Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.
J Comput Chem. 2010 May;31(7):1443-9. doi: 10.1002/jcc.21428.
Adsorption of pure and mixtures of O(2) and N(2) on isolated single-walled carbon nanotube (SWCNT) have been investigated at the subcritical (77 K) and different supercritical (273, 293, and 313 K) temperatures for the pressure range between 1 and 31 MPa using (N,V,T) Monte Carlo simulation. Both O(2) and N(2) gravimetric storage capacity exhibit similar behaviors, gas adsorption is higher on outer surface of tube, compared to the inner surface. Results are consistent with the experimental adsorption measurements. All adsorption isotherms for pure and mixture of O(2) and N(2) are characterized by type I (Langmuir shape), indicating enhanced solid-fluid interactions. Comparative studies reveal that, under identical conditions, O(2) adsorption is higher than N(2) adsorption, due to the adsorbate structure. Excess amount of O(2) and N(2) adsorption reach to a maximum at each temperature and specified pressure which can be suggested an optimum pressure for O(2) and N(2) storage. In addition, adsorptions of O(2) and N(2) mixtures have been investigated in two different compositions: (i) an equimolar gas mixture and (ii) air composition. Also, selectivity of nanotube to adsorption of O(2) and N(2) gases has been calculated for air composition at ambient condition.
采用（N，V，T）蒙特卡罗模拟方法，在亚临界（77 K）和不同超临界（273、293 和 313 K）温度下，对纯 O(2)和 N(2)混合物以及孤立单壁碳纳米管（SWCNT）在 1 至 31 MPa 压力范围内的吸附进行了研究。O(2)和 N(2)的重量储存能力表现出相似的行为，与内表面相比，气体在管的外表面吸附更高。结果与实验吸附测量结果一致。纯 O(2)和 N(2)混合物的所有吸附等温线均表现为 I 型（朗缪尔形状），表明增强了固-液相互作用。比较研究表明，在相同条件下，O(2)的吸附高于 N(2)，这是由于吸附质结构所致。在每种温度和特定压力下，O(2)和 N(2)的过量吸附量达到最大值，这表明存在 O(2)和 N(2)储存的最佳压力。此外，还研究了两种不同组成的 O(2)和 N(2)混合物的吸附：（i）等摩尔气体混合物和（ii）空气组成。还在环境条件下计算了空气中 SWCNT 对 O(2)和 N(2)气体吸附的选择性。
