Evaluation of an Ionic Porous Organic Polymer for Water Remediation

TLDR

The ionic porous organic polymer QUST‑iPOP‑1 was synthesized by quaternizing tris(4‑imidazolylphenyl)amine with cyanuric chloride and benzyl bromide, producing a Cl⁻/Br⁻‑rich, highly porous framework with a wide pore size distribution. QUST‑iPOP‑1 exhibited ultra‑high adsorption capacities for toxic oxo‑anions (Cr₂O₇²⁻, MnO₄⁻, ReO₄⁻) and anionic dyes (methyl blue, Congo red, methyl orange), matching or surpassing leading materials, and maintained high removal rates even in the presence of competing anions.

Abstract

The targeted synthesis of a novel ionic porous organic polymer (iPOP) was reported. The compound (denoted as QUST-iPOP-1) was built up through a quaternization reaction of tris(4-imidazolylphenyl)amine and cyanuric chloride, and then benzyl bromide was added to complete the quaternization of the total imidazolyl units. It featured a special exchangeable Cl–/Br–-rich structure with high permanent porosity and wide pore size distribution, enabling it to rapidly and effectively remove environmentally toxic oxo-anions including Cr2O72–, MnO4–, and ReO4– and anionic organic dyes with different sizes including methyl blue, Congo red, and methyl orange from water. Notably, QUST-iPOP-1 showed ultra-high capacity values for radioactive TcO4– surrogate anions (MnO4– and ReO4–), Cr2O72–, methyl blue, and Congo red, and these were comparable to some reported compounds of exhaustive research. Furthermore, the relative removal rate was high even when other concurrent anions existed.