Microwave plasma enhanced reduction of SO2 to sulfur with carbon

The emission of SO2 from industrial flue gas contributes to a large part of atmospheric pollution. With the more stringent regulations for SO2 emission, more efficient technologies for SO2 removal have to be developed. In the present work, we for the first time employed microwave plasma to reduce SO2 with three carbons (activated carbon, charcoal, and coke). At a microwave power of 110 W, SO2 can be completely reduced to sulfur by the activated carbon. The reactivity of the three carbons followed the order of activated carbon > charcoal > coke, which was consistent with that under conventional heating. However, much lower temperatures were required to obtain the same percentage conversion of SO2 under microwave plasma than that under conventional heating. Furthermore, in the presence of O-2 in the feed gas, SO2 can also be efficiently reduced with carbons under the microwave plasma.