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

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.