CHARACTERIZATION OF ROCKROSE WOOD, CHAR AND ACTIVATED CARBON

The starting rockrose (Cistus ladaniferus L.), as well as charred and activated products prepared by heat treatment conducted under different conditions, were characterized in terms of composition, calorific value, texture and surface chemistry. Techniques used were thermogravimetric analysis, gas adsorption, mercury porosimetry, density measurements, scanning electron microscopy and FT-IR. The rockrose composition and calorific value were similar to other woods. Rockrose chars were prepared by heat treatment of the material over the temperature range 200-1000-degrees-C. The production of charcoal occurred at 400-degrees-C. Above 600-degrees-C the microporous structure of the chars became partially closed. Activated carbons were prepared by gasification (burnoff = 40%) of a carbonized product (carbonization temperature = 600-degrees-C) in air at 600-degrees-C and in CO2 and steam at 750-degrees-C. Significant differences in properties of the activated carbons were noted depending on the activating agent. Activated carbon produced in steam possessed better textural characteristics, in particular the development of mesoporosity was observed. The presence of surface oxygen groups containing C-O bonds, which may be formed from C=C bonds, was greater with air and steam than with CO2.