Development of Recycled Expanded Polystyrene Nanofibers Modified by Chitosan for the Removal of Lead(II) from Water

Abstract

Water contamination by potentially toxic metals and the generation of polymeric wastes are major world concerns. Therefore, novel recycled expanded polystyrene nanofibers modified by chitosan were successfully developed by centrifugal spinning and applied as adsorbents on the removal of lead(II) from water. Expanded polystyrene was obtained from waste food packaging. Characterization of the nanofibers presented diameters of 806 nm and functional groups suitable for the adsorption of lead(II). Under the experimental conditions used, lead(II) adsorption was favored at pH 6, at a temperature of 303 K, presenting an adsorption capacity of 28.86 mg g−1 and a removal percentage of 61.19%. The pseudo-second-order model was the most suitable to describe the kinetic data. The equilibrium data could be fitted by the Aranovich–Donohue model. The maximum adsorption capacity under the experimental conditions used was 137.35 mg g−1. The thermodynamics parameters presented the adsorption as spontaneous, favorable, and endothermic. After four cycles of desorption and reuse, the nanofibers maintained 63.04% of their original adsorption capacity. The findings indicated that these recycled modified nanofibers present great potential as lead(II)- (as well as other similar metals) adsorbent, with significant environmental relevance due to the recycling of a waste polymer into a notable toxic metal adsorbent.