Removal of sulfur dioxide from diesel exhaust gases by using dry desulfurization MnO2 filter

• MnO2 has over 0.2 gSO2/gMnO2 at 250 °C because of its large specific surface area and pore diameter.
• SO2 capture rate of this MnO2 particle is 1.2 × 103 μgSO2/(gMnO2 min) at 250 °C in a TG experiment.
• The SO2 capture over 99.5% was possible under the high space velocity condition of 5000 h−1 in MnO2.

The sulfur dioxide (SO2) contained in combustion exhaust gases from medium-scale facilities or ocean ships must be removed because of its role as an air pollutant. In this study, dry DeSOx filter of manganese oxide was used to capture SO2 with a simple sulfate reaction. The thermogravimetry (TG), experiments shows that the MnO2 sample having a specific surface area of 250 m2/g absorbed SO2 at about 0.45 g-SO2/g-MnO2 and 0.18 gSO2/gMnO2 at 450 °C and 250 °C, respectively. Desulfurization breakthrough experiment in a packed bed was employed to evaluate the possibility of deep desulfurization. As a result, the inlet SO2 is almost absorbed by the high specific surface area (HSSA) MnO2 bed, over 99.5% absorbed at space velocity of 0.5 × 104 h−1. Higher space velocity condition is targeting a more compact filter. Under the condition of 5.0 × 104 h−1, SO2 over 80% against inlet SO2 can be absorbed at early time. Conclusively, this material has a large enough SO2 absorption rate to capture significant amounts of SO2 gas.