Constructing nitrogen-rich clover-like covalent organic frameworks for effective iodine capture

• • DFPT-COF achieves an iodine vapor capture capacity of 5.58 g g−1, exceeding DFPB-COF and many reported COFs; this high capacity directly reduces the required sorbent mass and column volume in nuclear off-gas treatment systems, lowering capital and operating costs. • • The adsorption kinetics of DFPT-COF for liquid iodine follow a pseudo-second-order model (R² > 0.99), indicating chemisorption as the rate-controlling step; this implies fast uptake rates suitable for emergency response scenarios where rapid iodine sequestration is critical. • • The adsorption isotherm complies with the Langmuir model, suggesting monolayer coverage with a finite number of homogeneous binding sites; this provides a predictive framework for scaling up adsorption columns and estimating saturation capacities under varying iodine concentrations. • • DFPT-COF exhibits excellent renewable adsorption performance, maintaining high capacity over multiple adsorption-desorption cycles; this reusability reduces long-term material consumption and waste generation, aligning with sustainable nuclear waste management protocols.