Photocatalytic degradation of salicylic acid using Bi2S3/TiO2/carbon xerogel as catalyst

• Grant number: 20/14575-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2021
• End date: December 31, 2021
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Liana Alvares Rodrigues
• Grantee: Flávia Maria Fernandes
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

In this project, a route will be developed for the preparation of the Bi2S3/TiO2/Carbon xerogel ternary composite. The objective of this study is the creation of a composite that is sensitive to sunlight and has a high potential for both oxidation and reduction processes. The oxidation efficiency of the material will be tested in the degradation of salicylic acid in water, since a large part of the industrial effluents contain organic pollutants in solution. The choice of Bi2S3 and TiO2 as semiconductors was based on the valence and conduction bands of the materials, aiming at the formation of heterojunctions. This coupling may facilitate the effective separation of charge, reducing the possibility of recombination of the pair electron/vacancy generated by photoexcitation, increasing the efficiency of the photocatalytic process. However, this binary system has a relatively low surface area and recombination time, which substantially reduces its photocatalytic activity. These problems will be suppressed by the coupling of the Bi2S3/TiO2 with carbon xerogel (XC), as the xerogel presents excellent electrical conductivity, high surface area and porosity, and its porous structure is easily manipulated by modifications in the synthesis parameters. Tannin will be used instead of resorcinol as a precursor to the XC, which will reduce costs and environmental impacts, therefore adding value to the proposed technological innovation. The effects of the calcination temperature and the Bi2S3, TiO2 and XC contents on the morphological, optical, crystalline and photocatalytic properties of the materials will be evaluated. The materials will be characterized by diffuse reflectance spectroscopy, scanning electron microscopy, energy dispersive spectrometry, X-ray diffractometry, infrared spectroscopy and raman spectroscopy. The photocatalytic action of the material will be evaluated through the decomposition of salicylic acid in a batch reactor.