Porous Model Research Articles

3D Reconstruction of Pore and Fracture Structures in Crushed Soft Coal with Low Permeability and Its Permeability Analysis: Implications for the Design of CO2 Injection and CH4 Production.

In order to improve the CO2 injection and CH4 production efficiencies during the CO2-ECBM process, it is necessary to clarify the relationship among the complexity of pore and fracture structures, the typicality of the fluid migration path, and the heterogeneity of reservoir permeability. In this study, crushed soft coal with low permeability from Huainan and Huaibei coalfields of China was taken as the research object. First, the three-dimensional (3D) visualization reconstruction of pore and fracture structures was realized. Second, the equivalent pore and fracture network model was constructed. Finally, the permeability evolution and its anisotropy of the coal reservoir were dynamically demonstrated. In this study, the implication of surface porosity on the heterogeneity of pore and fracture structures was first discussed, followed by the implication of coordination number on the anisotropy of fluid flow, and finally, the influence of the anisotropy of fluid flow on the CO2-ECBM process was discussed. The results show that the equivalent pore and fracture network models of the reservoir structure can be constructed based on the digital rock physics technology. The analysis results of porosity, interconnected porosity, typical path of fluid migration, absolute permeability, and surface porosity of each sample have good consistency in characterizing the complexity of pore and fracture structures and the heterogeneity of permeability. The average coordination numbers of RL and LZ samples are 5.99 and 5.78, respectively, and the number of pores and throats is well-balanced, which indicates that LZ and RL collieries are suitable for the development of CO2-ECBM industrial tests. When the interconnected pores and fractures are mainly developed vertically and horizontally, the construction of drilling technology of the CO2-ECBM process should be mainly designed for vertical wells and horizontal wells, respectively. This study has important theoretical and practical significance for the industrial testing and commercialization of CO2-ECBM technology in crushed soft coal with low permeability.

Migration behavior of water molecules and chloride ions at the nanopore scale based on molecular properties under temperature effect

The durability of cement-based materials is closely related to the transmission characteristics of water and chloride ions in the pores of calcium silicate hydrate (C-S-H) gel, especially in the climate conditions with significant temperature difference. The local structure and transport process of water molecules and chloride ions in gel pores are affected by interfacial effects. The unsaturated transport model of sodium chloride solution in C-S-H gel pores is established on the molecular scale, under different temperature and pore size conditions. Divide the regions in the C-S-H gel pore model into internal adsorption zone, external adsorption zone, and free zone. Taking into account the intrinsic mechanisms and molecular properties of water molecules and ions during transport in the C-S-H gel pores, the local structures and dynamic properties of water molecules and ions in the gel pores are quantitatively described. The electrical double layer and the double-layer water film overlap in the 1.5 nm gel pore, the water molecule and the chloride ion are closely arranged. Thus the diffusion coefficient is far lower than others, and is rarely affected by temperature. Considering the changes in the molecule properties of water and ion in different zones in molecular simulation results, a theoretical model of nanopore water and ion migration was established, revealing the migration behavior of water and ions. The results indicate that the steady-state diffusion fluxes of water and chloride ions are positively correlated with the effects of temperature and pore size, and the increasing amplitude of their diffusion fluxes is characterised by a similar phenomenon with that. This research provides a theoretical basis for the mechanism and durability of cement-based materials corroded by water and chloride ions in marine environments.

Comparison between two-step and single-step kinetic models for non-isothermal CO2 gasification of biomass char generated by fast pyrolysis

Kinetic analysis plays a critical role in the gasification process. The kinetics of CO2 gasification for various wood chars, which were prepared in a single particle reactor (SPR), were studied using a non-isothermal method in a thermogravimetric analyzer. To statistically derive significant conclusions, the data obtained from the gasification of fast pyrolyzed chars are used to compare the performance of the volumetric model (VM), grain model (GM), random pore model (RPM), integrated core model (ICM), and two-step (first step: VM; second step: ICM) parallel model. The obtained results show that most |DDTG| curves show one local minimum, representing at least one reaction step. When combined with the TG curves, the gasification process exhibits a distinct devolatilization and char gasification component. ICM has a better performance compared to the other single-step models. The two-step model significantly improves over the single-step model due to the additional equation. The two-step model's average deviation DEV(X) is 0.95 %, which shows an 80 % improvement compared to ICM (DEV(X) = 4.64 %). The predicted activation energy (devolatilization: 54.8–76.2 kJ/mol; gasification: 185.7–247.5 kJ/mol) falls within a reasonable range, which is consistent with the findings reported in the literature.

Steam gasification of tire char supported by catalysts based on biomass ashes

The aim of this work is to assess the feasibility of steam gasification of tire char and the impact of various biomass ashes (sunflower husk, beet pulp, beech chips and corn cobs) in the process. Samples of tire-char and char-catalysts (in the amounts of 5, 10 and 15 wt%) were subjected to gasification in isothermal conditions (800–1000 °C) at a pressure of 1 MPa, using the thermovolumetric method based on an analysis of the composition of the resulting gas. Changes in the formation rates of the main gas components (CO, H2, CO2 and CH4), maximum carbon conversion, half times conversion, yields and composition of gas components and H2/CO ratio were determined. Kinetic parameters (activation energy and pre-exponential factor) of the gasification reaction were calculated using the grain and random pore models. The correlations between the content of individual elements in ashes and parameters describing tire char gasification were assessed. The addition of a catalyst and increasing its loading improved the reactivity of the tire-char at up to 850 °C and had a significant but temperature-dependent impact on gas component yields. Performing catalytic tire char gasification under appropriate selected conditions (800–850 °C and 10/15 wt% of sunflower husk and beech chips ash as catalysts) may be an attractive way to efficiently obtain a hydrogen-rich gas.

Phase transitions of ionic fluids in nanoporous electrodes

In this work, we utilise grand canonical Metropolis Monte Carlo simulations, to establish pore-induced freezing of restricted primitive model fluids. A planar pore model is utilised, with walls that are initially neutral, and either non-conducting or perfectly conducting. The phase of the confined electrolyte (solid/fluid) displays an oscillatory dependence on surface separation, in narrow pores. Conditions are chosen so that the bulk is composed of a stable fluid electrolyte. The tendency for the electrolyte to freeze in narrow pores is somewhat stronger in systems with non-conducting walls. We also demonstrate that an applied potential will, above a threshold value, melt a frozen electrolyte. In these cases, the capacitance, as measured by the average surface charge density divided by the applied potential, will be almost vanishing if the applied potential is below this threshold value. We do not see any evidence for a “superionic fluid”, which has been hypothesised to generate a strong capacitance in narrow pores, due to an efficient screening of like-charge repulsions by image charges.Graphic abstract

A three-interface random pore model: the reduction of iron oxide in chemical looping and green steel technologies

Accurate modelling of the gaseous reduction of porous iron oxide powders or fines is important in industry for (i) reinventing the carbon intensive production of iron and steel and (ii) chemical looping technologies in the sphere of carbon capture and storage. A new three-interface random pore model is derived and applied to the gaseous reduction of hematite ( Fe 2 O 3 ) to iron (Fe). The structural reaction–diffusion model is able to describe three simultaneously reacting oxide layers, Fe 2 O 3 , magnetite ( Fe 3 O 4 ) and wustite ( Fe w O ). The geometric nature of the model encodes structural information about the particles (porosity, surface area, pore length and size distribution), measured here by experiment. The model is usefully able to separate structural particle properties from individual rates of reaction and product layer diffusion. The results have been compared and fitted to thermogravimetric experiments between 800 – 1000 ∘ C and three CO / CO 2 gas mixtures. Rate constants for each indvidual reaction have been obtained and fit well to Arrhenius plots. The reduction of Fe 2 O 3 – Fe 3 O 4 was controlled by diffusion and reaction kinetics, while the reduction of Fe 3 O 4 – Fe w O and Fe w O –Fe was limited by reaction kinetics. Metallization rates of the iron oxide powders were rapid, showing promise for both hydrogen-based direct reduced iron and chemical looping processes.

PoreSkel: Skeletonization of grayscale micro-CT images of porous media using deep learning techniques

Skeletonization, a crucial step in pore network modeling, traditionally involves the extraction of skeleton pixels from binarized, segmented X-ray images of porous materials. However, this conventional approach often suffers from user bias during segmentation, potentially leading to the loss of essential image details. This study addresses this limitation by developing deep learning model, called PoreSkel, designed to directly perform skeletonization and distance map extraction from unprocessed grayscale images, thus eliminating the need for additional image processing steps. The model was trained, validated, and tested using an expansive databank of micro-CT images from 20 distinct sandstones, carbonates, and sand pack samples, a total of 10,240 images, with each sample represented by a cube of size 5123. A fifth of these images, specifically 15.6 % from sixteen sandstone and sand pack samples, were used for training, while the remainder served for model validation (4.4 %) and extensive testing (80 %). PoreSkel showed an excellent performance, achieving a mean f1-score of 0.964 for skeletonization and an RMSE of 0.057 for distance map extraction during the testing phase. Our assessments revealed that the model is robust to bias toward the majority class, namely the background pixels. Furthermore, the model showed high generality, maintaining its performance when tested using unseen images from three carbonates and an additional sandstone. Notably, PoreSkel effectively handles disruptions caused often by the presence of minerals in pore spaces and perturbations on pore boundaries - a common challenge for the medial axis technique - resulting in fewer nodes (i.e., pore junctions) and pore coordination numbers, but a higher number of connected skeletons. Therefore, PoreSkel provided a more precise and representative pore structures of porous material that is needed for accurate pore network generation and modeling.

Two-stage bubble point pressure: A newly found feature of Dutch Twill weave porous screen

The porous screen is a vital material in the area of in-orbit propellant management, due to its efficient performance to separate gas and liquid in microgravity conditions. Among the diversities of screens, the Dutch Twill weave (DTW) screen is the most commonly used owing to its extensive adaptability of different fluids including storable and cryogenic propellants. This study focuses on the bubble point pressure (BPP), a quite important characteristic parameter of the screen applied to gas-liquid separation. It has been commonly considered by previous researchers that BPP for a given working fluid and fixed screen structure has a certain value. However, the two-stage-bubble-point pressure phenomenon that was newly found in an experiment reveals three new parameters of DTW screens: the first order BPP, the second order BPP, and the critical depressurizing level. After a bubble breakthrough occurs, only if the driving pressure is decreased to under the critical depressurizing level, can the screen be fully resealed; otherwise, the screen can be just partially resealed. For the pressurization beginning at the fully resealed state, the critical value of the driving pressure to trigger a bubble breakthrough is the first order BPP; but for the pressurization beginning at the partially resealed state, the critical value becomes the second order BPP. To understand this phenomenon, we analyzed the microstructure of DTW screens and then reconstructed the conceptual model of screen pore, according to the distribution mode of pore diameter. The new model explain the phenomenon by introducing three special character parameters: the first order BPP, the second order BPP, and the critical depressurizing level, which are corresponding to the locations of the first throat, the second throat, and the abdomen in a pore passage, respectively. The detailed mechanism was quantitatively illustrated by a CFD simulation. The discovery of this feature of DTW screens should be a meaningful reminder that after bubble breakthrough occurs, only when the driving pressure is decreased to below the critical depressurizing level, can the original performance of screen be recovered fully.

Insight into the Desolvation of Organic Electrolyte Cations with Propylene Carbonate as a Solvent in Flat Pores: A First-Principles Calculation

Supercapacitors have many applications in new energy and other high-tech fields. The desolvation effect on ions affects the capacity size of supercapacitors, and there are few relevant studies published in this field at present. In this experiment, bilayer graphene (BG) with a layer spacing of 4–10 Å was used as a model of flat pores and was calculated with first-principles calculations, which can effectively simulate the adsorption behaviour of porous carbon. The reaction energies of ions, propylene carbonate, and ionic complexes in bilayer graphene with different layer spacings were calculated, and the desolvation behaviour of lithium salt cations (Li+), tetraethyl quaternary ammonium salt cations (TEA+), triethyl methyl quaternary ammonium salt cations (TEMA+), and bipyrrolidinium quaternary ammonium salt cations (SBP+) was investigated. The calculation was based on density functional compact bound (DFTB+) software. The calculated results show that in the stacked system, the complete desolvation size of the TEA+ reaches 5.6 Å, the complete desolvation size of the TEMA+ reaches 4.9 Å, the complete desolvation size of the SBP+ reaches 4.8 Å, and the complete desolvation size of the Li+ reaches 5.4 Å, with the organic electrolyte cations showing a positive trend in the complete desolvation size as the ion radius increases. An in-depth analysis of the data shows that Li+, TEA+, TEMA+, and SBP+ ion radii play a dominant role in the size of desolvation. The results of this paper provide an effective aid for the selection of organic electrolytes to increase the capacity of supercapacitors.

Finding Infinities in Nanoconfined Geothermal Electrolyte Static Dielectric Properties and Implications on Ion Adsorption/Pairing.

Infinities should naturally occur in the dielectric responses of ionic solutions relevant to many geochemical, energy storage, and electrochemical applications at a strictly zero frequency. Using molecular dynamics simulations cross-referenced with coarse-grained Monte Carlo models, using nanoslit pore models at hydrothermal conditions, and treating confined mobile charges as polarization, we demonstrate the far reaching consequences. The dielectric permittivity profile perpendicular to the slit (ϵ⊥(z)) increases, not decreases, with ionic concentration, unlike in the more widely studied megahertz-to-gigahertz frequency range. In confined electrolytes, the divergences in ϵ⊥(z) correctly describe crossovers between bulk- and surface-dominated dielectric behavior. Nanoconfinement at low ionic concentrations changes monovalent ion energetics by 1-2 kJ/mol, but no dielectric property studied so far is universally correlated to ion adsorption or ion-ion interactions. We caution that infinities signal violation of the "electrical insulator" dielectric assumption.

Pyrolysis characteristics and kinetic parameters assessment of typical agricultural residues using high heating photothermal TGA

Understanding the complexity of thermal degradation characteristics, kinetic behavior, and thermodynamic parameters is pertinent for the efficient design and process optimization of large-scale conversion systems. Comparative assessment of pyrolysis characteristics and thermodynamic parameters of corn cobs (CC), peanut shells (PS) and sugarcane bagasse (SB) are investigated using high heating rates (100–1000 ℃/min) TGA results. Despite the effect of the heating rate increase on the degradation process of individual samples, increasing heating rates affect pyrolysis characteristics due to compositional differences. With increasing heating rates, the comprehensive pyrolysis index increased sporadically for CC (2.54–44.09 ×104%2/min2 ℃3) and PS (1.36–31.13 ×104%2/min2 ℃3), indicating easier release of volatiles at higher pyrolysis heating rates. The pyrolysis stability index (Rw), which relates to thermal degradation stability, presented an increasing trend (CC>PS>SB) with a heating rate increase (≥106%). Kinetic parameters estimated using model-free methods showed that the activation energies of CC and PS were significantly lower than that of SB. Comparative evaluation of fractional conversions and kinetic parameters using traditional and modified parallel models showed that the double random pore model (DRPM) fitted the best for simulating the experimental results at higher heating rates than other models. The change in Gibbs free energy (ΔG) trend for PS and SB showed a deviation, suggesting reaction difficulties due to higher temperature demands.

Potassium-Induced Phenomena and Their Effects on the Intrinsic Reactivity of Biomass-Derived Char during Steam Gasification.

The mineral content of biomass plays an important role in the gasification rate of biomass-derived char. The understanding and quantification of mineral-related phenomena are thus of importance when considering gasification reactor design. In the present work, the potassium-induced catalytic phenomena during gasification of biomass-derived char have been studied. Char samples with similar structure and different intrinsic potassium content were gasified in a steam atmosphere at a temperature range of 700-800 °C. It was found that for all the samples, irrespective of the temperature and the initial potassium content, there is a critical K/C ratio (5 × 10-3), whereafter the catalytic phenomena prevail. The instantaneous conversion rate of the char is positively correlated with the potassium content and the progressively increasing conversion. The application of the modified random pore model was able to capture the later stages of conversion by the introduction of two additional parameters (c and p). It was found that these constants are not just fitting parameters but that there is an underlying physical significance with c being directly related to the intrinsic potassium content while being temperature independent and with p being temperature dependent.

Pore Size Dependence of Mass Transfer of Zinc Myoglobin in a Single Mesoporous Silica Particle.

This study investigated the pore size dependence of the mass transfer of zinc myoglobin (ZnMb) in a single mesoporous silica particle through confocal fluorescence microspectroscopy. The ZnMb's fluorescence depth profile in the particle was analyzed by a spherical diffusion model, and the intraparticle diffusion coefficient was obtained. The intraparticle diffusion coefficient in the silica particle with various pore sizes (10, 15, 30, and 50 nm) was furthermore analyzed based on a pore and surface diffusion model. Although the mass transfer mechanism in all silica particles followed the pore and surface diffusion model, the adsorption and desorption of ZnMb affected the mass transfer depending on the pore size. The influence of the slow desorption of ZnMb became pronounced for large pore sizes (30 and 50 nm), which was revealed by simulation using a diffusion equation combined with the adsorption-desorption kinetics. The distribution of ZnMb was suppressed in small pore sizes (10 and 15 nm) owing to the adsorption of ZnMb onto the entrance of the pore. Thus, we revealed the mass transfer mechanism of ZnMb in the silica particle with different pore sizes.

A comprehensive random pore model kinetic study of hematite to iron reduction by hydrogen

The consistent growth of industrialization has intensified the need for Iron and steel. Thus, it is essential to improve the efficiency of iron manufacturing plants. This work studies the inherent kinetics of hematite reduction to Iron with H2 via a random pore model (RPM) as the most sophisticated non-catalytic gas–solid reaction model. In this regard, reduction tests were performed on a pure hematite pellet by changing the reduction temperature and H2 concentration. Then, kinetic parameters were calculated via an RPM based on the pellet's pore size distribution. Validations of the calculated kinetic parameters using other pure hematite pellets with different characteristics besides an industrial pellet proved the robustness of this inclusive approach. The activation energy for the H2 reduction was obtained at 40.87 kJ/mol. Also, the diffusion coefficient of oxygen ions through the iron product layer for the industrial pellet was measured at 2.83 × 10-17 m2/s.

Filling–adsorption mechanism and diffusive transport characteristics of N2/CO2 in coal: Experiment and molecular simulation

Enhanced coalbed methane (ECBM) is an effective development technology to improve energy utilisation and reduce greenhouse gas emissions by injecting N2/CO2 into coal seams. The process involves the adsorption, desorption, and diffusion of N2/CO2 in multi-scale coal pores. This results in gas storage and transport characteristics limited by the coal's structural distribution of nanoscale pores (≤100 nm). Thus, studying N2/CO2 storage and diffusive transport characteristics in pores at different scales is vital for efficiently implementing N2/CO2-ECBM. This paper performed low-pressure adsorption with N2/CO2 (LPA-N2/CO2) to evaluate coal samples' isothermal adsorption characteristics and pore structure, revealing the dual filling-adsorption mechanism of N2/CO2 in coal. A new coal pore classification method was proposed. Pores (≤50 nm) in coal-N2 or coal-CO2 adsorption systems were classified as inaccessible pores (<0.364 nm or < 0.33 nm), filling pores (0.364–1.65 nm or 0.33–1.36 nm), transition pores (1.65–2 nm or 1.36–1.60 nm), and adsorption pores (>2 nm or > 1.60 nm). Combining the experimental results to construct micropore and mesopore models, molecular dynamics were applied to simulate the loading and migration processes of N2/CO2 in the pore models. Filling, transition, and adsorption pores completed loading gas within 0.1–1 MPa, 1–5 MPa and 5–10 MPa in that order, visualising the gas filling-adsorption process in coal. Then, the adsorption capacity of N2 was controlled by the pore size and adsorption pressure, while CO2 was mainly influenced by adsorption pressure.

Study of Temperature Effect on Cascade Characteristics of Nanofluidic Energy Absorption System

Nanofluidic energy absorption system (NEAS) with cascade energy absorption characteristics can absorb energy on different levels simultaneously in one system, which greatly enriches its functions and applications. The pore structure and size distribution of porous media play a crucial role in the design and construction of cascade nanofluidic systems. In this paper, two cascade pore models were constructed using carbon nanotubes with different diameters, one was the model of two tubes with both one end immersed in water (DNEAS), and the other was the model of two tubes end to end, with the end of the big tube immersed in water (SNEAS). The effects of temperature-coupled pore size on the infiltration processes of water molecules into two models were investigated. The fitting correlations between critical pore size difference and temperature were established. The microscopic mechanism of temperature effect was illuminated. With the increase in temperature, systems displaying cascade characteristics transformed into a single-stage system without cascade characteristics. Due to the significant size effect of system temperature, the critical pore difference increased with both system temperature and the pore size. The research results expanded the basic database of cascade nanofluidic systems and provided guidance for the application design of cascade nanofluidic systems.

Influence of Different Redevelopment Measures on Water–Oil Immiscible Displacement and Mechanism Analysis

Understanding the two-phase displacement behaviors of oil and water in porous media under different reservoir development modes for enhanced oil recovery is essential. In this paper, the influence of development measures, such as increasing the injection rate, changing the inlet/outlet position, increasing the water viscosity, and reducing the surface tension coefficient, on oil–water dynamic behaviors was studied using a numerical simulation based on the study of the formation of a high-water-cut channel by water flooding at different injection rates. The results show that blockage and restart occur during displacement in the pore–throat channel and during staggered displacement in different pore channels. With an increase in the injection rate, the recovery increases first and then decreases. All the different development measures can increase the swept area and recovery factor. The recovery factor increases significantly by reducing the surface tension coefficient at medium/high injection rates (≥0.01 m/s) and by increasing the viscosity of the water at low injection rates (&lt;0.01 m/s). The numerical simulation study preliminarily revealed the influence of different development measures on displacement behaviors in the pore model. It thus provides theoretical support for understanding the law of oil and water movement in reservoirs.

Experimental and Modeling Study of the Nanofiltration of Alcohol-Based Molecules and Amino Acids by Commercial Membranes.

The nanofiltration performance of three commercial membranes was analyzed by the Steric Pore Model (SPM) and the extended Nernst-Planck diffusion equation inside membrane pores. The model was completed with the equation to predict the concentration polarization, and the mass transfer coefficient was determined by considering the presence of a feed spacer. The model parameters that characterized the performance of the membrane were the hydrodynamic coefficient, which accounts for the possible variations in solute size and membrane pore radius, the effective membrane thickness, and the water permeability coefficient. All experiments were conducted at fixed feed pH of 6. The rejections of uncharged solutes (glucose for membranes with a high molecular weight cut-off (MWCO) and glycerol and ethylene glycol for membranes with a low MWCO) allowed the model parameters to be determined. We found that glycerol and ethylene glycol overestimate the membrane pore radius due to their ability to interact with the membrane matrix. Therefore, the rejection of glycine as a small amino acid was explored to characterize the membranes with low MWCO since these molecules do not interact with the membrane matrix and have an almost zero charge at pH values between 4.5 and 6.5. Based on the experimental rejections, it was stated that glucose and glycine could be separated by these membranes operating in continuous diafiltration mode.

Molecular simulation investigation of pore structure impact on the wettability and flotation efficiency of coal gasification fine slag

Coal gasification slag is a kind of solid waste that exhibits suboptimal resource utilization and contributes to environmental pollution. Flotation is a common method of sorting coal gasification fine slag. However, the adverse influence of the well-developed pores structure of residual carbon on wettability and flotation efficiency is not adequately addressed in the literature. In this research, the adsorption characteristics of water molecules in the residual carbon model with different pore structures were investigated by Grand Canonical Monte Carlo simulation. We employed molecular dynamics simulations and mathematical models to investigate the mechanism of pore water movement. Additionally, the influence of pore structure on the flotation effect of coal gasification fine slag was explored for molecular dynamics simulations and flotation experiments. The results indicated that water molecules were adsorbed and aggregated in the residual carbon pores in the form of clusters. The cluster size decreased as the porosity decreased. Moreover, the same pore model showed an equivalent adsorption of water molecules. The binding effect of residual carbon on water molecules was stronger for smaller pore sizes. However, the simulation and experimental findings demonstrated that the more developed the pore structure of coal gasification fine slag, the lower its flotation efficiency. Finally, various methods of strengthening the flotation of coal gasification fine slag are theoretically verified. The findings of this research elucidate the underlying microscopic mechanism responsible for the adsorption of water molecules by residual carbon pores. Moreover, we explicate the principle of weakening the pore wetting effect and lay a theoretical foundation for developing advanced flotation techniques for coal gasification fine slag. It provides some theoretical guidance and technical support for realizing high-value utilization of coal gasification slag with specific environmental and resource benefits.

Effect of microstructure in mesoporous adsorbents on the adsorption of low concentrations of VOCs: An experimental and simulation study

This study evaluated the adsorption of five volatile organic compounds (VOCs) on Opoka, precipitated silica, and palygorskite, to elucidate the effect of their pore size on VOCs adsorption. The adsorption capacity of these adsorbents is not only highly correlated with their surface area and pore volume, but also notably improved by the presence of micropores. The variation in adsorption capacity for different VOCs was primarily influenced by their boiling point and polarity. Palygorskite, which had the smallest total pore volume (0.357 cm3/g) but the largest micropore volume (0.043 cm3/g) among the three adsorbents, exhibited the highest adsorption capacity for all tested VOCs. Additionally, the study constructed slit pore models of palygorskite with micropores (0.5 and 1.5 nm) and mesopores (3.0 and 6.0 nm), calculated and discussed the heat of adsorption, concentration distribution, and interaction energy of VOCs adsorbed on different pore models. The results revealed that the adsorption heat, concentration distribution, total interaction energy, and van der Waals energy decrease with increasing pore size. The concentration of VOCs in 0.5 nm pore was nearly three times that in 6.0 nm pore. This work can also provide guidance for further research on using adsorbents with mixed microporous and mesoporous structures to control VOCs.