Decomposition of H2O2 on activated carbon obtained from olive stones

Activated carbons were prepared from olive oil solid wastes by treatment in different schemes: impregnation with H3PO4 followed by pyrolysis at 300-70 0 degreesC, by steam pyrolysis at 600-700 degreesC, or by conventional stea m activation at 850 degreesC. Porosity characteristics were determined by a nalysis of nitrogen adsorption isotherms, and carbons of widely different p roperties and surface pH values were obtained. Decomposition of H2O2 in dil ute unbuffered solution was followed by measuring evolved oxygen volumetric ally. First-order kinetics was followed, and the catalytic rate coefficient s were evaluated. The carbons tested showed appreciable activity where evol ved oxygen attained approximate to 10% of the stoichiometric amount in I h. The degree of decomposition showed inverse dependence on surface area, por e volume and mean pore dimensions. The chemical nature of the surface, rath er than the porosity characteristics, was the principal factor in enhancing the disproportionation of H2O2 on the activated carbon surface. (C) 2001 S ociety of Chemical Industry.