An Improved Isothermal Adsorption Equation of Gaseous Molecules Under Low Pressure in Gas-Solid System

作者：Bian, Liujiao^*; Shi, Penghui

来源：Journal of Phase Equilibria and Diffusion, 2018, 39(2): 117-128.

DOI：10.1007/s11669-017-0613-0

• adsorption heat
• Freundlich adsorption model
• gas-solid system
• isothermal adsorption equation
• Langmuir adsorption model

Based on the thermodynamic equilibrium between gas phase and adsorbed phase in gas-solid system, an isothermal adsorption equation (Eq 12) was presented to illustrate the dependence of the amount of gas molecules adsorbed on the adsorbents upon the gaseous pressure under low pressure. Under different conditions of surface properties, this equation can be simplified to Eqs 15 and 33, the simplified equations are formally in agreement with the famous Langmuir and Freundlich adsorption equations, respectively. From this equation, it can be theoretically proved that when the surface of adsorbents is highly heterogeneous, the adsorption data can be described only by Eq 33; while when the surface of adsorbents is homogeneous or approximately homogeneous, the adsorption data can be described simultaneously by Eqs 33 and 15. In addition, it is further inferred that Eq 15 can be used to describe the adsorption data in either exothermic or endothermic process, while the Eq 33 can be used to describe the adsorption data only in exothermic process. The equation was tested with many adsorption data in literature, the results showed this equation can be used to describe the adsorption data well under low pressure and the theoretical predictions were consistent with the practical application.

• 出版日期2018-4
• 单位西北大学