Characterizing the adsorption behaviors of various adsorbates on activated carbons via the multi-layer theory

摘要

Wang and Hwang's multi-layer adsorption model provides a deep insight into the adsorption characteristics of various adsorbates involving alkanes, hydrogen sulfide and carbon monoxide on activated carbons. The adsorption parameters of the activated carbons correlated with the adsorbing ability of activated carbon, such as the saturated adsorption capacity, equilibrium constants, isosteric heat and energy heterogeneity, are obtained. The results show that the thermal expansion coefficient and the equilibrium constant for the first adsorption layer increases with carbon number but the saturated adsorption capacity and the energy heterogeneity decrease with carbon number in the alkane system adsorbed on the fiber activated carton. The energy heterogeneity of the first adsorption layer for the polar adsorbate is less than that for the non-polar adsorbate on the PCB activated carbon. But the reverse is true for the outer-layer adsorption. The polar adsorbate is more easily adsorbed on the PCB activated carbon than the non-polar adsorbate. It is found that the interaction between the polar ad-molecules is stronger than that for the non-polar ones, and the adsorption for polar adsorbate more easily tends to a multi-layer adsorption than that for the non-polar adsorbate on the PCB activated carbon. [References: 11]