Laser-induced in-situ carbonization of polystyrene for the facile fabrication of core-shell Fe3O4@LIG magnetic adsorbents with efficient dye removal performance

Adsorption technology plays a vital role in addressing water pollution issues stemming from dyes. Adsorption materials are the key, yet conventional graphene-based adsorbents are constrained by multi-step synthesis, high energy demand, and the use of hazardous etchants. In this study, a straightforward, swift and eco-friendly laser-induced method is employed to transform commercially available polystyrene and ferroferric oxide into core-shell structured graphene magnetic adsorbents. Graphene provides abundant porous structures and surface adsorption sites, while ferroferric oxide provides magnetic functions. This magnetic adsorbent exhibits excellent adsorption performance for methylene blue solutions, with a saturated adsorption capacity of up to 156 mg/g and good recycling stability. Its adsorption behavior conforms to the pseudo-second-order kinetic model, indicating that chemical adsorption dominates the process, which is mainly synergistically driven by electrostatic attraction, π–π stacking interaction and hydrogen bonding. The isothermal adsorption data fits the Langmuir model, revealing that it is dominated by uniform monolayer adsorption. This approach not only transcends the constraints of conventional polymer carbonization techniques but also successfully engineers a recyclable system for adsorption and recovery grounded on such methodology. The research also elucidates the mechanism behind polymer in-situ carbonization under laser irradiation, offering a novel approach to the treatment of dye-contaminated wastewater. • Laser-induced core-shell Fe 3 O 4 @LIG with 1098 m 2 /g specific surface area. • The formation mechanism of core-shell structure Fe 3 O 4 @LIG is clarified. • Activated Fe 3 O 4 @LIG shows 156 mg/g MB adsorption, and a large-scale cyclic system is designed..