cement 0.5%. It was indicated that the initial setting time was shortened from 744min (blank) to 76min (modified). Blast furnace slag powder was used to further improve water resistance and mechanical strength for the cementitious system. With the addition of slag 25%, the compressive strength of cementing material was 15.4MPa and the softening coefficient was up to 0.83. The changes of hydration rate and liquid ion concentration with time were investigated. The hydration products and hydration hardening mechanism of cementitious materials were analyzed by using XRD and SEM. The results showed that the composite additive promoted the dissolution of anhydrite-Ⅱ phosphogypsum as well as the formation and growth of dihydrate gypsum crystal nucleus, increasing the hydration rate. The combined use of the composite additive and blast furnace slag promoted the formation of a variety of low solubility double salts such as 3CaO·Al₂O₃·3CaSO₄·32H₂O and 3CaO·Fe₂O₃·3CaSO₄·32H₂O, which helped to improve the mechanical strength and water resistance of cementitious material.

Oxygen-containing functional groups were introduced on the surface of nano-diamond (ND) by the oxidation of edge defect carbons with KMnO₄ and concentrated H₂SO₄ to get the oxide diamond (OND). Under strong alkali conditions, ONDs were reacted with 1,4-butylene sulfonate lactone to get the sulfonic acid alkyl nano-diamond (SND). The structure of the SND was confirmed by TGA and FTIR, and the ion exchange capability (IEC) reached to 1.1mmol/g. After blending with SPAES, a series of SPAES-SND composite membranes with uniform surface were prepared by solution casting method. SPAES-SND composite membranes indicated high water absorption, low swelling rate, high oxidation stability and conductivity. SPAES-SND-0.5 displayed the maximum water absorption of 75% at 80℃, 31.3MPa of tensile strength, 25.1% of elongation at break and 166mS/cm of proton conductivity in 80℃ water, suggesting the good comprehensive properties. For the fuel cell performance at 80℃ and 100% RH, the maximum power density of the SPAES-SND-0.5 membrane reached to 527mW/cm², which was 51.9% higher than that of the pristine SPAES membrane (347mW/cm²). The excellent proton conductivity and battery power output SPAES-SND-0.5 showed its good application prospects.

Based on the bioremediation requirements of heavy-petroleum-contaminated sites, this study successfully constructed a highly efficient mixed bacteria group of heavy petroleum degradation and evaluated the degradation performance of mixed consortium by changes in the composition structure and functional groups of heavy oil before and after degradation. The results showed that the microbial community structure was significantly different at different stages of heavy oil degradation. Pseudomonas, Reyranella, Parvibaculum and Pseudoxanthomonas played a major role in the degradation of heavy oils, of which Parvibaculum and Pseudoxanthomonas played a major role in the degradation of heavy components. After long-term continuous intensive culture of heavy petroleum degradation mixed consortium, the degradation rate of heavy oil in 50 days could be increased from 25.42% to 41.57%.The heavy oil degradation rate of mixed culture QM composed by four kinds of mixed consortium enriched from different sources within 20 days and 50 days could reach 42.31% and 53.48%, respectively, and the degradation rate of asphaltene in 50 days could reach 25.56%.After microbial degradation,the content of light components and light groups such as methyl and methylene in heavy oil decreased significantly, while the saturation of heavy components increased, the polycyclic structure was activated, and oxygen-containing heavy components such as esters and ethers were reduced. Efficient and stable biodegradation of heavy oil has been achieved.

Water quality investigation were carried out on the waste water from a sugar and spice kitchen. The nano iron manganese catalyst was synthesized by co-precipitation method and utilized to activate peroxymonosulfate to produce active radicals for the degradation of sugar flavoring wastewater. The catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray energy spectrometry (EDS) and Brunauer Emmett Teller (BET). Effects of different condition factors on the degradation efficiencies of COD and ammonia nitrogen were investigated. Under the optimum conditions of 6h reaction time, PMS concentration 4mmol/L and catalyst dosage 0.6g/L, the removal rates of COD and ammonia nitrogen were 76.5% and 96.3% respectively, and the degradation process followed first-order kinetics (R²>0.9). Three-dimensional fluorescence and gas chromatography analysis of the water samples before and after degradation showed that the nonbiodegradable substances were converted into bioavailable organic carbon sources, which indicated that this system as a pretreatment could help to improve the biochemical treatment efficiency and thus has a good application prospect in advanced oxidation of wastewater treatment.

The screening of absorbent with high SO₂ absorption capacity and low desorption energy consumption is important to improve the amine-based SO₂ capture process from flue gas. The pK_a values of five diamines were calculated using SMD continuous solvation model and density functional theory at the M05-2X/6-31G* base set level. Two mathematical models of SO₂ absorption capacity and desorption reaction heat of diamines were established based on the predicted pK_a values. The relationship of SO₂ absorption capacity and desorption reaction heat was discussed for the diamine-acid-water ternary absorbent system. The results showed that the mathematical model met the requirement of engineering precision. The SO₂ absorption capacity and deprotonation reaction enthalpy of diamines were increased with the increase of pK_a value. In the screening of organic diamine absorbents, the multi-objective contradictory characteristics of SO₂ absorption capacity and reaction enthalpy were revealed. The numerical relationship between SO₂ cyclic absorption capacity and desorption reaction heat of the five diamines was obtained. The desorption reaction heat of hydroxyethylpiperazine (HEP) was the smallest under the same SO₂ circulating capacity among the five diamines. So, HEP is a promising absorbent in organic diamine-acid-water ternary systems.

Gasification technology can effectively alleviate the environmental threat caused by the increasing combustible municipal solid waste, but the H₂S and SO₂ produced by gasification still need to be removed to reduce the sulfur emission. The complex composition of combustible municipal solid waste requires suitable sulfur fixation reagent to remove H₂S and SO₂ simultaneously. In-situ sulfur fixation refers to the co-occurrence of gasification and sulfur removal after premixing raw materials and sulfur fixation reagent, and the sulfur pollutants are fixed in the ash. In this work, the typical components such as polystyrene particles and sawdust were mixed to simulate the combustible municipal solid waste and CO₂ was used as gasification agent. A series of Ca-Fe composite metal oxides were prepared by ball milling method and their in-situ sulfur fixation performance were further studied. The results showed that at 600℃, CaO/Fe₂O₃ mass ratio in Ca-Fe composite metal oxides has affected on the sulfur fixation rate. The sulfur fixation rate reached 82.65% when 1∶1 Ca-Fe composite metal oxides were used, better than other CaO/Fe₂O₃ mass ratios. In contrast, the sulfur fixation rates of using CaO and Fe₂O₃ solely were only 65.57% and 74.12% respectively. BET and SEM analysis showed the interactions between CaO and Fe₂O₃ during the composite metal oxides formation by ball milling, which affected the physico-chemical properties such as particle size distribution (PSD), pore size and specific surface area. Besides, the sintering phenomenon was much alleviated. Therefore, the best comprehensive performance was for the CaO/Fe₂O₃ mass ratio of 1∶1.

To achieve accurate prediction of PM_2.5 concentrations during heavy haze pollution events, the model of deep feature fusion (long short-term memory and multivariate linear regression, LSTM-MLR) was proposed in this paper to predict PM_2.5 concentrations in 3h, 6h, 12h and 24h of Xi’an and to explain the relationship between the main meteorological factors precursors and haze concentration. In the proposed model, a series of long short-term memory (LSTM) with different hyper-parameter were used to extract the deep features of PM_2.5 precursors and meteorological time series, and a full connect layer was used to adjust the dimensions of LSTM outputs. Then, a feature fusion model with the structure of multivariable linear regression (MLR) was used to obtain the predicted PM_2.5 concentrations. Data from January 2015 to March 2020 in Xi’an were used to determine parameters of the proposed model, and model performances for PM_2.5 concentration prediction in 3h, 6h, 12h and 24h were also evaluated. Results showed that LSTM-MLR, which was based on deep feature fusion of time series, can predict heavy haze pollution samples correctly with the accuracy of 94.12%, 85.29%, 77.57% and 51.10% in 3h, 6h, 12h and 24h, respectively. The true positive rate (TPR) of the proposed model outperforms random forest (RF), support vector regression (SVR), MLR, LSTM_PM_2.5 (PM_2.5 used only), multivariable LSTM (M_LSTM) and long short-term memory-random forest (LSTM-RF) which had the same input as LSTM-MLR. The fusion coefficients showed that the influence of current PM_2.5 concentrations on that in the future decreased from 80.89% (t + 3) to 16.34% (t + 24), and the influence of precursor concentration increased from 5.23% (t + 3) to 29.43% (t + 24), which illustrated the importance of time for taking emergency measures to reduce the peak value and decrease the pollution duration.