Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (8): 1499-1503.doi: 10.3866/PKU.WHXB201506191


Surface Absorption of a Solution at Equilibrium

Fei-Wu. CHEN*(),Tian. LU,Zhao. WU   

  1. 1 Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
    2 Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Beijing 100083, P. R. China
  • Received:2015-03-04 Published:2015-08-12
  • Contact: Fei-Wu. CHEN
  • Supported by:
    the National Natural Science Foundation of China(21173020);the National Natural Science Foundation of China(21473008)


Surface adsorption of a solution is still a challenging problem in the thermodynamics of surfaces. In this work, a new thermodynamic state function is defined. The equilibrium condition of surface adsorption is that the differential of this state function is equal to zero. Based on this condition, we derived a new equation to describe surface adsorption at equilibrium. No hypothetical dividing surface is needed in this derivation. The new equation is quite different from the Gibbs adsorption equation. We also performed molecular dynamic simulations of aqueous sodium chloride solutions. The simulated results are in good agreement with our theoretical predictions.

Key words: Surface absorption, Equilibrium condition, Gibbs absorption equation, Thermodynamic state function, Solution


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