Estudis d'estabilitat i absorció en microplàstics de nanopartícules metàl·liques presents en aigües naturals. Estudis previs a l'ús de tractaments terciaris basats en sistemes naturals

Abstract

In the last years, the nanotechnology importance has grown considerably due to the unique properties it offers. Among the different existing nanomaterials, nanoparticles (NPs) in particular show applications in sectors like medicine, chemistry, electronics and energy storage amongst others. The increased in the use of nanoparticles worldwide implies an increase in their accumulation in the environment, including soils and waters. On the other hand, microplastics (MPs) have also increased their presence in the environment and, unfortunately, have become part of the diet of some marine animals and birds. Therefore, it is essential to properly treat water in order to improve the health of humans, animals, plants and ecosystems, avoiding excessive accumulation of nanoparticles and microplastics. For this reason, the possibility of using Daphnia magna, a planktonic crustacean with filtration capacity, as a tertiary treatment for wastewater containing nanoparticles, microplastics, or both, is being studied. To carry out these studies, the behaviour of NPs and MPs and their interactions with each other must first be evaluated to draw useful conclusions for the studies with Daphnia. Spectroscopic techniques have been used to measure the size and concentration of nanoparticles in the facilities of the Technical Research Services of the University of Girona. This project has worked with silver nanoparticles (AgNP) and titanium dioxide nanoparticles (TiO2NP), as well as polyethylene microplastics. The conducted experiments focused on stability studies of nanoparticles in containers made of different materials, aiming to find suitable conditions to prevent aggregation or adhesion to the walls. The absorption of NPs and their corresponding metal ions on the surface of microplastics was also analysed. Additionally, the composition of the MPs after contact with NPs have been examined to determine if they are present on their surface