Synthesis and study of low-cost nitrogen-rich porous organic polyaminals for efficient adsorption of iodine and organic dye

The effective removal of environmental pollutants such as radioactive iodine in fission and organic dyes in industrial wastewater is important. Recently various porous solids have been constructed to solve the above problems. However, one of the challenges is to design and produce a large quantity of low cost, high efficiency, high capacity, and recyclable adsorbent for large-scale applications. Herein, the nitrogen-rich porous organic polyaminals, including PHPOA-N(CH3)2, and PAPOA-N(CH3)2, were prepared via the catalyst-free amine-formamido condensation reaction from two nitrogen-heterocycle triazine-based multiamine monomers with the readily available N,N-dimethylformamide (DMF), respectively. These two resultant polymers exhibited abundant porosities with large BET surface areas (972 and 1444 m2 g−1) and hierarchical pore sizes from 0.58 to 1.30 nm. Meanwhile, the structure-directing effect of the monomer unit on building porous architecture was also investigated. Owing to the excellent porous structure with large surface area and the abundant nitrogen active sites with high electron density offering the host–guest interactions, both of our POAs displayed high iodine adsorption capacities up to 3.58 g g−1, exceeding most of the reported porous aminals. The excellent Rhodamine B (RhB) adsorption performance up to 308 mg g−1 with fast adsorption also outperformed most of the reported adsorbents. This study may give useful guidance for the application of high-efficiency porous organic polymers in the removal of environmental pollutants.