Silver Nanocatalyst Supported on Waste-Based Polystyrene Foam for Thermal and Plasmonic Reduction of p-Nitrophenol

Disposal of plastics into the environment has been one of the major problems for the environment. The accumulation of polystyrene (PS) occurs in an accelerated way and, therefore, its reuse is challenging. Polystyrene nanocomposites impregnated with Ag nanoparticles (PS/AgNP) are generated from polystyrene residues and can be applied in the catalytic and plasmonic photo-catalytic reduction of phenolic compounds such as p-nitrophenol (PNP) to p-aminophenol (PAP). The AgNP were synthesized by a reverse micelle method resulting in nanoparticles with sizes in a range of 31.1-34.0 nm. The organocolloid was characterized by UV-Vis and dynamic light scattering (DLS), demonstrating the preparation of spherical nanoparticles. The preparation of the PS/AgNP, obtained using a thermally induced phase separation method (TIPS), was confirmed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), laser-induced breakdown spectroscopy (LIBS), and Fourier transform visible infrared spectroscopy (FTIR). Nanocomposites showed impressive performance in the catalytic and plasmonic photocatalytic reduction under blue light irradiation, reaching up to 98% conversion, being a promising material for wastewater treatment as well as other various environmental issues. We used blue light to observe the plasmonic effect of silver nanoparticles, and no previous reports of this composite for PNP reduction using blue light photocatalysis were found.