Graphene-based magnetic covalent organic frameworks and deep eutectic solvent functionalized adsorbents for polycyclic aromatic hydrocarbons: a review.

Polycyclic aromatic hydrocarbons (PAHs) are hazardous organic compounds defined by their long-lasting nature, carcinogenicity and mutagenicity, posing environmental and health risks. Conventional PAH removal methods usually have high costs, low efficiency and potentially produce secondary contaminants. Graphene-based magnetic covalent organic frameworks (MCOFs) emerged as an alternative, offering high surface area, tuneable functionality and superior magnetic separability. Graphene-based MCOFs facilitate strong π-π interactions, hydrophobic effects and improved adsorbent stability, leading to more efficient PAH removal. The distinctive focus of this review is on deep eutectic solvents (DESs) as a green modification strategy to further optimize adsorption efficiency by lowering reaction temperature, reducing synthesis time and eliminating the use of hazardous organic solvents. This review presents a comprehensive study of graphene-based MCOFs and DES functionalized adsorbent synthesis, adsorption mechanisms and their environmental applications in enhancing PAH adsorption performance as the next-generation sustainable materials for large-scale PAH remediation. Collectively, these advances align with the principles of green chemistry and are anticipated to contribute to global efforts towards the sixth, seventh and fourteenth sustainable development goals, namely clean water and sanitation, affordable and clean energy and the protection of aquatic ecosystems.