Latest advances in environmental applications of COFs and their derivatives towards marine biotoxins

Abstract

Marine biotoxins pose persistent threats to aquatic ecosystems and food safety, calling for advanced monitoring and remediation strategies. This review highlights covalent organic frameworks (COFs) as multifunctional materials for toxin sensing, adsorption, and catalytic degradation under marine conditions. Key advances in framework design, including pore engineering, surface functionalization, and hybridization, are summarized to illustrate how structural control enhances toxin-specific recognition. Representative applications targeting saxitoxin, domoic acid, okadaic acid, and microcystins are highlighted. COF adsorbents show high capacities for lipophilic shellfish toxins (e.g., okadaic acid/dinophysistoxin-1 up to 812/830 mg g⁻¹) and ultrafast adsorption for polar analytes (e.g., domoic acid reaching 66.5 mg g⁻¹ within 7 min), while retaining > 80 % efficiency after multiple regeneration cycles. COF-based sensors achieve detection limits as low as pg mL⁻¹ in seawater and 0.005 µg kg⁻¹ in shellfish. Moreover, mechanistic insights into pseudo-second-order adsorption kinetics, Freundlich/Langmuir isotherms, binding forces (π–π conjugation, hydrogen bonding, electrostatic, and hydrophobic interactions), and key signal transduction pathways (photoinduced electron transfer (PET), fluorescence resonance energy transfer (FRET)) are critically discussed, together with COF-based photocatalytic systems enabling ROS (•OH, ¹O₂, and O₂•⁻)-driven degradation of recalcitrant toxins. Despite these advances, challenges remain regarding scalability, long-term stability, and field deployment. Future opportunities include machine learning-guided COF design, integrated sensing–remediation systems, and alignment with regulatory standards, providing a roadmap toward next-generation solutions for marine toxin management.