Undoped polyaniline-modified sawdust as an adsorbent for lead removal

Abstract

Heavy metal ion adsorption employing abundant natural and agricultural wastes appears to be promising. Biodegradable sawdust is promoted as a green and sustainable alternative. In this work, potential application of sawdust has been explored for uptake of lead ions from contaminated water. Specifically, undoped polyaniline, a highly conductive polymer, was added to sawdust to improve its uptake capacity. Highest lead uptake capacity of 218 mg/g was observed at 318 K. Different surface-based characterizations for this material were performed. Morphology of prepared sawdust revealed a one-dimensional flake-like structure having a porous nature. FTIR and XRD analysis inferred successful incorporation of polyaniline into sawdust. In addition, XPS analysis revealed the importance of polyaniline chains during electrostatic adsorption of lead ions. At an adsorbent dosage of 1 g/l, optimal equilibrium conditions were reached. In accordance with Langmuir isotherm analysis, lead ion uptake was mainly driven by monolayer adsorption. As-prepared adsorbent was subjected to batch studies, where, effects of pH and interfering ions were carried out. Regeneration was also studied for four cycles.