With the rapid advancement of industrialization, CO₂ emissions are expected to continue to rise, and carbon dioxide capture, storage and reuse have been received widespread attention from researchers. In various CO₂ conversion technologies, electrocatalytic technology is one of the most promising strategies because of its mild and controllable reaction conditions, low energy consumption and low environmental pollution. In recent years, there have been many reports on the selective conversion of CO₂ into gaseous products such as carbon monoxide, syngas, methane, ethylene and ethane. In this paper, the reaction mechanism and catalyst design strategies of electrocatalytic CO₂ reduction to gas products are introduced. The electrocatalytic CO₂ reduction is summarized and prospected, including new electrocatalysts, mechanism studies, the influence of external factors and cascade reactions.

Low-temperature air separation equipment is a high energy consumption link for large chemical systems. If it is combined with liquid air energy storage technology, it can effectively balance the load of the grid peak valley and significantly improve the economic benefits of the system. This paper introduces an air separation unit with energy storage and generation (ASU-ESG). It uses valley electricity to liquefy air and recovers liquid air for electricity generation and air distillation, thus reducing peak compression loads and improving load regulation ability. The results show that for an ASU-ESG system with an air processing capacity of 60000 m³/h, the power consumption for oxygen production is 0.378 kW·h/m³. The oxygen extraction rates for energy storage and energy release processes reach 89.46% and 93.71%, respectively. Compared with conventional ASU, the ASU-ESG improves compression load by 28% during off-peak electricity periods and reduces it by 20% during on-peak electricity periods, resulting in annual electricity cost savings of 5.72%—6.88%. The dynamic payback period for the ASU-ESG system is 3.3—4.3 a, and the net present value (NPV) reaches 19714.6×10⁴—28074.7×10⁴ CNY. The ASU-ESG system can balance the peak-valley fluctuation in power grids as well as obtain economic benefits in ASU operations.

Based on the Beer-Lambert law, the densities of rocket kerosene were measured by a γ-ray absorption method under liquid-state or supercritical pressure conditions. The measurement temperature ranged from 293 K to 673 K and the measured pressure from 0.3 MPa to 30 MPa. The extended relative uncertainties of the measured densities were identified as 2.2%—3.2% (coverage factor k=2). The cyclohexane at normal pressure and temperature of 293 K was selected as the high-density standard fluid, and the cyclohexane at the pressure of 5 MPa and the temperature of 673 K was selected as the low-density standard fluid to offset the impact of temperature changes on the radiation absorption rate of the measuring device. The reliability and accuracy of the measurement method was verified by calibrating the density measurements of cyclohexane and toluene. On this basis, density measurements of petroleum-based and coal-based rocket kerosene were performed and the isobaric coefficients of thermal expansion of petroleum-based and coal-based rocket kerosene were calculated. The experimental data were used to fit the Tait functional equation for the density of the two types of rocket kerosene over a wide range of temperature and pressure, and the average absolute deviation of the experimental density data from the equation was 0.21%, with a maximum absolute deviation of 1.32%. The results show that the densities of coal-based kerosene are basically identical with the petroleum-based kerosene at the measured conditions, the densities of high-energy kerosene are slightly higher than those of petroleum-based kerosene at low temperatures and lower than those of petroleum-based kerosene at high temperatures. The experimental density measurements in this paper provide fundamental data for the study of high-parameter rocket kerosene physical properties and heat transfer.

Aiming at the problem of high energy consumption in traditional biomass drying, a low energy consumption non-phase transition second drying method was proposed to overcome the latent heat of phase transition. The 2 kg/h pilot test and 84 kg/h pilot test equipment of biomass non-phase change drying were independently developed, designed and built. The experimental results show that the drying conditions of straw with particle size 1—5 mm are 80℃, gas-solid ratio 9.75, gas velocity 18 m/s, residence time 10—30 s, water content can be reduced from 68% to the lowest about 15%, and the dehydration efficiency can reach more than 70%. The scaled up experiment was verified on the pilot plant. The effects of tangential, radial and axial velocities on solid-liquid separation in swirl field are revealed. In addition, 64.81% of the water removed in the drying process was removed in the form of non-phase change droplets, indicating that non-phase change plays a dominant role in the drying process. The changes of particle surface morphology before and after straw drying and the further mechanism study showed that water could be separated from the pore, which may be due to the microinterface oscillation induced by the self-rotating coupling of biomass particles in the swirl field, and the pore was created on the surface of the biomass particles to enhance the centrifugal force effect to remove water in the form of microdroplets. In addition, experiments on biomass such as corn germ, distilling grains and wood chips were carried out. Under the conditions of 100℃, atmospheric pressure and residence time of 30 s, the dehydration efficiency of nearly 70% was achieved, which proved the universality of the technology for biomass types.

The humidification-dehumidification seawater desalination technology shows significant potential as a method for freshwater production. Nevertheless, challenges such as heat and mass imbalances between the humidification and dehumidification processes caused by uneven spraying result in a low freshwater production rate per volume. In this regard, this paper proposes a compact two-stage humidification-dehumidification (HDH) desalination system. The device contains two humidifiers and a dehumidifier, wherein the dehumidifier is stacked between the vertically placed humidifiers. Its freshwater yield performance was evaluated through an electric heating steady-state experiment, varying the feed seawater mass flow rate, feed seawater temperature, and preheating conditions. The results show that the water production of the device increases with the increase of feed seawater flow rate and temperature. Specifically, an increase in feed seawater mass flow rate from 0.45 t/h to 0.96 t/h resulted in a corresponding increase in freshwater yield from 18.7 kg/h to 27.1 kg/h. At a feed seawater temperature of 85℃, the device achieves a freshwater yield of 33.7 kg/h with a gained output ratio (GOR) of 0.9. In addition,preheating the device can potentially enhance the freshwater yield by up to 6.8%. The maximum per unit volume freshwater yield of the device is 33.7 kg/(m³·h), which is obviously higher than traditional two-stage HDH device.

In view of the fact that the traditional discrete phase model (DPM) cannot accurately predict the pressure drop of microencapsulated phase change material slurry (MEPCMS) because it does not consider the effect of particle volume, the modified DPM is used to accurately predict the flow heat transfer characteristics of MEPCMS in the chip array, and the influence of chip heating power and power distribution on cooling characteristics is investigated. The results show that compared to pure base liquid cooling, the suspension can increase the average Nusselt number Nu_avof MEPCMS by up to 30.03%, resulting in a maximum decrease of ΔT_w by 7.19%. The comprehensive performance evaluation factors of the suspension are all greater than 1. The closer the high-power chip is to the inlet, the more favorable it is to suppress the highest temperature rise of the chip. When a high-power chip approaches the outlet, the Nu_av increase of the suspension is greater than the increase in friction factor and inlet/outlet pressure drop. Therefore, it is obvious that it is less affected by the chip heating power and more affected by the chip power distribution. This work helps to understand the heat transfer characteristics and influence laws of MEPCMS in chip thermal management.

Pneumatic logistics transmission system is widely used in medical and chemical industries. Pipe pressure drop and characteristic velocity are key parameters for vertical pipe pneumatic logistics transmission system, but related reports are few. Based on the vertical pipe pneumatic logistics transmission system constructed in the laboratory, experiments of compressed air flow conveying transfer bottle were carried out. Conveying characteristics analysis as well as the modeling of the pipe pressure drop and characteristic velocity were conducted. First, with the help of pressure drop signal analysis, high-speed camera and data processing, transfer bottle conveying characteristics were analyzed. And a method to identify the transfer bottle motion states was proposed based on the analysis of the pipe pressure drop signal. Secondly, comprehensively considering the structural characteristics of the flow channel, a pipeline pressure drop model of the vertical pipe gas flow transmission system was established, and the pipeline resistance coefficient was obtained through data regression. Finally, on the basis of force balance analysis and conservation of mechanical energy, characteristic velocity prediction models were established, which provide a new method for the transfer bottle status identification and tracking monitoring.

To explorethe effects of different phase separation structure parameters on the heat transfer performance and temperature uniformity of enhanced micro-channel flow boiling, a parallel counterflow minichannel test section with different phase separation structures was fabricated: PSS-1 (uniformly distributed in the upstream and downstream), PSS-2 (near the central part in the upstream and downstream), PSS-3 (close to both ends in the upstream and downstream) with different phase separation structure positions. Among them, PSS-1 is divided into three types: A, B and C, corresponding to 4 holes, 6 holes and 10 holes respectively. Ethanol was used as the test working medium, and the flow boiling test was performed on the rectangular minichannel with a cross-section of 2 mm×2 mm under the effective heat flux density ranges from 17.12 kW/m² to 87.25 kW/m², the inlet temperature of 70°C, and the mass flow rate of 86.11 kg/(m²·s). The visualization of the channel is studied by using high-speed camera. By introducing the heat transfer enhancement factor and the wall temperature standard deviation, the effects of different phase separation structures on the heat transfer performance and temperature uniformity of the enhanced micro-channel and the strengthening mechanism of phase separation structures in high pressure and low pressure channels were studied. The results show that under the experimental conditions, the heat transfer enhancement effect increases with the increase of the number of phase separation exhaust holes. The influence of exhaust position on heat transfer characteristics is different in high pressure channel and low pressure channel. In addition, the PSS-1-C micro-channel has the best temperature uniformity. When the heat flux is 83.11 kW/m², the average wall temperature of the micro-channel is 1.9℃ lower than the same channel without phase separation, and the temperature standard deviation is reduced by 14.2%. The visual image shows that the phase separation structure can realize gas phase transfer under the action of pressure difference, thereby enhancing heat transfer.

When the heat exchanger is working, the medium often contains small impurity particles, which are easily deposited in the channels to form particulate fouling. This paper combines the traditional pulsating flow with the longitudinal vortex generator, and uses numerical simulation to compare and analyze the particulate fouling characteristics of the smooth channel, pulsating flow channel, longitudinal vortex generator channel and pulsating flow combined with longitudinal vortex generator channel, and analyzes the effect of the six different longitudinal vortex generators on the particulate deposition in the pulsating flow combined with longitudinal vortex generator channel in detail. The results show that compare with the fouling resistance of smooth channel, the fouling resistance of the pulsating flow channel and the longitudinal vortex generator channel are reduced by 17% and 22%, respectively, while the combination of the two can be reduced by 45% in the pulsating flow combined with longitudinal vortex generator channel, which indicates that the fouling suppression effect is better after the combination of the two. In addition, comparing the pulsating flow combined with six different longitudinal vortex generators, it is found that the curved longitudinal vortex generator has a better anti-fouling effect than the unbent longitudinal vortex generator of the same type. By comparing with the asymptotic value of the resistance of fouling in the pulsating flow channel, it is found that the anti-fouling effects from low to high are: triangle 12.8%, curved triangle 14.7%, trapezoid 22.0%, curved trapezoid 23.8%, rectangle 29.4%, and curved rectangle 33.0%, among which the curved rectangular longitudinal vortex generator has the best anti-fouling effect.

The temperature signals in pulsating heat pipe (PHP) exhibit more complex transient fluctuation characteristics, which can be better analyzed by using continuous wavelet transform (CWT) method. Based on the visualization experiment (glass PHP), the wavelet analysis method was used to investigate the PHP temperature oscillation signal and flow pattern identification. The results revealed that the dominant frequency of the temperature signals is affected by the sampling frequency, wall material and heat flux. A sampling frequency of 1 Hz may lead to temperature signal distortion at high heat flux (q=2.65—3.18 W/cm²), and it is recommended to use a sampling frequency of 10 Hz or higher. The thermal inertia of the glass material introduces signal distortion in wall temperature measurements, particularly at high heat flux. With increasing heat flux (q=0.35—3.18 W/cm²), the fluctuation amplitude of the fluid temperature decreases, the frequency increases, and the dominant frequency of the temperature signal increases (0.02—3.88 Hz). Correspondingly, the internal flow of the PHP has gradually transformed from a slug flow to the annular flow, and the large one-direction circulation flow appears. The dominant frequency derived from the fluid temperature signal inside the tube can be generalized to copper tubes or other metal PHP, which helps to identify the internal flow pattern and the change in the flow regime, and to better understand their heat transfer characteristics.

To meet the heat dissipation requirements of highly integrated and high-power electronic devices in the 5G era, the use of ultra-thin heat pipes and ultra-thin vapor chambers is rapidly increasing. The extreme thinning of heat pipes/vapor chambers has become a hot research topic in the current industry and academia, as the heat generation of components is increasing and the space available for heat dissipation components inside electronic devices is becoming more compact. Some simulation studies have indicated that as the height of the vapor chamber is reduced to a certain extent, the flow resistance of vapor in the ultra-thin space increases sharply, consequently precipitating a steep decline in the thermal performance of ultra-thin heat pipes/vapor chambers.Hence, studying and analyzing the gas flow in extremely thin spaces is of great significance for exploring the pressure drop characteristics of vapor flow, assisting in solving the design challenges of ultra-thin heat vapor chambers/heat pipes, facilitating their further thinning and application. In this paper, the experimental apparatus for gas flow pressure drop in ultra-thin confined spaces was constructed, and preliminary air flow pressure drop experiments were conducted, obtaining data on air pressure drop changes under different channel heights (0.1—0.5 mm), surface mesh aperture (0.036—0.104 mm), and flow velocities (1—10 m/s). The results show that as the channel height increases, the Fanning friction factor f gradually decreases. The influencing factors of pressure drop were ranked by significance: channel height, flow velocity, mesh aperture. Flow velocity and channel height both have a significant impact on pressure drop, while mesh aperture has no significant effect. The pressure inside the channel gradually increases as the surface mesh aperture decreases. As the channel height decreases, the pressure drop inside the channel first increases slowly, and after decreasing to a critical height of 0.3 mm, the pressure drop inside the channel starts to increase significantly. As the air flow velocity increases, the pressure drop inside the channel increases, and the effect of air flow velocity on pressure drop follows an approximately proportional relationship. The Fanning friction factor f calculation correlation formula for rectangular microchannels was analyzed, and it was compared with the calculated values from the experimental results. Then, based on the commonly used laminar friction factor calculation formula f=64/Re, a correction was made, and it was found that the f calculation formula corrected based on the experimental data in this paper has better accuracy, and is more suitable for calculating gas pressure drop in microchannels with height ≤0.5 mm. Subsequently, the experimental apparatus was modified to include a steam generation device, but due to difficulties in adjusting the experimental setup, only a small amount of steam flow pressure drop data was obtained. Compared with the traditional calculation formula for laminar friction factor, the f correction relationship obtained through the air pressure drop experiment significantly improves the accuracy of calculating steam flow pressure drop.

Dimethyl ether (DME), as a key chemical raw material, is widely used in the synthesis of a multitude of important chemical products and energy commodities. In the industrial production, γ-Al₂O₃ used for the preparation of DME from methanol has been widely applied due to its high catalytic efficiency. However, the synthesis methods and preparation conditions of γ-Al₂O₃ have a significant impact on its catalytic performance. At present, there is still insufficient systematic research on how the synthesis conditions of γ-Al₂O₃ commonly used in industry affect its catalytic performance. This study successfully prepared γ-Al₂O₃ with different pore structures and acidic properties by adjusting the pH of the mother liquor during the sol-gel process using the double aluminum method. The influence of acidic site properties of γ-Al₂O₃ on the performance of methanol-to-DME synthesis was systematically investigated. Characterization results revealed that, with an increase in the pH of the mother liquor, the specific surface area, pore volume, and pore size of γ-Al₂O₃ exhibited a decreasing trend. Furthermore, as the pH increased, the weak acidity of γ-Al₂O₃ gradually decreased, while the moderate-strong acidity showed an initial increase followed by a decrease. Combining the results of catalytic performance evaluation, it was found that the quantity of moderate-strong acidic sites is closely related to methanol dehydration performance. γ-Al₂O₃ with the highest quantity of moderate-strong acidic sites exhibited the highest DME yield, suggesting that moderate-strong acid sites are the primary active centers for γ-Al₂O₃ catalyzing methanol dehydration to produce DME. Kinetic experiments were conducted on γ-Al₂O₃ with optimal performance, and the reaction order of methanol dehydration was 0.78, and the reaction activation energy was 83.27 kJ/mol. This study provides important guidance for the design of catalysts for methanol dehydration to produce DME, laying the foundation for further optimization of industrial production conditions and improvement of catalytic efficiency.

The production of dimethyl ether (DME) from syngas, followed by the carbonylation of DME to produce methyl acetate (MA), and the hydrogenation of MA to ethanol is a green process route with high conversion and selectivity, mild reaction conditions, and low separation energy consumption. Among them, the dimethyl ether carbonylation reaction, as an important intermediate reaction, has attracted great attention from scholars. The present work focuses on the reaction of carbonylation of DME to MA, using mordenite (MOR) with high carbonylation activity and stability to prepare shaped catalysts, which lays a foundation for further industrialization. A series of extruded MOR catalysts were prepared by using aluminum sol with different pH as binder and compared with shaped catalysts using pseudo-boehmite as binder. The effect of the binder on the strength of the shaped catalysts was investigated by strength tests as well as statistical analysis of the Weibull function. The role of the binder on the physical structure, acidity and catalytic performance of the MOR was investigated by characterization such as X-ray diffraction, N₂ physical adsorption, ²⁹Si MAS NMR, and in-situ pyridine adsorption infrared in combination with the evaluation of catalytic properties. The results showed that the pH of the aluminum sol had a very important effect on the pore structure, mechanical properties and catalytic performance of the shaped catalyst. When the pH of the aluminum sol is 4.9, the extruded catalyst had the largest mesoporous specific surface area and volume (70 m²/g and 0.20 cm³/g), the highest mechanical strength (110.7 N/cm) and the smallest decrease in the amount of Brønsted acid by unit mass of zeolite. Therefore, the extruded catalyst had the highest DME conversion and space-time yield by unit mass of zeolite.

This paper uses ZSM-5 zeolite to catalyze the alkylation of benzene and ethylene as a system to establish and verify a three-dimensional anisotropic diffusion-reaction mathematical model. This model takes into account the influence of zeolite morphology， pore structure and diffusion anisotropy. The simulation results show that changing zeolite particle shape would not significantly affect the apparent activity when the zeolite particle volume and sizes in a-, b-, and c-axis keep unchanged, indicating modifying zeolite particle shape is unnecessary in this case. When the particle volume remains constant, only shortening the size in b-axis could importantly reduce diffusion resistance and then enhance apparent catalytic activity, indicating that decreasing the size in b-axis is most favorable for diffusion and reaction in the preparation of ZSM-5 zeolites. When the particle size is 4 μm and the large pore diameter is 300 nm, the optimal large pore porosity that balances diffusion resistance and active material content is 0.16, corresponding to a maximum apparent reaction rate of 80.5 mol/(m³·s). Besides, due to the influence of diffusion anisotropy, introducing the macropores being parallel to c-axis is most favorable. These results provide some theoretical guidance for the optimal design of ZSM-5 zeolite catalysts for benzene alkylation with ethylene and other zeolite catalysts.

The influence of asphaltene removal and catalyst dosage on the hydro conversion efficiency of the coal/heavy oil co-processing system using MRAR and Indonesian lignite were investigated. The solid residues after co-processing reaction were characterized by XRD, XPS, TEM, TG, ¹³C NMR and SEM. The results show that the presence of asphaltene will promote the coking process and significantly reduce the conversion efficiency of coal in the co-processing system. When reaching the same conversion depth, the amount of catalyst required in the deasphalted oil system will be greatly reduced. For the MRAR systems with a relative high asphaltene content, the application of catalyst resulted in a decreased aromaticity of organic carbon components in the solid residues and a reduced proportion of oxygen-containing components. Additionally, residual organic carbon components were more prone to pyrolysis, indicating an excellent hydrogenolysis effect of the catalyst on the carbon components during the reaction process. Microscopic morphology analysis of the solid residues showed that the catalysts exhibited a favorable role in inhibiting coke formation, which helps to improve the hydrogenation conversion depth of the reaction system.

As a common adsorbent, metal-organic frameworks (MOFs) has been widely researched in the separation of ethane and ethylene gas mixtures, and the π-complexation generated by the introduction of metal ions can significantly improve the adsorption capacity of MOFs for ethylene. Cu(Ⅰ) was loaded into the dihydroxyl-functionalized UiO-66, and a Cu(Ⅰ)@UiO-66-(OH)₂ adsorbent that preferentially adsorbed ethylene was obtained. The hydroxyl functionalized framework has a synergistic effect with Cu(Ⅰ) while enhancing the polarity, which can effectively improve the adsorption and separation performance of ethylene/ethane. The calculated C₂H₄/C₂H₆ IAST selectivity of 3% (mass) Cu(Ⅰ)@UiO-66-(OH)₂ at 298 K and 1 bar is 2.98, which is approximately 3 times of the original UiO-66-(OH)₂. Single-component adsorption experiments show that the adsorption capacity of 3%Cu(Ⅰ)@UiO-66-(OH)₂ for ethylene is higher than that of ethane in the whole pressure range, and its adsorption heat of ethylene (42.81 kJ·mol^-1) is lower than that of many reported ethylene-selective adsorbents. The breakthrough experiments of 50/50 (volume ratio) C₂H₄/C₂H₆ mixture under simulated industrial conditions further demonstrate that the 3%Cu(Ⅰ)@UiO-66-(OH)₂ adsorbent can effectively separate the ethane/ethylene mixture.

Lactoperoxidase (LP) has received widespread attention in the fields of food, medicine and chemical industry because of its important biological functions and broad-spectrum antibacterial activity. In view of the shortcomings of traditional LP separation and purification methods, such as poor selectivity, high cost and easy contamination of separated materials, 2-hydroxyethyl methacrylate and poly(glycidyl methacrylate) nanogels (PGN) were used as composite substrates to prepare poly(2-hydroxyethyl methacrylate) composite cryogel embedded with PGN nanogels (pHEMA/PGN-based cryogel) by using the principle of low-temperature freezing polymerization. Then the pHEMA/PGN-based cryogel was grafted with the functional monomer 2-acrylamino-2-methyl-1-propanesulfonic acid to obtain pHEMA/PGN cation exchange nano-cryogel (pHEMA/PGN nano-cryogel) for the chromatography separation of LP from whey. The basic properties of pHEMA/PGN nano-cryogel were investigated, and the effect of buffer pH on chromatography performance was emphatically explored. The results showed that the obtained pHEMA/PGN nano-cryogel had large pore structure with uniform distribution, high permeability, excellent mass transfer performance, and strong adsorption capacity for lysozyme reaching 4.41 mg·ml^-1. The pHEMA/PGN nano-cryogel was used to isolate LP in whey, the purity was about 96.0%, the specific enzyme activity was 27.03 U·mg^-1, and enzyme activity recovery was 86.5% under the optimal conditions. The excellent separation performance indicated that the pHEMA/PGN nano-cryogel has good potential in the field of lactoperoxidase separation from whey.

Traditional solid-liquid two-phase membrane separation technology, which utilizes size effects, is easily constrained by the trade-off between permeability and selectivity, membrane fouling and concentration polarization. By introducing rotating shear dynamic membrane technology and applying solid-liquid slip boundary conditions, the time difference between particles penetrating the membrane pores radially and sliding over the membrane pores tangentially—temporal selectivity, can effectively enhance both permeability and selectivity simultaneously. By establishing a slip boundary rotating shear dynamic filtration membrane model, conducts finite element simulation of its microfiltration process for dilute suspensions, and theoretically revealed the influence of key parameters such as slip velocity, membrane thickness and porosity on membrane separation performance. The results show that for membrane pore diameters that are 1—10 times larger than the particles, under the synergistic effect of time dimension selectivity and shear-induced migration of particles, there is still a particle selectivity of over 95% and an effective water flux of more than 350 L/(m²·h). This result further verifies and expands the applicability of the temporal selectivity mechanism at the micron scale, and provides a new idea for high permeability-selectivity dynamic membrane water treatment technology.

In this study, Na₂S modified biochar (BCS) with efficient adsorption properties for Pb²⁺, Cd²⁺, and Zn²⁺ was prepared by using waste reed as raw material and sodium sulfide (Na₂S) as modifier. The biochar before and after modification was characterized by scanning electron microscopy-EDS (SEM-EDS), infrared spectroscopy (FTIR) and elemental analysis. The results showed that the Na₂S modification was able to introduce various sulfur-containing functional groups into the biochar, enhance the pore volume and increase the specific surface area. The Langmuir model fitting results indicated that the adsorption capacity of BCS for heavy metal ions was enhanced with the increase of the concentration of the modifier Na₂S solution. In the pH range of 2.0—6.0, the adsorption capacity of BCS on heavy metal ions was gradually enhanced with the increase of pH. At pH=6.0, the maximum adsorption amounts of BCS on Pb²⁺, Cd²⁺ and Zn²⁺ were 494.99, 131.14 and 94.89 mg/g, respectively. Based on the results of the kinetic experiments, it can be seen that the adsorption behaviors of BCS on heavy metal ions were in accordance with the pseudo-secondary kinetic model. The adsorption mechanism mainly includes complexation of surface functional groups, ion exchange and electrostatic adsorption. Overall, this study provides an environmentally friendly and feasible solution for the reuse of waste and the efficient removal of heavy metals from wastewater.

The simulation of processes with cyclic streams faces challenges in providing initial values and encounters difficulties in convergence with traditional algorithms. To address this issue, an adaptive variable-step homotopy-based algorithm is proposed. The algorithm adjusts the step size in the homotopy parameter during the process, handling situations where convergence fails in intermediate stages, which improve the convergence efficiency of the algorithm. A backtracking line search method is employed to constrain the iterative variables within the defined domain, enhancing the algorithm’s robustness. Homotopy algorithms are constructed based on direct iteration, Wegstein, Broyden, and Newton methods. The impact of homotopy parameters and auxiliary functions is analyzed. Taking the production of high-density polyethylene using the slurry method as a case study, simulation results indicate that the homotopy algorithm improves the convergence of the model under different operating conditions. The built-in solver of the commercial process model software Aspen Plus can only obtain feasible solutions in 21% of the test conditions, while the homotopy algorithm converges in 88% of cases.

Ensemble learning often achieves significantly superior generalization capabilities than a single learner by building and combining multiple learners. However, it is still a challenge to build a high-performance ensemble learning soft sensor model when the proportion of labeled data is small. In order to solve this problem, this paper proposes a soft-sensor modeling method based on the semi-supervised ensemble learning: Tri-training Gaussian process regression (Tri-training GPR) model. The modeling strategy gives full play to the advantages of semi-supervised learning, reducing the demand for labeled sample data in the modeling process. Under low data labeling rate, the labeled sample data set for modeling can still be expanded by filtering unlabeled data. Furthermore, a new idea of selecting high-confidence samples is proposed by combining the advantages of semi-supervised learning and ensemble learning. The proposed method was applied to the penicillin fermentation and debutanization tower process, and the soft sensor models for predicting penicillin and butane concentrations were established. Compared with the traditional modeling methods, the proposed method obtained better prediction results, which verified the effectiveness of the model.

Ursolic acid (UA) is a plant pentacyclic triterpenoid carboxylic acid with a variety of physiological and pharmacological activities. Although the de novo synthesis of UA has been achieved in Saccharomyces cerevisiae, there are still problems such as low yield, by-product accumulation, and redundant nutrient supply, which cannot meet the demand of industrial production. In order to improve the ability of synthesizing ursolic acid in Saccharomyces cerevisiae, the expression of heterologous CYP450 enzymes in the UA synthesis pathway was optimized by different methods. Position effect has an important impact on the expression level of exogenous genes, and the expression ratio of CYP450 and CPR can affect electron transport and thus regulate the catalytic activity of CYP450 enzymes. Therefore, the effect of position effect on CYP450 gene expression was investigated in this study. The optimal integration site (HO site) of CYP450 in the genome was preliminarily selected. By increasing the copy number of CYP450 alone or CYP450 and CPR simultaneously, it was determined that CYP450 enzyme had the best catalytic activity when there were three copies of CYP450 and CPR. After medium optimization, the UA yield in shake flask experiment reached (266.54±6.50) mg/L. Finally, the UA production was scaled up in a 5 L fermentation tank and reached (2825.58±36.26) mg/L. This study provides an reference for regulating the synthesis of other triterpenoids through expression optimization in Saccharomyces cerevisiae.

Brivaracetam is a new generation of anti-epileptic drugs with broad market prospects. The nitrilase-catalyzed synthesis of (R)-3-cyanohexanoic acid from 3-cyanocapronitrile, followed by hydrogenation, cyclization and chiral resolution to synthesize brivaracetam is a promising route due to the high atomic economy. However, the poor enantioselectivity of the exploited nitrilases has strongly restricted its application. In this study, the nitrilase PgNIT from Paraburkholderia graminis was exploited. The catalytic pocket and subunit interface domain were modified and a mutant F164W/I202R with significantly improved enantioselectivity was obtained. As a result, the ee_p value of F164W/I202R was increased from 86% to 97%, while the E value rose from 17 to 111 compared to wild type, respectively. Molecular dynamics simulation analyses revealed that the mutation of F164 reduced the steric hindrance on the entry of (R)-3-cyanocapronitrile into the catalytic pocket. On the other hand, the modification of I202 site at the “A” interface increased the association distance between subunits and increased the dynamic coordination of atoms in the catalytic pocket domain, thus significantly improved the enantioselectivity.

The modeling of the high-temperature rapid pyrolysis process for heavy oil holds significant implications for enhancing product yields, adding value, and reducing energy consumption. In this paper, we employed the automatic reaction network generator, reaction mechanism generator (RMG), to construct a mechanistic model for the high-temperature rapid pyrolysis of heavy oil. A stepwise construction approach was selected, culminating in a model that encompasses 230 substances and 1468 reactions. Rapid pyrolysis experiments were conducted in a high-frequency furnace by using eicosane, decahydronaphthalene, ethylbenzene, and their mixtures at different ratios to validate the model. The mechanism model can accurately simulate the main gas product generation results of high-temperature rapid pyrolysis of heavy oil. Specifically, when heavy oil contains a higher amount of alkanes or aromatics, maintaining the temperature around 1300℃ and 800℃, respectively, is conducive to ethylene production.

With the development of metal smelting and other industries, a large amount of arsenic sulfide slag that is difficult to handle is accumulated, causing serious harm to resources, the environment and human health. The stabilization/solidification technology represents a highly efficient method for fixing arsenic with promising applications. However, the high reagent consumption and cost, along with limited efficacy in treating complex and highly concentrated arsenic slag, have hindered the progress of this technology. In this study, low-cost and highly active steel slag and carbide slag were employed instead of chemical stabilizers to create an advanced oxidation/stabilization system through acid-activated steel slag, iron ions, and H₂O₂, then it was solidified with cement. The aforementioned processes were characterized by using XRD, FTIR, XPS techniques and so on. It is demonstrated that the low-valence arsenic compounds, sulfur compounds, and organic substances are effectively oxidized to form stable high-valence calcium iron salts while maintaining structural stability after solidification. Following process optimization steps involving 0.2 g steel slag, 0.5 g H₂O₂, 0.3 g carbide slag, and 1.0 g cement for stepwise synergistic stabilization/solidification treatment of 1.0 g arsenic sulfide slag, the compressive strength of the solidified body is 5.7 MPa, and the arsenic leaching concentration is only 0.66 mg·L^-1,^{which is far lower than the safe landfill standard of 1.2 mg·L-1.}

Compared with single-stage reverse electrodialysis, multi-stage reverse electrodialysis (MSRED) has more advantages in the output power of reverse electrodialysis heat engine, because it can convert more salinity gradient energy into electricity. In order to further improve the output power of MSRED, the total net output power of the device when used as the MSRED working solution was compared between the previously developed LiCl-NH₄Cl aqueous solution (mass molar ratio of 2∶8) and the traditional NaCl aqueous solution. The parameters include current density, initial molality concentration of feed solution and the flow velocity of feed solution. The results show that MSRED with LiCl-NH₄Cl aqueous solution can achieve higher current output, and the total net output power of MSRED can be increased by up to 28.6% compared with that of NaCl aqueous solution with the same mass molar concentration. In addition, no matter how the relevant operating parameters change, the MSRED using LiCl-NH₄Cl aqueous solution can obtain higher total net output power than that of NaCl aqueous solution with the same mass molar concentration. At the same time, the number of stacks employed in the system is smaller, which can save equipment costs and reduce the volume of the device.

High-performance transparent conductive films are important components of optoelectronic devices such as photovoltaic cells and flat panel displays. This study introduces a novel method for fabricating single-walled carbon nanotube transparent conductive films via water-phase exfoliation. The interdependence among transmittance, sheet resistance, and SWCNT concentration in the films is explored. Additionally, the impact of hybrid treatments on film transmittance and conductivity is examined. The results demonstrated accurate predictions of the films' transmittance (ranging from 50% to 96%) within the solar spectrum (300—2500 nm). Precise control over sheet resistance characteristics, ranging from 3 Ω·sq^-1 to 100 Ω·sq^-1, was achieved by adjusting the concentration of single-walled carbon nanotubes. Through the purification process of acid reflux and strong oxidation, the light transmittance increased by an average of 3.1% in the 750—2000 nm band, and the sheet resistance was reduced by more than 50%. These transparent conductive films demonstrate excellent overall performance, characterized by high transmittance and low resistance, thereby presenting extensive prospects for the advancement of optoelectronic devices.

Based on the polypropylene (PP) homopolymer and its copolymers with different ethylene contents, the effects of the contents of sorbitol nucleating agents and ethylene units on the crystallization kinetics, crystalline structure, crystalline morphology, transparency and mechanical property were systematically investigated. The self-organization behavior of the nucleating agent upon cooling was also analyzed through rheological behavior. The results show that, the crystallization, transparency and mechanical property of PP were dependent on the contents of nucleating agents and ethylene units. When the nucleating agent content increased to 0.1% (mass), the crystallization rates of PP and its copolymers were significantly accelerated, and their crystallinities were enhanced, resulting in the improvement of the rigidity of PP and its copolymers. However, the increase in ethylene unit content slows down the crystallization rate of PP, reduces the crystallinity and the rigidity of the material. The incorporations of ethylene units and nucleating agents facilitated the formation of γ crystals of PP. The relative fraction of γ crystals increased with increasing the contents of ethylene units and nucleating agents. As the contents of ethylene units and nucleating agents increased, the transparency of PP was also improved.

Hydrogel is a polymer material with a three-dimensional network structure and can be used as an ideal new wound dressing. However, the releasing rate of hydrogel wound dressing is slow under natural conditions. To promote wound healing, the hydrogel is prepared by using carboxymethyl chitosan and sodium alginate as matrix, and polypyrrole as the conductive agent. The ciprofloxacin hydrochloride is added into the hydrogel as the antibacterial drug. The drug releasing device driven by the electrostimulation is constructed. The impacts of polypyrrole content on the swelling property, mechanical property and electrical conductivity, and the releasing property of ciprofloxacin hydrochloride under electrical stimulation are studied. When the ratio of polypyrrole to the matrix is 0.4, the hydrogel shows the optimized comprehensive performance in physicochemical property and mechanical property, and is more suitable for wound dressing. The electrical stimulation can effectively accelerate the releasing rate of drugs interior the hydrogel, and benefit the treatment of wounds.

Recently, the conductive hydrogels have attracted increasing attention because of the applications in various fields, including electronic drivers, medical monitoring sensors, and wearable devices etc. However, most hydrogels suffer from low mechanical properties, short service life, and poor frost resistance, which limit the applications in low-temperature. To solve this problem, the present work fabricated the self-healable and low temperature resistant multifunctional ionic hydrogel used for strain sensors, where poly(vinyl alcohol), ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), and phytic acid were used as the raw materials, which were dissolved in deionized water and dimethyl sulfoxide (DMSO) binary solution. The mixed polymer solution spontaneously transferred into ion hydrogel with the help of supramolecular self-assembly caused by the multiple hydrogen bonds and electrostatic interactions between ionic groups. At the same time, adjusting the content of DMSO can optimize the strength and toughness of the gel. When the DMSO volume fraction is 40%, the maximum tensile strength and elongation at break can reach 4.43 MPa and 869.1% respectively. The microstructure, thermal and mechanical properties of the ionic hydrogel were carried out by scanning electron microscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, tensile testing, and rheological test. The results showed that the hydrogel had outstanding mechanical properties, rapid self-healing ability, and exceptional redox driven shape memory effect. The hydrogel could maintain high elasticity, conductivity, and sensitivity for strain sensing even at -25℃. In addition, the piezoresistive sensing performance of the gel sensors was tested by using electrochemical methods to accurately detect large-scale and subtle human behaviors by monitoring the real-time current change. The materials (PVA, PA, and IL) used in the hydrogel possess unique advantages, such as non-toxicity and high biocompatibility. The safety, biocompatibility and frost resistance of the ionic hydrogel enhance the potential applications in the fields of low-temperature strain sensors, intelligent wearable responsive components, and soft robotics.