Selection of metal oxides in the preparation of rice husk ash (RHA)/CaO sorbent for simultaneous SO2 and NO removal

In this work, the removal of SO2 and NO from simulated flue gas from combustion process was investigated in a fixed-bed reactor using rice husk ash (RHA)/CaO-based sorbent. Various metal precursors were used in order to select the best metal impregnated over RHA/CaO sorbents. The results showed that RHA/CaO sorbents impregnated with CeO2 had the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO2 and NO. Infrared spectroscopic results indicated the formation of both sulfate (SO42-) and nitrate (NO3-) species due to the catalytic role played by CeO2. Apart from that, the catalytic activity of the RHA/CaO/CeO2 sorbent was found to be closely related to its physical properties (specific surface area, total pore volume and average pore diameter).