ADSORPTION OF ORGANICS ON SURFACE-TREATED ACTIVATED CARBON-FIBERS

Activated carbon fibre was subjected to various treatment procedures i n order to introduce or eliminate surface functional groups. Adsorptio n isotherms of organics with different polarity and acid-base characte r were determined to study the effect of surface chemistry on adsorpti on equilibrium. Surface chemistry was considerably changed without ser ious modification of the pore structure. Of the surface properties stu died, acidity showed the strongest correlation with adsorption equilib rium parameters. Adsorption of acidic and neutral organic substances d ecreases with surface acidity, while that of organic bases is consider ably enhanced by acidic groups. These groups were found to assist ther mal desorption of phanol, but the opposite was experienced in the case of water vapour. Competitive adsorption of water to the acidic sites is thought to be an important factor in the case of phenol and toluene adsorption. By the modification of surface chemistry, adsorption equi librium can be significantly improved for a wide variety of organics.