Prediction of The Equilibrium Constant of An Adsorption Model by VOC Adsorption on Microporous Adsorbents

摘要

Activated carbon adsorption has widely been accepted as a promising technique to control volatile organic compounds (VOCs) pollution. However, the evaluation of adsorption capacity of activated carbon usually relies on the empirical or semi-empirical adsorption isotherms, which are seldom taken into account of the effects of physicochemical properties of the activated carbon and the adsorbate. Therefore, the objective of this study is to study the primary physicochemical properties in VOC adsorption processes, and to suggest a characteristic equation for predicting the adsorption equilibrium constant by statistical analyses. Eight types of activated carbons and ten VOCs are used in this study. The physicochemical properties of activated carbon are determined by proposed methods and the properties of VOC species are referred to the literature or estimated theoretically. In addition, the factor analysis and correspondence analysis are utilized to extract the major physicochemical properties in adsorption processes and the regression procedure is used to obtain the characteristic equation. The results show that the combination of factor analysis and correspondence analysis is a good way to characterize the VOC adsorption on activated carbon. The effect of surface physicochemical properties of the activated carbon is more important than that of its raw material. Specific surface area and pore volume of the activated carbon, and boiling point, dipole moment, solubility, critical parameters, vapor pressure, and heat of vaporization of VOC are found to be the most important properties on adsorption process. According to the adsorption capacities and the primary properties, a characteristic equation for predicting the adsorption equilibrium constant is suggested to impart the adsorption model more substantially.