A columnarbamboo/lignite material was prepared by briquetting a mixture of bamboo carbon and lignite. Activated carbons were Obtained by carbonizing the material at 500 degrees C for 30 min, followed by activation at 850 degrees C for 2 h using either steam or a gaseous mixture of ammonia in water with an ammonia concentration of 2.42 mass%. The ammonia-activated carbon was soaked in 21.91% ammonia water for 5 h and dried at 200 degrees C to modify its surface chemical properties. The pore structure and surface chemical states of the activated carbons were investigated by physical adsorption and XPS. Their desulfurization performance was evaluated in a simulated flue gas (SO2 0.1439%, O-2 8.02% and water vapor 10.11%) at 100 degrees C. Results show that the activated carbons produced with and without ammonia have similar pore size distributions in the range 1-2.5 nm. Sulfur adsorption capacity of the ammonia-activated one (106.1 mg/g) is significantly higher than those of the steam-activated one (69.8 mg/g). Surface modification of the ammonia-activated carbon further improves its sulfur adsorption capacity to 155.9 mg/g. The surfaces of the two kinds of activated carbons contain the same type of carbon groups. The ammonia-activated carbon and its surface modified derivative have similar nitrogen contents with a similar proportion of pyridine or nitrile groups (398.3-398.9 eV), amine, amide, imide and pyrrole class groups (400.2-400.8 eV).