Photoreduction of methylene blue using nanoporous composite materials

Abstract

Currently, the application of semiconductor materials for environmental remediation is very common, especially in the area of photocatalysis. However, these materials are very deficient because they do not have a large surface area. Therefore, it is important to generate advanced materials that combine their properties, as is the case of combining semiconductor materials with porous materials such as zeolites. In this work Titanium Oxide (TiO₂₎ nanoparticles were synthesized by the Sol-Gel method, later natural Zeolites (Erionite, Clinoptilolite and Mordenite) were added to obtain TitaniumOxide /Zeolites (TiO₂/Zeolites) compounds. Furthermore, these composite materials were subjected to heat treatment at 500 °C. Furthermore, the compounds were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Nitrogen (N₂) adsorption. Through XRD the different crystallographic structures were determined, being anatase (TiO₂), hexagonal (Erionite), monoclinic (Clinoptilolite) and orthorhombic (Mordenite). In addition, thanks to EDS, the elemental composition of each compound in relation to oxides was determined. While pore diameters and pore volume were determined in N₂ adsorption by various methods (eg, BJH (Barret, Joiner and Halenda)). As a result, the average pore size ranges from 0.8 to 5.08 nm and the pore volumes are 0.0007–0.2614 cm³/g. In addition, the surface area was determined by BET (Brunauer-Emmett-Teller) and Langmuir, where the sample with the lowest surface area was Titanium Oxide -Clinoptilolite (25-75) (TiO₂-Cli (25-75)) with a value of 14.1 m²/g and the one with the highest surface area was Titanium Oxide -Mordenite (25-75) (TiO₂-Mor (25-75)) with a value of 456 m²/g, which means that this sample is the one with the highest adsorption. Indicating with these results that the aggregation of porous materials for the formation of new compounds generates an increase in the surface area, thereby improving the material. Resulting in a wide range of applications such as: sensors, photocatalysis and irreversible adsorption of polluting gases among other applications.