Robust Hierarchical-pore covalent triazine framework for efficient iodine capture and ammonia adsorption

Radioactive iodine (I2) in nuclear waste and corrosive ammonia gas (NH3) are harmful to human health and efficient removal of them is a serious task. Herein, two 2D covalent triazine frameworks (CTF) with hierarchical-pore structure were prepared by the nitrile trimerization of 2, 4, 6 trinitrile styryl-s-triazine (TCST) monomer via an ionic thermal strategy. The resulting CTF-TCSTs have high porosity and excellent chemical stability. The obtained CTF-TCST-500 has a richer mesoporous structure than that of CTF-TCST-400 and the introduced mesoporous structure can increase the I2 adsorption of CTF-TCST-500. Specifically, the I2 adsorption capacity of CTF-TCST-500 for I2 vapor and solution are 4.72 g g−1 and 4.02 g g−1, respectively. Surprisingly, CTF-TCST-500 exhibits the record I2 adsorption capacity in hexane solvent. In addition, CTF-TCST-400 with ultramicroporous structure possesses excellent adsorption performance for alkaline NH3 and the adsorption capacity is up to 7.2 mmol g−1. To our knowledge, this is the first report of CTF adsorbent for NH3 adsorption. This work not only provides two robust CTF adsorbents with conjugate structure and high adsorption capacities for I2 and NH3, but also emphasizes the significant contribution of defective mesoporous structure for I2 capture and ultramicroporous structure for NH3 adsorption.