Effects of O2, SO2, H2O and CO2 on As2O3 adsorption by γ-Al2O3 based on DFT analysis

Abstract

In order to reveal the affecting mechanisms of flue gas on As2O3 adsorption by γ-Al2O3 and to enhance the adsorbing capacities of γ-Al2O3, the influences of flue gas constituents on As2O3 adsorption on γ-Al2O3(0 0 1) surface are investigated theoretically via density functional theory (DFT) in this study. The flue gas constituents selected include O2, H2O, SO2 and CO2. O2 converts nearly all of the physisorption structures into chemisorption structures except one structure, in which the O2 electron cloud does not interact with As2O3 molecule and therefore does not enhance the capture of As2O3. For the effects of H2O, SO2 and CO2, they behave almost the same as those of O2, but the physisorption structures vary from different constituents. The difference of stable adsorption structures of O2, H2O, SO2 and CO2 on the surface of γ-Al2O3 and their corresponding properties are the main reason for variance of positions and quantities of As2O3 physisorption structures. Results of this study could provide useful information for enhancing capture capacities of γ-Al2O3 under actual flue gas environments.