Enhanced tetracycline adsorption in aqueous samples via solvent-free in situ growth of ZIF-8 on MAF-6-derived carbon

In this work, we present a novel route for preparing a MOF-derived composite, CMAF-6@ZIF-8, specifically designed for the removal of emerging contaminants from water. The composite was synthesized via a solvent-free in situ growth of ZIF-8 (Zeolitic Imidazolate Framework-8) directly on a porous carbon matrix obtained by thermal conversion of MAF-6 (Metal Azolate Framework-6). Notably, the ZnO nanoparticles formed during carbonization were strategically reused as reactive precursors, enabling ZIF-8 crystallization without the need for external metal salts or solvents. The optimized material exhibited a high surface area (903 m 2 g −1 ) and a micro/mesoporous structure, that facilitated rapid diffusion of target molecules. The composite demonstrated outstanding adsorption performance for tetracycline, achieving a maximum adsorption capacity of 769 mg g −1 and a kinetic rate constant of 0.00205 g mg −1 min −1 , both values being among the highest reported for ZIF-8-based materials. Furthermore, the material showed excellent reusability over five cycles. This sustainable, high-performance adsorbent offers a promising solution for addressing the global challenge of antibiotic contamination in water systems. • Solvent-free in situ growth of ZIF-8 on MAF-6-derived carbon was developed. • ZnO residues in carbon enabled direct ZIF-8 formation with 2-methylimidazole. • Composite showed 903 m 2 g −1 surface area and hierarchical pore structure. • Tetracycline was rapidly adsorbed with a capacity of 769 mg g −1 .