نبذة مختصرة : Dissertação de Mestrado em Engenharia Química apresentada à Faculdade de Ciências e Tecnologia ; Plastic production has been growing to meet consumers’ needs in several applications. However, plastics constitutes one of the biggest contributors to environmental pollution, being generated millions of plastics waste annually worldwide. Microplastics (MPs), mostly resulting from plastics degradation, persist in the environment for long periods and cause serious problems to aquatic organisms, constituting a toxic source to them.In order to respond to this concern, several studies have been developed to reduce the MPs contamination; in wastewater treatment plants (WWTP), the larger plastics are trapped in the primary treatment step, but the smaller ones continue in the effluent and can reach the water streams. One approach recently highlighted to overcome this limitation of WWTP to remove MPs is the use of flocculants to increase the size of MPs particles and allow their removal. The sustainability issue has been increasing of concern, so it is important not only to develop efficient flocculants but also to develop those with less environmental impact. In this way, since a previous work assessed the ecotoxicity of cellulose-based polymers, cationic and hydrophobically modified, in three different key freshwater species, the present work has theaim of assessing the ecotoxicity of these modified polymers when combined with two MPs: polyethylene (PE) and polyethylene terephthalate (PET).Three cationically modified cellulose-based polymers (CDAC), with varying degrees of substitution (DS +1.8, DS +1 and DS +0.3), and one cationic and hydrophobically modified cellulose-based polymer (HCDAC) were used combined with PE and PET MPs. Three key freshwater species, representative of three trophic levels, were used to assess the toxicity of thepolymer/MPs complexes: Raphidocelis subcapitata, as producer, Brachionus calyciflorus, as primary consumer, and Danio rerio, as secondary consumer. Before the assays were performed with ...
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