The mercury sorbent was prepared from raw rice husk char impregnated with 10 g·L-1 NH4Br solution. The physical-chemical characteristics of sorbents before and after modification were analyzed by surface area and porosity analyzer

scanning electron microscopy and X-ray energy dispersive spectroscope. The mercury oxidation and adsorption performance of the modified sorbents were investigated by analyzing mercury speciation (Hg0 and Hg2+) in the outlet of a fixed bed reactor system in N2 and N2+6.4%(vol)O2 atmosphere at different temperatures. No obvious Hg2+ was detected in N2

N2+6.4%(vol)O2 atmosphere at 50℃ and N2 atmosphere at 150℃. Modified rice husk char exhibited a mercury removal efficiency of 90% at 50℃ and 150℃. Total mercury (HgT) removal efficiency of 98.2% was obtained in N2+6.4%(vol)O2 atmosphere at 150℃

82.2% Hg0 was bound to the sorbent surface

the remaining was removed in the form of Hg2+ which was generated from heterogeneous oxidation by O2 at the surface of sorbent. The heterogeneous reaction between O2 and gaseous Hg0 at relatively elevated adsorption temperature promotes the Hg0 oxidation efficiency of modified sorbents. Desorption performance of adsorbed mercury was identified by analyzing HgT at the outlet of temperature programmed tube furnace. Peak mercury desorption temperature of 300℃ manifested that mercury was bound to sorbent surface in the form of Hg-Br compound most likely. Mercury desorption temperature between 220℃ and 350℃ suggested high thermal stability of adsorbed mercury. Mercury balance ratio of 100.14%—118.62% verified the accuracy of experimental results in this study.