Abstract: Xylan, which is the main model compound of hemi-cellulose, was used to prepare hemi-cellulose-based granular activated carbon by phosphoric acid activation without addition any binder. The effects of impregnation ratio and carbonization/activation process on the adsorptive properties and porous texture of granular activated carbon were discussed.The result showed that specific surface area (BET),adsorption capability of methylene blue,intensity,total pore volume and mesopore volume of granular activated carbon increased with impregnation ratio increased. As the increasing of carbonization/activation temperature, the adsorption capability of iodine and methylene blue, BET, total pore volume and micropore volume of granular activated carbon were decreased,while the intensity was increased. The analysis of N₂ adsorption-desorption isotherms and pore size distribution showed that the microporous structure of granular activated carbon was developed, and the increasing of carbonization/activation temperature was not benefit for the development of porous structure.

Key words: phosphoric acid activation, hemi-cellulose, granular activated carbon, porous texture