Mass Transfer Mechanisms Research Articles

Enhanced carburization efficiency and performance of vacuum carburized layers by La2O3-doped supersonic fine particle bombardment

In this work, the fabrication of supersonic fine particle bombardment (SFPB)-doped rare-earth pretreatment modified vacuum carburized layers were applied. The SFPB-doped La2O3 pretreated vacuum carburized reinforced layer was explored by common testing methods such as XRD, XPS, SEM, and TEM, focusing on the effects of La2O3-doped SFPB pretreatment on the decomposition, adsorption and diffusion of active carbon atoms and the diffusion mechanism. The composite carburizing behavior of La2O3-doped SFPB pretreatment modified layer under the action of thermal coupling is explored, and the influence law of rare earth modified carburizing and nano-modified carburizing on the thickness, residual stress, impact toughness, tribological properties of the carburized layer were clarified. The mechanism of mass transfer under the coupling role of pre-set surface defects and rare earth pinning was revealed. The case depth of the LSPC layer was increased by 14.3%, and the residual stress was significantly higher. The carbon diffusion coefficients of LSPC were 1.31 times superior to that of the vacuum carburizing layer, which is mainly attributed to the formation of a large number of nanocrystals with high-angle grain boundaries (HAGBs) by the rare-earth doped nanosized pretreatment, and the multiple synergistic strengthening effects of rare-earth oxides and nanocrystals.

The role of the LATP particle size as a cornerstone of the cold sintering process

An innovative sintering technique, the Cold Sintering Process (CSP), has been employed to obtain dense Li1.3Al0.3Ti1.7(PO4)3 (LATP) Solid-State Electrolytes (SSE) by optimising the particle size (d50) of the starting powder. The CSP is carried out at 700 MPa, 150 ºC, and 90 min of sintering time, using acetic acid solution as Transient Liquid Phase (TLP). The CSP lowers the LATP sintering temperatures almost 1000 ºC. To study the electrical properties, an in operando Electrochemical Impedance Spectroscopy (EIS) technique has been used. The optimum d50 is 0.415 µm, yielding to competitive microstructure and electrical properties (ionic conductivity of 6.93·10−5 S cm−1 at 30 ºC, activation energy of 0.363 eV, and a relative density of 81.2 ± 0.8%). Relative density, ionic conductivity and TLP content must be balanced, because at small d50, although relative density is enhanced the ionic conductivity is reduced. A packing model has been used to understand this behaviour and the mass transfer mechanisms.

Mass transfer kinetics of polyethylene degradation by bacterial-fungal consortium

Understanding the biodegradation rate of polyethylene (PE) plastic waste mediated by bacterial-fungal consortium (BFC) is important to ensure effective design process of the bioremediation technology. The aims of this study were to scrutinize the behaviors of PE plastic degradation mediated by the BFC colonies numerically simulated the experimental data using the modified mass transfer factor models and to analyze the kinetics and mechanisms of internal, external and global mass transfer. The performance of rectangular reactor (RR) to biologically degrade the PE plastic increased up to 61.5% shows an increased efficiency of 55.9% stimulated by the presence of BFC colonies. Trend in the variation of internal mass transfer is almost the same with that of global mass transfer and is far higher than that of external mass transfer (EMT). The rate-limiting step of PE plastic degradation is dependent on the resistance of EMT. The application of BFC colonies aimed to improve the biodegradation rate of PE plastic waste contributes to advancing the future environmental engineering technologies.

Mass transfer research on the regeneration process of an air-conditioning battery system

Developing a sustainable and low-carbon society calls for energy conservation of buildings. On this purpose, green air-conditioning systems driven by renewable energy have been encouraged as alternative to the present vapor-compression air-conditioning system. Absorption system is one promising representative, but relatively lower performance impedes its application. To improve, we propose an air-conditioning battery system (ACBS) that evolves from the traditional absorption system. Its COP attains four by incorporating a refrigeration cycle with a battery cycle, realizing energy storage when producing cooling effect. Driven by renewable energy, ACBS is a green air-conditioning system for being environmental friendly with refrigerant water and avoiding the combustion of fossil fuels that emits a large amount of CO2 bringing in environmental issues. The critical part of ACBS is the capacitive deionization (CDI) regeneration process, which concentrates absorbent by electrical adsorption. The mass transfer mechanism of regeneration is important for system optimization. Simulation investigation has been made in this paper to reveal the mechanism. A two-dimensional model has been established and validated to depict the dynamic response at different electric adsorption stages. Analysis has been conducted based on the models to expose the influence of some critical parameters. The results show that the enhancement of COP could exceed 50% with optimum design parameters.

Enabling All-Solid-State Lithium-Carbon Dioxide Battery Operation in a Wide Temperature Range.

Flexible all-solid-state lithium-carbon dioxide batteries (FASSLCBs) are recognized as a next-generation energy storage technology by solving safety and shuttle effect problems. However, the present FASSLCBs rely heavily on high-temperature operation due to sluggish solid-solid-gas multiphase mass transfer and unclear capacity degradation mechanism. Herein, we designed bicontinuous hierarchical porous structures (BCHPSs) for both solid polymer electrolyte and cathode for FASSLCBs to facilitate the mass transfer in all connected directions. The formed large Lewis acidic surface effectively promotes the lithium salt dissociation and the CO2 conversion. Furthermore, it is unraveled that the battery capacity degradation originates from the "dead Li2CO3" formation, which is inhibited by the fast decomposition of Li2CO3. Accordingly, the assembled FASSLCBs exhibit an excellent cycling stability of 133 cycles at 60 °C, which is 2.7 times longer than that without BCHPSs, and the FASSLCBs can be operated repeatedly even at room temperature. This BCHPS method and fundamental deactivation mechanism provide a perspective for designing FASSLCBs with long cycling life.

Mass transfer mechanism of multiphase shear flows and interphase optimization solving method

Slurry mixing is a key process in the production of lithium-ion batteries. The interphase mass transfer and refinement problems involved in the shear mixing process have important engineering significance and research value. In this study, a CFD-DEM numerical simulation method is constructed for high shear flow, which based on the internal frictional momentum transfer mechanism and liquid-solid traction. The reliability of the proposed model was verified by single particle settling and particle cluster entry cases, and the computational results showed that the proposed model was in good agreement with the analytical results and literature. High Shear Mixer (HSM) as a typical multiphase shear equipment. We apply the developed multiphase shear flow model to study the effect of its operating conditions on the mixing and mass transfer performance. The results show that the appropriate rotation speed can effectively reduce the local accumulation of solid-phase particles, but the width of the inner shear zone is not related to the stator rotation speed; the shear jet forms a local circulation in the stator gap and reduces the through-flow capacity; the shearing effect of the inner shear zone is obvious for the declustering of large particle clusters, and the particle collision plays a certain role in the early stage of declustering. The CFD-DEM model developed in this paper improves the accuracy of interphase trajectory capture and provides a reliable numerical simulation method for the study of multiphase shear flow.

Tungsten in barium stars

Abstract Classical barium stars are red giants that received from their evolved binary companions material exposed to the slow neutron-capture nucleosynthesis, i.e., the s-process. Such a mechanism is expected to have taken place in the interiors of Thermally-Pulsing Asymptotic Giant Branch (TP-AGB) stars. As post-interacting binaries, barium stars figure as powerful tracers of the s-process nucleosynthesis, evolution of binary systems, and mechanisms of mass transfer. The present study is the fourth in a series of high-resolution spectroscopic analyses on a sample of 180 barium stars, for which we report tungsten (W, Z = 74) abundances. The abundances were derived from synthetic spectrum computations of the W i absorption features at 4843.8 Å and 5224.7 Å. We were able to extract abundances for 94 stars; the measured [W/Fe] ratios range from ∼0.0 to 2.0 dex, increasing with decreasing of metallicity. We noticed that in the plane [W/Fe] versus [s/Fe] barium stars follow the same trend observed in post-AGB stars. The observational data were also compared with predictions of the fruity and Monash AGB nucleosynthesis models. These expect values between −0.20 and +0.10 dex for the [W/hs] ratios, whereas a larger spread is observed in the program stars, with [W/hs] ranging from −0.40 to +0.60 dex. The stars with high [W/hs] ratios may represent evidence for the operation of the intermediate neuron-capture process at metallicities close to solar.

Seasonal performance research of heat-source tower systems using different work materials

Abstract The heat-source tower system has been evaluated in an enthalpy difference laboratory. This study analyzes the seasonal performance under various operating situations and fluid quality. In the summer and fall seasons, water is used as the circulating fluid in the tower. In the spring and winter seasons, glycol solution is used as the circulating fluid. Some parameters of the heat-source tower (e.g. the temperature of the solution inlet and outlet, the flow rate of the solution inlet and outlet, the temperature of the air inlet and outlet, the inlet air volume and the moisture content of the inlet air) are considered and measured to obtain its heat transfer characteristics. The simulation model of heat-source tower is constructed based on the mechanism of heat and mass transfer. This model is validated by the experimental results. The heat exchange and latent heat exchange of the system are analyzed under different parameters, as well as the variation law of inlet and outlet temperature and moisture content differences. The results show that the system has solution moisture absorption during winter operation. However, for every 9000 m3/h increase in air volume, the rate of solution dilution decreases between 9 and 43%. The rate of solution dilution is reduced by 11–31% for every 1°C in addition to the inlet solution temperature. Meanwhile, the heat dissipation in summer is about 2.8 times of the heat dissipation in winter.

Evaluation of multiscale mechanisms of ultrasound-assisted extraction from porous plant materials: Experiment and modeling on this intensified process

Ultrasound-assisted extraction (UAE) is an intensified mass transfer process, which can utilize natural resources effectively, but still lacks detailed mechanisms for multiscale effects. This study investigates the mass transfer mechanisms of UAE combined with material’s pore structure at multiscale. Porous material was prepared by roasting green coffee beans (GCB) at 120 °C (RCB120) and 180 °C (RCB180), and their UAE efficiency for phytochemicals (caffeine, trigonelline, chlorogenic acid, caffeic acid) were evaluated by experiment and modeling. Besides, the physicochemical properties, mass transfer kinetics, and multi-physical field simulation were studied. Results indicated that positive synergy effects on extraction existed between ultrasound and material’s pore structure. Higher mass transfer coefficients of UAE (GCB 0.16 min−1, RCB120 0.38 min−1, RCB180 0.46 min−1) was achieved with higher total porosity (4.47 %, 9.17 %, 13.52 %) and connected porosity (0 %, 3.79 %, 5.98 %). Moreover, simulation results revealed that micro acoustic streaming and pressure difference around particles were the main driving force for enhancing mass transfer, and the velocity (0.29–0.36 m/s) increased with power density (0.64–1.01 W/mL). The microscale model proved that increased yield from UAE-RCB was attributed to internal convection diffusion within particles. This study exploited a novel benefit of ultrasound on extraction and inspired its future application in non-thermal food processing.

Groundwater remediation by in-situ membrane ozonation: Removal of aliphatic 1,4-dioxane and monocyclic aromatic hydrocarbons

Groundwater contamination by widespread and persistent organic compounds requires extensive treatment efforts, for example by in-situ chemical oxidation (ISCO). In this study, we investigated ozone mass transfer and removal mechanisms of ozone-resistant monocyclic aromatic and non-aromatic compounds in a novel in-situ treatment method using ozone-permeable membranes as reactive barrier. Initial batch experiments confirmed fast depletion of ozone in presence of sub-stoichiometric benzoic acid (BA), in contrast to the non-aromatic 1,4-dioxane (DIOX), where ozone depleted much slower. Simulated in-situ membrane ozonation treatment of contaminated groundwater led to lower removal of 5 mg L−1 BA (52.7%) compared to DIOX (60.6%). Inhibited removal of BA compared to additional batch experiments could be explained by quick depletion of ozone by reactive intermediates on the membrane surface. Surprisingly, reactive porous media did not lead to substantial changes of in-situ DIOX oxidation, although a stronger impact of the media on DIOX oxidation was hypothesized. Furthermore, experimental ozone mass transfer coefficients were determined (3.94∙10−7 – 3.12∙10−6 m s−1) and compared to modeled values for different membrane types (polydimethylsiloxane and polytetrafluoroethylene). Finally, a mathematical model based on mass transfer data was developed to support upscaling efforts. We concluded that contaminant properties are crucial for the feasibility assessment of in-situ ozone membrane treatment technology.

Numerical simulation and environmental impact assessment of oil vapor diffusion in surrounding residential areas before/after vapor recovery at petrol stations

ABSTRACT Oil vapor emitted during refueling process has caused serious issues of air pollution, especially the environmental impact in surrounding residential areas. Most petrol stations have installed oil vapor recovery systems, but some stations did not properly maintain or switch on them. With the increasing emphasis on ecological environmental protection, it is more crucial to investigate the internal mechanism of vapor-air mass transfer. In this study, a computational fluid dynamic (CFD) model was developed and verified to analyze the effects of wind speed, vehicles number, and residential layout on oil vapor diffusion in residential areas. Simultaneously, the effectiveness of oil vapor recovery was assessed by comparing contamination before and after recovery. Results indicate that wind speed greatly affects the area and location of excess emission areas (EEAs). As the wind speed increases from 2 m/s to 4 m/s, highest concentration, distance to buildings and width of EEAs decreases by 49.1%, 43.8%, and 33.3%, respectively, and EEAs disappear at the wind speed of 6 m/s. Vehicles number has a more significant effect on the symmetry of EEAs, and EEAs become gradually symmetrical as the number increases from 3 to 12. Further, the enclosure layout proves to be an effective layout for protecting residential air, with a minimum concentration of 0.18 mg/m3. Notably, the effectiveness of oil vapor recovery is remarkable, with a purification rate of 98.5%. These findings can offer a valuable guidance for controlling air pollution in residential areas and enhancing the environmental protection level of petroleum enterprises.

Exploring mass transfer mechanisms in sintering processes through molecular dynamics simulation

Molecular dynamics simulation was employed to delve into the mechanism of neck formation in a two-particle sintering model. Specifically, this study simulated the behavior of two nickel (Ni) nanoparticles, each with a diameter of 12 nanometers, utilizing the Embedded Atom Method (EAM) interatomic potential at a high temperature of 1200 K. Indeed, in this study, a meticulous examination of atom displacements enabled the evaluation of the neck formation mechanism through both qualitative and quantitative analyses. The qualitative assessments, encompassing forward and backward imaging techniques, indicated that diffusion and semi-convection were likely the most prominent mass transfer mechanisms during the sintering process of two nickel nanoparticles. For a quantitative analysis of the mass transfer mechanisms, Mean Square Displacement and Relative Mean Square Displacement were employed. The results of this analysis pertaining to neck formation revealed that the diffusion mechanism contributed to 17.6 % of the atomic displacement, with an associated magnitude of 2.7 Å. Furthermore, the analysis revealed that the contribution and average value of the semi-convection movement accounted for 82.4 % and 12.6 Å, respectively. Consequently, given the concurrent operation of both mass transfer mechanisms in this study, it becomes evident that semi-convection mass transfer can be established as the primary mechanism regulating the rate of neck formation.

Conjugate heat and mass transfer in vacuum membrane distillation for solution regeneration using hollow fiber membranes

To avoid problems such as low efficiency of liquid desiccant processes in high humidity environments, vacuum membrane distillation (VMD) solution regenerators are proposed. This study investigates the conjugate heat and mass transfer mechanism in the vacuum membrane distillation solution regeneration. The study reveals that the solution temperature and concentration in the hollow fiber membrane tube exhibit a tower-shaped distribution, with the lowest temperature near the membrane surface and the highest concentration at the outlet. The membrane flux decreases along the direction of the solution flow, ranging from 0.62 to 0.36 g/(m2·s). Increasing the solution flow rate and vacuum degree enhances the heat and mass transfer, while increasing the solution concentration reduces the heat and mass transfer. The Nusselt and Sherwood number formulas applicable to the VMD solution regeneration process were fitted, which is more accurate than the empirical formulas at atmospheric pressure. The resistance distribution during the solution regeneration process in VMD shows that the membrane-side resistance has a significant impact on the heat and mass transfer during solution regeneration, with the membrane-side thermal resistance accounting for 91 % of the total resistance in the heat transfer process and 67 % in the mass transfer process. The findings in this paper can more accurately guide the design of vacuum membrane distillation solution regenerators.

Insights into the spatial effects of carbon source type on oxygen mass transfer mechanism and microbial community characteristics

The dissolved oxygen (DO) concentrations in wastewater and biofilm under four types of carbon sources were explored to further reveal the mechanism of oxygen mass transfer (OMT). In aerobic fluidized bed biofilm reactor (AFBBR) system, microbial community composition and functional microorganisms were analysed to characterize the influence of OMT on microbial metabolism. The DO concentrations with sodium acetate, sodium propionate, glucose, and starch reached to 6.43 ± 0.36 mg/L, 5.92 ± 0.21 mg/L, 6.91 ± 0.50 mg/L, and 7.20 ± 0.43 mg/L, respectively. Differences in carbon source led to significant differences in wastewater and biofilms OMT efficiency. The oxygen transfer rate (OTR) under four types of carbon sources was in the order starch>glucose>sodium acetate>sodium propionate, but the parameters for diffusion dynamics [Db = (3.68 ± 0.09) × 10−6 cm2/s, Di = (3.26 ± 0.99) × 10−4 cm2/s, ki = (5.94 ± 0.16) × 10−3 cm/s, and LF = (2174 ± 72 μm)] in the biofilms were highest with sodium propionate. With sodium propionate and glucose, Actinobacteria was the dominant bacteria (60.3 % and 78.5 %). However, with sodium acetate and starch, the dominant bacteria was Proteobacteria (88.9 % and 45.0 %). Sodium propionate improved wastewater treatment efficiency by altering microbial community composition and metabolic functions. The average removal of CODcr, NH4+-N, TN, and TP reached to 93.1 %, 86.9 %, 81.3 %, and 57.2 %, respectively.

Mechanism of pH Effect on Mass Transfer During Bubble Evolution on Photoelectrode Surfaces

This study conducted in-depth research on the limitation problem of mass transfer of gas molecules on the surface of the photoelectrode to the efficiency of photoelectrochemical water splitting. Experimental results reveal significant differences in the dynamic characteristics of bubbles and mass transfer mechanisms during bubble growth under different pH conditions. As the pH deviates from 7.0 (vs RHE), the reaction rate increases, the bubble nucleation voltage decreases, and the terminal rising velocity increases significantly. During the rapid growth phase of bubbles, the mass transfer coefficient reaches its peak, accounting for only 1% of the entire evolution cycle. In a neutral environment (pH = 7.0), the transient mass transfer coefficient reaches a maximum at approximately 1 s of bubble growth, while in an alkaline environment (pH = 12.0), it reaches a maximum at around 0.1 s. In strongly alkaline environments (pH = 13.0), the PEC reaction rate and mass transfer rate increase, resulting in the highest gas production efficiency. The mass transfer coefficients were improved by about 72.4% and 42.8% (vs Ag/AgCl) and by about 22.2% and 33.3% (vs RHE) in the strong alkaline environment relative to the strong acid environment (pH = 1.0) and the neutral environment, respectively.

INFLUENCE OF BUBBLE GROWTH AND LIQUID FILM INSTABILITIES ON DROPLET IMPACT PHENOMENA UNDER SATURATED BOILING REGIMES

Evaporation and boiling are processes that occur in many industrial applications involving multiphase flows. For liquid films, however, studies are scarce regarding heat and mass transfer mechanisms and require further research. The main objective of this work is to evaluate bubble formation and detachment, followed by the impact phenomena. Therefore, an experimental setup was built and adapted for this purpose. A borosilicate glass impact surface is placed over a heat source, which consists of an aluminum block with four embedded cartridge heaters that heat the liquid film by conduction. Water and n-heptane are the fluids adopted for the experimental study, as the differences in thermophysical properties allow for a wider range of experiments. Study cases include dimensionless temperatures of θ > 0.6 for similar impact conditions. In terms of bubble formation, n-heptane displays smaller bubble diameters and higher release rates, whereas water exhibits larger bubbles and lower rates. Qualitatively, liquid film temperatures close to the saturation temperature do not reveal a direct influence on the crown development and posterior secondary atomization. For later stages of the impact, the central jet height and breakup are influenced by the film temperature, which is associated with the variation of thermophysical properties.

UVIT/AstroSat Investigation of a Low-luminous Blue Straggler Star in NGC 362: Detection of an Extremely Low-mass White Dwarf as Companion

In the present study, we identified an extremely low-mass white dwarf as a companion to a low luminous blue straggler star within the Galactic globular cluster NGC 362. To conduct the analysis, we utilized data obtained from various sources, including AstroSat’s Ultra Violet Imaging Telescope, UVOT, and the 2.2 m ESO telescope. By examining the spectral energy distribution of the blue straggler star candidate, we successfully identified an extremely low-mass white dwarf as its binary companion. We determined the effective temperature, radius, and luminosity for both, the extremely low-mass white dwarf and the blue straggler star candidate. Specifically, the extremely low-mass white dwarf exhibits an effective temperature of 15000 K, a radius of 0.17 R⊙, a luminosity of 1.40 L⊙, and a mass range of 0.19-0.20 M⊙. Furthermore, the position of the straggler star within the cluster suggests their formation via the Case A/B mass-transfer mechanism in a low-density environment.

Managing heat transfer effectiveness in a Darcy medium with a vertically non-linear stretching surface through the flow of an electrically conductive non-Newtonian nanofluid

<abstract><p>This study encapsulated the research methodology utilized in the flow behaviors of Williamson nanofluid and analyzed the associated mass heat transfer. The study concentrated on examining the magnetohydrodynamic behavior of nanofluids in the presence of heat generation effects and the inclusion of dissipative energy on a vertical nonlinear stretching surface submerged within a Darcy porous medium. The rationale for including variable viscosity and variable conductivity in this research was to precisely evaluate the mechanisms of heat and mass transfer, particularly with regard to the fluctuations in fluid properties. The objective was to enhance the understanding of how these varying properties impact the overall heat and mass transfer processes. The initial formulation of the phenomenon, initially presented as partial differential equations, was transformed into ordinary differential equations by employing appropriate dimensionless variables. The ultimate streamlined version of the model was then numerically solved utilizing the shooting method. By employing the numerical shooting method, we portrayed nanofluid patterns in velocity, temperature, and concentration fields, alongside essential parameters such as skin friction coefficient, Sherwood number, and Nusselt number. The significant key findings highlighted that both the porous parameter and the magnetic number increasingly affected temperature and concentration distributions. Additionally, increasing the thermophoresis parameter resulted in higher concentration and corresponding temperature levels. Graphical presentation and physical explanations were used for analysis, and the study's outcomes were compared to existing literature, affirming a strong agreement that validated the solutions.</p></abstract>

Photo‐Induced Evolution of Randomly Rough Surfaces of Amorphous Chalcogenide Films

Photoinduced (PI) evolution of statistically rough surfaces of amorphous chalcogenide films As20Se80 at room temperature has been studied by measuring the angular dependence of the intensity of light scattered from a surface illuminated by CW laser (λ = 660 nm). The interpretation of the scattering data based on the resonant scattering theory enables to confirm unequivocally the diffusion mechanism of PI mass transfer. It is detected that the change of the amplitude of a spatial harmonic in the roughness spectra strongly depends on its period ∧ . During illumination, the amplitude increases at ∧ > ∧*, whereas harmonics with ∧ < ∧* decreases by ∧*, which corresponds to zero evolution rate, is found to be 6.7 μm. In accordance with our theoretical prediction, both growth and decrease are exponential with the rates depending on ∧. As the result, the roughness with initial rms height of 50–70 nm transforms into quasiperiodic surface grating with the average amplitude of about 400 nm and average period close to 15 μm. From the kinetics of time variation of the scattered intensity, the PI diffusion coefficient D is calculated. When the laser intensity changes from 5.6 to 14 W cm−2, D is found in the range 1 × 10−13–3.4 × 10−13 m2 s−1.

The mechanisms underlying Li+/Mg2+ separation in ZIF-8 under an electric field from atomistic simulations.

In this study, we explore the mass transfer and separation mechanism of Li+ and Mg2+ confined within the flexible nanoporous zeolite imidazolate framework ZIF-8 under the influence of an electric field, employing molecular dynamics simulation. Our results highlight that the electric field accelerates the dehydration process of ions and underscore the critical importance of ZIF-8 framework flexibility in determining the separation selectivity of the ZIF-8 membrane. The electric field is shown to diminish ion hydration in the confined space of ZIF-8, notably disrupting the orientation of water molecules in the first hydration shells of ions, leading to an asymmetrical ionic hydration structure characterized by the uniform alignment of water dipoles. Furthermore, despite the geometrical constraints imposed by the ZIF-8 framework, the electric field significantly enhances ionic mobility. Notably, the less stable hydration shell of Li+ facilitates its rapid, dehydration-induced transit through ZIF-8 nanopores, unlike Mg2+, whose stable hydration shell impedes dehydration. Further investigation into the structural characteristics of the six-ring windows traversed by Li+ and Mg2+ ions reveals distinct mechanisms of passage: for Mg2+ ions, significant window expansion is necessary, while for Li+ ions, the mechanism involves both window expansion and partial dehydration. These findings reveal the profound impact of the electric field and framework flexibility on the separation of Li+ and Mg2+, offering critical insights for the potential application of flexible nanoporous materials in the selective extraction of Li+ from salt-lake brine.