Adsorption Behavior of Fe(II) and Fe(III) Ions on Polyaniline Coated Sawdust: Batch and Fixed-Bed Studies

The aim of this study is to investigate the suitability of polyaniline coated-sawdust (SD/PAni) as an adsorbent for removal of Fe(II) and/or Fe(III) ions from aqueous solutions. The study includes batch and column tests. With column experiments, the influence of different experimental parameters on the adsorption behavior of Fe(II), Fe(III), and a mixture of both ions were studied and it was found that the optimum adsorption conditions for individual iron species and a mixture of them were similar. The optimal values for pH, flow rate, temperature, and adsorbent mesh size were found to be 4.0, 5.0 mL min-1, 25 °C, and 100 BSS mesh, respectively. Batch experiments were carried out to study the adsorption isotherms at ambient temperature. The results demonstrated that the adsorption isotherms for both iron species were best represented by the multilayer adsorption isotherm model. The adsorption-desorption stability performance of the adsorbent was evaluated and confirmed over 5 cycles.