Preparation of activated carbon from cherry stones by chemical activation with ZnCl2

Cherry stones (CS), an industrial product generated abundantly in the Valle del Jerte (Cáceres province, Spain), were used as precursor in the preparation of activated carbon by chemical activation with ZnCl₂. The influence of process variables such as the carbonisation temperature and the ZnCl₂:CS ratio (impregnation ratio) on textural and chemical-surface properties of the products obtained was studied. Such products were characterised texturally by adsorption of N₂ at −196 °C, mercury porosimetry and density measurements. Information on the surface functional groups and structures of the carbons was provided by FT-IR spectroscopy. Activated carbon with a high development of surface area and porosity is prepared. When using the 4:1 impregnation ratio, the specific surface area (BET) of the resultant carbon is as high as 1971 m² g⁻¹. The effect of the increase in the impregnation ratio on the porous structure of activated carbon is stronger than that of the rise in the carbonisation temperature, whereas the opposite applies to the effect on the surface functional groups and structures.