Remoção de microplásticos de policloreto de vinila (PVC) por clarificação com cloreto férrico para tratamento de água de abastecimento

Abstract

With population growth and the consequent increase in the use of plastic polymers in everyday life, the presence of microplastics (MP) has been observed as emerging contaminants in atmospheric, lithospheric and hydrospheric ecosystems such as rivers, seas, aquifers and lakes, as well as in living organisms. In this context, the presence of PM in water supplies is the focus of studies and its removal in traditional water treatment processes is the subject of this study. The aim was therefore to carry out a literature review of water treatment techniques and their respective removal of PM and to evaluate the removal of polyvinyl chloride (PVC) by the water clarification process on a bench scale using the coagulant ferric chloride, using a coagulation diagram. The clarification tests and the construction of the diagram were carried out in the Jar-Test apparatus with the coagulation stages at 300 rpm for 1 minute and flocculation at 100, 80 and 60 rpm for 10, 5 and 5 minutes, respectively, followed by 20 minutes of settling. For this purpose, 40 mL of the coagulant FeCl3 were used at concentrations of 0, 10.67, 21.33, 32.00, 42.67 and 53.33 mg/L. After the tests, gravimetric analyses of PM and water characterization (pH) were carried out. The literature review published the average removals of each water treatment technique. The clarification process showed a maximum PVC removal capacity of 70%, at neutral pH with coagulant concentrations of 32,00 to 42,67 mg/L. From the regression obtained with the observed data, it is estimated that these are the ideal concentrations for maximum removal of PVC PM. In the coagulation diagram, the removal process occurred by the adsorption/neutralization mechanism and the sweeping mechanism with maximum efficiencies of 90% in both mechanisms.