Abstract
Microplastics (MPs), generated from the fragmentation of plastic waste, have become an emerging environmental concern because of their widespread occurrence, persistence, and potential ecological risks. In this study, a reusable Fe/Co-modified activated carbon (Fe/Co-AC) was prepared and evaluated for the efficient removal of MPs from water. Negatively charged polystyrene (PS) microspheres (1.0–1.9 μm, 100 mg/L) were used as representative microplastics to evaluate the adsorption performance of the prepared adsorbents. The removal efficiencies of Fe-modified activated carbon (Fe-AC), Co-modified activated carbon (Co-AC), and Fe/Co-AC were 93.09%, 90.90%, and 98.91%, respectively. The adsorption process is affected by solution pH and competitive ions, and Fe/Co-AC has good stability. After 5 cycles, the regeneration efficiency retention of the Fe/Co-AC remained 95.3%, and the removal efficiency of PS MPs by Fe/Co-AC remained 96.4%. The adsorption kinetics and isotherms indicate that adsorption is more consistent with the pseudo-second-order kinetics model and Langmuir model, suggesting that adsorption involves physical and chemical interactions. Mechanistic investigations revealed that surface adsorption, hydrophobic interactions, π–π stacking, and electrostatic attraction between negatively charged PS MPs and the modified activated carbon surface collectively contributed to the enhanced adsorption performance. These results will provide an idea for obtaining magnetic Fe/Co-AC to remove PS MPs from aqueous systems.