A Study of the Optical and Structural Properties of SnO2 Nanoparticles Synthesized with Tilia cordata Applied in Methylene Blue Degradation

Water contamination is one of the most worrisome problems in the world. Industrial dyes are discharged without previous treatment, promoting water pollution and affecting the environment. In this paper, semiconductor SnO2 nanoparticles (NPs) were synthesized using Tilia cordata extract, as a reducing agent, at different concentrations, 1%, 2%, and 4% (weight/volume; w/v). These NPs were used as photocatalysts characterize an alternative for degrading wastewater compounds. Nanoparticle symmetry is an important factor for understanding the properties that provide tools for further treatments. Additionally, the structural, morphological, and optical properties of the green-synthesized SnO2 NPs were studied. Fourier transform infrared spectroscopy (FTIR) showed the characteristic absorption band of Sn-O centered at 609 cm(-1). Meanwhile, X-ray diffraction (XRD) confirmed a tetragonal rutile-type crystalline phase without impurities whose crystallite size increased from 15.96 nm and 16.38 nm to 21.51 nm for SnO2-1%, SnO2-2%, and SnO2-4%, respectively, as extract concentration was increased. NPs with a quasi-spherical morphology with agglomerations were observed through scanning electron microscopy (SEM). On the other hand, the bandgap remained at similar to 3.6 eV throughout all samples, even at variable extract concentrations. The NPs yielded great photocatalytic activity capable of degrading methylene blue (MB) dye under ultraviolet radiation and solar radiation, achieving degradation percentages of 90% and 83% of MB under UV and solar radiation at 90 and 180 min, respectively.