Assembly of core-shell Fe3O4@CD-MOFs derived hollow magnetic microcubes for efficient extraction of hazardous substances: Plausible mechanisms for selective adsorption

Hazardous heavy metals and organic substances removal is of great significance for ensuring the safety of aquatic-ecosystem, yet the highly effective and selective extraction always remains challenging. To address this problem, magnetic hollow microcubes were fabricated through thermal carbonization of Fe3O4-COOH@γ-CD-MOFs, and core-shell structured precursors were in-situ greenly constructed on a large scale via microwave-assisted self-assembly strategy. As noted, the development of secondary crystallization was utilized to achieve uniform dispersion of cores within MOFs frameworks and thus improved magnetic and adsorption ability of composites. Acquired magnetic Fe3O4@HC not only can harvest excellent extraction of heavy metals (Cd, Pb, and Cu of 129.87, 151.05, and 106.98 mg·g-1) but also exhibit highly selective adsorption ability for cationic organics (separation efficiency higher than 95.0%). Impressively, Fe3O4@HC achieved outstanding adsorption (60-80%) of Cd in realistic mussel cooking broth with no obvious loss in amino acid. Characterizations better offer mechanistic insight into the enhanced selectivity of positively charged pollutants can be attributed to synergistic effect of ions exchange and electrostatic interaction of abundant oxygen-containing functional groups. Our study provides a feasible route by rationally developing core-shell structured composites to promote the practical applications of sustainable water treatment and value-added utilization of processing by-products. Hazardous substances removal is imperative to ensure the safety of aquatic-ecosystem, yet the highly effective and selective extraction always remains challenging. Thus, novel hollow microcubes derived from Fe3O4@CD-MOFs are fabricated. Core-shell structured composites were in-situ assembled on a large scale via microwave-assisted strategy. Acquired magnetic Fe3O4@HC can not only realize extraction of heavy metallic ions, but also exhibit highly selective adsorption for positively charged organic pollutants. Due to excellent structural stability and functionality, the composites harvested stable performance toward Cd in practical mussel cooking broth, providing a green and sustainable strategy for refractory pollutants removal. So the work should be published in J. Hazard. Mater.