A pharmaceutical hydrogen-bonded covalent organic polymer for enrichment of volatile iodine

Porous organic polymers (POPs) are emerging porous materials for various applications. So far, POPs are currently synthesised by a few limited synthetic chemical reactions, leading to a lack of new structures and properties. Thus, expanding structural diversity is highly desired for the development of this promising class of porous materials. Herein, adopting pharmaceutical isoniazid as a difunctional linker, a pharmaceutical hydrogen-bonded covalent organic polymer (pha-HCOP-1) has been synthesised for iodine enrichment. The structure and morphology are studied by TGA, FT-IR, FE-SEM, HR-TEM and C-13 CP/MAS NMR. Powder X-ray diffraction and N-2 adsorption-desorption analysis show that pha-HCOP-1 is amorphous and porous with a surface area of 217.31 m(2) g(-1). The pha-H(C)OPs are spherical particles with an average size of 20 nm. Due to the abundant porosity, pi-conjugated phenyl rings, as well as functional -CO-NH-building units, pha-HCOP-1 exhibits a good adsorption ability for iodine molecules. The phaH(C)OP-1 has a high uptake value of 131 wt% via vapor trapping adsorption. Meanwhile, pha-HCOP-1 also exhibits an outstanding iodine adsorption in solution, and the maximum adsorption capacity reaches as high as 833.33 mg g(-1) analyzed using a Langmuir model. In addition, the thermodynamic parameters Delta G, Delta H and Delta S indicate that the adsorption of iodine by pha-HCOP-1 is feasible, spontaneous and endothermic. pha-HCOP-1 represents an elegant example of using pharmaceutical molecules as building blocks to construct porous POPs for reversible adsorption of radioactive iodine.