Gas-liquid two-phase flows are common in engineering and nature, and bubble breakup in liquids affects mass/energy transfer and emits acoustic signals. Establishing a correlative relationship between bubble dynamic behavior and acoustic characteristics is crucial for passive acoustic monitoring. This study investigates the dynamic behavior and acoustic characteristics of bubble breakup processes in turbulent flows by combining experimental observations and numerical simulations. Three breakup types are identified: tensile breakup (driven by inertial forces and surface tension, producing large daughter bubbles with low-frequency acoustic signals below 2 kHz), shear breakup (dominated by viscous shear and turbulent eddies, generating small daughter bubbles with high-frequency signals similar to 5 kHz), and instability breakup (a combination of tensile and shear effects, yielding broadband acoustic signatures). The Bu number is proposed to quantify the coupling between dynamic behavior and acoustic frequency, with tensile breakup (Bu <= 1) and shear breakup (1 < Bu <= 20) showing distinct distributions, while the instability breakup represents the transitional state between the two types. This correlation not only elucidates the underlying physical mechanisms of multiphase flows but also provides a non-invasive monitoring strategy for optimizing multiphase flow processes in chemical engineering.

Partial coalescence of drops on a liquid-liquid interface is a complicated process that encountered in numerous fields of chemical engineering. The drop diameter is a key parameter determining the coalescence behavior but the corresponding mechanisms are far from clear. The present work simulated the coalescence process of drops with diameters from 0.080 to 15.000 mm on the liquid interface. It suggests that partial coalescence occurs within a specific range of the drop diameter. Additionally, there is a critical drop diameter D* denoting the sudden transition from the complete coalescence to the partial coalescence of small-size drops. Moreover, the diameter ratio xi between the daughter and mother drops, is not a constant as traditionally supposed but first increases and then decreases as the mother drop diameter increases. A maximum ratio value 0.581 is obtained when the mother drop diameter is 2.988 mm. Besides the normal first-stage expansion-contraction partial coalescence, two-stage expansion-contraction partial coalescence is also noticed. It first occurred just at the drop diameter permitting the maximum diameter ratio. It also demonstrated that the liquid neck expands when the joint effect of the capillary pressure arising from local azimuthal curvature and the negative flow-induced pressure due to the Bernoulli effect overcomes the capillary pressure arising from local axial curvature at the liquid neck. This pressure driving model also explains the transition from complete to partial coalescence of small-size drops, and the transition from first-stage to two-stage expansion-contraction partial coalescence of middle-size drops.

Cyclohexanol is not only an important intermediate in the chemical industry, but also a key component in the production of green energy. Catalyzed hydrogenation of phenol to produce cyclohexanol is a green and efficient method. This work employed the soft template method to prepare hollow carbon-coated cobalt nanoreactors with different physical microenvironments by varying the amount of HMT (Hexamethylenetetramine) added. The results show that the cavity size and curvature of the hollow carbon spheres reactor have a significant effect on the reaction. Comprehensive characterizations (TEM, XRD, XPS, H2-TPR, etc.) and experimental data indicate that the optimized Co@HCS-0.25-500 promotes the adsorption and hydrogenation of phenol through the synergistic effects of curvature-induced electronic metal-support interactions and enhanced reactant enrichment in the larger cavities. The optimized Co@HCS-0.25-500 achieved a phenol conversion of 56.4% and >99% cyclohexanol selectivity under conditions of 140 °C, 1 MPa H2, 1 h. Co@HCS-0.25-500 exhibited excellent stability in six consecutive cycles and demonstrated good general applicability in the hydrogenation of biomass-derived phenolic compounds.

Drop coalescence on an air-liquid interface is widely encountered in separation engineering. The present work investigated coalescence of water-methanol drops of varying concentrations on both the air-water interface and the air-methanol interface. It generally noticed normal partial coalescence when drops coalesced on the air-water interface because the induced downward Marangoni flow field intensified the contraction of the liquid neck. When drops coalesced on the air-methanol interface, it successively witnessed the partial coalescence (w > 0.9), complete coalescence (0.1 < w <= 0.9), and drop ejection (w <= 0.1) as the methanol mass fraction w in drops decreased from 1 to 0. The upward Marangoni flow might weaken the downward drainage flow field and inhibit the contraction of the liquid neck, leading to the transition from partial coalescence to complete coalescence. If the weakening effect became stronger, it would hinder downward liquid drainage, making the liquid column become thinner and eventually break up due to Rayleigh-Plateau instability.

The electrochemical nitrate reduction reaction (NO3 -RR) represents a promising green synthesis technology, enabling both resource utilization of nitrate (NO3 -) pollutants in wastewater and provision of a sustainable ammonia (NH3) source for carbon neutrality. The key challenge in advancing NO3 -RR toward practical application lies in developing catalytic systems that maintain excellent activity, high selectivity, and long-term stability at industrial-level current densities (>300 mA cm-2). Although NO3 -RR has been developed to a certain extent, there has yet to be a comprehensive summary and analysis of the advancements in this field at industrial-level current densities up to now. This review begins with an introduction to the mechanism and theoretical basis of NO3 -RR, systematically summarizes and analyzes catalyst design strategies for industrial-level current densities, including alloying methods, in situ derivation strategy, heterostructure construction, doping engineering, and self-supporting electrode fabrication. In addition, the progress of industrial-level NO3 -RR-based electrolyzers, including flow reactor and membrane electrode assembly (MEA) technology are discussed. Meanwhile, techno-economic analysis (TEA) and life cycle assessment (LCA) are employed to investigate the economic viability and environmental impact of NO3 -RR, providing a comprehensive evaluation of the feasibility for large-scale application. Furthermore, the current challenges of catalytic systems under industrial electrolysis conditions are clarified, and the future development directions toward industrial-scale NH3 synthesis are proposed, aiming to promote the value-added electrochemical conversion of pollutants and develop the industrial application of NO3 -RR technology.

Polymorphic transformation could highly affect the polymorph purity of active pharmaceutical ingredients (APIs). Azelaic acid was selected as the model drug for this study. The alpha form was innovatively prepared in propionic acid solvent. Then the Solvent-mediated polymorphic transformation (SMPT) was conducted at various temperature and solvents, and the adsorption energy and molecular conformation simulation were performed to interpret the process. Surprisingly, it was found that the alpha form changed to (3 form during drug storage. The stability, shelf life, and manufacturing control of drugs can be seriously affected. So the Solid state polymorphic transformation (SSPT) was investigated. We found that high temperature or 3 wt% (3 form doping could promote the process. The quantum chemical and molecular dynamic calculation indicated that SSPT started from crystal surface (002) of alpha form and gradually transmitted to the whole crystal lattice. Even though SMPT and SSPT followed different mechanisms, it was found that the molecular conformation change was somehow similar in the case of azelaic acid. This work provides a new idea for the mechanism of polymorphic transformation.

Capacitive deionization (CDI), with the benefits of environmental friendliness, ease of use, and low cost, is currently showing great promise in desalination. The characteristics of the electrode materials have significant impact on desalination capacity of CDI technology. Here, we synthesized 1 T-rich phase MoS2 with sulfur vacancies (SV@1 T-rich MoS2) via the magnetic field-assisted hydrothermal strategy and mild H2O2 etching strategy. This dual modification strategy enables SV@1 T-rich MoS2 to exhibit greater layer spacing and abundant sulfur vacancies, which facilitates to increase the number of active sites and specific surface area, thereby accelerating ion transport and enhancing CDI performance. These advantages enable SV@1 T-rich MoS2 to exhibit greater desalination capacity (36.6 mg g-1 for Na+ at 1.2 V). This work opens up new ideas and perspectives for designing novel CDI electrode materials based on MoS2.

Microfluidics is widely used in enzyme biotechnology. Wall-coated immobilized enzyme micro-channels (W-IEMRs) offer significant advantages in stability and hydrodynamic performance but have limited catalytic efficiency due to long diffusion paths in the microreactor. This study used a computational fluid dynamics (CFD) model to simulate flow fields and concentration distributions in serpentine micro-channels, quantifying mixing efficiency via the mixing index (MI) and Dean number (De). By testing channels with different curvature radius, bending ratios, and inner diameters, the geometry was optimized to enhance mass transfer and mixing. Simulations showed that a smaller curvature radius, larger bending ratio, and smaller inner diameter strengthen Dean vortices, improving mixing. However, catalytic efficiency has a non-monotonic relationship with these parameters: a curvature radius below 6.31 mm reduces enzyme-substrate contact due to excessive vortices, while a bending ratio exceeding 60 % leads to uneven substrate distribution caused by counter-rotating vortices in adjacent sections, impairing performance. Optimal design parameters are: curvature radius 6.31 mm, bending ratio 60 %, inner diameter 0.5 mm. For micro-channels with varying reaction kinetics, careful consideration must be given to balancing mass transfer and catalytic performance.

Despite the huge scale of coal being employed, its efficiency and depth remain insufficient. The accurate analysis of the chemical composition of coal is the foundation for enhancing the utilization of its high-value resources. The coal extraction and back-extraction processes of coal enable the classification and separation of its organic matter, which has significant potential for structural research and resource utilization. However, this process generates an N-methyl-2-pyrrolidone (NMP), CS2, and H2O mixture, whose effective separation is crucial for achieving process optimization and resource recovery. Developing energy-efficient and environmentally friendly separation technologies to unlock the full potential of coal-based extraction and back-extraction processes can promote the sustainability and energy efficiency of coal resources. This study employed a liquid-liquid separator combined with distillation to separate the NMP-CS2-H2O mixture. By analyzing the vapor-liquid equilibrium (VLE) of the mixture, a feasible separation process was determined, and the effect of pressure on relative volatility was investigated. Subsequently, based on sequential optimization results, a heat-integrated separation process coupled with heat pump distillation was designed. The molar purity of NMP, CS2, and H2O reached over 99.9 mol % for both the sequential optimization and integrated processes. Compared with the sequential optimization process, the total cooling duty of the thermal integration process was reduced by 90.42%, and the exergy loss was reduced by 50.42%. This study presents an energy-integrated optimized process for the efficient separation of NMP-CS2-H2O mixtures generated during coal extraction and back-extraction, which provides valuable insights into coal structural research and the deepening of coal resource utilization.

Abstract The combination of immobilized enzymes and microreactors offers great advantages in green biomanufacturing. However, improving the catalytic loading and reusability of immobilized enzymes remains a challenge. This study developed a magnetically separable immobilized enzyme system for continuous-flow biocatalysis. Candida antarctica lipase B (CALB) was covalently immobilized onto polydopamine-modified Fe3O4 nanoparticles to prepare a magnetic nanoimmobilized enzyme (CALB@PNMNs). Compared to free enzymes, CALB@PNMNs exhibited enhanced stability in organic solvents and storage stability. CALB@PNMNs microreactor was constructed, with CALB@PNMNs immobilized on its inner walls by an external magnetic field. This layer of magnetic particles allows for the convenient recovery and reuse of the catalyst by removing the applied magnetic field. After optimizing the immobilization process, the actual CALB loading per unit area was 0.30 mg/cm2, and the adsorption yield reached 86.89%. The microreactor was applied to the transesterification of n-butanol and ethyl acetate, with the optimal conditions identified as an alcohol–ester ratio of 1:3, a total flow rate of 10 μL/min, and a reaction temperature of 60 °C, yielding an n-butanol conversion of 63.72%. After short-term continuous operation for 6 h, the microreactor retained 87.63% of the enzyme adsorption capacity and CALB@PNMNs maintained a n-butanol conversion above 50% after 8 reuse cycles. This work has established a stable magnetically controlled immobilized enzyme microreactor (IMER) platform, offering application potential for continuous-flow bioprocesses.

Investigating the effect of liquid viscosity on droplet dispersion behavior is of great significance for optimizing gas-liquid dispersion devices. In this paper, a high-speed camera was used to directly observe and analyze the droplet dispersion behavior inside the combined trapezoidal spray tray (CTST). It shows that the main droplet dispersion modes in a CTST are intra-cap liquid film tearing and extra-cap liquid column breakup, while an additional mode-extra-cap liquid film breakup-emerges in the arrayed holes region when the viscosity is higher than 65 mPa & sdot;s. Furthermore, as the liquid viscosity increases, the number of droplets generated by the breakup of a single liquid column increases from 1 to 2-5-7. The droplet dispersion frequency decreases significantly with increasing viscosity, with the peak value dropping by more than 60 %. However, the decrease in the dispersion frequency of small-sized droplets is not obvious, and an increasing trend is even observed in the arrayed holes region. Finally, an empirical correlation was established to predict the droplet dispersion frequency as a function of droplet diameter and liquid viscosity.

In this study, the thermodynamic and kinetic characteristics of the esterification reaction catalyzed by sol-gel immobilized enzyme in a batch reactor were systematically investigated. Parameters including catalyst particle diameter, stirring speed, initial molar ratio, catalyst dosage, reaction temperature, and catalyst reusability were studied and optimized. Finally, the esterification rate of methyl oleate reached 90.01%. The standard enthalpy change in the reaction was calculated using the Van't Hoff equation. A pseudo-homogeneous (PH) model was employed to simulate the kinetic process of the reaction, and the simulation results provide a reference for the scale-up of the reaction process.

In gas bubbling process, dynamic behaviors of bubbles such as oscillation, breakup, and coalescence radiate acoustic signals that contain information about the bubbling state, laying the foundation for Process Acoustic Monitoring (PAM) of bubbling processes. After collecting tremendous acoustic and image data of bubbling process, this study proposes an end-to-end one-dimensional convolutional neural network, aiming to establish a nonlinear mapping relationship between one-dimensional acoustic time-series signals and two-dimensional bubble size distributions. Integrating an attention mechanism and physical constraints of bubble acoustics, the model focuses on solving two core challenges: extraction of weak acoustic signals and prediction of bubble size distribution. Eventually, the prediction accuracy of bubble size distribution is more than 90%. Significantly, this framework exhibits excellent transferability for bubble size distribution prediction across different bubbling systems, providing a reliable technical approach for intelligent monitoring and optimal control of bubbling processes.

The separation of 6-chloro-2-nitrotoluene and 4-chloro-2-nitrotoluene, two close-boiling isomers with highly similar physicochemical properties, poses a significant challenge in the chemical industry. In this study, melt crystallization was investigated as an effective separation method for this difficult isomer pair. The solid-liquid equilibrium phase diagram for the binary system was experimentally constructed, revealing a simple eutectic behavior that provided the thermodynamic foundation for crystallization separation. Systematic crystallization experiments were performed to evaluate and optimize the key process parameters, including crystallization temperature, sweating temperature, cooling rate, heating rate, and initial feed composition. The results demonstrate that under optimized conditions, the crystallization process consistently achieved a high product purity exceeding 98% across a range of feed concentrations. A detailed parameter analysis showed that the crystallization and sweating temperatures are the dominant factors influencing product purity and yield. The cooling rate and heating rate exhibited minimal impact on the final separation performance, indicating that the process is primarily governed by thermodynamic equilibrium rather than kinetic effects. Through systematic optimization, the trade-off between product purity and recovery was effectively balanced by identifying the optimal operating window for each parameter. Overall, this work provides a comprehensive experimental investigation of the solid-liquid equilibrium and crystallization behavior of the 6-chloro-2-nitrotoluene and 4-chloro-2-nitrotoluene system, offering a practical and efficient separation strategy for such challenging isomer pairs.

White light-emitting diodes (WLEDs) are the core technology in solid-state lighting and display fields. However, the commercial GaN/YAG: Ce3+ scheme suffers from bottlenecks such as insufficient color rendering index, limited color gamut, and reliance on rare earth resources, creating an urgent need for novel, high-efficiency, and environmentally friendly luminescent materials to overcome these limitations. Metal halide perovskites have emerged as ideal candidates for WLEDs due to their high defect tolerance, high photoluminescence quantum yield (PLQY), excellent solution processability, and broad spectral tunability. Nevertheless, the biotoxicity of lead-based perovskites severely hinders their commercialization. Consequently, green and environmentally benign lead-free metal halide perovskites (LFMHPs) have gained prominence. Through isovalent and heterovalent ion substitution strategies, LFMHPs form diverse crystal structures, including 3D perovskites, double perovskites, and low-dimensional derivatives. Their crystal structures directly determine the luminescent mechanisms: regular lattices support narrowband emission from free excitons (FEs), making them suitable for high-color-gamut three-primary-color devices; distorted or low-dimensional structures induce broadband emission from self-trapped excitons (STEs), providing a platform for single-component white LEDs. This review focuses on the core application demands of WLEDs, clarifying the intrinsic correlation between the crystal structure and exciton behavior of lead-free metal halide perovskites, exploring the regulatory mechanisms of narrowband/broadband luminescence, defining performance adaptation thresholds for high-color-gamut display and high-color-rendering lighting, comparing key regulation strategies, summarizing device construction pathways and core parameters of typical systems, and analyzing core bottlenecks in commercialization, aiming to provide theoretical support for next-generation green and high-performance WLED technologies.

2-methyltetrahydrofuran (2-MeTHF) and acetonitrile (ACN) are widely used as solvents in the pharmaceutical industry. As 2-MeTHF and ACN form azeotrope that cannot be separated via regular distillation. Therefore, in this study, the molecular mechanism, experiment-based extractant screening, and process design for the separation of the 2-MeTHF-ACN azeotrope were investigated. According to Fourier-transform infrared spectroscopy and density functional theory, the azeotropy was destroyed via the formation of hydrogen bonds between the extractant dimethyl sulfoxide, 2-MeTHF, and ACN. Vapor-liquid phase equilibrium experiments validated the screening results and develop a thermodynamic model of the binary system. Batch distillation experiments obtained 2-MeTHF with a mass purity of 99.6 wt% and ACN with a mass purity of 99.8 wt%. The ED process was designed using Aspen Plus and improved via the integration of the recovered waste heat (ED-HI). A sequential iterative approach was used to minimize the total annual cost (TAC). The ED-HI process resulted in reductions in the TAC, reboiler heat load, and CO2 emissions of 20.06 %, 25.77 %, and 22.77 %, respectively, compared to those of the ED process. This study provides valuable insight into the effective separation of 2-MeTHF and ACN.

Aqueous zinc-based batteries (AZBs) with conversion mechanism have garnered widespread attention thanks to their low cost, high safety, and environmental friendliness. Currently, the traditional conversion mechanism of AZBs, such as the two-electron reaction, faces the problem of low capacity and energy density. The emerging multi-electron conversion mechanism that beyond the traditional transformation mechanism has made extensive research progress. Here, this review systematically and comprehensively summarizes the recent developments in the multi-electron reaction mechanism of AZBs. The main focus of the article is on the multi-electron conversion mechanism between electrode materials and electrolyte modulation. Meanwhile, this review discusses the present challenges and future development prospects for AZBs with multi-electron conversion mechanism, intending to facilitate the advancement of AZBs with conversion mechanism.

Aqueous batteries with conversion mechanisms show promise for large-scale energy storage due to the inherent safety, cost-effectiveness, high energy density, and eco-friendly advantages. However, redox species migration and sluggish kinetics critically impede the further development of aqueous-conversion batteries. The integration of catalytically active sites into host cathode materials has been proposed as an effective solution to these challenges, with notable advancements in research. This review systematically summarizes recent advances in catalytic host materials for aqueous metal-ion batteries (zinc-iodine, zinc-bromide, zinc-sulfur, zinc-selenium, zinc-tellurium, copper-sulfur, and iron-iodine), analyzing their catalytic mechanisms and conversion processes. Meanwhile, this review identifies current research limitations while proposing targeted strategies to overcome the challenges. This work deepens the understanding of aqueous metal (Zn, Cu, and Fe)-ion batteries and guides the rational design of advanced energy storage technologies.

Aqueous zinc-ion batteries (AZIBs) have gained great attention due to their nontoxicity, low-cost, and high theoretical capacity. However, the scarcity of suitable cathode materials with excellent performance limits the practical application of AZIBs. Herein, we develop a conducting polymer (polyaniline) and divalent ions (Ca2+) co-intercalated method to synergistically regulate the property of V2O5 to enhance Zn2+ storage performance. The synergistic effect of co-insertion Ca2+ and polyaniline (PANI) not only enlarges the interlayer spacing but also regulates multiple oxidation states of vanadium, which dramatically improves the conductivity, diffusion kinetics, and structural stability of host V2O5. Consequently, the resultant Ca/PANI/V2O5 center dot nH(2)O (CPVO) as AZIBs cathodes exhibits extraordinary specific capacity of 512 mAh g(-1) (0.5 A g(-1)) and cycling stability with an outstanding coulombic efficiency of around 100% after 2000 cycles (25 A g(-1)). Moreover, the Zn2+ storage mechanism is elaborated by combining comprehensive characterizations and DFT calculations.

Aqueous zinc-selenium (Zn-Se) battery shows promising applications because of its inherent safety and high theoretical capacity. However, the slow redox reaction kinetics of Se cathode limit its development. The strategy of designing functional catalytic host materials with suitable adsorption ability is essential to promote Se redox reaction kinetics. We construct a catalytic host material consisting of axially oxygen-coordinated Cu single atoms and neighboring Cu atomic clusters (Cu-N4O/CuACs) to probe its modulation mechanism of suitable adsorption ability on Se redox reaction. The Cu-N4O/CuACs enable the aqueous Zn-Se battery to exhibit a specific capacity of 643 mAh g-1 at 0.2 A g-1 and fast Se redox reaction kinetics. Experimental characterization and density functional theory confirm the "adsorption balance effect" of Cu-N4O/CuACs. The neighboring CuACs can enhance the adsorption ability for Se species. The axially coordinated O atoms can promote electron delocalization and downshift d-band center, weakening the excess adsorption ability brought by CuACs and lowering the energy barrier of redox reaction. The adsorption balance effect between clusters of CuACs and axial O atom causes CuN4O/CuACs to exhibit excellent catalytic effect. This work gives new insights for the optimization of the catalytic behavior between the adsorption ability of SACs and redox reaction kinetics in aqueous Zn-Se battery.