Estudo da capacidade fotodegradante de um compósito à base de TiO2 frente à bactéria Staphylococcus aureus

Abstract

The photodegradation or photocatalysis is a process of chemical degradation of matter through its decay into other elements molecularly simpler and harmless to humans and the environment. The process of when an inorganic semiconductor such as TiO2, is irradiated with ultraviolet light (wavelength 320 and 400 nm). The absorbed energy causes electronic excitation, causing electrons to peel off the outermost atomic orbitals of the semiconductor. These electrons detached in contact with the water and the O2 form oxidizing and reducing regions. Various tarnishes, organic and inorganic, in contact with these regions degrade electronics, dissociating into substances simpler and less offensive, like CO2 and H2O. Researchers from various countries studying composites based TiO2 coating surfaces as diverse as roads, window glazing and surgical scalpels. The photocatalysis is quite an interesting process, and environmentally, for inactivation of resistant nosocomial pathogens, such as fungi and bacteria, since it eliminates the use of chemical antiseptics. Studied in this work, the potential of photocatalysis of a composite base TiO2 encapsulated in epoxy resin, the degradation of Staphylococcus aureus and Escherichia coli, pathogens with high hospital infection, with a view to its application in construction, as floor coverings, walls, ceilings and furniture hospital facilities. The experiments were those with only manufacturing of tablets and lozenges epoxy resin with the composite at various concentrations of TiO2 and/or glass powder. The pads were contaminated with bacteria broth and exposed to sunlight and ambient light (solar indirect and fluorescent lamp) for certain periods. The pellets were washed in sterile saline. Part of this solution was transferred to plates containing Mueller Hinton Agar and incubated for 48 hours. After this time visual count was made of the number of CFUs in the board. The obtained results, mainly at ambient light, indicate the potential ability of the composite fotodegradante.