Factors governing the formation of porosity in metal loaded cellulose during pyrolysis and the effects of pore structure on reactivity in O-2 and NO

A series of carbons have been made from cellulose that has been loaded with varying amounts of calcium, potassium and iron. Small angle X-ray scatteri ng showed that the calcium-loaded chars produced carbons with mass fractal properties whereas potassium loaded chars produce carbons with surface frac tal properties in the mesopore region. Calcium loaded chars were more micro porous than potassium loaded chars. Iron loaded cellulose produced a Small Angle X-Ray Scattering (SAXS) pattern with two linear regions. The high q-s cattering was characteristic of a highly microporous material. Differences in carbon properties were attributed to crosslinking reactions induced by t he metals during pyrolysis. The reactivity of the carbons in O-2 and NO was determined and the ratio of the reactivities, R(NO)/R(O-2) noted. It was f ound that the presence of calcium and potassium both decreased R(NO)/R(O-2) , but iron increased R(NO)/R(O-2) for a certain loading range. The latter w as attributed to the reduced catalytic activity of iron for O-2 gasificatio n and the pore structure of the iron loaded carbons. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.