Fe catalysts supported on activated carbon untreated and treated by HNO3 were prepared by an ultra-sound- assisted incipient wetness method and characterized using N-2 adsorption/desorption, scanning electron microscopic (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Desulfurization activity was evaluated at a fixed bed reactor under a simulated flue gas. The results showed that the SO2 adsorption capacity of AC is 74 mg/g; when Fe is loaded on activated carbon untreated by HNO3, SO2 adsorption capacity increases to 244 mg/g; and when Fe is loaded on activated carbon treated by HNO3, SO2 adsorption capacity increases to 322 mg/g. Fe3O4 species exists on the surface of fresh catalysts, but after desulfurization, Fe-2(SO4)(3) is detected, indicating that Fe species could react with generated H2SO4 in the desulfurization process and may be the main reason of the deactivation of Fe catalysts supported on activated carbon. (C) 2014 Elsevier Ltd. All rights reserved.