Biomass is devolatilized to produce both a combustible fuel (syngas) and activated carbon. The activated carbon is used as an adsorbent to capture a contaminant, such as mercury, and stored in a landfill, is impregnated with components with inherent fertilizer properties and tilled into arable land, is used along with coal in an electric power generation facility, or is used to remove mercury or other heavy metals from the flue gas of a coal fired power generation station prior to being stored so as to sequester both carbon and the heavy metal. Thus, both the carbon and the adsorbed mercury or other chemical are sequestered.