Polymer strategies for water purification based on photocatalysis and molecular imprinting

Abstract

Nanomaterials show a better performance in environmental remediation than other conventional techniques because of their high surface area and their associated high reactivity. Nanostructured photocatalysts, especially TiO2, are widely studied for the treatment of contaminated water. They can indeed degrade organic pollutants and biological substances. In the first part of this thesis, the fundamentals of heterogeneous photocatalysis are described, with particular attention to the most important recent progresses in the field of nanostructured TiO2 for water treatment. The strategies used to improve its efficiency and to enhance its photocatalytic performance in the visible region are also illustrated. However, although the nanoscale catalysts show considerable improvement in terms of their physical and chemical properties, their size remains the main problem in a large-scale process because of the need of a post-treatment recovery, necessary to avoid their impact on the environment. For this reason, immobilization of photocatalysts on different substrates has been drawing a significant attention. Considering the various substrates, polymers seem to be very promising. Aim of this dissertation is to propose polymer nanocomposites for water treatment as potential alternative to the traditional methods. This thesis describes the synthesis, the characterization, and the photocatalytic and antibacterial properties under UV light of the PMMA/TiO2 nanocomposites. It reports also the combination of these nanocomposites with carbon nanotubes to increase their photocatalytic efficiency and the functionalization of the TiO2 surface with a porphyrin, in order to obtain active systems under visible light. In the last part, the use of molecularly imprinted polymers for wastewater treatment is discussed, showing preliminary results and future perspectives for the selective removal of emerging contaminants from water.