Regenerative treatment of aquatic pollutants of microplastic and antibiotics based on synergistic effect of magnetic biochar/protonated g-C3N4

Microplastics as emerging contaminants can easily form composite pollutants with other organic substances like antibiotics with higher environmental risks, posing a significant threat to aquatic ecosystems. Herein, a composite was prepared though electrostatic self-assembly of magnetic biochar and protonated g-C 3 N 4 for the simultaneous removal of microplastics and antibiotics. This composite serves as a dual-function material, leveraging its porous structure and functional groups to promote both photocatalytic degradation of antibiotics and effective adsorption of microplastics, which exhibited an adsorption capacity of PS microplastic of 56.90 mg/g and achieving stable removal of TC (30 mg/L) under irradiation of 2 h over multiple cycles with minimal efficiency loss. Magnetic biochar component not only critically enhances photocatalytic degradation efficiency of antibiotic by enriching pollutants and promoting charge separation, but also enables convenient separation and allows for excellent reusability. Moreover, sequential dissolution and electrospinning strategy not only facilitates adsorbent regeneration but also achieves the upcycling of microplastics into a high-value-added plastic film. Additionally, regenerated composite also exhibited excellent performance of PS microplastic removal with low adsorption activity decay over four cycles. This synergistic adsorption-photocatalysis system provides an effective and practical strategy for purifying water contaminated with complex emerging pollutants, offering a valuable reference for development of integrated environmental remediation technologies.