Activated carbon from some agricultural wastes under action of one-step steam pyrolysis

A one-step steam pyrolysis scheme was applied, in the range 600-700 degrees C, for the production of activated carbons from five lignocellulosic materials. The products were characterized by N-2/77 K adsorption for evaluating their surface area and pore volume. Simple carbonization at 700 C resulted in poor adsorbing carbons whereas porosity was remarkably enhanced under action of steam. Carbon precursors derived from date palm wastes (branches, leaves and date pits) proved feasible raw materials that produced good adsorbing carbons. Rice husks and barbecue charcoal developed porosity to a lower extent, due to the inherent ash content. All obtained carbons were essentially microporous due to the limited gasification. Steam is suggested to play a double role: it promotes both the release of volatiles with partial devolatalization, and enhances carbon formation.