Carbon sequestration in unmineable coal seams has been proposed as one of the most attractive technologies to mitigate carbon dioxide (CO₂) emissions in which CO₂ is stored in the microporous structure of the coal matrix in an adsorbed state. The CO₂ adsorption process is hence considered one of the more effective methodologies in environmental sciences. Thus, adsorption isotherm measurements and modelling are key important scientific measures required in understanding the adsorption system, mechanism, and process optimization in coalbeds. In this paper, three renowned and reliable adsorption isotherm models were employed including Langmuir, Freundlich, and Temkin for pure CO₂ adsorption data, and the extended-Langmuir model for multicomponent, such as flue gas mixture-adsorption data as investigated in this research work. Also, significant thermodynamics properties including the standard enthalpy change (\(\Delta H^\circ\)), entropy change (\(\Delta S^\circ\)), and Gibbs free energy (\(\Delta G^\circ\)) were assessed using the van’t Hoff equation. The statistical evaluation of the goodness-of-fit was done using three (3) statistical data analysis methods including correlation coefficient (R²), standard deviation (σ), and standard error (SE). The Langmuir isotherm model accurately represent the pure CO₂ adsorption on the coals than Freundlich and Temkin. The extended Langmuir gives best experimental data fit for the flue gas. The thermodynamic evaluations revealed that CO₂ adsorption on the South African coals is feasible, spontaneous, and exothermic; and the adsorption mechanism is a combined physical and chemical interaction between the adsorbate and the adsorbent.

已提出在不可开采的煤层中封存碳作为减少二氧化碳（CO ₂）排放的最有吸引力的技术之一，其中CO ₂以吸附状态储存在煤基质的微孔结构中。因此，CO ₂吸附过程被认为是环境科学中更有效的方法之一。因此，吸附等温线测量和建模是理解煤层吸附系统、机理和工艺优化所需的关键重要科学措施。在本文中，采用了三种著名且可靠的吸附等温线模型，包括 Langmuir、Freundlich 和 Temkin，用于纯 CO ₂吸附数据，以及多组分的扩展朗缪尔模型，例如本研究工作中研究的烟气混合物吸附数据。此外，重要的热力学性质包括标准焓变（\(\Delta H^\circ\)）、熵变（\(\Delta S^\circ\)）和吉布斯自由能（\(\Delta G^\ circ\) ) 使用 van't Hoff 方程进行评估。拟合优度的统计评估是使用三 (3) 种统计数据分析方法完成的，包括相关系数 ( R ² )、标准偏差 ( σ ) 和标准误差 (SE)。Langmuir 等温线模型准确地表示纯 CO ₂比 Freundlich 和 Temkin 对煤的吸附。扩展的 Langmuir 给出了适合烟气的最佳实验数据。热力学评估表明，CO ₂在南非煤上的吸附是可行的、自发的和放热的；吸附机理是吸附质与吸附剂之间的物理和化学相互作用。