Regeneration of Fe Modified Activated Carbon Treated by HNO3 for Flue Gas Desulfurization

The Fe/NAC for SO2 removal was prepared using incipient wetness impregnation. The fresh Fe/NAC exhibits good SO2 removal capacity and has a sulfur capacity of 231 mg/g, but in the SO2 removal process, the generated H2SO4 and Fe2(SO4)3 are deposited in a pore or on the surface of catalysts, causing the decrease of SBET and Vmicro to 399 m2/g and 0.112 cm3/g. The thermal regenerative sample at different temperatures has different SO2 removal capacity, and the sample first regenerated at 900 °C under N2 atmosphere achieves a sulfur capacity of 251 mg/g. Fe2(SO4)3 can be decomposed into Fe2O3 at 500 °C, but SBET and Vmicro recover to 733 m2/g and 0.243 cm3/g. Upon increase of regeneration temperatures from 700 to 900 °C, SO2 removal ability continues to increase, and Fe2O3 is reduced to Fe3O4 and Fe0, but small Fe2(SO4)3 is still detected. SBET and Vmicro of Fe/NAC900–1 increase to 802 m2/g and 0.286 cm3/g. When the thermal–regeneration cycles at 900 °C increase from 1 run to 3 run, SO2 removal ability shows ...