High Temperature Adsorption of SO2 on Mixed Oxides Derived from CaAl Hydrotalcite-Like Compounds

Abstract

SO2 which is usually emitted at high temperature is one of the most important air pollutants. It is of great significance to develop high temperature SO2 adsorbent with high efficiency and low cost. In this work, a series of hydrotalcite-like compound-derived CaAlO and CaXAlO(X = Ce, Co) were prepared by coprecipitation and calcination method, and were employed as adsorbents for SO2 adsorption at high temperature (700 °C). The structure and surface properties of these adsorbents were characterized by XRD, Brunauer–Emmett–Teller (BET), Derivative thermogravimetric analysis (DTG) and CO2-TPD (temperature programmed desorption) measurement. Addition of a minor amount of Ce, Co (5 wt%) could significantly increase the number of weak alkalinity sites. CaO in CaCeAlO showed the best SO2 adsorption capacity of 1.34 g/g, which is two times higher than that of CaO in CaAlO (0.58 g/g).