Density Functional Theory Study of Steam Effect on SeO2 Capture by CaO Adsorbents

Emission of volatile and hazardous trace elements, including selenium emission from fossil fuel combustion, has become a major environmental concern. The CaO adsorbent has proved to be highly effective in SeO2 capture. Steam is an important component in flue gas, which has been fully confirmed to be able to promote the adsorption of CO2 using the CaO adsorbent. Because of the similar structure of SeO2 and CO2 molecules, the promotion effect provided by H2O for CO2 adsorption is expected to behave in a similar way to promote SeO2 adsorption by CaO. In this study, the promotion effect of steam on SeO2 adsorption was investigated and confirmed by density functional theory calculation. The superficial OH formed during the decomposition of H2O greatly promotes SeO2 adsorption.