The role of sodium ions on the development of micro-sized pores in a high alpha-cellulose content woody biomass under ambient temperature

Woody biomass can be used as excellent raw materials for producing porous carbon materials such as active carbon or carbon molecular sieve, due to their excellent absorption ability. However, the formation mechanism and relations between graphite spherical grains and the development of micro-sized pores in the woody biomass during carbonization treatment are still unknown. In this study, a stepwise heat-treatment process was used to treat high alpha-cellulose biomass raw materials; several metal oxides were used as catalysts. From our study results, only the Na2O catalyst can cause the swelling of graphite spherical grains at 1500 °C, and leave holes sized 0.5–1 um on the cytoskeleton surface of carbon materials. Therefore, we can produce carbon materials with precision-controlled pore sizes by adding sodium oxide as the catalyst. We expected that this pretreatment of biomass could reduce the water vapor use amount by about 40%–60% in the production of activated carbon.