Engineered magnetic metal-organic frameworks for efficient and broad-spectrum adsorption of micro/nanoplastics in...

Micro/nanoplastics have raised significant concerns due to their intrinsic toxicity and synergistic effects with co-existing pollutants, posing substantial risks to environmental ecosystems and human health. Although metal-organic frameworks (MOFs) demonstrate promising potential as efficient adsorbents for microplastic removal, the structure-activity relationships governing their adsorption mechanisms remain poorly understood. In this study, engineered magnetic MOFs materials (Fe₃O₄@carboxymethyl-cellulose(CMC)-MOFs) were designed and synthesized to adsorb micro/nanoplastics. The adsorption behavior of five Fe₃O₄@CMC-MOFs composites toward micro/nanoplastics was systematically investigated, with particular emphasis on clarifying structure-property correlations. Furthermore, starting from the structural differences, the adsorption mechanism was systematically analyzed by physicochemical characterization, adsorption kinetics and isotherms, and density functional theory. Results showed that Fe₃O₄@CMC-MIL-101-NH₂ demonstrated superior adsorption performance for polystyrene (PS) mainly through van der Waals interactions. Under optimal conditions, Fe₃O₄@CMC-MIL-101-NH₂ enabled adsorbing 98.0 % and 245.1 mg/g PS, the maximum adsorption amount was 1923 mg/g based on Langmuir isotherm model. And it remained > 89.0 % efficiency after five cycles. As well as it showed satisfactory adsorption performance for other types of microplastics such as (polypropylene and polyethylene) with different shapes, micro/nano-size, and chargeability (>250 mg/g). Moreover, Fe₃O₄@CMC-MIL-101-NH₂ can effectively remove > 81.0 % micro/nanoplastics in beverages. The developed engineered magnetic MOFs material has excellent adsorption performance, efficiency and cost-effectiveness, possessing great potential for the removal of micro/nanoplastics in environment and food systems.