化学学报 ›› 1987, Vol. 45 ›› Issue (4): 322-327. 上一篇    下一篇

研究论文

理想吸附混合物在二位不均匀模型表面上的活度系数

顾惕人   

  1. 北京大学物理化学研究所
  • 发布日期:1987-04-15

Surface activity coefficients of ideal mixtures adsorbed on two-site heterogeneous surface model

GU TIREN   

  • Published:1987-04-15

对理想吸附混合物在二位不均匀模型表面上的表面活度系数进行了系统的计算.结果表明,表面不均匀性将导致理想吸附混合物表观地呈现与Raoult定律的负偏差(表面活度系数小于1).但在与固-液界面相似的情况,即总覆盖度接近于1的条件下,算得的表面活度系数-吸附相成分关系皆呈现几乎完全对称的形状.因此实验测得的表面活度系数-吸附相成分关系所呈现的不对称性,可能是不同分子之间非理想的相互作用所引起,而不是表面不均匀所造成的.

关键词: 计算, 表面化学, 活度, 表面性质, 表面张力, 固体-液体混合物, 吸附度

The surface activity coefficients of ideal mixtures adsorbed on the heterogeneous surfaces were calculated systematically by using the 2 site heterogeneous surface model. The apparent surface activity coefficients are always <1; i.e., there are neg. deviations from Raoult's law and the results always found experimental On the other hand, the calculated surface activity coefficient curves are always nearly sym. if the total surface coverage is ~1 (>99% of the saturation value of unity). This situation is comparable with those of adsorption from solns. Therefore, the asym. curves for the experimental measured surface activity coefficients are probably not due to the heterogeneity of the surface, but rather to nonidealities in the mol. interactions between the unlike components of the adsorbed mixture1

Key words: CALCULATION, SURFACE CHEMISTRY, ACTIVITY, SURFACE PROPERTY, SURFACE TENSION, SOLID-LIQUID MIXTURE, ADSORPTIVITY

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