The Application of Tannic Acid-Coated Magnetite Nanoparticles for Recovery of Microplastics from the Water System

Abstract

The presence of microplastics (MPs) is rapidly increasing in the environment, posing a significant threat to public health and the ecosystem. To monitor the impact of MPs, it is crucial to have standardized detection methods and MPs remediation techniques. Therefore, this study aimed to use tannic acid-coated magnetite nanoparticles to recover MPs, specifically polystyrene (PS) and polyethylene terephthalate (PET), from water bodies. A facile method for MPs recovery was established using the synthesized tannic acid-coated magnetite (TA-Fe3O4) as an adsorbent. TA-Fe3O4 was synthesized using tannic acid, iron (II) sulfate heptahydrate, and iron (III) chloride hexahydrate through a one-pot co-precipitation method. The adsorbent material was then characterized using a scanning electron microscope coupled with an energy dispersive x-ray spectroscopy (SEM–EDS), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, zeta potential, and N2 adsorption–desorption (BET) techniques, confirming its successful synthesis. The maximum adsorption efficiencies for PS and PET were 83% and 98%, respectively, under the experimental conditions of pH 6–7, a contact time of 300 min, an adsorbent dose of 2.5 g/L, and an initial MPs concentration of 1.25 g/L. The study also found that the presence of ions in wastewater had a significant effect on MP recovery. However, when it came to recovering MPs from the spent adsorbent, the maximum values were observed in an acidic medium at pH 3–4 under sonification conditions. In conclusion, TA-Fe3O4 showed potential and efficiency in the recovery of MPs in aqueous media. However, further investigation is needed to improve the method and explore its application for multi-MPs recovery performance.