Nanopartículas magnéticas e sua aplicação como suporte de catalisadores utilizados na fotodegradação de corantes : uma revisão da literatura

Abstract

It is estimated that there is a loss of 10-15% of the annual production of dyes to the environment through effluents, a very high number considering the world production of 800,000 tons per year. One of the environmental responsibilities of the Brazilian textile industry is the treatment of effluents used in the production process, sewage from the textile industry has been considered as the most pollutant in relation to composition and volume among industrial sectors, with dyes being a large part of the components of these effluents. The photocatalytic process has gained prominence for the treatment of industrial and domestic effluents, mainly with the use of nanotechnology to significantly increase the surface area, due to factors such as less use of chemical reagents for the degradation process, less generation of residues by the possibility of total mineralization of the treated residue and the possibility of using sunlight to supply energy for the reaction. In view of the environmental impacts caused by the presence of dyes in industrial effluents and the ability of nanocatalysts to degrade organic compounds, this work aims to conduct a literature search on the main magnetic supported nanostructured catalysts used as photocatalysts in the degradation of dyes. The main magnetic nanoparticles used in catalysis are magnetite (Fe3O4), maghemite (γ-Fe2O3) and ferrites (MFe2O4), where M can be Fe, Mn, Zn or Co. There are several methods for the production of these magnetic nanoparticles, such as ball mill grinding methods, sonochemical method, sol-gel, microemulsion, thermal decomposition nucleation, co precipitation and synthesis using natural products. Due to the benefits of using the photocatalysis process, the incorporation of nanotechnology and the use of magnetic supports, the photocatalysis procedure is optimized, also allowing the reuse of catalysts in multiple cycles.