Study On Preparation And Properties Of Pitch/Resin-based Activated Carbons

With the broadening of applications, the requirements for activated carbons havebeen improved gradually. Due to their high yield and low ash content, pitch based andphenolic resin based activated carbon have been attracted great attention. In thisresearch, by using coal tar pitch and phenolic resin as raw materials, we study the porestructure, mechanical and adsorption/desorption properties of pitch/resin basedgranules activated carbon and pitch/resin based activated carbon spheres, meanwhileinvestigated the electrochemical properties of pitch/resin based granule activatedcarbons by electric double-layer capacitor (EDLC). Besides, using the resole-typephenolic resin as a precursor, the millimetre-sized hollow carbon spheres wereprepared, the spherical technologies and activated conditions were investigated at thesame time.With the adding of naphthalene, the CP and PF were mixed by mechanical stirand then different proportions’ pitch/resin based granules activated carbon wereprepared and characterized. It were proved that the pitch/resin based granulesactivated carbons not only have pitch-based fast-adsorption/desorption properties, butalso embrace phenolic resin based high mechanical strength. Finally, the adsorptionamount of benzene and mechanical strength(CP/PF-A50/50) were reached472mg/gand6.5N respectively, but only took60min for desorption process.For preparing different proportion’s pitch/resin based activated carbon spheres,the suspension method has been used. Results shows that adding phenolic resin caneffectively improve the mechanical properties, widen the pore size distribution andmaintain the static benzene’s adsorption. Finally, the specific surface area andadsorption mount of CP/PF-S-A70/30reach1049m2/g and407mg/g, and themechanical strength get close to6.2N.Considering three granuled activated carbons as electrode materials,30wt%KOHas electrolyte, the electrochemical properties of those materials have been examinedby EDLCs. It turns out that the pitch based activated carbon exhibits excellentelectrochemical properties even though its low specific surface area and narrow poresize distribution, which was caused by their light pore structure and good connectionsbetween pores. The sample CP/PF-A50/50shows best electric double-layer properties, highest discharge specific capacitors (176F/g in current density at50mA/g) and smallinternal resistance.The resole-type phenolic resin has been chosen as raw materials for preparingmillimeter size hollow carbon spheres, which was made at ordinary pressure andwater bath condition, the best spherical and activation conditions have been exploredat the same time. Presumably the hollow spheres were caused by gathering a largesums of gas at the center of those spheres during the curing stage, and finally formedlargest hollow parts about300μm. The specific surface area and mechanical strengthof the hollow activated carbon spheres were reached1117m2/g and3.5N.