Fabrication of metal oxides-based adsorbents for SO2 capture with equimolar adsorption

A series of novel porous metal oxides (MO, M = Mg, Ca, Ba, Mn and Zn) adsorbents were synthesized through simple thermal treatment of the corresponding metal sulfite for the remotion of sulfur dioxide (SO 2 ). The obtained MO adsorbents were characterized by various techniques including scanning electron microscopy (SEM), thermal gravimetric analyzer (TGA), X-ray diffraction (XRD) and nitrogen adsorption studies. The results show that the SO 2 adsorption capacity of manganese oxide (MnO) is much higher than that of other MO. And due to its highly dispersed and large specific surface area, especially its well-developed pore structure, equimolar adsorption of SO 2 can be achieved for the first time among similar SO 2 adsorbents. In addition, different sources of MnO were explored and it was found that the MnO obtained from the decomposition of MnSO 3 had the highest SO 2 adsorption capacity. Adsorption kinetic studies show that the reaction between MnO and SO 2 conforms to the pseudo-second-order kinetic equation. Furthermore, it was found through seven-cycle experiments that the adsorption amount tended to stabilize in each of the following cycles, except for the first high temperature, which led to changes in the adsorbent and a decrease in cycling performance. This strategy has three advantages: one-step preparation at low temperatures, equimolar adsorption of SO 2 as well as good reusability and selectivity.