ZIF-8-derived nanoporous carbon for highly efficient adsorption of microcystin-LR: synthesis, characterization, and mechanistic insights

Microcystin-LR (MC-LR), a cyanotoxin frequently generated during algal blooms, has drawn significant attention owing to its widespread occurrence and severe toxic effects. The development of efficient methodologies for removing MC-LR is essential to address the challenges posed by eutrophication-related pollution. In this study, we synthesized three porous carbon materials derived from zeolitic imidazolate framework-8 (ZIF-8) at varying carbonization temperatures and systematically evaluated their adsorption efficiency for MC-LR removal. The experimental data indicated that the saturation capacities of MC-LR adsorption on ZIF-8, CZIF-700, CZIF-950, and CZIF-1200 were 3.10, 3.98, 35.97, and 13.53 mg g −1 , respectively. Remarkably, CZIF-950 exhibited both the highest adsorption capacity and the fastest equilibrium time (< 5 min), outperforming all other adsorbents by a significant margin. Furthermore, adsorption isotherm and kinetic analyses revealed that the adsorption process aligned with the Langmuir model and followed the pseudo-second-order kinetics. Material characterization revealed that CZIF-950 achieves highly efficient MC-LR removal through synergistic adsorption mechanisms involving electrostatic interactions, hydrogen bonding, hydrophobic effects, and π-π stacking, facilitated by its optimal pore structure, large specific surface area, and unique structural characteristics. Our study provides valuable insights into the design of advanced metal–organic framework-derived adsorbents for the efficient removal of MC-LR and other environmental contaminants. Graphical abstract