Aerogel is a kind of dry gel material with air as the dispersion medium. It has a complex three-dimensional network structure formed by random aggregation and interconnection of nanoparticles. Therefore, it shows excellent performances such as low density, high specific surface area, high porosity and low thermal conductivity at the same time and exhibits promising application prospects in many sophisticated and civil fields. As a high-performance material, polyimide (PI) has been widely used in aerospace, fireproof fabrics and many other fields. More importantly, PI aerogel has higher mechanical strength compared with traditional fragile inorganic aerogel, showing a noticeable trend to replace them, and therefore, it has received extensive attention from researchers. In this review, the research progress of PI-based aerogel materials is mainly summarized from the perspectives of preparation method, modification method, and applications of PI aerogel. Finally, the future development direction is prospected based on the current challenges in this field to provide a reference for subsequent research and practical application in industry and our daily lives.

By combining the advantages of photocatalysis and biocatalysis, photocatalysis-biological hybrid system could achieve high light collection efficiency and broad spectrum absorption, as well as the mild, efficient and specificity reaction process. On this basis, green and sustainable synthesis of various high-value compounds could be realized, which is in line with the development direction of “carbon neutral”. Photocatalysis-biological hybrid system can be classified into photocatalysis-enzyme hybrid system and photocatalysis-microbial hybrid system. The former can be divided into indirect reaction system based on cofactor-mediated, directly electron transfer reaction system and mixed photocatalysic-enzyme hybrid system, according to the catalytic mechanism. The latter can be divided into extracellular energy supply mode based on directly electron transfer, extracellular energy supply mode based on chemical-mediated, and intracellular energy supply mode. A comprehensive review is made on the specific mechanism of these models, their advantages and disadvantages, and key issues, and a future prospect in this field is proposed.

Oxidation reaction is the key reaction in the synthesis and modification of many plant natural products, oxidase is an indispensable biocatalyst for catalytic oxidation, and it is also an indispensable key enzyme in the synthesis of plant natural products by microorganisms. In this article, the oxidative modification of terpenoids, alkaloids, flavonoids and other plant natural products was reviewed, the oxidases in the synthesis of plant natural products were classified and introduced according to the differences of auxiliary groups, and the mechanism of the different auxiliary groups involved in the oxidation reaction was explained. In addition, this paper also introduces the difficulties of plant natural product oxidation in microbial synthesis and methods to improve the catalytic efficiency of oxidase. Finally, the future prospects of oxidase in the field of microbial synthesis of plant natural products in synthetic biology are prospected.

Redox flow battery (RFB) is a promising electrochemical energy storage technology and an effective solution for large-scale renewable energy storage. Among them, aqueous organic redox flow battery (AORFB) is not only cost effective, but also its active materials could be rationally designed by molecular engineering, so as to efficiently obtain new active materials with accurate target properties. The development history and research status of AORFB active materials are reviewed, and the molecular engineering research of active materials with different structures is mainly introduced. Combined with the current research trends, the future development direction and ideas of active material molecular engineering research are proposed.

A safe, efficient and responsive online hydrogen source can effectively accelerate the commercial application of proton exchange membrane fuel cells (PEMFCs), and the development of hydrous hydrazine as a promising online hydrogen source for PEMFCs requires superior catalysts with low cost and high activity. The structure-activity relationship between the alloying modification of the catalyst, the control of the morphology and structure, the loading of the carrier and the addition of strong basic additives and the catalytic performance are summarized. The reasons for the improvement of catalytic performance are discussed from the aspects of the increase of active sites and the improvement of intrinsic activity. Combined with theoretical calculations, the adsorption performance and decomposition path of N₂H₄ on the surface of different metal catalysts were summarized, and the reasons for the differences in the catalytic activity, H₂ selectivity and stability of N₂H₄ on different active site structures were analyzed. In order to realize the multi-scale precise control of the geometric structure and electronic structure of the specific surface interface structure and active site of the efficient catalyst, it will lay a foundation for the realization of the precise design of the catalyst structure under the guidance of the mechanism.

Graphene quantum dots (GQDs) are widely used in biomedicine as nanocarriers. However, there has been insufficient research conducted on the cellular internalization pathway of graphene quantum dots with heterostructures. Based on the spatial heterogeneity structure design, Janus GQDs with varying oxidation levels and spatial heterogeneity distributions are constructed. Through molecular dynamics simulations, the transmembrane transport behavior of Janus GQDs with different structures was studied by analyzing configuration changes, intermolecular interactions, and solvent-accessible surfaces during transmembrane transport. According to simulation results, the transmembrane transport behavior of Janus graphene quantum dots is determined by the hydrophilic-lipophilic balance and spatially heterogeneous distribution, also showing the pull force-dependent change. This paper systematically studies the interaction between Janus graphene quantum dots and cell membranes at the molecular level, and provides theoretical guidance for their structural design and biomedical applications.

Hexamethyldisiloxane (HMDSO) is an important precursor for the combustion synthesis of high-purity silica nanoparticles. The pyrolysis of hexamethyldisiloxane was investigated in this work by using ReaxFF reactive molecular dynamics simulations. The effects of three different reaction force fields on the simulations are evaluated and the reliability of each force field is analyzed. The most suitable force field was selected to investigate the pyrolysis products at different temperatures and pressures. The simulation results were used to reveal the pyrolysis path and mechanism of hexamethyldisiloxane together with the gas chromatography experiments. The results show that the reaction force field has important influences on the results of ReaxFF molecular dynamics simulations and the optimal reaction force field is obtained through the comparative analysis. The initial reaction step for HMDSO pyrolysis is the removal of CH₃ radical induced by Si—C bond breaking. Temperature is a major factor affecting the pyrolysis of HMDSO. The total molecular number of pyrolysis products increases with the temperature increasing and the products tended to be fragmented. The small hydrocarbon molecules (i.e., CH₃, CH₄, C₂ hydrocarbons, H₂, CH₂O, etc.) and Si-containing products (i.e., SiH₄, SiH₂, CH₄Si, etc.) appear in the middle and last stages of the pyrolysis process. The change of pressure will cause the change of the concentration of the pyrolysis system, thus affecting the probability of intermolecular collision and the occurrence of the reaction. The higher the pressure, the easier it is to form a stable pyrolysis product.

The gas-phase swirling flow in the cyclone has strong instability, which is manifested in the eccentric swing of the rotational center of the swirling center around the geometric center, which causes the instantaneous velocity of the flow field to fluctuate with time. It is not accurate to describe the instability characteristics of this swirling flow with time averaged flow field parameters, which need to be described with dynamic flow field parameters. Therefore, the instantaneous tangential velocity in ?300 mm cyclone was measured by hot wire/film anemometer. The results show that the instantaneous tangential velocity is the superposition of high-frequency pulsation formed by gas turbulence and low-frequency pulsation formed by eccentric swing of swirling flow. Based on this, the formation mechanism of swing of swirling flow was discussed. The low-frequency fluctuation of instantaneous tangential velocity comes from the eccentric swing of forced vortex, and the fluctuation amplitude is proportional to the eccentricity. According to the frequency domain of instantaneous tangential velocity, the calculation model of swing frequency related to the inlet velocity, cylinder diameter and vortex finder diameter of swirling flow was established.

Considering the phenomenological characteristic of steady state condensation process, this work mainly focused on the evolution conformation and laws of nanoscale clusters within the near-wall space with a thickness of hundreds of microns. Resorting to molecular dynamics simulation, the schema of cluster evolution and temperature distribution within the near-wall space was constructed through multiple sampling system simulations under different supersaturations. The results showed that there was a “transition point” in the curve of steam temperature in response to the distance from the wall, that was, the near wall space could be divided into two regions: the dense distribution region of clusters near the wall and the diffusion development transition region far from the wall. Specifically, the transition point could be changed. As the initial vapor pressure decreased, the transition point position moved closer to the subcooled wall, resulting in a relatively thinner molecule dense region. In addition, with the increase of noncondensable gas content, the corresponding cluster diffusion development region became wider. This indicated that a higher subcooling was needed so as to achieve a similar thickness of molecule dense region to that in the pure steam system without noncondensable gas, which explained the considerable influence of noncondensable gas on the condensation heat transfer efficiency from phenomenological perspective. Finally, according to these characteristics of cluster distribution evolution in the near-wall region, a new concept of enhancing or regulating heat and mass transfer is pointed out, that is, not only the micro-nano functional structure on the wall surface can be designed, but also the material structure design in the near wall space can also be considered, starting from the vapor phase space to control the cluster evolution.

The rapid development of electronic technology has put forward higher requirements for heat dissipation technology. As one of the key materials of heat dissipation technology, thermal interface materials are facing the challenge of improving thermal conductivity and reducing heat transfer resistance. In this paper, a novel VACNTs/PA/SR phase change gasket was developed by combining vertically aligned carbon nanotubes (VACNTs) and a solid-liquid phase change material, paraffin (PA), with silicone rubber (SR). It is shown that the magnetic field calibration method could make the surface modified nickel coated multi-wall CNTs vertically oriented in SR, and the obtained VACNTs/SR gaskets had higher thermal conductivity than the gaskets with CNTs randomly arranged. The appropriate content of CNTs in the VACNTs/SR gasket was determined to be 6% (mass), and the corresponding gasket reached a thermal conductivity of 0.71 W /(m·K). As for a series of VACNTs/PA/SR phase change gaskets at different loadings of PA, it is found that, the leakage problem of the liquid PA was overcome at the addition of PA of less than 12.5% (mass). After the solid-liquid phase transition of PA, the gasket shows a significant decrease in hardness, and even the thermal resistance can be reduced by up to 55.14%, and has excellent thermal reliability. By comparing the heat dissipation performance between the optimal VACNTs/SR gasket and the optimal VACNTs/PA/SR phase change gasket it is revealed that, when employing the phase change gasket, the simulation chip not only showed a lower rising rate in temperature but also had a lower equilibrium temperature with a decline of 3.5℃, suggesting the better heat dissipation performance of the VACNTs/PA/SR phase change gasket than the VACNTs/SR gasket. The VACNTs/PA/SR phase change gasket shows promise in the fields of electronic equipment heat dissipation.

The complex reactions and heat and mass transfer processes in porous media involved in the thermal chemical cycle solar fuel technology process have not yet established a relatively complete mathematical model. In this paper, the thermochemical cycling hydrolysis process of porous cerium oxide is taken as the research object, the oxygen transport and surface chemical reaction at particle scale is coupled with the heat and mass transport at macro scale, and complete thermal-mass nonequilibrium model of porous media driven by photo-thermal is proposed. The effects of local thermal nonequilibrium, incident radiant heat flux and reactant concentration on the dynamic process at two scales (particle and bed) are analyzed. Under the volume effect of the bed by incident radiation, the axial temperature gradient makes the maximum oxygen vacancy concentration controlled by thermodynamic equilibrium of the defect reaction appear in front of the bed. High incident radiation density can increase the reaction rate, and the effect is more obvious at the initial stage of the reaction. In the dynamic process of the defect reaction, the oxidation process is faster than the reduction reaction. Increase of H₂ concentration in the porous oxygen carrier reactor should mainly start from the reaction process and conditions in the reduction stage. Compared with the existing experimental data, the reliability of the kinetic and heat and mass transport model is verified. This paper can provide a relatively complete theoretical basis and reference path for the modeling and process design of this kind of problems.

The transport mechanism of gas in porous structures is widely used in aerospace, energy, and chemical industries. In low-pressure environments or micro/nano-scale pores, there is a phenomenon that the apparent gas permeability in porous structures is significantly higher than its intrinsic permeability due to the rarefaction effect. The existing models of the apparent permeability are mostly empirical formulas obtained by fitting experimental or simulated data, which are not universal. Based on the geometric topology characteristics of pore-scale streamlines, a method using intrinsic permeability, porosity, tortuosity and shrinkage is proposed. Subsequently, a novel model of the rarefied gas permeability was theoretically derived by combining the effective pore size with the existing model of rarefied gas flowing in pipeline. Using this model, the apparent gas permeability could be predicted under the condition that the pore geometry and physical properties are known. Furthermore, the accuracy of the proposed model was verified by the direct simulation Monte Carlo (DSMC) method. The numerical simulation of the gas flow process under the Knudsen number in the range of 0.01—10, the porosity in the range of 0.17—0.90, different gas working fluids and various ordered pore forms shows the average deviation of the proposed theoretical model from the simulated data is less than 10%.

The ultraviolet-induced fluorescence (UIF) experimental method was used to study the effect of the confined scale of the Hele-Shaw slit on the hydrodynamics and gas-liquid mass transfer behavior of the buoyant bubble in the confined space. In the experiment, dibenzo [b, e] pyridine was used as a fluorescent agent to realize the quantitative measurement of CO₂ solution concentration distribution and bubble velocity in the confined space. The mass transfer and bubble dynamics parameters of CO₂ in the confined space were obtained, and the mass transfer rates of liquid film area and free contact area in the confined space were calculated respectively. The mass transfer behavior of CO₂ in different slit widths in confined space was analyzed, and the influence of confined scale on the mass transfer process of CO₂ water system was analyzed as well.

When transcritical CO₂ expands at a high speed, the pressure and temperature drop sharply, and a non-equilibrium phase change occurs. The non-equilibrium condensation phase change of CO₂ would occur in natural gas supersonic separation equipment and supercritical CO₂ centrifugal compressor. Besides, the non-equilibrium flashing phase change of transcritical CO₂ occurs in the ejector primary nozzle in the ejector expansion refrigeration system. In order to solve the problem that the physical properties of transcritical CO₂ change sharply during the expansion process and it is difficult to simulate the non-equilibrium phase change, a new non-equilibrium phase change CFD model was constructed to study the transcritical CO₂ non-equilibrium condensation and flashing phase change process and expansion mechanisms in the supersonic converging-diverging nozzle. The model coupled the temperature-driven evaporation-condensation phase change mechanism and the pressure-driven cavitation-condensation phase change mechanism, and the accuracy of the model was verified by the experimental results in literature. The results showed that the pressure-driven condensation mass transfer had a major influence on condensation phase change. The pressure-driven condensation mass transfer mainly existed in the nozzle throat and internal flow zone, and the temperature driven condensation mass transfer mainly existed on the wall of the nozzle diverging section. The condensation mass transfer rate increased with the increase of inlet pressure and the decrease of inlet temperature, so that the non-equilibrium degree of condensation and the quality in the nozzle were reduced, and the position of speed of sound was delayed accordingly in the nozzle diverging section. In addition, the temperature-driven evaporation mass transfer dominated the flashing phase change, the evaporation phase change mainly occurred near the nozzle throat, the cavitation phase change mainly occurred in the nozzle diverging section, and the two-phase CO₂ reached speed of sound in the nozzle diverging section. With the increase of inlet pressure and the decrease of inlet temperature, the non-equilibrium degree of flashing increased and the quality in the nozzle decreased. This study was helpful to clarify the non-equilibrium flashing and condensation phase change mechanism in the rapid expansion of transcritical CO₂, and it provided a method for the analysis and optimization design of transcritical CO₂ expansion equipment.

This paper investigated the flow and heat transfer of corrugated double-tube heat exchanger with non-Newtonian fluid in the tube side experimentally. The heat transfer and resistance characteristics of non-Newtonian fluid (0.2% Xanthan gum (XG) solution) were studied in double-tube heat exchangers with different corrugated tubes to reveal the effects of geometry of corrugate tube and flow condition on the heat transfer enhancement. The results show that the overall heat transfer coefficient k and pressure difference between inlet and outlet Δp increases with the increase of the Reynolds numberof XG solution Re_XG. The corrugated height H and distance S have significant influence on the flow and heat transfer of XG solution in the tube side of the casting heat exchangers. With the increase of corrugate height H, the XG solution is affected more obviously by the vortex effect at the corrugate node, so the interlayer shear force of the fluid increases with higher corrugate node and the viscosity of XG solution decreases, then the degree of turbulence increases to have better heat transfer performance and higher pressure drop, but the comprehensive heat transfer factor keeps increasing. With the increase of corrugate distance S, the number of corrugate nodes per unit length decreases, the disturbance on XG solution slows down and the degree of turbulence decreases. The heat transfer coefficient of XG solution side increases firstly and then decreases with longer node distance, while the flow resistance decreases with longer distance, the comprehensive heat transfer factor increases first and then decreases. The tube with H=3.5 mm, S=30 mm has the highest comprehensive heat transfer factor η_tube, which is 5.11—6.69 times that of smooth tube.

Capacitive deionization (CDI) is an emerging technology for water treatment and desalination, which has received much attention because of its excellent performance. To this end, a new two-dimensional concentration transfer model of CDI was proposed in this paper by analyzing the existing empirical models, which considers the electric field migration and mass transfer diffusion from both along and vertical flow directions. The ion diffusion and concentration distribution of CDI in the process of desalination were simulated and explored. According to the actual experimental results, the model is verified experimentally and its parameters are corrected. The results show that the two-dimensional model can simulate the CDI desalination process well. This two-dimensional model was simulated using COMSOL software to observe the internal concentration changes of CDI during the desalination process. And rationalization suggestions are made for the existing problems to provide theoretical support for the future development of CDI technology.

With the help of high-speed camera, the hydrodynamics of successive droplets impacting on heated cylindrical surface were captured. Under different impact velocities, the local convective heat transfer characteristics along the circumferential and axial directions were obtained by combining the directly measured experimental data with numerical calculation method. The results show that, when the droplet impact velocity is small and liquid film does not splash, due to the anisotropy of cylindrical surface, the convective heat transfer coefficient monotonically decreases in the axis, while in the circumference, the convective heat transfer coefficient firstly decreases and then augments slightly. According to the change of convective heat trasnfer coefficient along the circumference direction, the circumference is divided into impingement zone, heat diffusion zone and tail detachment zone. The improvement of convective heat transfer coefficient by increasing the droplets impact velocity is mainly reflected in the impingement and heat diffusion zones, but not obvious in the tail detachment zone. When the droplet impact velocity exceeds a certain critical value (about 1.53 m/s under the current experimental condition), the liquid film will splash. If continuously increasing impact velocity, the reduction of wall temperature is no longer obvious.

Vertical microgroove capillary structures are widely used in heat transfer devices such as gravity heat pipes, evaporator and other heat transfer devices. The capillary rise in microgrooves attracts increasing attentions since it affects capillary limit significantly, which is easy to be reached due to the structure, gravity and other factors, and has a great influence on the heat transfer performance of the heat pipes. Thus, to improve the capillary limit of the vertical microgrooves, electric field, as one of the active enhanced technology, is introduced to the experiment system. The influence of the electric field on the wetting and capillary flow characteristics of the liquid in the vertical microgroove is studied experimentally and a mathematical model is established to understand the wetting and flow mechanisms of liquid in the vertical microgrooves under the action of electric field. The results show that the electric field can improve the wetting height of the liquid in the vertical microgrooves. When the electric field is 5.0 kV, the wetting height enhancement ratio can reach 30.0% compared with no electric field. Besides, the liquid wetting and capillary flow in the microgrooves under electric field are segmented: at the beginning of the capillary wetting flow, the square of the wetting height is linearly related to time, that is, h-t^1/2, and at the long-term of the wetting flow, the wetting height is linearly related to the 1/3 power of time, that is, h-t^1/3. Besides, the relationship between the wetting velocity and the wetting height first follows v-1/h, then is governed by v-1/h². Moreover, the wetting velocity decreases with time.

The maximum operating power of the device is limited by the critical heat flux (CHF), however, the flow oscillation can cause premature critical heat flux (called PM-CHF) and reduce the stable operating range. In order to study the critical heat flux in a narrow rectangular channel under flow oscillation conditions, this paper conducted experiments to visualize the boiling crisis in a narrow rectangular channel under vertical upward flow condition with deionized water as the working medium, with mass flux range of 350—2000 kg/(m²·s), narrow gap size range of 1—5 mm, and system pressure range of 1—4 MPa. The results show that CHF increases linearly with increasing mass flow rate in the narrow rectangular channel. The flow oscillation occurs when the mass flux is small, and the oscillation period is about 0.1 s. The flow oscillation leads to the early onset of boiling crisis, during which the flow pattern is slug-churn flow. Based on the flow oscillation and the bubble dynamics characteristics in the narrow rectangular channel, the theoretical analysis and derivation are carried out from the perspective of flow oscillation. In results, a PM-CHF mechanism model is established, and the error is within 30%.

According to the special properties of microencapsulated phase change material to store and release latent heat, microencapsulated phase change material suspension (MPCMS) and pure water were used as spray media respectively to build a small spray tower device, in which the core material of microencapsulated phase change material is n-dodecane (C₂₂H₄₆). Five spray temperatures (35, 40, 44, 47, 51℃), three air flows (0.011, 0.018, 0.025 m³/s) and two diameters (SMD=80, 240 μm) were set as experimental variables. The heat transfer characteristics between the two media that described and air were investigated. The experimental results show that the supercooling of the phase change microcapsules will affect the heat transfer process. Under normal temperature and humidity, for small droplets, when the air flow rate is 0.018 and 0.025 m³/s, MPCMS at 44 and 47℃ can promote heat transfer better than pure water at the same temperature. When air flow rate is 0.011 m³/s, MPCMS at 44℃ can promote heat transfer better than pure water at the same temperature. For large droplets, MPCMS with spraying temperature of 44℃ has better heat transfer effect than pure water with spraying medium at the same temperature under three kinds of air flow.

To investigate the influence of feedstock oil vaporization characteristics, a multi-phase Eulerian model coupling with the models of EMMS drag and mass transfer, oil droplet vaporization and twelve lumped reaction kinetics were used to simulate a million ton scale industrial FCC riser for predicting complex three-phase flow, reaction and coking behaviors. A coking model was proposed to predict the coking extent. The distribution of concentration and temperature of each phase, reaction component and coking extent were investigated under different droplet sizes of atomized feedstock oil and initial vaporization temperatures. The results show that the simulation can well predict the vaporization, reaction coking and fixed coking. The atomized droplet size and initial vaporization temperature affect the oil droplet vaporization rate and cracking reaction conversion rate through the interphase momentum transfer and vaporization speed. Appropriate droplet size (60 μm) and initial vaporization temperature (654 K) can improve the yield of light oil, gasoline and liquefied petroleum gas and alleviate the degree of coking.

Magnetic multimetallic catalytic materials were synthesized by using electroplating sludge from electroplating industry as precursors, which were applied for the transfer hydrogenation of bio-based furfural using methanol as hydrogen donor. The calcined electroplating sludge was characterized by X-ray diffraction (XRD), liquid nitrogen adsorption and desorption, NH₃ temperature-programmed desorption (NH₃-TPD) and scanning electron microscopy (SEM). The effects of calcination temperature and reaction conditions on furfural conversion using methanol as hydrogen source were conducted. The results showed that the magnetic polymetallic materials had strong acid sites and partial mesoporous structure. Moreover, the copper component could be partially activated into Cu⁰ during the reaction, which benefited the hydrogen production from methanol reforming and followed furfural hydrogenation. Using electroplating sludge calcined at 700℃ as catalyst, furfural was almost completely transformed at 240℃ when prolonging reaction time over 2 h, in which the yields of furfuryl alcohol and 2-methylfuran reached up to 70.9% and 31.9% respectively. Noticeably, 2-furylmethyl methyl ether and 2-(dimethoxymethyl) furan were detected as the main by-products during the reaction. In addition, on the basis of the coupling effect among methanol reforming into H₂, in-situ reduction of copper/nickel components and furfural hydrogenation, the plausible reaction mechanism for furfural hydrogenation over magnetic polymetallic materials derived from electroplating sludge using methanol as hydrogen source and solvent was proposed.

The bromide ion content in the potassium-extracted old brine from the Indo-China Peninsula rock salt mine is about 3000 mg/L, which is a valuable raw material for bromine production. The effective utilization of associated bromine resources in rock salt mines provides a number of significant economic, social, and environmental benefits, which will improve the comprehensive utilization value of rock salt mine resources and alleviate the shortage of bromine resources in our country. In this work, a three-electrode system was designed in which the anode was graphite electrode, the cathode was platinum sheet electrode, and the reference was Ag/AgCl electrode. Firstly, the suitable potential for selective electro-oxidation of Br^- in the potassium-extracted brine from rock salt mines was determined by linear sweep voltammetry (LSV) method. Then, the kinetic and the expression of the oxidation rate of the electro-oxidation of Br^- in bromine-containing simulated brine under this potential condition were explored through the electro-oxidation experiments in the three-electrode system. Finally, the influence of Cl^- concentration, effective electrode area and stirring rate on the oxidation rate of Br^- in bromine-containing simulated brine was investigated, and the optimal operating conditions were obtained. The results show that 1.150 V is a suitable electrode potential for the selective oxidation of bromide ions, and the reaction conforms to the first-order kinetic law. For the potassium-extracted brine from the rock salt mines with the Cl^- concentration of 280 g/L, when the effective area of the graphite electrode is 50.18 cm² and the stirring rate is 400 r/min, the fastest electro-oxidation rate of Br^- was observed, the corresponding reaction rate constant is 0.3042 h^-1, and about 91.9% of Br^- was converted after 8 h of electro-oxidation.These results validate the feasibility of the selective oxidation of bromine in potassium-extracted brine from the rock salt mines by electro-oxidation.

Most organic reaction substrates in organic electrochemical synthesis are insoluble in water, and it is often necessary to add an appropriate amount of organic solvent to form an organic-water mixed solvent. As a mediator, chloride ion (Cl^-) has attracted extensive attention in organic electrochemical synthesis, but it is often soluble in aqueous solution. Solvent is a very important factor in electrochemical system, therefore, the electrochemical properties of Cl^- in organic-H₂O mixed solvent should be studied systematically. In this paper, the kinetic parameters of Cl^- in organic aqueous solution were investigated by cyclic voltammetry (CV), linear scanning method (LSV) and chronocoulometry. The effects of anode material, scanning rate, water content, and organic solvent on the electrochemical behaviors of Cl^- were studied systematically. The apparent activation energy (E_a) of the electro-oxidation of Cl^- on Pt electrode was measured by constant overpotential method. At the same potential difference, the E_a decreased more rapidly at lower potential than that at high potential. Using Cl^- as a mediator, the indirect electrochemical cyanidation of p-methoxytoluene (p-MeOBT) under the condition of 12.5 mA·cm^-2 current density, 60℃ in CH₃CN-H₂O (volume ratio 7∶3) organic aqueous solution containing 0.15 mol·L^-1 hydroxylamine sulfate and 0.05 mol·L^-1 tetrabutyl ammonium perchlorate (TBAP) was studied. The yield of p-methoxybenzonitrile (p-MeOBCN) was 80%. A possible mechanism of the indirect electro-oxidative cyanidation of C—H bonds was proposed by monitoring the intermediate species in the electrochemical cyanidation process. Cl^- showed good catalytic performance in the indirect electro-oxidative cyanidation of C—H bonds, which provided the experimental and theoretical basis for the use of inorganic mediators in the indirect electrochemical conversion of organic substrate.

The MgFe₂O₄ precursor was prepared by the sol-gel method, the MgFe₂O₄ catalyst was obtained by calcination, and the core-shell structure catalyst MgFe₂O₄@SiO₂ and MgFe₂O₄@SiO₂@HZSM-5 (MSH) were prepared by the St?ber method. The magnetic properties and structural characteristics of the catalysts were investigated by VSM, XRD, SEM, FT-IR, and N₂ physical adsorption. In a fixed bed reactor, under an N₂ atmosphere, the magnetic catalysts were investigated for the catalytic properties and recovery and regeneration of tar-rich coal from the Bulianta (BLT). The results show that the MgFe₂O₄ has a cubic spinel structure with a saturation magnetization of 181.50 emu/g and good thermal stability. The above series of magnetic catalysts all show good catalytic activity, among which MSH has the best catalytic activity. Compared with non-catalytic pyrolysis, the tar yield of MSH catalytic pyrolysis increased by 57.7%, the content of aliphatic hydrocarbons and benzene in the tar increased by about 2 times, and the content of polycyclic aromatic hydrocarbons decreased by 8.6%—9.8%. The magnetic separation method can effectively realize the recovery of the catalyst, and regeneration of the catalyst can be realized by roasting in 700℃. The SiO₂ coating helps to improve the magnetocaloric stability and catalytic lifetime of the core-shell catalyst.

Using magnesium sulfate and sodium hydroxide as raw materials and potassium hydrogen phthalate as complexing agent, basic magnesium sulfate nanowires were prepared by complexation-hydrothermal method. The crystallization mechanism of magnesium oxysulfate (MOS) nanowire was investigated, and the crystallization kinetic equations were established by analyzing the concentration of Mg via the hydrothermal synthesis process. Then, the surface nucleation mode of the nanowire was confirmed. The results illustrated the crystallization of the nanowire was controlled by multi-core surface growth mode at 140℃ and 160℃. However, it changed to linear surface growth mode at 180℃ and 200℃. The microstructures of MOS nanowires were investigated by transmission electron microscopy. There are many edge dislocations and screw dislocations in the crystals, their effects in MOS nanowires on growth kinetics are to decrease the two-dimensional nucleation barrier and act as a self-perpetuating step sources.

The iron-cobalt bimetallic composite catalyst was prepared by solvothermal method followed by high-temperature calcination to activate peroxymonosulfate (PMS) to degrade the azo dye orange Ⅱ (OGⅡ). The composites were characterized by X-ray diffractometer, scanning electron microscope, vibrating sample magnetometer and X-ray photoelectron spectrometer. The effects of cobalt compound amount, different removal systems, catalyst dosage, PMS dosage, pollutant concentration, pH and coexisting anions on the degradation effect of OGⅡ were investigated, and the reuse effect of iron-cobalt composite catalyst was explored. The experimental results show that the iron-cobalt composite catalyst can effectively activate PMS to degrade OGⅡ. When n(Co₃O₄)∶ n(Fe₂O₃)=0.1, the dosage of catalyst is 1.0 g/L, the dosage of PMS is 0.4 mmol/L, the concentration of OGⅡ is 30 mg/L and pH of solution is 6.2, after 60 min of reaction, the degradation rate of OGⅡ reached 95.81%, the degradation process conformed to the pseudo-first-order kinetic model, and the maximum reaction rate constant was 0.0491 min^-1. The composite catalyst still had a degradation rate of 68.85% to OGⅡ after 4 cycles. ·SO{}_{\mathrm{4}}^{-}, ·OH and ¹O₂ are reactive oxygen species produced in the reaction system, and ¹O₂ plays a major role in the degradation of OGⅡ.

Phosphorus is a non-renewable resource. In order to solve the problems of existing phosphorus pollution and phosphorus resource loss, a NiFe-LDH/rGO electroactive hybrid film material was successfully prepared in this study by a combination of oil bath and thermochemical reduction. An ESIX process allows the NiFe-LDH/rGO hybrid film achieving a controllably selective uptake and release of the phosphate anions. This route involves tuning potential steps to regulate the redox states of the composite film and the variable metal (e.g., Ni, Fe (Ⅱ)/(Ⅲ)) in coordination centers, as the inner-sphere complexation of the metals to phosphate anions is combined with the assistance of the outer electric field. A high absorption capacity (270 mg·g^-1) and regeneration rate (>85%) were achieved, together with good cycle stability. This route provides an efficient, theoretical and technical support to solve the problems phosphogypsum leachate and various phosphorus wastewater pollution, which presents a broad application prospect.

In this paper, Cu₃(BTC)₂-MMT was prepared by combining cation exchange with in situ synthesis of Cu₃(BTC)₂, while Cu₃(BTC)₂-MMT-NH₂ hybrid materials were prepared by amino functionalization of 3-aminopropyltriethoxysilane (KH550). Hybrid materials were added to polyvinylamine (PVAm) matrix as selective coating solution, which was coated on polysulfone (PSf) support to obtain mixed matrix membrane (PVAm/Cu₃(BTC)₂-MMT-NH₂). The crystalline and chemical structures of the hybrid materials were characterized by XRD and FTIR, and hydrogen bonding between the Cu₃(BTC)₂-MMT-NH₂ hybrid materials and the PVAm matrix was confirmed using ATR-FTIR. The effects of exchange of copper and sodium ions, mass ratio of Cu₃(BTC)₂-MMT to KH550, loading of Cu₃(BTC)₂-MMT-NH₂, operating pressure, wet membrane thickness, operating temperature, and under mixed gas feed on membrane CO₂ permeability and CO₂/N₂ selectivity in mixed matrix membranes were systematically investigated. The results show that under the conditions of pure gas atmosphere, operating temperature of 25℃ and operating pressure of 1 bar, the membrane had the best gas separation performance with a CO₂ permeation rate of 203 GPU and CO₂/N₂ selectivity of 100.7, which is much higher than that of the mixed matrix membrane with MMT, Cu₃(BTC)₂ or the mixture of MMT and Cu₃(BTC)₂. This is attributed to the interlayer transmission channel of Cu₃(BTC)₂-MMT-NH₂ and its good compatibility with polymer matrix. In addition, under the mixed gas test condition, the mixed matrix membrane can still maintain excellent stability in CO₂ separation performance over 360 h.

The high-concentration wastewater rich in nitrates and sulfates produced in industrial fields such as coal chemical industry and energetic materials has a huge amount of discharge and serious environmental damage. It is an important research direction to realize the regulation of high-quality crystallization process while treating high-concentration composite brine with low energy consumption. Aiming at the typical high-concentration Na⁺//NO{}_{\mathrm{3}}^{-}, SO{}_{\mathrm{4}}^{\mathrm{2}-}-H₂O solution system, this paper proposes a membrane distillation and crystallization coupling method to treat this kind of high-concentration composite inorganic brine. The nucleation energy barrier of the target salt is effectively regulated at the microporous membrane interface, which effectively controls the diffusion difference and explosive nucleation of multi-salt ions in the typical evaporative crystallization process. In addition, the formation of hollow and high-impurity ion crystals can be avoided, and the crystal purity and separation performance is improved. The design strategy of evaporating for concentrating the solvent in the advantageous range of membrane distillation, and then evaporating for crystallization under vacuum vaporization, is proposed to reduce the risk of membrane surface scaling and membrane pore wetting. In addition, this strategy further improves the energy efficiency of the entire separation process. The above research provides a new idea for the technology development of high-concentration inorganic brine treatment.

Dividing wall column (DWC) has outstanding advantages in terms of energy saving and investment cost for distillation separation. The positioning of the dividing wall effectively affects the separation efficiency and energy consumption, especially when the feed contains vapor phase. In the present paper, ternary mixture of benzene, toluene, and p-xylene is selected as the separation system to study the effect of the feed vapor fraction on the optimal positioning of the dividing wall in a DWC and proposes a method for determining the optimal position. By using rigorous simulation and the total annual cost (TAC) as the objective function, the economic performance of the DWC is investigated under different vapor fractions of the feed, and feed with vapor can save up to 23.33% of TAC compared to feed with liquid. The results demonstrate the importance of optimal dividing wall positioning when the feed contains vapor phase by sensitivity analysis.

Under the condition of ensuring the purity of products, an extra-column and binary-partial-discard strategy is proposed to improve the productivity of the simulated moving bed. The process point is selected in the area of pure extract products and non-pure raffinate products to increase the feed flow, and the raffinate products with more impurities is temporarily discarded. The discarded raffinate products is fed as a recycling feed into an extra chromatographic column for further separation, some extra products that cannot reach the specified purity are permanently discarded. In this way, the total products consist of the products collected at the simulated moving bed and the extra chromatographic column respectively. This paper analyzes the effects of the selection of process point, the integral purity threshold of raffinate products and the integral purity threshold of extra products on the performance parameters of total products. The research results show that the proposed strategy can not only use raw materials with high recovery rate, but also can significantly improve the productivity of the simulated moving bed, and its separation effect is better than the conventional simulated moving bed process as well as than the partial-discard strategy.

The traditional neighborhood preserving embedding (NPE) algorithm uses the k-nearest neighbors (k-NN) method to select neighborhoods for reconstruction to achieve dimensionality reduction. However, the samples collected in the actual industrial process have time series correlation. Selecting the nearest neighbor samples only by Euclidean distance cannot fully reflect the information contained in the data, which will affect the detection performance. Therefore, a local time difference constrained neighborhood preserving embedding (LTDCNPE) algorithm is proposed, which establishes a more accurate fault detection model by fully considering the temporal and spatial relationship between samples. Firstly, the algorithm selects the neighborhoods based on the time and spatial characteristics of the samples within a fixed scale time window. Secondly, the time differences between samples are used to weight the neighborhood samples. In this way, the reconstructed samples retain the local structure of the high-dimensional space. Then, T^{\mathrm{2}} and SPE statistics are calculated for the principal component space and residual space obtained through LTDCNPE. Next, the control limits are determined to detect the process faults. Finally, the performance of LTDCNPE is described by a numerical example and Tennessee Eastman (TE) simulation study.

Batch processes have multimode characteristics. The high-dimensional characteristics of process data and the selection of mode center in the existing batch process mode partitioning method directly affects the rationality of the mode partitioning results, which in turn affects the accuracy of online prediction of batch process quality variables. To cope with this challenge, an online prediction method of batch processes quality variables based on improved density peaks clustering relevance vector machine (IDPC-RVM) is proposed. First, based on the DPC algorithm, the sample similarity is measured by considering the high-dimensional characteristics of the process data, and the mode centers of the batch process are accurately obtained by the mode centers selection strategy with the unbalanced sample density. Then, the optimal number of modes is obtained without prior knowledge according to the mode partitioning index (MPI), and the transition modes are identified to complete the mode partitioning of batch processes. Finally, the RVM prediction model of each mode data is established to realize the online prediction of batch process quality variables. The experimental results of penicillin fermentation process show that compared with RVM, SCFCM-RVM and DPC-RVM methods, the RMSE of the proposed method for the prediction of penicillin concentration was reduced to 0.0093, and the R² was increased to 0.9995, which effectively improving the prediction accuracy.

Refrigeration and air-conditioning systems are widely used in building environmental regulation and are an important part of building energy consumption, and system failures will increase energy consumption by 15%—20%. The data-driven method represented by deep learning has become the mainstream method for fault diagnosis. However, data-driven method needs to rely on a large amount of labeled data, which limits their applications. Focus on the above problems, a fault diagnosis method based on digitized knowledge representation is proposed, which makes up for the problem of insufficient real labeled data by prior knowledge of fault diagnosis in a data form. A method of knowledge digitization using random scaling strategy is proposed, and a noise addition strategy is used to achieve the goal of better consistency between the generated sample and the real sample. A characterization method of target system deviation characteristics based on benchmark model is proposed, which unifies the format of target system data and generated data. Using the generated data to train the model and verify it on the ASHRAE RP-1043 data set, the comprehensive diagnosis accuracy rate is 82.67%, which is close to the supervised learning method. Combined with that it does not need to labeled data at all, makes it has a wide range of application prospects.

Mass exchange network is an important part of chemical process system, and its optimal design is of great significance to reduce pollution emissions. When the heuristic algorithm is used to optimize the mass exchange network, there is a problem that it is difficult to take into account both the global search and the local search. By analyzing the optimization results under different precision optimization parameters, this paper reveals the causes of the problem, and proposes a fine search strategy for the in-depth optimization of the structure obtained by the basic algorithm. The strategy includes two methods. Method 1 adopted a high-precision random walk algorithm with compulsive evolution (RWCE) with individual back substitution and differentiation, which can retain the ability of individual structure variation. Method 2 used the deterministic approach to perform a one-dimensional search for each variable in the multidimensional objective function in turn, which has the advantages of high precision and fast convergence. Applying this strategy to coke oven gas sweetening and ammonia removal problem, the results are 407308 USD·a^-1 and 127807 USD·a^-1, which are better than the best results in the current literature. The effectiveness of the proposed strategy is verified.

The observation data of complex chemical processes often contain both nonlinear and strong dynamic characteristics, and the traditional soft sensing method of chemical process cannot accurately extract the nonlinear dynamic characteristics of the observation data, so as to affect the accuracy of data modeling and quality prediction. In this paper, a deep fusion features extraction network (DFFEN) is proposed. Under the framework of variational auto encoder, the nonlinear dynamic latent variables are extracted by constructing latent feature information transfer channel. In addition, a self-attention mechanism is used to fuse key hidden layer information and optimize the problem that the potential features are forgotten, which is mainly caused by the excessively long information transmission channel. Then, the regression model between latent variables and key quality variables is constructed in the backend network to achieve the prediction of key quality variables. Finally, the feasibility and effectiveness of the proposed DFFEN model are verified by numerical cases and an actual ammonia synthesis process.

The non-catalytic oxidation of cyclohexane has the characteristics of nonlinearity, multi-variable coupling, large time delay, etc., and the ideal control performance cannot be achieved by using the conventional PID control scheme. In this paper, an interval type-2 fuzzy immune PID controller is proposed, which is essentially a nonlinear controller based on immune PID. The interval type-2 fuzzy logic system (IT2FLS) is used to approximate the nonlinear function in the immune feedback law, so as to improve the ability of the controller to deal with and approach complex uncertain nonlinear systems. Finally, the proposed controller is applied to temperature control system for uncatalysed oxidation of cyclohexane, and the simulation results show that the method is effective.

Polymer composites composed of polymer, filler, bond agent and other functional additives are widely used in tire, energetic materials, medical treatment, environmental protection, construction, transportation and other industries. It has been well recognized that the adsorption properties of bond agents on the surfaces of nano-fillers have profound effects on the performance of the entire polymer composites. Herein, three kinds of nano-fillers are considered including the unmodified ammonium perchlorate, carbon black and SiO₂ fillers, and by means of the first-principles calculation, the adsorption energies of five bond agents (TEA, T313, DOTG, DPTU and DPG) on the surfaces of these filler are evaluated. The calculation results show that with the increase of the number of filler substrate layers, the adsorption energy gradually increases, and finally tends to a stable value. In addition, the influences of point defects (single vacancy defects, double vacancy defects, and Stone-Wales defects) and hydroxyl groups grafted on SiO₂ surface on the adsorption energy are investigated. It is found that the presence of single vacancy defects or double vacancy defects has little influence on the adsorption energy. However, the Stone-Wales defect and grafted hydroxyl groups can significantly promote the adsorption energy.

The corrosivity of molten chloride salt is an important factor limiting its application. Its corrosion to chromium-rich metal materials mainly results in the preferential loss of chromium from metals to molten salt. The effect of chromium valence on the subsequent corrosion of metal in molten salt is the key to understand the continuous corrosion of metal. In this paper, the effects of Cr⁰, Cr²⁺ and Cr³⁺ on the corrosion of a chromium-poor Hastelloy B-2 (HB-2) and two chromium-rich Hastelloy C-276 (HC-276), Hastelloy X (HX) nickel-based alloys are studied by immersion corrosion test. By analyzing the results of mass change, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), the corrosion difference of molten salts containing different valence chromium on chromium-rich and chromium-poor metals are discussed. The experimental results show that Cr⁰ and Cr²⁺ can significantly reduce the corrosion mass loss rate and inhibit their corrosion by consuming active oxides such as H₂O and O₂. Cr³⁺ can inhibit the corrosion of chromium-poor alloy HB-2, but can promote the corrosion of chromium-rich alloy HC-276 and HX. The results of SEM and XRD show that Cr³⁺ not only enhance the preferential loss of chromium, but also enhance the loss of Fe. The standard Gibbs free energy variation {?}_{\mathrm{r}}{G}_{\mathrm{m}}^{?} of oxidation of CrCl₃ oxidized Ni, Cr, Fe are calculated respectively. The results show that the oxidation of Cr and Fe by CrCl₃ are -142.9 kJ/mol and -87.4 kJ/mol, indicating that the reaction is carried out thoroughly. The oxidation of Ni and Mo by CrCl₃ is limited. Therefore, CrCl₃ in molten salt promotes the corrosion of chromium-rich alloy by oxidizing Cr and Fe in the alloy, while Cr⁰ and CrCl₂ inhibit corrosion by consuming oxidizing species in molten salt.

Nowadays, ground-level ozone has emerged as a strong candidate pollutant for PM_2.5. Catalytic ozone decomposition is widely considered to be the most promising method to remove ozone. However, its practical application is severely restricted by the poor moisture resistance of the catalyst. In this paper, a novel manganese borate/oxygen-doped boron nitride [Mn(BO₂)₂/BNO] composite was successfully obtained based on in situ growth strategy. The strong interfacial interaction between the two components induces electron directional transfer from BNO to Mn(BO₂)₂, which not only promotes the decomposition of ozone, but also reduces the water adsorption capacity to avoid the poison of active sites by water molecules. Ozone decomposition performance test shows that 10% Mn/BNO [10% molar ratio of Mn(BO₂)₂ loaded on BNO] exhibits the best ozone removal performance of 92% at a relative humidity of 60% after 20 min. This provides a new design idea for obtaining ozonolysis catalytic materials with excellent performance.

Using homologous sequence alignment and molecular phylogenetic tree analysis, two flavonoid synthase genes are successfully cloned from the Glycyrrhiza inflata: Gur.gene26505 and Gur.gene26116. Gur.gene26505 is characterized as a flavonoid synthase Ⅱ, catalyzing liquiritigenin to specifically synthesize 7,4'-dihydroxyflavone, while Gur.gene26116 is a flavanone 2-hydroxylase that catalyzes liquiritigenin to synthesize three products including 7,4'-dihydroxyflavone. The reason for the specificity of 7,4'-dihydroxyflavone catalyzed by flavonoid synthase Ⅱ (Gur.gene26505) was further explored through protein structure prediction, molecular docking, and molecular dynamics simulations. Due to the unique rigid structure β-sheet near the active pocket of Gur.gene26505, the large sterically hindered phenylalanine residue is turned over to the lower part of the hydroxylation center, which eliminates the resistance of the hydroxylated product 2-hydroxyliquiritigenin to enter the dehydration center, occurring dehydration at C₂-C₃ positions and generating 7,4'-dihydroxyflavone. Finally, the optimal cell catalysis process for the specific synthesis of 7,4'-dihydroxyflavone is established through gene overexpression, optimization of reaction conditions and enhancement of bacterial growth, and the conversion rate of liquiritigenin reaches 76.67%.

Cu-Al bimetallic composite ionic liquid is a novel green catalyst for isobutane alkylation in oil refining industry, and small amount of catalyst is inevitably emitted during industrial application. Electrochemical treatment is one of the effective ways for the resource utilization of Cu-Al bimetallic composite ionic liquid, and the in-depth exploration of electrochemical behavior and electrodeposition mechanism provide theoretical guidance for the efficient utilization of metal resources. By cyclic voltammetry, it was found that there were three cathodic reduction regions for Cu-Al bimetallic composite ionic liquid in cyclic voltammograms on Pt electrode, W electrode and glassy carbon electrode, and the reactions were copper underpotential deposition, Cu(Ⅰ) reduction and copper overpotential deposition. The anodic oxidation peaks were Cu→Cu(Ⅰ), Cu(Ⅰ)→Cu(Ⅱ). For W electrode, the copper underpotential deposition process and the Cu(Ⅰ) reduction process were both irreversible electrochemical reaction processes controlled by diffusion. Chronoamperometry indicated that the nucleation and growth process of copper was three-dimensional instantaneous nucleation. Long-term electrodeposition of Cu-Al bimetallic composite ionic liquid showed that the decreasing trend of Cu(Ⅰ) concentration with time slowed down, indicating that the rate of copper electrodeposition decreased with time. The electrodeposition potential had a certain effect on the morphology of the deposited products. The morphology of the deposited product obtained at -2.60 V was smooth and dense, and presented regular granular shape. XRD patterns of the electrodeposits showed that there was only copper produced on cathode by the electrodeposition of the composite ionic liquid.

The air cooled hydrogen fuel cell adopts an open cathode, which has the characteristics of self-humidification, simple and portable system, etc. However, its performance is not as well as a water cooled fuel cell. It is necessary to reveal the relationship between temperature and water content in the air cooled fuel cell in order to increase the output power. An 800 W air cooled fuel cell stack assembled in the laboratory was tested and analyzed. The voltage-current curve, net power, mass and heat transfer characteristics of the stack under different air fan speeds were compared. The experimental results show that at low currents the low flow rate under slow fan speed can maintain high temperature in the stack to reduce the activation loss of the catalyst, so that the stack could achieve large net output power. While under high current conditions, low flow rate will lead to excessive temperature and decrease the consistency. The distribution of oxygen concentration, water content and temperature in the fuel cell are visualized by numerical method. It is indicated the ohmic loss caused by low water content is the key factor limiting the output power, and by increasing fan speed and increasing the air flow, a better cooling effect can be ensured, thereby increasing the content water volume, reducing ohmic losses.

The hydroxypropyl sulfomethylated lignin was modified by a two-step method, and the effect of hydroxypropyl sulfomethyl lignin on cellulase hydrolysis and its interaction mechanism with the enzyme were studied. The structure and surface properties of modified lignin were characterized by infrared spectroscopy, proton nuclear magnetic resonance spectra, surface charge measurement and contact angle analysis. The non-productive adsorption of cellulases on the modified lignin were investigated by using quartz crystal microbalance with dissipation (QCM-D). The results showed that compared with unmodified lignin, hydroxypropylation and sulfomethylation could block the phenolic hydroxyl groups with introduction of hydrophilic sulfonic acid groups. The modified lignin had high surface electronegativity and low hydrophobicity, which led to the decrease in the non-productive adsorption capacity of cellulase thus promoting the efficiency of enzymatic hydrolysis of cellulose.

A gel electrolyte was prepared by using lithium hexafluorophosphate (LiPF₆) as the polymerization initiator of tetrahydrofuran, and at the same time as a fluorine source, a LiF-rich solid electrolyte interface (SEI) was constructed in-situ on the surface of the lithium metal anode to suppress the growth of lithium dendrites and side reactions between metallic lithium/electrolyte. The as-prepared gel polymer electrolyte presents an ionic conductivity of 1.33 mS·cm^-1 at room temperature and shows a high electrochemical stability up to 4.5 V. Compared with linear sweep voltammetry in 335C electrolyte, lower reduction current is observed at the range of 0—1.5 V (vs Li/Li⁺) in the cell with gel polymer electrolyte, which indicates that gel polymer electrolyte can mitigate the side reaction of metallic lithium with electrolyte. The lithium metal anode in the symmetric-cell with in-situ polymerization gel polymer electrolyte exhibits no obvious lithium dendrite and damaged morphology. X-Ray photoelectron spectroscopy results further reveal that the lithium metal anode in gel polymer electrolyte is formed a stable SEI with LiF-rich compound, which is much enhanced than that of in 335C electrolyte. Consequently, the Li|LiFePO₄ cells with gel polymer electrolyte exhibits a long-term cycling stability, which can release a reversible capacity 118.7 mAh·g^-1 after 400 cycles at a current density of 1 C, as well as coulombic efficiency of 99.5%. Benefit from the ring opening polymerization process of tetrahydrofuran, PF₅ participates the formation reaction of intermediate product [(THF)⁺(PF₅)^-], which caused the equilibrium of the decomposition reaction shift to the right and therefore increase the formation of LiF on the surface of lithium metal anode. This process results in a great enhancement of the cyclability due to LiF-rich formed in the SEI. Therefore, the growth of lithium dendrite can be prevented by the stable SEI, as well as the side reaction between lithium metal and electrolyte.

The surfaces of fine particles that emitted from power generation processes with the direct combustion of biomass and with the co-combustion of biomass and coal usually contain a certain amount of soluble inorganic salt. Based on the classical heterogeneous nucleation theory, an improved model for vapor heterogeneous nucleation on the surfaces of particles containing a spherical insoluble core and soluble inorganic salt was developed, taking into account the embryo growth mechanisms of surface diffusion and direct deposition. Using the numerical simulation method, the nucleation behaviors of four types of particles (insoluble particle and three types of particle containing soluble inorganic salt) were compared and analyzed. The results show that in cases of medium contact angles, the critical free energy of embryo formation and the critical embryo radius of an insoluble particle are the largest, followed by the particles containing KCl, NaCl and CaCl₂, respectively. Under the condition with critical embryo radii, the ratio of water molecule addition rates due to mechanisms of surface diffusion and direct deposition increases slightly at first and then keeps constant with increasing particle radius, and decreases monotonically with increasing contact angle. It is also found that when the contact angle is small, the critical saturation ratio for nucleation of a particle containing soluble inorganic salt is lower than that of the insoluble particle, whereas when the contact angle is larger, the critical saturation for nucleation of particles containing KCl and NaCl exceeds that of insoluble particles successively.

Vacuum baking before electrolyte injection has an important impact on the cycling performance, safety and stability of lithium battery. Differences in cell structure design, material system, oven size, etc. will lead to differences in the vacuum drying process. For vacuum baking, drying performance varies with different cell design, materials and oven size. Reaction engineering approach (REA) to drying modelling has been widely used for convective drying under atmospheric pressure and high initial water content materials. Here, REA was applied to the extremely low moisture process for battery vacuum baking. The results matched well with the experimental results. The influence of environmental humidity on drying process is considered in this work, and the prediction error is less than 10%. The rules of thumb established in this work by single factor experiment can guide the improvement of vacuum drying process of lithium-ion battery. The application in mass production is also briefly introduced here. The current work has demonstrated that REA can have excellent application in vacuum drying for lithium battery.

Unconventional natural gas after pretreatment still contains high concentration of N₂, which can not meet the requirements of pipeline transportation. As an efficient separation method, membrane separation of unconventional natural gas has an ideal application prospect, and the membranes used for separation of unconventional natural gas can be divided into CH₄ preferential permeation membrane and N₂ preferential permeation membrane. Compared with the CH₄ preferential permeation membrane, the advantage of N₂ preferential permeation membrane is that the CH₄ product is at the high pressure side after separating N₂/CH₄ mixture, which is conducive to the subsequent treatment. In this work, trimesoyl chloride was used as the oil phase monomer, m-phenylenediamine was used as the water phase monomer, and a dense ultra-thin polyamide separation layer was prepared on polysulfone by interfacial polymerization. By introducing ZIF-90 nanoparticles with pore size that can allow N₂ molecules to pass through but not CH₄ molecules, a fixed N₂ transfer channel was formed in the membrane and the mixed matrix membrane with N₂ preferential permeation was successfully prepared for N₂ removal and CH₄ purification. The permselectivity test results show that the permeation rate of N₂ is 1.16×10^-9 mol·m^-2·s^-1·Pa^-1 and the separation factor of N₂/CH₄ is 16.6 when the content of nanoparticles in the composite membrane is 0.30 g·L^-1 and the feed pressure is 2 bar. The separation factor is 46.5% higher than that of the non doping ZIF-90, which shows the potential of the mixed matrix membrane to remove N₂ and_{purify CH4 for unconventional natural gas.}

Metal-organic frameworks (MOFs)-derived carbon materials have abundant pore structures and ultra-high specific surface areas, showing great potential in energy storage fields such as supercapacitors. Using environmental-friendly ZnO nanospheres (ZnO NS) as templates, the core-shell structured ZnO@Ni/Co-ZIF-8 precursor was prepared by hydrothermal method. The Ni, Co and N doped MOF-derived carbon materials Ni/Co-CN with different morphologies were obtained by pyrolysing ZnO@Ni/Co-ZIF-8 at different temperatures (700, 800, 900 and 950℃). The effect of the pyrolysis temperature on their energy storage performance was investigated. The results show that with the increase of the pyrolysis temperature, Ni/Co-CN gradually changes from porous carbon to carbon nanotube bridged porous carbon structure. When the pyrolysis temperature is 900℃, Ni/Co-CN-900 shows the highest specific capacitance. In the electrolyte of 1 mol/L KOH, the cyclic voltammetry curve remains a good symmetry, indicating superior electrochemical reversibility. By calculating the capacitance contribution and diffusion contribution ratios of charge storage in this process, it is found that the dominate capacitance contribution is due to the double-layer adsorption of porous carbon and a small amount originates from the Faradaic reaction caused by N doping. At a current density of 0.5 A/g, the specific capacitance of Ni/Co-CN-900 is up to 273.5 F/g. At the current density of 10.0 A/g, the specific capacitance still remains 93.8% after 5000 galvanostatic charge/discharge cycles, exhibiting excellent electrochemical performance.