A novel sulfonated waste polystyrene / iron oxide nanoparticles composite: Green synthesis, characterization and applications

Abstract A composite of sulfonated waste expanded polystyrene (SWPS) and iron(II) oxide nanoparticles (FeO-NPs) was created through sulfonation of the polymer followed by synthesis of the nanoparticles by extracts of green tea leaves ( Camellia sinensis ). The SWPS was characterized by Fourier Transform Infrared spectroscopy (FT-IR), while the degree of sulfonation (DS) was determined through elemental analysis. The bioreduction of the nanoparticles was monitored in the solutions by UV–vis spectroscopy. The FeO-NPs + SWPS composite was characterized using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Moreover, FeO-NPs + SWPS composites were used to degrade the organic pollutant indigo carmine dye. The results show the degree of sulfonation of the composite is 23.5% and its ion exchange capacity is 1.2 meq g −1 . TEM analysis revealed that the FeO-NPs are predominantly quasi-spherical with average diameters of 25 nm. The FeO-NPs + SWPS composite achieved 86.7% destruction of indigo carmine dye in a 100 mg/L solution with 60 min of contact time at an initial pH of 3.2 and a 6 g/L catalyst dose.