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Percorrer por autor "Ribeiro, Gabriel"

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  • Production and characterization of metal oxide nanoparticles and study of their incorporation into polymeric membranes
    Publication . Ribeiro, Gabriel; Barreiro, M.F.; Gomes, Helder; Sgorlon, Juliana; Gomes, Maria Carolina Sérgi
    Membrane technology is applied as a separation process in different process, such as gas separation, wastewater treatment, biodiesel purification, food and fermentation industry. This technology contributes to reduce water used and save energy in these processes. They can be defined as a physical barrier between two phases, which regulates the mass transport between them. The performance of this type of technology in purification processes depends on parameters such as permeability and selectivity with the material to be filtered. Membranes can be produced from different materials. This study aimed to produce polymeric membranes composed of polyvinylpyrrolidone (PVP) and polyethersulfone (PES) with and without the addition of metal oxide nanoparticles, such as zinc oxide and iron oxides. The membranes were synthesized using the phase inversion method, with different amounts of solvent, PVP and nanoparticles. Nanoparticles were synthesized by the co-precipitation method. The nanoparticles were characterized by techniques such as infrared spectrum (FTIR), thermogravimetric analysis (TGA) and laser diffraction (LS). Membranes were characterized by techniques such as water absorption, porosity, hydraulic permeability, thermogravimetric analysis and optical microscopy. With the incorporation of nanoparticles, it is intended to study whether they change important properties such as hydrophilicity, pore size and permeability, to prevent membrane pore blocking, a phenomenon known as fouling, which is responsible for the drop in membrane performance in processes of filtration. Through the analyses, the relationship between membrane permeability and water absorption, pore size and permeate flux of each of the different compositions studied was verified. The analyses carried out, allowed to verify that the properties of the membranes were modified when the nanoparticles were incorporated. Permeability analysis allowed to verify the behaviour of membranes when applied to a fluid pressure. In this study, distilled water was used and even so it was verified a reduction in the permeate flux, which is due to membrane compaction. However, the incorporation of nanoparticles and the variation in the amount of PVP were able to reduce the reduction in permeate flux.
    2021Dissertação de mestrado Acesso aberto Ver mais