Desenvolvimento de compósitos poliméricos como ferramentas para remoção e detecção de contaminantes orgânicos e metálicos da água

Abstract

Environmental remediation is a highly explored field in materials chemistry due to its importance in maintaining and rescuing the environment. In general, the combination of materials from different origins resulting in composites can be an interesting alternative to increase the performance of materials used for this purpose. This thesis explored the development of polymer composites, in their various forms, with improved properties for use in adsorption and sensing processes in aqueous media. The first contribution describes a polymer composite in the form of alginate/polypyrrole beads containing ZnFe2O4 nanoparticles. This composite was able to adsorb ibuprofen and paracetamol in appreciable quantities ((94% e 98%)). Due to the magnetic properties of ZnFe2O4, exposing the beads to an external magnetic field accelerated the kinetics of the adsorption process by around 15%, especially in the initial stages of adsorption. In the second part, a composite hydrogel containing biochar was manufactured using 3D printing. The use of the additive manufacturing technique allowed obtaining a composite with a more complex structure and high performance in the adsorption of methylene blue and ibuprofen in tap water. In the last contribution, the preparation of a composite of cross-linked β-cyclodextrin and carbon quantum dots is described. In addition to being applied in the adsorption of metallic species in aqueous media, this composite was also tested in the detection of metallic ions. This last characteristic was possible due to the fluorescence capacity that the composite presented due to the quantum dots. When interacting with metals, part of the fluorescence is lost, which can be used to detect them, even at low concentrations (ppm). In short, three new original polymer composites were developed and demonstrated to be efficient in the remediation of the aqueous environment with potential for use in practical conditions.