INFLUENCE OF PYROLYSIS TEMPERATURE ON THE ADSORPTIVE PROPERTIES OF ADSORBENTS PRODUCED FROM NOVOLAC AND BIOMASS

Mixtures of novolac resin and olive stone biomass are cured and pyroly zed at different temperatures to yield carbonaceous adsorbents. The we ight losses and the shrinkages taking place in the carbonization proce ss increase up to ca. 600 degrees C. The pyrolysis residues are invest igated with respect to their ability to adsorb toluene and cyclohexane from the vapor phase. Toluene is adsorbed on all adsorbents stronger than cyclohexane. The overall diffusion coefficient D of the adsorptio n process, the specific surface area, and the pore volume of the adsor bents are calculated. The adsorptive properties of the products are in terpreted taking into account the size and shape of the pores, the pol arity of the adsorbate, and the dispersion forces between adsorbent an d adsorbate. Slit-shaped pores, which are charac--- teristic of carbon molecular sieves, are likely to be present in the adsorbents which ar e pyrolyzed at higher temperatures and particularly at 1000 degrees C. This adsorbent shows the highest adsorption concerning the equilibriu m uptake, specific surface area, and pore volume of toluene and cycloh exane. However, the diffusion coefficient D is lower as more micropore s are present. (C) 1995 John Wiley and Sons, Inc.