Removal of Polystyrene Nano-plastics from Contaminated Water by a Magnetic Graphene Oxide Adsorbent

Abstract

Nanoplastics (NPs) in aquatic environments have gained considerable consideration because of their persistent and adverse effects on the environment. Several methods have been studied for their efficient removal from water bodies. This study assessed the adsorption efficiency of magnetic graphene oxide in eliminating 80 nm sized polystyrene NPs (PSNPs). Initially, the adsorption potential of graphene oxide and magnetic nanoparticles were evaluated both separately and together through computational methods using Material Studio. The adsorption process was simulated under NPT (constant number of molecules, pressure, and temperature) conditions, The results indicated strong hydrogen bonding interactions between the adsorbent and the PSNPs. In the next phase, magnetic nanomaterials were synthesized by coating graphene oxide with iron oxide (Fe3O4) in the laboratory. The morphological properties of the adsorbent were studied through SEM, whereas the chemical nature was assessed using Energy Dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD). These analyses confirmed the successful synthesis of magnetic graphene oxide, demonstrating its ability to effectively remove PSNPs from aqueous solutions. Furthermore, the pH range between acidic and neutral conditions enhances the adsorption of PNPs, with removal efficiencies of PSNPs lie between 81% at pH 3 to 77% at pH 7. Further, studies on the adsorption mechanism, utilizing kinetic and isothermal models, revealed that electrostatic attractions are the main forces driving the adsorption process. Adsorptiondesorption experiments showed that the adsorbent has excellent reusability, sustaining high efficiency over four cycles. Our study highlights the potential of magnetic graphene oxide as a robust and reusable adsorbent for the mitigation of NP removal from waterbodies