Hydrophobic Treatment of Coconut Shell by Acetylation: Kinetics and Thermodynamic Studies.

Chemical modification of coconut shell using acetic anhydride has been investigated. Batch mode experiments were carried out to study the effects of time, temperature and catalyst on extent of acetylation. The kinetic data obtained at different temperatures were analysed with pseudo first-order, second-order and intra-particle diffusion model. The experimental data fitted very well the pseudo first-order kinetic model. Thermodynamic models used enabled the evaluation of activation energy, heat of acetylation, critical temperature, critical degree of acetylation, heat capacity, entropy changes, Gibbs free energy and showed that under standard conditions that the acetylation of coconut shell occurs spontaneously. Chemical characterization by FTIR, X-ray diffraction (XRD) and Scanning electron microscope (SEM) showed clear evidence of acetylation. Swellability studies showed that the raw coconut shell had its swelling capacity reduced after treatment indicating a considerable increase in hydrophobicity, and thereby enhancing its potentials for use in oil spill remediation.