Capture of Trace Sulfur Gases from Binary Mixtures by Single-Walled Carbon Nanotube Arrays: A Molecular Simulation Study

详细信息    查看全文

• 作者：Wenjuan Wang ; Xuan Peng ; Dapeng Cao
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：June 1, 2011
• 年：2011
• 卷：45
• 期：11
• 页码：4832-4838
• 全文大小：958K
• 年卷期：v.45,no.11(June 1, 2011)
• ISSN：1520-5851

文摘

Adsorption of H₂S and SO₂ pure gases and their selective capture from the H₂S-CH₄, H₂S-CO₂, SO₂-N₂, and SO₂-CO₂ binary mixtures by the single-walled carbon nanotubes (SWNT) are investigated via using the grand canonical Monte Carlo (GCMC) method. It is found that the (20, 20) SWNT with larger diameter shows larger capacity for H₂S and SO₂ pure gases at T = 303 K, in which the uptakes reach 16.31 and 16.03 mmol/g, respectively. However, the (6,6) SWNT with small diameter exhibits the largest selectivity for binary mixtures containing trace sulfur gases at T = 303 K and P = 100 kPa. By investigating the effect of pore size on the separation of gas mixtures, we found that the optimized pore size is 0.81 nm for separation of H₂S-CH₄, H₂S-CO₂, and SO₂-N₂ binary mixtures, while it is 1.09 nm for the SO₂-CO₂ mixture. The effects of concentration and temperature on the selectivity of sulfide are also studied at the optimal pore size. It is found that the concentration (ppm) of sulfur components has little effect on selectivity of SWNTs for these binary mixtures. However, the selectivity decreases obviously with the increase of temperature. To improve the adsorption capacities, we further modify the surface of SWNTs with the functional groups. The selectivities of H₂S-CO₂ and SO₂-CO₂ mixtures are basically uninfluenced by the site density, while the increase of site density can improve the selectivity of H₂S-CH₄ mixture doubly. It is expected that this work could provide useful information for sulfur gas capture.