Preparation of activated carbons using poplar wood and bark as precursors

A. BAHRTON; G. I. HOROWITZ; E. G. CERRELLA; P. R. BONELLI; M. C. CASSANELLO; A. L. CUKIERMAN

Biomass: A Growth Opportunity in Green Energy and Value-Added Products

PERGAMON, ELSEVIER SCIENCE

Lugar: AMSTERDAM, HOLANDA; Año: 1999; p. 549 - 554

Residues from fast growing tree species used in the wood industry have been recognized as suitable precursors for preparing activated carbons (AC). In this work the feasibility of preparing AC from popular wood and its bark is experimentally examined. The method employed involves pyrolysis of the raw materials and subsequent activation of the resulting solids with CO2 under mild operating conditions which involve relatively low temperatures, from 873 to 1003 K, and reaction times up to 2 hours. The work determined the surface areas developed by the reaction and the characteristics of the solid products obtained at different conversion levels. The effect of activation conditions on AC features is examined by several techniques, including proximate and ultimate analyses, adsorption measurements employing N2 at 77 K and CO2  at 298 K as adsorbates and mercury porosimetry. Activation temperature has a marked influence on the adsorption capacity of the prepared AC, as inferred from the developed surface area. Results indicate that, for certain conditions, poplar wood can be a convenient precursor for preparation of AC with surface area figher than 700m2/g. Although AC prepared from poplar bark shows moderate surface areas, about 450 m2/g, the product obtained from this precursor is comparable to some others commercially available.