Nitrogen-Rich Porous Polymers for Carbon Dioxide and Iodine Sequestration for Environmental Remediation

Abstract

The use of fossil fuels for energy production is accompanied by carbon dioxide release into the environment causing catastrophic climate changes. Meanwhile, replacing fossil fuels with carbon-free nuclear energy has the potential to release radioactive iodine during nuclear waste processing and in case of a nuclear accident. Therefore, developing efficient adsorbents for carbon dioxide and iodine capture is of great importance. Two nitrogen-rich porous polymers (NRPPs) derived from 4-bis-(2,4-diamino-1,3,5-triazine)-benzene building block were prepared and tested for use in CO and I capture. Copolymerization of 1,4-bis-(2,4-diamino-1,3,5-triazine)-benzene with terephthalaldehyde and 1,3,5-tris(4-formylphenyl)benzene in dimethyl sulfoxide at 180 °C afforded highly porous NRPP-1 (SA = 1579 m g) and NRPP-2 (SA = 1028 m g), respectively. The combination of high nitrogen content, π-electron conjugated structure, and microporosity makes NRPPs very effective in CO uptake and I capture. NRPPs exhibit high CO uptakes (NRPP-1, 6.1 mmol g and NRPP-2, 7.06 mmol g) at 273 K and 1.0 bar. The 7.06 mmol g CO uptake by NRPP-2 is the second highest value reported to date for porous organic polymers. According to vapor iodine uptake studies, the polymers display high capacity and rapid reversible uptake release for I (NRPP-1, 192 wt % and NRPP-2, 222 wt %). Our studies show that the green nature (metal-free) of NRPPs and their effective capture of CO and I make this class of porous materials promising for environmental remediation.

Fluorescent aminal linked porous organic polymer for reversible iodine capture and sensing

“…More recently, Pan et al developed N-and S-rich covalent organic framework (COFs) possessing high iodine uptake of 276 wt.% 29 . Triazine-based conjugated polymers have also been reported to have respectable iodine uptake, presumably due to their nitrogen-rich nature 4,15,[30][31][32][33][34][35] . The high number of basic nitrogen sites on the triazine unit enhances the uptake capacity that originates from the formation of charge-transfer complexes of nitrogen-iodine (donor-acceptor) systems formed during iodine adsorption on the polymers 7,12,15,36 .…”

Polymer sequestrants for biological and environmental applications

“…Radioisotopes 129 I and 131 I are released in exhaust fumes from nuclear power plants. Their capture and storage are a major environmental and public health concern due to their bioaccumulation . The incorporation of heteroatoms such as nitrogen into POPs has enabled the storage and capture of radioactive iodine .…”

“…Abdelmoaty et al reported the synthesis of two imino‐based POPs based on 1,4‐bis‐(2,4‐diamino‐1,3,5‐triazine)benzene using terephthalaldehyde (POP‐3) and 1,3,5‐tris(4‐formylphenyl)benzene (POP‐4) (Fig. ) . Vapor‐phase iodine uptake studies revealed maximum iodine uptake capacities for POP‐3 and POP‐4 of 192 and 222 wt%, respectively.…”

Larger pore volume tetraphenyladamantane‐based hybrid porous polymers: Facile Friedel–Crafts preparation, CO2 capture, and Rhodamine B removal properties

“…However, their lower removal capacities, poorer stabilities, and tedious synthesis procedures cannot meet the growing industrial demands. Covalently linked porous polymers have been recognized as the most promising adsorbents for the wastewater treatment and CO 2 capture due to their featuring with large surface area, good thermal stability, designable pore structure, and versatile synthetic methods . For example, Tan et al .…”