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Activated carbons were prepared from olive stones either by the addition of zinc chloride (25-50 wt%) or by gasifying non-activated carbon with steam to burn-offs between 25% and 49%. The adsorption of nitrogen at 77 K was investigated and the adsorption data interpreted by the application of the Langmuir equation, the BET equation and the a S -method. The adsorption of carbon dioxide at 273 K was also followed and the data analyzed using the DR and DA equations. The adsorption of iodine from aqueous potassium iodide solution, and of Methylene Blue and p-nitrophenol from aqueous solutions at 298 K was also determined.Activation with zinc chloride produced physical and chemical changes which modified the thermal degradation process. Carbonization with zinc chloride restricted the formation of tars with the subsequent formation of solid carbon, the amount of zinc chloride incorporated in the precursor governing the porosity of the resulting carbon. The atmosphere under which activation of samples containing zinc chloride was undertaken was another factor in determining the texture of the carbon. Activation with steam to low burn-offs created new micropores by burning off the more reactive carbon atoms, but at high burn-offs erosion of the pore walls occurred leading to pore widening.Adsorption from solution was determined by the solubility of the solute in the solvent and by competition for this solute between the solvent and the adsorbent. The pore size of the carbon adsorbent and the molecular size of the adsorbate molecule were prominent factors in determining the extent of adsorption from solution.

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Activated carbons were prepared by carbonizing ground apricot stones impregnated with 20–60 wt% phosphoric acid at 300–600°C, in a limited air supply. Highly activated carbons with surface areas amounting to 1200 m2/g and pore radii of 8–10 Å were obtained when a mixture of apricot stones and 50 wt% phosphoric acid was carbonized at 450°C. Activation with phosphoric acid proceeds via the creation of pores of radii between 8 Å and 10 Å. The adsorption data for nitrogen at 77 K obey models based on surface coverage satisfactorily and also models based on pore volume filling. Although a slight upward deviation was shown in the Dubinin–Radushkevich (DR) plots, this model was still verified and allowed the determination of useful sorption parameters.