Department of Mechanical Engineering and Yuan Ze Fuel Cell Center, Yuan Ze University, 135 Yuan-Tung Rd., Chung-Li, Taoyuan 32003, Taiwan.
J Hazard Mater. 2010 Jun 15;178(1-3):729-38. doi: 10.1016/j.jhazmat.2010.02.003. Epub 2010 Feb 4.
The adsorption of sulfur hexafluoride (SF(6)) on multi-walled carbon nanotubes (MWNTs) was investigated. The properties of MWNTs were characterized and the adsorption capacities of SF(6) on MWNTs at different concentrations and temperatures were collected. H(2)SO(4)/H(2)O(2) oxidation or KOH activation of MWNTs has effectively introduced the surface oxides and modified the microstructure without destruction of their graphitic crystalline structure. The MWNTs, especially the modified samples, are expected to be promising adsorbents for SF(6) removals from air. The saturated capacities of SF(6) with a concentration of 518 ppmv on the MWNTs ranged from 278 to 497 mg/g at 25 degrees C. The Toth equation has been reported to fit the adsorption data better than the Freundlich or Langmuir equation. The pi-pi dispersion interaction followed by the multi-layer adsorption and the electron donor-acceptor interaction were proposed to be the major adsorption mechanisms, depending on the adsorption temperature. The isosteric heat of adsorption, ranging from 51 to 124 kJ/mol with a loading of 30-300 mg/g, decreased with increasing SF(6) loading, reflecting the energetic heterogeneity of the MWNTs. These results suggest that the adsorption of SF(6) on MWNTs could be associated with binding to defect sites.
研究了六氟化硫（SF(6)）在多壁碳纳米管（MWNTs）上的吸附。对 MWNTs 的性质进行了表征，并收集了 SF(6)在不同浓度和温度下在 MWNTs 上的吸附容量。H(2)SO(4)/H(2)O(2)氧化或 KOH 活化的 MWNTs 有效地引入了表面氧化物并改变了微观结构，而不会破坏其石墨结晶结构。MWNTs，尤其是经过改性的样品，有望成为从空气中去除 SF(6)的有前途的吸附剂。在 25°C 下，浓度为 518 ppmv 的 SF(6)在 MWNTs 上的饱和容量范围为 278 至 497 mg/g。据报道，Toth 方程比 Freundlich 或 Langmuir 方程更能拟合吸附数据。根据吸附温度，提出了π-π色散相互作用，随后是多层吸附和电子供体-受体相互作用，作为主要的吸附机制。吸附热，在 30-300 mg/g 的负载范围内，从 51 到 124 kJ/mol，随着 SF(6)负载的增加而降低，反映了 MWNTs 的能量异质性。这些结果表明，SF(6)在 MWNTs 上的吸附可能与结合到缺陷位有关。
