Obtenção de híbridos nanoestruturados para aplicações ambientais

Abstract

Hybrid materials are used in various applications due to the versatility of their compositions and syntheses. The nano scale of nanostructured hybrids facilitates dispersion and interactions of all components in the resulting hybrid material. Nanostructured hybrids may be applied to reduce negative environmental impacts, either by reducing waste during their produ ction or in the treatment of waste streams in production of other materials. The least negative environmental impact dictates that the hybrid material components be renewable, biodegradable and easily obtained. Such materials include biopolymers (cellulose and chitosan) and iron oxides (magnetite). The work for this thesis focused on developing hybrid materials for environmental applications. The first part is a bibliographic review on hybrid materials and their components and applications. The second part was divided into two papers. The first paper presented the development of a hybrid catalyst, composed of cellulose nanofibrils and magnetite to be used in Fenton-like reactions to degrade methylene blue, with the goal of treating textile effluents. The resulting hybrid catalyst retained activity in 10 consecutive cycles resulting in the total degradation of methylene blue solution (50 ppm) in 180 min. The second paper included the development of a thin film hybrid composed of cellulose nanofibrils, chitosan, magnetite and glycerol. The film was developed and tested for use in the production of capacitors in order to reduce the generation of toxic and nonrenewable e-waste. The resulting films had high dielectric constant at a 100 Hz frequency being able to be used as a dielectric in capacitors.