Remoção de microplástico de efluente sintético através de adsorventes tratados com microemulsão

Abstract

The accumulation of plastics in the environment is increasingly becoming a global concern. As part of the UN report of October 2021 and other important organizations, the need to discuss the issue and seek solutions is noticeable. Among the impacts of these materials, microplastics (particles smaller than 5 mm) have been gaining prominence due to their often imperceptible presence in the environment. Because, in the oceans, they are mistaken for food by the fauna and are often not properly removed in wastewater treatment plants (WTP). Thus, this work researched ways to remove this contaminant from effluents. The way studied was through the use of adsorbents treated with surfactants using decantation to separate them. According to the structure of the surfactant and the adsorbents, these could have some interaction with the microplastics, making their extraction possible. The effluent used in the tests was obtained through the contamination of distilled water by synthetically acquired microplastics. However, they were compared through the FTIR spectrum with real microplastics, taken from the UFRN WTP. Among the surfactants analyzed, Tween 80 was chosen because, in addition to its low toxicity, it showed efficient interaction with plastic, proven via FTIR analysis. As for adsorbents, five were selected: bentonite, diatomite, coconut bagasse, sugarcane, and banana peel; all of them underwent microemulsion treatment. The quantification of microplastic was done through the FTIR spectrum of the peak area for different masses of microplastic that varied with absorbance. For adsorption tests, it was necessary to apply the NOAA method to separate microplastics from adsorbents after removal. As a result, banana peel bagasse presented the highest efficiency among untreated adsorbents: 70%. Among treated products, sugarcane bagasse had almost 80% of plastic removed. Therefore, it is observed that adsorption can be a viable method for the removal of microplastics in water.