Green synthesis of photocatalytic TiO2/Ag nanoparticles for an efficient water remediation
Maria Cantarella, Marco Mangano, Massimo Zimbone, Gianfranco Sfuncia, Giuseppe Nicotra, Elena Maria Scalisi, Maria Violetta Brundo, Anna Lucia Pellegrino, Federico Giuffrida, V. Privitera, G. Impellizzeri
Abstract
This work reports a green method to produce efficient photocatalytic nanopowders. Titanium dioxide nanoparticles were easily synthetized by an extract of Thymus vulgaris, and then decorated with commercial silver nanoparticles. A detailed morphological, structural, and chemical characterization was performed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) adsorption–desorption of N2, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), Raman spectroscopy, transmission electron microscopy (TEM), and UV–Vis spectroscopy. The synthetized TiO2 nanoparticles showed a mean size of 10–15 nm, and had the anatase crystallographic phase. The photocatalytic efficiency of the TiO2 nanoparticles was demonstrated by the photo-degradation under UV-light irradiation of different pollutants in aqueous solution (methylene blue, diclofenac, and sodium dodecyl sulfate). TiO2 was coupled to Ag nanoparticles with different percentage in weight (from 0.25 to 3%), to investigate an eventual improvement of its photocatalytic efficiency. The best photocatalytic composite among the tested compositions was the one with the lowest Ag percentage (0.25%). Zebrafish embryo toxicity tests ruled out the toxicity of the synthetized nanoparticles. The present results offer a new, green, and easy method to prepare TiO2/Ag nanoparticles with high photocatalytic efficiency. The proposed materials are therefore promising for applications in photocatalysis, especially for wastewater remediation and reuse.