Selection of metal oxides in the preparation of rice husk ash (RHA)/CaO sorbent for simultaneous SO_2 and NO removal

摘要

In this work, the removal of SO_2 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 CeO_2 had the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO_2 and NO. Infrared spectroscopic results indicated the formation of both sulfate (SO_4~(2-)) and nitrate (NO_3~-) species due to the catalytic role played by CeO_2. Apart from that, the catalytic activity of the RHA/CaO/CeO_2 sorbent was found to be closely related to its physical properties (specific surface area, total pore volume and average pore diameter).