Division of Energy Science∕Energy Engineering, Luleå University of Technology, 97187 Luleå, Sweden.
J Chem Phys. 2013 Nov 21;139(19):194705. doi: 10.1063/1.4825078.
The perturbed-chain statistical associating fluid theory (PC-SAFT) density functional theory developed in our previous work was extended to the description of inhomogeneous confined behavior in nanopores for mixtures. In the developed model, the modified fundamental measure theory and the weighted density approximation were used to represent the hard-sphere and dispersion free energy functionals, respectively, and the chain free energy functional from interfacial statistical associating fluid theory was used to account for the chain connectivity. The developed model was verified by comparing the model prediction with molecular simulation results, and the agreement reveals the reliability of the proposed model in representing the confined behaviors of chain mixtures in nanopores. The developed model was further used to predict the adsorption of methane-carbon dioxide mixtures on activated carbons, in which the parameters of methane and carbon dioxide were taken from the bulk PC-SAFT and those for solid surface were determined from the fitting to the pure-gas adsorption isotherms measured experimentally. The comparison of the model prediction with the available experimental data of mixed-gas adsorption isotherms shows that the model can reliably reproduce the confined behaviors of physically existing mixtures in nanopores.
我们之前的工作中开发了扰动链统计关联流体理论（PC-SAFT）密度泛函理论，将其扩展到混合物在纳米孔中不均匀受限行为的描述中。在开发的模型中，使用修正的基本测量理论和加权密度逼近分别表示硬球和无弥散自由能泛函，而界面统计关联流体理论的链自由能泛函用于描述链的连接性。通过将模型预测与分子模拟结果进行比较，验证了所开发模型的可靠性，表明该模型能够可靠地描述链混合物在纳米孔中的受限行为。进一步将所开发的模型用于预测甲烷-二氧化碳混合物在活性炭上的吸附，其中甲烷和二氧化碳的参数取自于体相 PC-SAFT，而固体表面的参数则通过拟合实验测量的纯气体吸附等温线来确定。将模型预测与混合气体吸附等温线的可用实验数据进行比较，表明该模型能够可靠地再现纳米孔中物理存在混合物的受限行为。
