Helically coiled tube (HCT) steam generators are widely used in chemical engineering, aerospace industry and nuclear engineering, etc., and especially, in small modular nuclear reactors because of their high heat transfer efficiency, compact structure and free thermal expansion behavior. The special geometry of the HCT leads to complex flow characteristics such as secondary flows and the resulting special phase distribution and flow patterns in the tube and relatively high pressure drop compared to that in straight tubes. The difference of geometrical parameters usually leads to the significant difference in the characteristics of gas-liquid flow in HCTs. In the present study, the pressure drop and flow-pattern transition characteristics of subcritical pressure water-steam two-phase flow in an HCT with a special small tube diameter were investigated by experiments and numerical simulations. It can be concluded that the frictional pressure drop firstly increased with the increase in thermal equilibrium quality, and reached a peak at the quality of 0.75, and then decreased gradually. This was due to the flow regime transforms from annular flow to dispersed flow (or mist flow) when the quality equaled to 0.75, which led to the reduction of frictional pressure drop. The flow regimes of high-pressure steam-water two-phase flow in HCTs can be divided into bubble flow, intermittent flow, annular flow and dispersed flow (or mist flow). The transition criteria between bubble flow and intermittent flow was at the quality of 0.038, the transition criteria between intermittent flow and annular flow was at the quality of 0.500, the transition criteria between annular flow and dispersed flow (or mist flow) was at the quality of 0.751, and the dry-out point was at the quality of 0.93. This study can provide guidance for the design and safe operation of HCT steam generators.

Circulating fluidized bed is widely used in industrial production due to its good gas-solids mixing. Clustering characteristics affect the gas-solids contacting and therefore the heat/mass transfer and the yield of the products as well as the selectivity. To get more detailed information effectively, a high-speed camera was used to visualize the flow field in a two-dimensional circulating fluidized bed at the superficial gas velocity, U_g, equal to 5—9m/s, and the solids circulating rate, G_s, of 50—300kg/(m²·s). The k-means machine learning algorithm was then utilized to assist the image processing to identify the cluster effectively and quantificationally. Results showed that as G_s increased from 50kg/(m²·s) to 300kg/(m²·s) at U_g=9m/s, the cluster frequency almost doubled from 116Hz to 327Hz. The average cluster concentration was correlated with the local lateral position. The average cluster concentration was more uniformly distributed in the central region (y/Y from 0 to 0.7). Toward the near wall region (y/Y from 0.7 to 0.9) it increases rapidly. The change of the average cluster concentration near the wall was nearly three times higher than in the central region. Both the average cluster velocity and the average cluster equivalent diameter displayed a similar trend, decreasing from the center toward the wall in the lateral direction. Quantitative prediction equations for cluster parameters were obtained based on the experimental data. The relative errors were all within 30%. Cluster characteristics were studied quantitatively and systematically in this study. These results can support the development of a gas-solids flow model and process intensification for circulating fluidized beds.

The development of mass exchange networks is a pivotal strategy for minimizing pollutant emissions and reducing economic costs in chemical processes. This study introduced a novel optimization model based on Mixed Integer Nonlinear Programming (MINLP), facilitating the synchronous optimization of mass exchange networks. The model incorporated a continuous non-structured model (NSM), which allowed for the integration of split-stream mixing of unequal concentrations and the consideration of stream stock regeneration. The NSM was characterized by its absence of predetermined structural parameters and fixed matching patterns, using continuous real number intervals to delineate different stream stocks and randomly generating specific real numbers to represent the positions of mass transfer units in these streams. This approach endowed the mass exchange network with remarkable randomness and flexibility, significantly broadening the search domain for optimal solutions. Building on this, the random walk algorithm with compulsive evolution (RWCE) algorithm was employed to simultaneously optimize both integer and continuous variables within the NSM. This algorithm was distinguished by the independent evolution of individual variables. The effectiveness of this model and algorithm was validated through three case studies, which demonstrated that the NSM combined with heuristic algorithms can achieve better results than the current best reported in literature, flexibly representing complex mass exchange network structures and confirming the method’s efficacy.

In order to solve the problem of rapid volume expansion caused by phase change in the heat transfer process of two-phase flow in microchannels, which triggers the problems of uneven flow rate, pressure drop fluctuation, and local overheating, the flow boiling two-phase pressure drop in countercurrent microchannels with different phase-separated vents densities (PSP00, PSP04, PSP06, PSP10) with and without electric field was investigated. The integrated heat transfer performance of countercurrent microchannels with and without phase-separated structures under the action of different voltages (0, 200V, 400V and 600V) was investigated by introducing the performance evaluation criteria (PEC). The results showed that the greater the density of the vents of the phase-separated structure, the lower the flow resistance and pressure drop in the channel, and the reduction of the two-phase pressure drop was more pronounced with the increase of the heat flow density. The applied electric field increased the pressure drop of two phases in the channel, but the increase of the pressure drop of two phases in the channel was reduced after synergizing with the phase-separated structure, and the pressure drop of two phases in the channel was reduced after applying 600V voltage. Applying 600V to the PSP10 channel with the phase-separated structure reduced the two-phase voltage drop by 14.2% compared to the PSP00 channel without the phase-separated structure. Both the electric field and the phase-separation structure could reduce the length-to-diameter ratio of the confined bubbles in the microfine channel, and the greater the phase-separation pore density and voltage, the smaller the length-to-diameter ratio of the confined bubbles. The electric field alone, the phase separation structure alone, and the combined effect of the electric field and the phase separation structure were all conducive to the improvement of the integrated heat transfer performance PECof the microfabricated channels. Among them, the combined effect of electric field and phase-separated structure was the best, and the larger the density of permeable pores and voltage of phase-separated structure, the larger the PEC. The maximum PEC of the simultaneous action of electric field and phase separation structure (PSP10-600V) was 1.30, which was 13.0% higher than the maximum PEC of the action of electric field alone (PSP00-600V), and 7.4% higher than the maximum PEC of the action of phase separation structure alone (PSP10).

In order to effectively separate the methanol-acetonitrile azeotrope system, N-octylpyridinium hexafluorophosphate imide salt ([Opy][PF₆]) was selected as entraining agent, and the isobaric vapor-liquid equilibrium of methanol-acetonitrile-[Opy][PF₆] ternary system was determined. The isobaric vapor-liquid equilibrium (VLE) data of ternary system were obtained, and the influence of ionic liquid on the vapor-liquid equilibrium of methanol-acetonitrile was investigated. The experimental data were correlated with the non-random two-liquid (NRTL) models and the binary interaction parameters were obtained. The separation mechanism was explained by intermolecular interaction energy and excess enthalpy analysis. And the results showed that the addition of [Opy][PF₆] could increase the relative volatility of methanol relative to acetonitrile and make the salting-out effect more pronounced. The NRTL model was in good agreement with the experimental results, and these data were correlated by NRTL model in Aspen Plus software. It was found that when the molar fraction of [Opy][PF₆] was 0.0345, the system was no longer azeotropic. Aspen Plus software was used to simulate the extractive distillation process and optimize the process parameters, and the best operating conditions of the extractive distillation process were obtained. The simulation results could be used as guidance for further extractive distillation experiment and process design.

To solve the heat dissipation problem of high heat flux electronic components, multiscale structured groove surfaces were prepared by sintering copper powder with different particle diameters. Combining visualization, the effect of multiscale structure on liquid replenishment and bubble escape was studied using FCM-47 electronic fluoride solution as the working fluid. Exploring the effects of copper powder particle diameter and groove structure size on bubble generation, growth, detachment, and boiling heat transfer, The results showed that the size of the groove structure had a significant impact on boiling heat transfer performance, with the valley width affecting the bubble detachment diameter, and there was an optimal width value. The influence of ridge height and groove bottom thickness was the result of a balance between the number of nucleation points that the groove could provide, the area of phase change heat transfer, and the vapor-liquid flow resistance. Both theoretical analysis of pores and visualization of boiling indicated that multiscale structures were beneficial for boiling heat transfer. Compared to spherical copper powder, branched copper powder formed multiscale structural channels with different pore sizes after sintering, which effectively met the different needs of liquid replenishment and bubble escaping, and significantly improved heat transfer performance. The branched copper powder multiscale surface with particle diameter of 150μm was significantly better than other surfaces in the present experiment, and heat transfer coefficient in electronic fluorinated liquid could reached 46.0kW/(m²·K).

The turbopump isolation seal system plays a crucial role in the safe and reliable operation of liquid rocket engine turbopumps, and the design of the seal system must ensure that it has the ability of high speed resistance, long life, and strong resistance to external excitation. In order to solve the problem of seal failure caused by the change of seal leakage due to the change of rotational speed and pressure of the double bellows helium isolation seal under the operation condition, the simulation model of air film between sealing surfaces and the deformation model of dynamic and static rings were established to analyze the influence of the change of rotational speed and isolation medium pressure on the dynamic opening characteristics and the deformation of sealing surface under the operation condition, and the leakage volume of the seal under the different rotational speeds and isolation medium pressures was measured through the test. The leakage of the seal was measured under different speeds and pressures of the isolating medium. The results showed that the opening of the double bellows hydrostatic helium isolation seal did not depend on the rotational speed, the leakage almost did not change with the rotational speed, and it still had stable sealing performance when the rotational speed changes. With the increase of isolation medium pressure, the stiffness of the gas film showed an overall increasing trend, but there was a tendency to level off at 0.5—0.6MPa, which indicated that the isolation seal gas film stiffness will not increase indefinitely, and there was a stiffness limit. The seal was able to pass through the membrane pressure, and it can open under the different rotational speeds and isolation medium pressures. The seal can adaptively adjust the axial position of the static ring to establish a new balance through the mutual coordination of membrane pressure, membrane thickness and bellows. When the isolation medium pressure changed, the pressure in the stabilizing tank and the isolation medium pressure change trend was the same, and the seal can quickly respond to the pressure change.

Rectisol process is a relatively mature purification process in China's coal chemical production, and its modeling research is conducive to the intelligent construction and development of the plant. In this paper, based on the need of intelligent construction of rectisol plant in a petrochemical enterprise, real-time data preprocessing rules were established, and the CO₂ content prediction model of purified gas was built based on the Bayesian optimization (BO) long short-term memory (LSTM) neural network. The results showed that after preprocessing the real-time data of the device by manual screening and correction and the maximum information coefficient (MIC) method, the number of variables of the collected real-time data could be reduced from 84 to 22, which reduced the redundancy of the data. The six hyper-parameters of the LSTM model were tuned by using the BO, and the BO-LSTM prediction model was established based on the optimized hyper-parameter combinations. The evaluation indexes of RMSE, MAE and R² of the prediction model were 0.0395, 0.0275 and 0.9843, respectively, which were higher in precision and better in regression effect than the traditional BP and LSTM model, proving the feasibility and accuracy of the model in the prediction of the rectisol purified gas composition, and it could guide the optimization of the production of purified gas products. The product optimization modeling method based on the CO₂ content prediction model of rectisol purified gas could provide ideas for the digital and intelligent construction of related processes.

Concentric circular tube bundles are widely used in the nuclear industry, with transitional arrangements being the most representative configuration among them. Studying the vortex shedding characteristics of transitional tube bundles can provide valuable insights for the design, manufacturing, and maintenance of this type of heat exchanger. This study aimed to explore in depth the vortex shedding characteristics of concentrically arranged transitional tube bundles under different pitch-to-diameter ratios (1.25, 1.5, 1.75, and 2.0). By employing numerical simulations combined with monitoring of flow velocity and lift coefficient, vortex shedding data were obtained and Fourier transformed to determine the vortex shedding frequency. The results indicated that in the transitional arrangement, tube bundles with pitch-to-diameter ratios between 1.25 and 2.0 were significantly influenced by adjacent tubes, making it difficult to produce clear vortex shedding phenomena and resulting in lower vortex shedding frequencies. The pitch-to-diameter ratio was one of the main factors affecting vortex shedding. As this ratio increased, the vortex shedding phenomena became more pronounced. The findings provided practical guidance for optimizing the design of concentric circular transitional tube bundle structures and reducing vortex-induced vibrations.

Polysilicon is a key material for solar panels in the field of photovoltaics, and the modified Siemens method is a common method for preparing polysilicon, with the core equipment being a reduction furnace. The structure of the reduction furnace is complex, and the furnace contains complex physicochemical phenomena. In order to study the polycrystalline silicon vapor deposition characteristics, a reactor model with 12 pairs of rods was established, coupling the vapor phase reaction and surface reaction mechanisms, and the velocity, temperature, and silicon deposition rate distributions under different conditions were discussed in detail. Response surface methodology coupled with two variables, inlet velocity and temperature, was used to explore the combined effects on the average silicon deposition rate and the feedstock conversion rate. The results showed that higher inlet velocity and temperature were favorable to increase the heat and mass transfer rate and the average silicon deposition rate. Temperature was the main factor influencing the process and the effect was significant in the low temperature region. Due to the increase of inlet velocity and the decrease of feedstock conversion, the optimal process conditions were predicted to be 1460—1500K and 25—36m/s, taking into account the effects of average deposition rate (≥10μm/min) and feedstock conversion (≥10%).

Safety evaluation is a prerequisite for the normal operation of chemical processes. Although the traditional quantitative risk assessment method can reduce the frequency of accidents, it relies heavily on the experience of experts and is difficult to assess the potential risk of accidents caused by dynamic chemical conditions. To address this problem, an intelligent quantitative risk assessment method based on dynamic simulation (DQRA-BiLSTM) was proposed in this paper. The process under study was first simulated with process simulation software to obtain a dynamic data set under abnormal conditions. Then, the potential relationships between variables were deeply learned using bi-directional long short-term memory (Bi-LSTM) to characterize the complex mechanistic relationships between predictor variables that had a direct impact on the severity of accident hazards. A reliable control scheme was proposed to ensure the safe operation of the process. The method was applied to the system of carbon di-hydrogenation and deethanization in the ethylene separation process, and the experimental results showed that the model had good performance for the dynamic risk assessment of the ethylene separation process, which had some practical application value.

This paper gradually regenerates the spent HDCCR catalyst through calcination, acid washing, and impregnation, so that the physical properties and activity of the regenerant are as close as possible to the level of fresh catalyst. Under the optimal roasting conditions, carbon deposition was removed, resulting in the recovery of the pore volume and the surface area of the regenerant to 90.4% and 89.4% of those of the fresh catalyst, respectively; the deposition of NiO was 1.17%, and the deposition of V₂O₅ was 2.56%. Under the optimal acid washing conditions, the deposited metal impurities were removed to restore the pore structure; the content of metal impurities V₂O₅ reached 1.03%, NiO content restored to that of fresh catalyst, but the active metal MoO₃ lost 4.16%. The active metals were supplemented using equal volume impregnation method, making the active metal content of the regenerant basically the same as that of the fresh catalyst, while restoring the specific surface area and pore volume of the regenerant to 102.6% and 107.7% of the fresh catalyst, respectively. Through XRD detection, it was determined that the phase of the regenerant was basically the same as that of the fresh catalyst. Through H₂-TPR detection, it was found that the reduction temperature of the regenerant was higher than that of the fresh catalyst. NH₃-TPD detection showed the acidity of the regenerant was stronger than that of the fresh catalyst. Through HRTEM analysis, it was found that the MoS₂ crystal of the regenerant was longer and the number of layers decreased compared to the fresh catalyst. The initial activity of the regenerant was evaluated by a high-pressure reactor, and it was found that the demetallization activity, desulfurization activity, and residual carbon removal activity of the regenerant were 99.9%, 91.0%, and 106.6% of those of the fresh catalyst, respectively. The stability of the regenerant was evaluated by a fixed bed, and it was found that the stability of the regenerant was equivalent to that of the fresh catalyst.

During the nucleate boiling process, the continuous disturbance of bubbles enhances heat transfer efficiency in the fluid domain. However, the influence of the dynamic characteristics of boiling bubbles on boiling heat transfer still needs to be further clarified at periodic thermal oscillation conditions. A visualisation experiment was used to verify the accuracy of lattice Boltzmann boiling simulation. Based on the multi-relaxation time lattice Boltzmann model, the effects of boiling bubble internal flow field on nucleation, growth, and detachment processes under different pulse conditions were investigated. The bubble motions under constant heating and pulse heating conditions were compared, and the influence of different pulse periods and amplitudes on the bubble internal temperature field was discussed. The results indicated that with an increase of pulse period and amplitude, a reverse vortex opposite to the growth direction appeared inside the bubble, and the stable growth stage and necking-detachment stage gradually advanced. The bubble heat exchange increased, leading to an accelerated bubble growth rate under pulse heating conditions. This article provided a theoretical basis for the investigation of the dynamic characteristics and control of boiling bubbles.

Liquid argon on the nano-copper substrate was taken as the research object to investigate the effect of heated surface wettability on the pool boiling heat transfer. The bubble nucleation of hydrophobic/hydrophilic surface was explored to reveal the enhanced mechanism of heat transfer from the microscopic point of view. A Cu-Ar pool boiling model was built by the large-scale atomic/molecular massively parallel simulator (LAMMPS). The degree of surface wettability was adjusted by changing the interfacial energy coefficient α. The effect of α(hydrophobicity α=0.2, 0.4, 0.5, neutral α=1.0 and hydrophilicity α=1.5, 2.0) on the bubble growth, combination and breakup was investigated at a temperature of 160 K. The heat transfer mechanism of liquid argon pool boiling on the surface was revealed through the bubble volume, heat flux absorbed from liquid argon, and interface thermal resistance. The results showed that no bubbles were observed under α = 0.2 (super hydrophobic), due to weak heat transfer and large interfacial thermal resistance. Moreover, as α increased from 0.4 to 2.0, the bubble nucleation and detachment time of liquid film shortened from 7ns to 4ns, and increased 8.5ns to 7ns, respectively. At the same time, the bubble volume and heat flux increased from 291.1nm³ to 373.4nm³ and 130kW/cm² to 161.3kW/cm², with the increment of 22.1% and 19.4%, respectively. It indicates that compared to hydrophobic surface, stronger liquid-solid interaction of hydrophilic surface continuously absorbs heat energy to grow the coalesce bubbles, which increases the bubble volume. Before forming the gas film, more heat of liquid film is absorbed from the hydrophilic surface, leading lower interface thermal resistance. Consequently, more favorable boiling conditions can be provided from the hydrophilic surface to shorten the transition time from liquid phase to gas phase, accelerate the formations of bubble nucleation and gas film, and improve the efficiency of bubble nucleation and boiling heat transfer.

High-temperature heat pump steam generation system has the potential to replace small coal-fired boilers, not only to meet the demand for steam above 110℃ in the industrial field, but also to reduce the carbon dioxide emissions of heating equipment. In this paper, a high-temperature heat pump steam generation system for R245fa was constructed. The performance of the system was investigated under the matching conditions of different evaporation temperatures (35—50℃) and condensing temperatures (95—125℃), as well as different heat source temperatures (45—65℃) and hot water/steam generation temperatures (95—120℃), and the effect of different heat source temperatures on the start-up state of the system was also investigated. The results showed that COP, η_iso, and η_vol generally showed a decreasing trend with the increase of the evaporation/condensation temperature difference. Compared with the conventional heat pump system, high-temperature heat pump system compression ratio level was higher, and the average level of this unit was 6.09, up to 8.28. The system isentropic efficiency and volumetric efficiency by the operating temperature of the unit was more pronounced. In this experiment, while the compression ratio basically stayed unchanged in the case of the evaporation temperature rises from 35℃ to 45℃, isentropic efficiency and volumetric efficiency decreases by 3.65% and 6.16%, respectively. COP, heat production decreased with the increase of the difference between the heat source temperature and the generated hot water/steam temperature. The direct evaporation principle of this unit made the generated steam pressure lower than 0.170MPa, and the equipment met the standard of normal pressure vessel. The heat source temperature had a certain effect on the change of the system refrigerant flow rate, but the magnitude of the effect was limited. Taking this unit as an example, when the heat source temperature changed from 50℃ to 60℃, the increase of system refrigerant flow rate due to the increase of heat source temperature was less than 5%. The load switching in the start-up process led to rapid changes in the system performance. The increase of heat source temperature accelerated the start-up speed of the system. The change of the heat source temperature from 45℃ to 65℃ reduces the time taken for start-up by 520s. There was a significant impact on the system startup stability, and too high or too low heat source temperature would reduce the system start-up stability. According to the stability analysis results, the suitable heat source temperature range for this unit was 50—60℃.

In order to meet the environmental protection requirements and enhance the flow boiling heat transfer capacity of microchannel heat sinks, a new environmentally friendly low surface tension working fluid, SF-33, was selected for flow boiling heat transfer research. Large-sized microchannel heat sink with an open gap between the top of channels and the bottom of the cover plate was designed and fabricated. A flow boiling heat transfer experimental platform was established. The characteristics of subcooled flow boiling heat transfer and pressure drop of the low surface tension coolant SF-33 at different inlet temperatures and mass fluxes were investigated. The influence of flow pattern transitions on heat transfer was analyzed based on visualization results. The results revealed the presence of four flow patterns, including bubbly flow, slug flow, slug-localized churn flow, and slug-localized stratified flow. The open structure and large flow space affected the flow pattern distribution inside the microchannel heat sink. With the increase in heat flux and outlet vapor quality, both the heat transfer coefficient and pressure drop of the microchannel flow boiling increased gradually. Lowering the coolant's inlet temperature could delay the occurrence of CHF and reduce the inlet and outlet pressure drops. Additionally, it was observed that under different mass flux conditions, there were significant differences in the trend of inlet and outlet pressure drop changes with increasing heat flux.

The highly selective production of higher alcohols from syngas is of great significance for the clean and efficient utilization of coal. The two active sites of Co-based catalysts have unique advantages in the synthesis of higher alcohols, and CuCo-based catalysts have become a research hot spot in recent years due to their low cost and high yield. However, the action mechanism of the bi-functional active sites is unclear, and theoretical research is still desirable. This article provides an overview of the latest research progress in catalysts in this field, with a focus on the properties and reaction mechanisms of the active sites in Co-based catalysts for the synthesis of higher alcohols. It clarifies the role of Cu/Co ratio and uniform distribution of CoCu in improving the catalyst performance, which is crucial for the design of next-generation catalysts. This article reviews the effects of alkali metals, La and other additives on the structure-activity relationship of catalysts, as well as their effects on improving carbon chain growth, inhibiting methane formation, preventing carbon deposition, and enhancing catalyst stability. The system discusses the impact of LDHs with unique layered structures and carbon-based carriers such as CNTs and AC as on the performance of Co-based catalysts. By deeply analyzing the synthesis mechanism and developing catalysts with new structures and support materials, we could further improve the performance of Co-based catalysts and thus achieve the more efficient, environmentally friendly, and sustainable higher alcohol synthesis, so as to provide a solid foundation for its commercialization.

ZSM-5 zeolite is a solid acid catalyst with open pore structure, and the structure-activity relationship between its structure and catalytic performance has become a research hotspot in this field. Herein, this review provides a comprehensive overview of the recent advancements in the structural regulation of ZSM-5 zeolite (framework aluminum distribution, pore structure, and framework defects). The diversity distribution of framework aluminum atoms and its characterization techniques are introduced, and the impacts of framework aluminum atoms distributions on the catalytic performances of ZSM-5 zeolite are described. In addition, the pore structure regulation strategies of ZSM-5 zeolite are summarized, and the effects of pore size and diffusion path length on the adsorption/diffusion of guest molecules, shape selectivity and catalysis are discussed. Modulation strategies of ZSM-5 zeolite framework defects are also summarized and the corresponding impacts on the acidity, hydrophilicity/hydrophobicity, and capability of coke tolerance of zeolite are elucidated. Finally, a perspective on future research was proposed. i.e. precise characterization of aluminum distribution, establishment of the relationship between aluminum distribution and catalytic performance, preparation of specific structured zeolites based on a profound understanding of the synthesis mechanism, and controllable modulation of defects according to reaction requirements are important directions in the future researches of ZSM-5 zeolite.

Electrochemical nitrogen reduction to ammonia is the most promising frontier technology that is expected to replace the traditional Haber-Bosch ammonia synthesis process in the future. It enables decentralized production and flexible application of renewable energy sources. Due to the stable chemical properties of nitrogen and the competitive hydrogen evolution reaction (HER) in the catalytic process, the efficiency of electrochemical nitrogen reduction is still very low, and there is still a long way to achieve industrialization. Electrolyte environment is one of the effective ways to improve the efficiency. Starting from the electrochemical reaction environment, it summarizes the types of electrolytes, application status and optimization strategies, compares the influence of electrolyte types on the efficiency of electrochemical nitrogen reduction to ammonia. The efficiency in different electrolytes is quite different, but there is still no qualitative breakthrough, and the ammonia production rate of electrochemical nitrogen reduction cannot meet the industrial requirements. From regulatory strategy, the development of electrolytes with high N₂ solubility is an effective way to improve the reaction rate. By regulating the electrolyte proton concentration and further studying the catalytic coordinated interface reaction to further inhibit the hydrogen evolution competitive reaction, the efficiency of electrochemical nitrogen reduction will be greatly improved, and the industrialization process of this technology will be promoted.

The high-value utilization of carbon dioxide (CO₂) is an important measure to address global climate change and energy shortages. Low-carbon olefins, as basic chemical raw materials, are one of the main products of CO₂ hydrogenation. Iron (Fe)-based catalysts, with their high CO₂ catalytic activity and low preparation cost, have become the most promising catalytic materials for this conversion process, but their selectivity for low-carbon olefins still needs to be improved. With the focus on Fe-based catalysts for CO₂ hydrogenation to produce low-carbon olefins, this paper introduces the adsorption, activation and reaction mechanism of CO₂ on the surface of Fe-based catalysts, elucidates the evolution of catalyst structure during the reaction process (activation, carburization, and deactivation), and analyzes the composition and structural factors affecting the performance of Fe-based catalysts. Moreover, it proposes strategies and methods to further improve the performance of catalysts, namely deepening the understanding of reaction mechanisms through simulation calculations and in-situ characterizations, systematically exploring the regulation mechanism of additives and carriers on the structure and properties of Fe-based catalysts, and designing catalysts rationally based on reaction characteristics.

The cyclo-addition of carbon dioxide (CO₂) with epoxides is an effective and clean way to produce cyclic carbonates. As a kind of renewable resource, biomass-based catalysts have attracted wide attention because of their unique properties such as non-toxicity, low cost, non-pollution, and containing a large number of amino and hydroxyl groups. In this paper, the recent research progress in the synthesis of cyclic carbonates from CO₂ and epoxides catalyzed by biomass-based materials such as lignin, cellulose, chitosan, and β‍-cyclodextrin is systematically reviewed. The synthesis methods, structural characteristics, and catalytic reaction mechanism of various biomass-based catalysts are discussed. The catalytic activity and reaction conditions of biomass-based catalysts for CO₂ cycloaddition are summarized. However, CO₂ cycloaddition with biomass-based catalysts is facing the problems of limited large-scale application, low catalytic efficiency, and difficulty in balancing CO₂ capture and conversion. Finally, the application prospects were discussed to provide references and new ideas for the utilization of biomass materials and CO₂ conversion.

Lamellar mordenite has become a research hotspot due to its excellent catalytic performance by the short orientation length. In this paper, the in-situ synthesis methods of lamellar mordenite, including single template method, double template method and adjusting synthetic factors, are reviewed, and their catalytic performance in carbonylation, cyclization and MTO reactions is analyzed. It also indicates that double template method has more advantages than single template method from the perspectives of cost and synthetic method. Using theoretical calculation to explore the directional design and mechanism of template agents, the development direction of template method is to synthesize specific oriented and well mesoporous mordenite. The adjustment of synthetic factors is effective in controlling the orientation length, but it still needs to be compatible with specific templates. In the applications, lamellar mordenite oriented along the b-axis and c-axis has shown good catalytic activity in specific reactions. On a macro level, the relationship between the orientation length ratio and specific reactions should be established. On the micro level, the research on lamellar mordenite focuses on the correlation between the template and acid distribution and catalytic reactions by theoretical calculation and advanced characterization technologies.

Ternary spinel-type ZnGaAl metal oxide and twinned ZSM-5 zeolite were integrated to prepare bifunctional catalyst which were then applied in the methylation of benzene with carbon dioxide. Experimental results revealed that the ternary spinel effectively promoted the activity and the twinned ZSM-5 increased the para-xylene content in the products, compared with the bifunctional catalyst made from the binary ZnAl or ZnGa spinel and conventional ZSM-5 counterparts. This phenomenon can be attributed to the higher concentration of oxygen vacancies provided by the ternary ZnGaAl spinel which enhanced the adsorption towards carbon dioxide and therefore generated more intermediates to react with benzene. Besides, the weak surface acidities as well as the low exposure degree of (010) surface of twinned ZSM-5 efficiently suppressed the isomerization of xylene on zeolite surface and magnified the diffusion advantages of para-xylene. The optimal bifunctional catalyst at 425℃ and 3.0MPa exhibited a benzene conversion of 39.2% and a CO₂ conversion of 37.1%, with a total toluene and xylene selectivity of 91.2% and 55.6% of all the xylene isomers being para-xylene, which is significantly better than the bifunctional catalyst composed of binary spinel and conventional ZSM-5 zeolite.

Y zeolites were modified by different concentrations of iron nitrate solutions. Catalysts were prepared by incipient wetness impregnation method using nickel nitrate and ammonium molybdate as active metal precursors. The physical and chemical properties of the zeolites and catalysts were characterized by X-ray diffraction (XRD), low-temperature nitrogen adsorption (BET), scanning electron microscopy (SEM), NH₃-temperature programmed desorption (NH₃-TPD), hydrogen-temperature programmed reduction (H₂-TPR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and other analytical methods. The hydrodesulfurization (HDS) performance of the catalysts was evaluated on a fixed-bed reactor using dibenzothiophene as a probe. The experimental results showed that the introduction of Fe species increased the specific surface areas and pore volumes of Y zeolite, modulated the acidity of Y zeolite, weakened the interactions between NiMo metals and supports, and modulated the electronic structure of NiMo. The introduction of Fe species also resulted in a shorter MoS₂ average slab length of the sulfide catalysts, a higher average number of stacked layers, higher metal Ni and Mo sulfidation degrees and higher NiMoS active phase ratios, which significantly improved the hydrodesulfurization activity of the catalyst. The NiMo/0.12MFe-Y catalyst showed 81% HDS conversion at 260℃, 18 percentage points higher than that of NiMo/USY catalyst, and also a higher direct desulfurization path selectivity.

After the discovery of the dehydrogenation activity of Sn- and Pb-based catalysts, Ge, in the same main group, has also been confirmed to have catalytic activity for propane dehydrogenation. In this study, the In species were introduced into Ge/SiO₂ catalysts by silica sol-gel method, and the effects of In species and their amounts on the dehydrogenation performance of Ge/SiO₂ catalyst were investigated. In addition, various characterization techniques, such as XRD, XRF, N₂ adsorption-desorption, XPS, TEM, and H₂-TPR were used for reaction optimization. The results showed that In₂(Ge₂O₇) was formed and relatively stable during the reaction, which could efficiently inhibit the reduction and sintering of Ge species. The introduction of In species not only could lower the deactivation rate of Ge/SiO₂ catalyst in single reaction, but also could weaken the irreversible deactivation during reaction-regeneration cycles. As a result, the deactivation rate parameter could be decreased from 0.044h^-1 to 0.019h^-1 after introducing of 6 wt% In species, and the initial activity of the regenerated 6In10Ge/SiO₂ catalyst was only decreased by 7.1% as compared with 22.3% of the regenerated 10Ge/SiO₂ catalyst.

N-TiO₂/MoS₂/N-TiO₂ (NT/MS/NT/ACFF) photocatalyst supported by activated carbon fiber felt (ACFF) was prepared by ultrasound assisted hydrothermal method, and used as the carrier of laccase. The NT/MS/NT/ACFF immobilized laccase was then obtained by covalent bonding method. The morphology and microstructure of the catalyst were characterized by means of SEM, XRD, BET, Raman, UV-vis DRS and FTIR. The effects of different systems on the degradation of bisphenol A (BPA). The reaction kinetics, mineralization rate and reusability of NT/MS/NT/ACFF immobilized laccase were studied. The results showed that compared with other systems, NT/MS/NT/ACFF immobilized laccase in visible light had the best degradation rate of BPA (82.5%), the apparent rate constant k_obs was 0.00764 min^-1, and the mineralization rate was up to 64.5%. NT/MS/NT/ACFF immobilized laccase has good photocatalysis performance, enzyme catalytic activity and stability, and the degradation rate of BPA can still reach 69.4% after 4 cycles. Through GC-MS analysis, we concluded that the catalytic degradation of BPA by NT/MS/NT/ACFF immobilized laccase includes steps of fracture recombination, oxidative decomposition and ring-opening reactions.

Mercury pollution has a wide range of sources and emissions and has become one of the ten most serious pollution sources in the world because of extensive source and massive emission. Among the many mercury ion removal technologies, adsorption has evolved into a more sophisticated and extensively adopted processing technology because of its high efficiency and low cost. The key to adsorption is the adsorbent with excellent performance, while the adsorption performance of traditional adsorption materials is limited. Based on this, this paper summarized the novel adsorption materials for mercury ion in recent years, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), conjugated microporous polymers (CMPs), conductive polymers, MXenes and composite materials. The relationship between the structural characteristics of these materials and their adsorption properties for mercury ions was discussed in detail. The prospect of mercury ion adsorption materials in water was summarized. It was pointed out that adjusting the structure of the material and adding specific functional groups were the directions for further research and development of new materials. It was hoped that this paper can provided some reference and inspiration for the design and development of the research of novel adsorption materials for mercury ion.

The design of all-wood-based hydrogels using the "top-down" method is a novel strategy for preparing functionalized materials. The obtained materials retain the original resilience of hydrogels and have good mechanical properties and anisotropy, which are widely used in biomedicine, flexible sensors and environmental protection. This review provided the research trend and development of the "top-down" design of all-wood-based hydrogels in recent years. Firstly, the background of the two design methods, "bottom-up" and "top-down", and the research of all-wood-based hydrogels were described. Secondly, inspired by the natural structure of wood, the principles of "top-down" design of wood-based hydrogels were induced including the preparation of cellulose scaffolds and the selection of matrix polymers. The cutting-edge applications of the "top-down" design of all-wood hydrogels was discussed including wearable electronics, bone repair scaffolds, supercapacitors, and solar evaporators. Finally, the existing challenges of "top-down" design of wood-based hydrogels were summarized and outlooked. It was suggested that subsequent research should focus on the anisotropy, mechanical property, universality and green production of the material in the future, further providing reference for the structure design and cutting-edge application of wood-based hydrogels.

Gas membrane separation technology is extremely common in the chemical industry. Compared with traditional gas separation technology, it has advantages such as a small footprint, low energy consumption, simple operation, energy conservation and environmental protection, and thus has a wide range of application prospects. Membrane materials, as the core of gas membrane separation technology, have been widely studied. Among them, the mixed matrix membranes (MMM) based on metal-organic frameworks (MOF) have high permeability and selectivity, making them a promising gas separation membrane material. There are various types of MOF materials with adjustable pore structure and surface modifiability. However, there are differences in properties between MOF particles and polymers, poor compatibility and uneven dispersion, leading to interface defects such as particle aggregation, polymer chain segment stiffness and particle pore blockage in MMM, which in turn affect the gas separation performance and mechanical properties of the membrane. This article summarized four methods to improve the compatibility of MOF-based MMM based on different modification principles, namely functionalization of MOF, encapsulation of MOF, modification of polymer and post-treatment of MMM. Based on the examples of researchers, the types of polymers and MOF used in the preparation of MMM, the target gas, the mechanism of modification methods and the modification objectives were explained. Comparing the permeability, selectivity and mechanical properties of MMM before and after modification, the separation effect achieved after interface modification was demonstrated. Finally, the existing modification methods were discussed and the development space for existing interface optimization methods was proposed, such as considering the characteristics of the molecules themselves, temperature and aging conditions, and using predictive models to pre-screen polymer filler combinations. In the future, it should be focused on the industrial application scenarios of MMM to increase the load capacity, maximize the advantages of porous MOF, enhance the mechanical and aging resistance of membranes, and promote the further commercial development of MMM.

Photopolymerization is a relatively ideal green synthetic route, but currently, most commercial photoinitiators face toxicity and environmental issues. Therefore, more environmentally friendly natural compounds have become a new hot topic in the field of photoinitiating systems research. This study outlined the research progress of utilizing various natural compounds from different sources in free radical polymerization and cationic polymerization photoinitiating systems. It was based on the chemical properties of different types of natural compounds that can directly or indirectly participate in photoinitiated reactions, thereby expanding the absorption wavelength range of the system. It demonstrated the unique advantages and application potential of various natural compounds-based photoinitiating systems such as vanillin and eugenol, and outlined the challenges faced such as purification difficulties, low yield and oxygen inhibition polymerization. Suggestions were made for future research to focus on the green extraction and modification of natural compounds as well as the development of natural compound-based cationic photoinitiating systems, providing reference for the design and application of natural compounds in photoinitiating systems.

Lignocellulose-derived biochar has been widely used in the fields of catalysis, adsorption and electrochemistry due to its merits including abundant surface functional groups, tunable structures and stable chemical properties. Among them, in the construction of photocatalysts, biochar can improve the weak light absorption, low separation efficiency of photo-generated charge carriers, insufficient active sites and low specific surface area of semiconductors so as to optimize their photocatalytic performances. This review mainly focused on different semiconductors (TiO₂, g-C₃N₄ and ZnO, etc.) decorated by cellulose and lignin-derived biochar. The modification strategies included carbon combination and carbon doping, and the strategy of carbon combination could be further distinguished into carbon dot combination and carbon as scaffolds. Meanwhile, performances of modified catalysts in diverse photocatalytic applications (photocatalytic degradation of organic pollutants, reduction of Cr(Ⅵ), H₂ evolution and H₂O₂ production, et al.) were introduced in detail. Finally, the research status and existing problems of lignocellulose-derived biochar-modified semiconductors for photocatalysis were discussed respectively from the perspective of catalyst design and photocatalytic application, and the corresponding solutions were proposed. In addition, the future development prospects in this field were also presented. This review could provide insight and guidance on the application of biomass-derived carbon and the design of photocatalysts.

Fluoride removal is an urgent water treatment problem worldwide. In this paper, Magnesium oxide adsorbents were synthesized through a simple precipitation-calcination method and applied to the study of wastewater defluorination. The pH had a great influence on the specific surface area of the synthesized magnesium oxide material, and the specific surface area of the synthesized material was the largest (101.1—154.8m²/g) when the pH was in the range of 10—10.5. The maximum adsorption capacity was 61.337mg/g through batch adsorption experiment and isotherm study. This process conformed to the Freundlich model, which proved that the adsorption process was based on the heterogeneous adsorption. Through kinetic studies, the adsorption process conformed to the pseudo-second-order kinetic model, which proved that the adsorption process included chemisorption. The adsorption mechanism over MgO was deduced to be electrostatic interaction and ion exchange mechanism by characterization results of XRD, SEM, FTIR and XPS. In the range of pH 2—10, magnesium oxide can effectively remove fluoride from water. Among the common competitive anions, only CO{}_{\mathrm{3}}^{\mathrm{2}-} and PO{}_{\mathrm{4}}^{\mathrm{3}-} had adverse effects on the adsorption of fluoride. The cyclic adsorption test showed that the magnesium oxide adsorbent had the potential of renewable utilization. Therefore, through the batch adsorption test of the synthesized magnesium oxide material and the exploration of the adsorption mechanism, the theoretical accumulation of the industrial application of wastewater defluorination was provided.

Ge-ZSM-5 membranes were prepared by in-situ hydrothermal crystallization method on two kinds of α-Al₂O₃ substrates. The synthesized membranes were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The effect of the content of water in the synthesis solution on the microstructure of the membranes and the pervaporation separation performance of the membrane were investigated. The results showed that there were molecular sieve crystals at the top of the membranes when the water content in the synthesis solution was smaller. With the increase of water content, the crystals on the surface of the membranes were gradually covered by amorphous material, and finally amorphous material could form a continuous layer with the best separation performance. When the water content was bigger, the membranes were discontinuous. With the increase of water content in the synthesis solution, the content of aluminum in the membranes increased, the content of germanium decreased and the separation performance of the membranes was gradually optimized. On the substrate which was easier to melt aluminum, the content of aluminum in the membranes was higher and the separation performance of the membranes was better. At 30℃, the water permeation flux of 1%—35% ethylene glycol solution ranged from 35.7—116.7g/(m²·h) and the separation factor ranged from 1138.5 to 46.5 on the Ge-ZSM-5 membrane, which had the best separation performance and the membrane had the potential application for dehydration of low concentration ethylene glycol solution.

To investigate the interfacial adhesion performance and adhesion mechanism between graphene/rubber composite modified asphalt and aggregate, photoelectric colorimetry and contact angle method were used to study the interfacial adhesion performance between graphene/rubber composite modified asphalt and aggregates. The interfacial model of asphalt and aggregate was constructed by using the molecular dynamics software MS, and the interfacial adhesion properties of asphalt and aggregate were quantified in terms of the work of adhesion, while the effects of temperature and water on the interfacial adhesion properties of asphalt and aggregate were considered. The adhesion mechanism and temperature and humidity sensitivity between asphalt and aggregates were analyzed and studied at the atomic scale. The results showed that the adhesion effect between graphene/rubber composite modified asphalt and granite was the best. Therefore, it was recommended to use graphene/rubber composite modified asphalt as asphalt binder in areas lacking alkaline aggregates. Graphene/rubber composite modified asphalt can significantly improve the adhesion performance between asphalt and aggregates. As the alkalinity of aggregate oxides increased, the polar molecules in asphalt changed from “inclined distribution” to “parallel distribution” on the surface of aggregates, thereby enhancing the adhesion performance between asphalt and aggregates. In this study, the interfacial adhesion mechanism of graphene/rubber composite modified asphalt and aggregate was analyzed at the atomic level, which would provide guidance for the design of graphene/rubber composite modified asphalt pavement.

In this study, the graphite powder/Nafion-Pb electrode was prepared by using Nafion solution as binder and coated with graphite powder on Pb electrode. The prepared electrode was characterized by BET and SEM and used in electrolysis experiment. It was observed that the specific surface area of the graphite powder/Nafion-Pb electrode was 0.3022m²/g, which was much larger than that of the bare Pb-electrode, and the graphite powder supported on the surface of Pb formed flake patches, which could provide more active sites for electroreduction of oxalic acid. The oxalic acid reduction activity and glycolic acid selectivity were evaluated through a series of electrolysis experiments at a range of potential and temperature. The results showed that the conversion rate of oxalic acid reached 50.85%, glycolic acid selectivity reached 73.26% and Faraday efficiency reached 80.85% of the graphite powder/Nafion-Pb electrode were significantly higher than those of the Pb electrode when the saturated calomel electrode was used as reference electrode at a constant reduction potential of -1.6V and a temperature of 60℃.

To enhance the liquid transmission capacity of fibrous water evaporator, a trilayer structured polylactic acid/polyethylene glycol@sodium dodecyl sulfate microfiber fabric was designed and prepared using a melt blown-thermal bonding process. The morphology and liquid transmission behavior were assessed through scanning electron microscope, liquid contact angle tester and liquid water management tester. Results indicated that benefiting from the regular distribution of fiber diameter and water wettability in the thickness direction, the prepared samples possessed a large water evaporation rate of 1.27kg/(m²·h) under the solar intensity of 613.52W/m² which resulted from the one-way transport index increased to 533.19% and the liquid absorption rate increased to 2.37mg/s. Besides, the sample exhibited remarkable washability for multiple reuses along with longitudinal and transverse tensile fracture strengths of 67.37N and 35.39N, respectively. This work provided a novel approach to improve the liquid transfer capacity of degradable seawater evaporators.

In order to solve the problem of uneven graphitization and large modulus difference of laser irradiation of carbon fiber, the experiments studied the unilateral and bilateral gaussian laser irradiation of carbon fibers, and determined that the unevenness of carbon fiber graphitization was caused by the uneven temperature, and laser intensity distribution and fiber beam heat transfer led to the uneven temperature. The discreteness of the mechanical properties of carbon fiber was statistically analyzed by the Weibull distribution function. The results showed that the graphitization uniformity of thin-layered carbon fibers irradiated by top-hat laser irradiation was significantly improved, and the average tensile modulus was increased from 227.37GPa to 311.90GPa, an increase of 37.18%, compared with direct gaussian laser irradiation. The coefficient of variation of tensile modulus of thin-layered carbon fiber irradiated by top-hat laser was reduced from 44% to 12%, the Weibull modulus of modulus was significantly increased, and the discreteness was reduced.

Docosahexaenoic acid-rich phosphatidylserine (DHA-PS) possesses superior health benefits in improving lipid metabolism, protecting the nervous system, and alleviating and improving neurodegenerative diseases. DHA-PS products are mainly extracted from marine organisms, with shallow content, complicated processes, and high cost. To solve this problem, an efficient lipase-mediated solvent-free transesterification reaction system was constructed to prepare DHA-PS with edible algal oil as the DHA donor. The strategies of enriching phosphatidylserine (PS) from the solvent-free system by extraction with methanol and the detection of the fatty acid composition of PS by thin-layer chromatography coupled with gas chromatography were investigated. The experimental results showed that the highest incorporation rate of DHA in PS was 21.7%. The molecular docking results revealed that strong hydrogen bonding and hydrophobic interactions were presented between the substrates (PS and algal oil) and the enzyme, providing a theoretical possibility for transesterification. In addition, the higher affinity indicated that the catalyst preferred DHA over the other fatty acids involved.

Spent lead-acid battery paste is an important source of secondly lead. Traditional pyrometallurgical process produces lead dust, sulfur dioxide, and smelting lead slag, which brings environmental risk. Therefore, hydrometallurgical process for lead recovery has become a hot research field. Electrowinning process for lead recovery from spent lead paste was reviewed in this paper, including acid leaching-electrodeposition, alkali leaching-electrodeposition, other solvent leaching -electrodeposition, solid-phase electrolysis. The principles, processes, and technical parameters of these processes were discussed in detail. In addition, the key technical parameters of the electrodeposition processes of the current research, such as pretreatment method for spent lead paste, electrolyte, anode by-product, current efficiency, energy consumption, product purity, and morphology regulation etc., were summarized. At the same time, prospects of the electrodeposition technology were provided. The green and environmentally friendly leaching solution or electrolyte, short process flow, low energy consumption, and electrolyte recycling for lead recovery by electrodeposition processes should be focused in the future research.

Intensive land-based aquaculture technology is thriving in China due to the serious wastewater pollution, overuse of drugs, and low product quality caused by conventional aquaculture practices. However, a large amount of highly polluted aquaculture wastewater of land-based aquaculture must be purified to be recycled or discharged. Therefore, developing efficient and cost-saving wastewater treatment technologies is crucial to the widespread application of land-based aquaculture. The main technologies, including operation principles, treatment effect and advantages & disadvantages were discussed in this paper and then the biofloc technology was considered as the promising treatment technology for land-based aquaculture wastewater in the future, and its main development in the future was concluded.

The acceleration of urbanization brings increasing pressure on sludge disposal. Pyrolysis is an effective means of resourceful sludge disposal, and heavy metals are a kind of pollutants that need extra attention in the disposal process. In this paper, the co-pyrolysis experiments of sludge and agroforestry wastes were carried out in a horizontal fixed-bed reactor to investigate the effects of different pyrolysis temperatures (500℃, 700℃), types of agroforestry wastes (rice hulls, wood chips, corn stover) and blending ratios (25%, 50%) on the migration and transformation characteristics of heavy metal elements, Co, Cr, Cu, Mn, Ni, Pb and Zn, in the biochar. It was found that with the pyrolysis temperature increasing from 500℃ to 700℃, the residual rate of heavy metals in biochar reduced. The co-pyrolysis with agroforestry wastes would be beneficial to the enrichment of Co, Cr and Mn in biochar. By studying the morphology of the heavy metals, it was found that increasing the pyrolysis temperature would be beneficial to the transformation of the heavy metals towards the stable morphology in most cases, and the co-pyrolysis with agroforestry wastes would facilitate the transformation of the heavy metals into more stable morphology in biochar. However, it should also be noted that at 700℃, co-pyrolysis with agroforestry wastes was not conducive to the stabilization of Ni. Generally, co-pyrolysis with agroforestry wastes reduced the potential ecological risks of biochar. The results of this paper would provide a valuable reference for the control of heavy metal emissions in the thermal disposal of sludge in practical industrial production.

In this study, the waste catalytic cracking catalysts (sFCCc) and waste hydrocracking catalysts (sHCc) produced in the refining process were taken as objects, and their adsorption performance to nitrobenzene and the characteristic pollutant in refining wastewater was investigated. sFCCc and sHCc retained the Y-type zeolite framework of fresh catalysts, but had a larger average pore diameter and a higher lattice oxygen content. In the pH range of 2—12, sFCCc reached the adsorption equilibrium of nitrobenzene after 30min with the adsorption capacity of 18.65mg/g, while sHCc reached the adsorption equilibrium after 5min with the adsorption capacity of 20.01mg/g, better than that of sFCCc. The adsorption properties of the two refinery waste catalysts kept stable after five circles of elution and regeneration, and adsorption processes followed Freundlich isothermal adsorption model and the pseudo-second-order kinetic model, indicating the existence of multilayer non-ideal adsorption with both physical and chemical adsorption processes. Characterization results showed that the lattice oxygen in the waste catalysts and the Lewis acid site-bound hydroxyl groups could combine with the electron-withdrawing functional group (—NO₂) through the electron donor-acceptor interaction and hydrogen bonding, respectively, and were recognized as the active sites for nitrobenzene adsorption. This study would provide data support for the resource utilization of refinery waste catalysts.

High performance cobalt-nitrogen co-doped waste microbiochar (Co-N@MSBC) was prepared from agricultural waste mushroom stick by impregnation-calcination method. The biochar was characterized by scanning electron microscopy (SEM), specific surface area (BET), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Gatifloxacin (GAT) was removed by Co-N@MSBC activated permonosulfate (PMS). The experimental results showed that, compared with PMS, MSBC, MSBC/PMS, Co-N@MSBC, the removal rate of GAT in Co-N@MSBC/PMS system was up to 96.5% within 60min under the best conditions, and remained above 90% removal efficiency at a wide pH range (3—11). Cl^-, \mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-} and \mathrm{H}\mathrm{C}{\mathrm{O}}_{\mathrm{3}}^{-} had a certain inhibitory effect on the removal of GAT, while {\mathrm{H}}_{\mathrm{2}}\mathrm{P}{\mathrm{O}}_{\mathrm{4}}^{-} had a slight promotion effect. After three cycles of recycling, the GAT removal rate of Co-N@MSBC for tap water and ultra-pure water was still higher than 85%, indicating that it has good stability. The quenching experiments showed that sulfate radicals (\mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{·-}), ·hydroxyl radicals (·OH), and singlet oxygen (¹O₂) were involved in the degradation. There was a metastable complex mediated non-free radical pathway. Electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) experiments showed that there was direct electron transfer between ternary systems during GAT removal, which meant PMS, Co-N@MSBC and GAT act as electron acceptor, electron bridge and electron donor, respectively, and doped Co and N promote electron transfer between PMS and Co-N@MSBC.

The pollution of nitrate nitrogen (NO₃^--N) in water has attracted wide attention in the world, which causes the deterioration of water ecological environment and poses a serious threat to human health. In this work, the Ti foam-Ni-Sn/Bi electrode was prepared by electroless Ni and electrodeposition plating Sn/Bi on titanium foam plate. The SEM, XRD and electrochemical tests indicated that Ni and Sn/Bi were successfully deposited on the Ti substrate and intermediate layer Ni, respectively, with a larger electrochemical active area and more active sites. The system of Ti foam-Ni-Sn/Bi electrode as cathode and Ti/RuO₂-Ir₂O₃ electrode as anode was constructed and used for electrocatalytic reduction of the NO₃^--N simulated water. The results indicated the degradation rate of nitrate nitrogen was 87.43% and the N₂ selectivity was 90.73%, as the initial NO₃^--N concentration was 150mg/L, electrocatalytic reduction time was 6h, the current density was 20mA/cm², pH was 3, stirring rate was 600r/min, and the distance between electrodes was 3cm. The Ti foam-Ni-Sn/Bi cathode prepared in this work showed high electroreduction activity and N₂ selectivity in electrocatalytic reduction of the NO₃^--N.

Biological drying was employed to treat the dewatered sludge derived from sewage treatment plants, the effects of residence time and air volume on the bio drying process were investigated under continuous operating conditions, and the mechanism of water removal was elucidated. After 8d, the results showed that, the average reactor temperature in the system with residence time of 4d was 61.2℃, and the average biodrying index was 6.1. When the intensity of induced air was 0.95m³/(h·kg VS), the reactor temperature usually fluctuated within the range of 51.9—64.6℃, and the water removal and the apparent water reduction were 35.55% and 22.90kg, respectively. When the air flowrate increased to 1.30m³/(h·kg VS), the moisture reduction slightly improved but it was not significant. In a sludge biodrying system, those normal and mesophilic microorganisms decayed, then Firmicutes became the dominant microbial phylum, and the abundance of Bacillus in the sludge compost was above 75%; the fluorescence intensity of microorganisms in the central area of the reactor increased to 837.5, but the proportion of live bacteria was only 14.6%. After the wet mixture was added to the reactor, the dissolved organic matters in the feeding presented a rapid increase due to the fact that the sludge experienced thermophilic digestion, the contents of soluble protein and polysaccharide increased to 5.6mg/g and 5.0mg/g, respectively. The analysis of low field Nuclear Magnetic Resonance showed that the main form of water in wet sludge was bound water. With the biodrying process continued, the relaxation time of sludge samples became short, indicating the water migration slowed down, thus the moisture reduction was no longer obvious. Based on the analysis of water and heat balance, the releasing biological heat was 1.91MJ/d for the biodrying system with 4d residence time and 0.95m³/(h·kg VS) aeration intensity, and the efficiency of heat utilization was 65.58%. The moisture reduction was directly related to the temperature and the aeration intensity in the bio drying system, and it was also affected by the factors such as the content of organic matters and the relative humidity of water vapor.

The pyrolysis experiment of waste wood building formwork was carried out in a horizontal fixed bed reactor to explore the influence of pyrolysis temperature (400—800℃) on the pyrolysis products of waste wood building formwork. In addition, two typical biomass, wood chips and rice husks, were selected to compare and analyze the distribution and properties of the pyrolysis products of the three raw materials. The results show that with the increase of pyrolysis temperature, the solid phase yield of waste wood building formwork and two typical biomass shows a decreasing trend, while the gas phase yield shows an increasing trend, and the liquid phase product yield reaches a peak at 500℃ and then gradually decreases. The content of functional groups on the surface of biochar decreases continuously, and the pore structure of biochar tends to be abundant except rice husk. The oxygen-containing heavy organic molecules in the pyrolysis oil are gradually transformed into light aromatic and hydrocarbon molecules. The proportion of combustible components in pyrolysis gas increases. The solid phase yield of wooden building formwork is the highest at 400℃, reaching 40.16%. The pyrolysis liquid phase yield is the highest at 500℃, reaching 53.6%. With further increase in temperature, the gas phase yield reaches 43.3% at 800℃. At the same pyrolysis temperature, the liquid phase yield of wood building formwork is the highest, and the proportion of oxygen and aromatic organic compounds in pyrolysis oil is relatively high. The proportion of combustible components in pyrolysis gas at low temperature is higher than that of wood chips and rice husks. This study provides a useful reference for the resource utilization of waste wood building formwork.

At present, the problem of high CO concentration in the flue gas emission occurs during the flexible peaking process of coal-fired power plants, which affects the denitrification performance of the vanadium-titanium catalyst in the denitrification system. In this study, vanadium-titanium catalysts and Sb-modified vanadium-titanium catalysts were prepared by ultrasonic impregnation, and the effect of CO on the NH₃-SCR denitrification performance of vanadium-titanium catalysts was investigated, while the mechanism of Sb-modification in improving the anti-CO poisoning performance of vanadium-titanium catalysts was also explored. The catalyst samples were characterized and analyzed by N₂ adsorption and desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and in-situ infrared diffuse reflection (in-situ DRIFT). The results showed that the presence of CO deteriorated the NH₃-SCR denitrification performance of the 2.5V/Ti catalysts, while the Sb modification could improve it by weakening the inhibitory effect of CO. With the introduction of CO, the V⁵⁺ and O_α contents on the surface of 2.5V/Ti catalyst were decreased, which inhibited the NH₃-SCR reaction on the catalyst surface. CO would compete with NH₃ and NO for adsorption on the surface of the 2.5V/Ti catalyst, thus inhibiting the adsorption of NH₃ and the formation of NH₂ intermediates. Meanwhile, because of the presence of CO, surface active bidentate and bridge nitrate production was limited and the reactions between bidentate nitrate and NH₃ as well as NH₃(L) and NO+O₂ were slowed down, which inhibited the NH₃-SCR denitrification performance of the 2.5V/Ti catalysts. The Sb modification significantly increased the O_α content on the catalyst surface and weakened the effect of CO on the V⁵⁺ content on the V-3Sb/Ti catalyst surface through a redox cycle of 2V⁴⁺+Sb⁵⁺\stackrel{}{\rightleftharpoons }2V⁵⁺+Sb³⁺. In addition, the Sb modification promoted the formation of SCR reactive species on the catalyst surface and improved the reactivity of NH₃(L) on the surface of the V-3Sb/Ti catalysts in the presence of CO, and thus, the V-3Sb/Ti catalysts exhibited excellent NH₃-SCR performance and better resistance to CO poisoning.

Enzyme pretreatment is an effective means to alleviate the rate-limiting step of hydrolysis in anaerobic digestion of kitchen waste, but the high cost of enzymes and the low conversion rate of raw materials limit the practical application of this technology. In this study, to improve the bioconversion efficiency of kitchen waste by pretreatment and anaerobic digestion technology, different biological enzymes were used to pretreat kitchen waste, and the appropriate enzyme type, dosage and treatment time were explored. According to the changes of soluble chemical oxygen demand (SCOD), the pretreatment conditions of 700U/g cellulase, 400U/g acidic protease, 80U/g α-amylase and 300U/g glycosylase for 16h showed the optimal pretreatment effect, and the contents of SCOD, soluble reducing sugar and free amino acid in the hydrolysate were 89200.00mg/L, 39.91g/L and 43.26g/L, respectively, which were 2.74 times, 2.45 times and 1.44 times that of the control group. In addition, the content of macromolecular organic compounds such as starch and cellulose also decreased significantly in the pretreatment group. Economic accounting showed that the cost of multi-enzyme collaborative pretreatment of kitchen waste with 80% moisture content was about 381.38CNY/t, and the total benefit of "pretreatment+dry anaerobic digestion" was about 189.95CNY/t. The results showed that multi-enzyme cooperative pretreatment was superior to single enzyme pretreatment, effectively promoted the hydrolysis of insoluble macromolecular substances in kitchen waste, improved the substrate fluidity, facilitated the contact and direct utilization of microorganisms, and provided favorable conditions for subsequent anaerobic digestion. At the same time, the optimization of multi-enzyme cooperative pretreatment conditions provided a theoretical reference for the practical engineering application of "pretreatment+anaerobic digestion" of kitchen waste.

As a new membrane separation technology, organic solvent nanofiltration (OSN) has been widely used in medical and chemical industries. However, the common nanofiltration membranes do not have good solvent resistance, so the selection of suitable membrane materials is the key to the industrial application of organic solvent nanofiltration. Using piperazine (PIP) as an aqueous monomer and TMC as an organic monomer, PA/PEEK composite nanofiltration membranes with good solvent resistance were prepared by interfacial polymerization. The microstructure and hydrophilicity of the membranes were studied. The microstructure and hydrophilicity of the membrane were also studied. The effect of PIP concentration on the permeation separation performance of the composite membranes was investigated, and the flux of various organic solvents and the retention performance of low salt ions and small molecule organic compounds were tested for the membranes with the best performance. The results showed that the membranes prepared with 0.3%(weight fraction) PIP concentration had the best permeation separation performance. The water flux reached (4.81±0.04)L/(h·m²·bar)(1bar=10⁵Pa) and the retention rate of Na₂SO₄ was 98.23%. The flux of the composite film to methanol solvent reached (2.77±0.22)L/(h·m²·bar) and the retained molecular weight in ethanol solvent was about 519g/mol. In addition, the composite membrane exhibited stable long-term organic solvent nanofiltration performance.

In order to solve the problems of low beryllium purity, low beryllium yield and large amount of hazardous waste residue in the modern beryllium metallurgy process, the team focused on the basic theories of beryllium metallurgy and proposed a new beryllium extraction method of low-temperature dissociation of beryllium ores plus physical purification of beryllium-containing compounds. For the decontamination process of aluminum-containing fluorides in beryllium ores, the solubility law and purification mechanism of AlF₃ impurities were investigated in the context of the HF system. From the results of the solubility experiments, the concentration of Al³⁺ and the concentration of F^- from the direct dissociation of AlF₃ were very low, at the level of 10^-5, and it was difficult to form the AlF{}_{\mathrm{6}}^{\mathrm{3}-} complex. Therefore, the solubility of AlF₃ in the H₂O system was lower than that in the HF system, while under the HF-H₂O-AlF₃ system, the ligand ion of F would be formed so that the originally insoluble AlF₃ had certain solubility instead. Based on this, low-temperature calcination was used to destroy the structure of H₃AlF₆ and decompose H₃AlF₆ into AlF₃, avoiding the effect of H₃AlF₆ on the solubility of AlF₃, and thus solving the separation problem of impurities.

Metal cyanide complexes are highly stable and refractory environmental pollutants in nature, making them challenging to be removed through chemical oxidation. In the present study, potassium ferricyanide and potassium ferrocyanide we used as representative model substrates to investigate the biodegradation of iron complexes by a previously screened consortium capable of degrading metal-cyanide complexes. Our findings revealed an initial lag phase of approximately 8 hours for the growth of the degrading consortium in a system containing (45±2.5)mg/L Fe-cyanide complex, reaching a stationary phase after 36 hours. Under condition of 30℃ and 120r/min, the degradation efficiency reached 71.7%±1.2% within 5 days. It was found that the Fe-cyanide complexes could be served as a nitrogen source for the growth of degrading consortium and were degraded into formic acid, ammonium and ferric/ferrous ions. Furthermore, our results demonstrated that the degrading consortium effectively remediated simulated soils contaminated with (52.00±1.00)mg/kg of Fe-cyanide complexes, achieving a remediation efficiency of 64.3%±1.8% within 14 days by adding glucose at a C/N of 6∶1. This study would lay the groundwork for further developing an environmental-friendly technology of removing metal cyanide complexes.

An efficient Bayesian network (BN) construction and analysis method is proposed for multi-level domino accidents within large chemical tank farms. Leveraging probabilistic graphical model decomposition and integration, the method addresses various wind conditions and common accident modes adhering to quantitative risk assessment guidelines. It is capable of managing domino accidents involving over 10² tanks and 10⁶ possible scenarios, facilitating automated causal and diagnostic inference. The method was applied to an example tank area derived from a realistic large chemical logistics facility in Shanghai. It revealed that domino accidents significantly contribute to the overall tank failure risk, particularly in facilities comprising numerous atmospheric-pressure liquid tanks or those situated downwind from pressurized spherical tanks. Seasonality plays a crucial role in the spatial distribution of domino accident risks due to the impact of wind on incidents like vapor cloud explosions. BN’s automatic inference capabilities were employed to identify the most probable accident sequences and infer unobserved parameters, such as leak sizes, based on actual accident progression. The approach proves invaluable for pre-accident prevention, emergency response, and post-accident investigations.