Rahimi Mahshid, Singh Jayant K, Müller-Plathe Florian
Technische Universität Darmstadt, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany.
Phys Chem Chem Phys. 2016 Feb 7;18(5):4112-20. doi: 10.1039/c5cp06377a. Epub 2016 Jan 18.
The adsorption and separation behavior of SO2-CO2, SO2-N2 and CO2-N2 binary mixtures in bundles of aligned double-walled carbon nanotubes is investigated using the grand-canonical Monte Carlo (GCMC) method and ideal adsorbed solution theory. Simulations were performed at 303 K with nanotubes of 3 nm inner diameter and various intertube distances. The results showed that the packing with an intertube distance d = 0 has the highest selectivity for SO2-N2 and CO2-N2 binary mixtures. For the SO2-CO2 case, the optimum intertube distance for having the maximum selectivity depends on the applied pressure, so that at p < 0.8 bar d = 0 shows the highest selectivity and at 0.8 bar < p < 2.5 bar, the highest selectivity belongs to d = 0.5 nm. Ideal adsorbed solution theory cannot predict the adsorption of the binary systems containing SO2, especially when d = 0. As the intertube distance is increased, the ideal adsorbed solution theory based predictions become closer to those of GCMC simulations. Only in the case of CO2-N2, ideal adsorbed solution theory is everywhere in good agreement with simulations. In a ternary mixture of all three gases, the behavior of SO2 and CO2 remains similar to that in a SO2-CO2 binary mixture because of the weak interaction between N2 molecules and CNTs.
采用巨正则蒙特卡罗（GCMC）方法和理想吸附溶液理论，研究了SO₂-CO₂、SO₂-N₂和CO₂-N₂二元混合物在排列整齐的双壁碳纳米管束中的吸附和分离行为。模拟在303 K下进行，使用内径为3 nm且管间距不同的纳米管。结果表明，管间距d = 0的堆积方式对SO₂-N₂和CO₂-N₂二元混合物具有最高的选择性。对于SO₂-CO₂体系，具有最大选择性的最佳管间距取决于所施加的压力，因此在p < 0.8 bar时，d = 0表现出最高的选择性，而在0.8 bar < p < 2.5 bar时，最高选择性属于d = 0.5 nm。理想吸附溶液理论无法预测含SO₂的二元体系的吸附情况，尤其是当d = 0时。随着管间距的增加，基于理想吸附溶液理论的预测结果与GCMC模拟结果越来越接近。只有在CO₂-N₂体系中，理想吸附溶液理论在各处都与模拟结果吻合良好。在所有三种气体的三元混合物中，由于N₂分子与碳纳米管之间的相互作用较弱，SO₂和CO₂的行为与在SO₂-CO₂二元混合物中的行为相似。
