Adsorption of p-Nitrophenol on Inshas Incinerator Ash and on the Pyrolysis Residue of Animal Bones

Abstract

The potential use of (a) Inshas incinerator ash and (b) the pyrolysis residue of animal bones for removing p-nitrophenol (PNP) from aqueous solutions by adsorption has been investigated. The experimental results have been fitted to the Langmuir and Freundlich isotherms. The maximum adsorptive capacity of Inshas incinerator ash was found to be 116 mg/g and of the pyrolysis residue of animal bones to be 111 mg/g. The extent of removal was dependent on the pH and the temperature of the solution and on the type and mass of adsorbent employed. Desorption results indicated that not more than 15% of the adsorbed amounts of PNP are released from the loaded matrix into the bulk solution. The activation energy of the process was 5.67 kcal/mol which shows that the rate-controlling step is intraparticle diffusion.