Urea-engineered porous organic polymers for efficient iodine capture in vapor and liquid phases

Abstract

The careful handling of radioactive elements in nuclear wastewater is of utmost importance, especially for radioiodine, which has been demonstrated to be harmful to human health and the environment. In this context, porous organic polymers (POPs) serve as a novel class of porous materials and have shown potential in many fields, especially for the removal of I₂, attributed to their specific surface areas, tunable open pore structures and adjustable functional building blocks. Herein, we report the preparation of two urea-based POPs (POP-TFPB-U-1 and POP-TFPB-U-2) via the Schiff base reaction between 1,3,5-tris(p-formylphenyl)benzene (TFPB) and two distinct urea-based phenylamine compounds. Their nucleophilic nitrogen atoms, phenyl rings, hydrogen-bonding sites and porosity endow them with effective I₂ vapor adsorption capacities of 5.56 g g⁻¹ and 4.55 g g⁻¹, achieving 89.1% and 97.7% of the theoretical adsorption efficiency in cyclohexane solution, respectively.