Pore-Size-Dependent Competitive CH4/CO2 Adsorption in HRTEM-Informed Short-Chain-Aromatic Organic-Matter Nanopores of Coal-Measure Shale
- 1College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
- 2Yi'an Lanyan Coal and Coalbed Methane Co-mining Technology Co., Ltd. Taiyuan 030006, China
- 3State Key Laboratory of Coal and CBM Co-Mining, Taiyuan 030006, China
Abstract
This study investigates pore-size-dependent competitive CH4/CO2 adsorption in coal-measure shale organic-matter nanopores represented by HRTEM-informed short-chain aromatic fragments. Coal-measure shale from the eastern Yushe Block of the Qinshui Basin was selected as the research object. High-resolution transmission electron microscopy was employed to quantitatively characterize the aromatic lamellar structure of the organic matter. Based on the obtained structural parameters, organic-matter pore models with pore sizes ranging from 1 to 4 nm were constructed. Grand canonical Monte Carlo simulations were subsequently performed to investigate the single-component and competitive adsorption behaviors of CH4 and CO2 at temperatures of 288–308 K and pressures of 0.25–8 MPa. The results indicate that the aromatic structure of the organic matter is characterized by short chains and a low degree of condensation, while the pore system is dominated by micropores and small mesopores. CH4 exhibited its highest nominal-pore-volume-normalized adsorption in the 1 nm pore, consistent with micropore filling, whereas CO2 reached its maximum in the nominal 2–3 nm pore models. These maxima may be influenced by model geometry and normalization because the probe-accessible pore volumes and surface areas after annealing were not quantified. In the smaller 1 and 2 nm pore models, CO2 exhibits a pronounced competitive adsorption advantage. As the pore size increases to 3–4 nm, the relative adsorption capacity of CH4 increases, thereby narrowing the adsorption difference between CH4 and CO2. These findings provide molecular-scale insights into pore-size-dependent equilibrium CH4/CO2 adsorption in experimentally informed organic-matter nanopores, offering a reference for future evaluations of CO2-enhanced gas recovery and storage in coal-measure shale.
Related
- An Affinity-Based Model for Competitive Surfactant Adsorption in Microemulsions
- Interfacial Mechanisms of Reactive Dye Adsorption on a Waste-Cotton Derived PVA/TiO2/Cellulose Biofilm: A Molecular Dynamics and Physics-Informed Predictive Framework
- Prediction of MOF Adsorption Isotherms and High-Throughput Screening Using a Physics-Informed Membranes Graph Neural Network
- Distance-dependent fluorescence modulation under continuous flow in an LTCC-integrated plasmonic competitive immunoassay
- Humidity-dependent formaldehyde adsorption on porous frameworks: A comparative study of MOFs, zeolites, and activated carbon
BibTeX
@article{long2026poresizedependent,
title = {{Pore-Size-Dependent Competitive CH4/CO2 Adsorption in HRTEM-Informed Short-Chain-Aromatic Organic-Matter Nanopores of Coal-Measure Shale}},
author = {Miao Long and Kunjie Li and Peng Xia and Yangyang Li and Jie Wu},
journal = {Molecules},
year = {2026},
month = nov,
doi = {10.3390/molecules31214038},
url = {https://www.mdpi.com/1420-3049/31/21/4038},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Pore-Size-Dependent Competitive CH4/CO2 Adsorption in HRTEM-Informed Short-Chain-Aromatic Organic-Matter Nanopores of Coal-Measure Shale
AU - Miao Long
AU - Kunjie Li
AU - Peng Xia
AU - Yangyang Li
AU - Jie Wu
PY - 2026
DA - 2026/11/09
JO - Molecules
DO - 10.3390/molecules31214038
UR - https://www.mdpi.com/1420-3049/31/21/4038
AB - This study investigates pore-size-dependent competitive CH4/CO2 adsorption in coal-measure shale organic-matter nanopores represented by HRTEM-informed short-chain aromatic fragments. Coal-measure shale from the eastern Yushe Block of the Qinshui Basin was selected as the research object. High-resolution transmission electron microscopy was employed to quantitatively characterize the aromatic lamellar structure of the organic matter. Based on the obtained structural parameters, organic-matter pore models with pore sizes ranging from 1 to 4 nm were constructed. Grand canonical Monte Carlo simulations were subsequently performed to investigate the single-component and competitive adsorption behaviors of CH4 and CO2 at temperatures of 288–308 K and pressures of 0.25–8 MPa. The results indicate that the aromatic structure of the organic matter is characterized by short chains and a low degree of condensation, while the pore system is dominated by micropores and small mesopores. CH4 exhibited its highest nominal-pore-volume-normalized adsorption in the 1 nm pore, consistent with micropore filling, whereas CO2 reached its maximum in the nominal 2–3 nm pore models. These maxima may be influenced by model geometry and normalization because the probe-accessible pore volumes and surface areas after annealing were not quantified. In the smaller 1 and 2 nm pore models, CO2 exhibits a pronounced competitive adsorption advantage. As the pore size increases to 3–4 nm, the relative adsorption capacity of CH4 increases, thereby narrowing the adsorption difference between CH4 and CO2. These findings provide molecular-scale insights into pore-size-dependent equilibrium CH4/CO2 adsorption in experimentally informed organic-matter nanopores, offering a reference for future evaluations of CO2-enhanced gas recovery and storage in coal-measure shale.
SN - 1420-3049
ER -