ACTIVATED CARBONS FROM A SUBBITUMINOUS COAL - PORE TEXTURE AND ELECTROKINETIC PROPERTIES

Activated carbons were prepared from an original and demineralized sub bituminous coal by a two-stage, pyrolysis and steam activation, treatm ent. The effect of demineralization, pyrolysis and steam activation pr ocesses on the evolution of the surface area, pore texture, and zeta p otential has been investigated. The pyrolysis step increased the micro porosity of the samples and decreased the negatively charged surface. The steam activation step increased the surface area and porosity as w ell as the surface basicity of the activated carbons. The electrokinet ic behaviour of the carbons was affected by the presence of KNO3, beca use they specifically adsorbed either K+ or NO3- ions depending on the sample. Finally, the demineralization process after the pyrolysis and steam activation was more effective than if the demineralization was carried out prior the two-stage treatment.