Influência do microplástico de polietileno na adsorção de antibiótico em óxidos de ferro

Abstract

Antibiotics and microplastics are considered emerging pollutants and the terrestrial ecosystem is an important final destination for them. In this way, they may occur concomitantly in soils. The Fe oxides have the capacity to interact and adsorb organic pollutants, acting in their bioavailability. To this moment, the influence of microplastics in the adsorption behavior of antibiotics in iron oxides is not understood. In this work, the influence of the presence of polyethylene (PE) microplastic was assessed in the adsorption of ciprofloxacin (CIPRO), an antibiotic of the fluoroquinolone class, in synthetic iron oxides hematite (Hm) and ferrihydrite (Fh) under different pH conditions. The quantification of CIPRO concentrations was achieved by UV-vis spectroscopy. The matrix effect was tested and it was considered small (-2,88 and - 0,99%). The CIPRO adsorption revealed a gradual increase with the pH rise of pure ferrihydrite and pure PE. The order of adsorption capacity was Ferrihydrite > Hematite > Polyethylene (PE) microplastic, which matches the specific surface area of each adsorbent. The addition of microplastic in the CIPRO and iron oxides system predominantly caused the decrease of CIPRO adsorption when compared to the adsorption of pure adsorbents.