Construction of a conjugated covalent organic framework for iodine capture

Radioactive iodine in the nuclear field is considered very dangerous nuclear waste because of its chemical toxicity, high mobility and long radioactive half-life. Herein, a conjugated two-dimensional covalent organic framework, TPB-TMPD-COF, has been designed and synthesized for iodine capture. TPB-TMPD-COF has been well characterized by several techniques and showed long order structure and a large surface area (1090 m2 g-1). Moreover, TPB-TMPD-COF shows a high iodine capture value at 4.75 g g-1 under 350 K and normal pressure conditions, benefitting from the increased density of adsorption sites. By using multiple techniques, the iodine vapor adsorbed into the pores may readily generate the electron transfer species (I3- and I5-) due to the strong interactions between imine groups and iodine molecules, which contributes to the high iodine uptake for TPB-TMPD-COF. Our study will stimulate the design and synthesis of COFs as a solid-phase adsorbent for iodine uptake. A conjugated two-dimensional covalent organic framework, TPB-TMPD-COF, has been constructed for iodine capture, which exhibited a vapor high iodine capacity of 4.75 g g-1 at 350 K and atmospheric pressure conditions.