A comparative study of lead adsorption by activated Khaya Ivoresnsis and Pycanthus Angolensis sawdust

Experiments investigating lead adsorption by activated sawdust of different particle sizes of two timber species were conducted. The experimental data were fitted to isothermal and kinetic models. The optimum particle size was 0.85 mm for Khaya ivorensis and 1.18 mm for Pycanthus angolensis. The adsorption of lead by Khaya ivorensis and Pycanthus angolensis conformed to the Langmuir isotherm (0.83 ≤ R² ≤ 0.96 and 0.86 ≤ R² ≤ 0.98, respectively) and Freundlich isotherm (0.69 ≤ R² ≤ 0.97 and 0.94 ≤ R² ≤ 1.0, respectively). The adsorption process for the two species of timber was controlled by solute transport in the bulk liquid and intraparticle diffusion which was confirmed by good agreement of experimental data with pseudo-first-order kinetics (0.96 ≤ R² ≤ 1.0 for Khaya ivorensis and 0.9 ≤ R² ≤ 1.0 for Pycanthus angolensis) and the intraparticle diffusion model (0.9 ≤ R² ≤ 0.99 for Khaya ivorensis and 0.84 ≤ R² ≤ 0.97 for Pycanthus angolensis). A new kinetic model was developed with R² of 0.93 ≤ R² ≤ 0.99 for Khaya ivorensis and 0.88 ≤ R² ≤ 1.0 for Pycanthus angolensis.