Imidazolium‐Functionalized Chemically Robust Ionic Porous Organic Polymers (iPOPs) toward Toxic Oxo‐Pollutants Capture from Water

Abstract

Fabricating new and efficient materials aimed at containment of water contamination, in particular removing toxic heavy metal based oxo-anions (e. g. CrO 42À , TcO 4 À ) holds paramount importance. In this work, we report two new highly stable imidazolium based ionic porous organic polymers (iPOPs) decorated with multiple interaction sites along with electrostatics driven adsorptive removal of such oxoanions from water. Both the iPOPs (namely, iPOP-3 and iPOP-4) exhibited rapid sieving kinetics and very high saturation uptake capacity for CrO 4 2À anions (170 and 141 mg g À 1 for iPOP-3 and iPOP-4 respectively) and ReO 4 À (515.5 and 350.3 mg g À 1 for iPOP-3 and iPOP-4 respectively), where ReO 4 À anions being the non-radioactive surrogative counterpart of radioactive TcO 4 À ions. Noticeably, both iPOPs showed exceptional selectivity towards CrO 4 2À and ReO 4 À even in presence of several other concurrent anions such as Br À , Cl À , SO 4 2À , NO 3 À etc. The theoretical binding energy calculations via DFT method further confirmed the preferential interaction sites as well as binding energies of both iPOPs towards CrO 4 2À and ReO 4À over all other competing anions which corroborates with the experimental high capacity and selectivity of iPOPs toward such oxo-anions.

A bifunctional imidazolium-functionalized ionic porous organic polymer in water remediation

“…S6, ESI †). The PXRD data showed the amorphous nature, which is very common for this type of ionic polymeric material 72,74 (Fig. S7, ESI †), and it was further confirmed by the electron diffraction…”

“…[65][66][67][68] In recent years, a series of iPOPs have been synthesized and their application in various fields has been explored. 69 To achieve anion capture using iPOP, a stable cationic skeleton with exchangeable counter anions is the primary requirement, [70][71][72][73][74][75][76][77][78][79][80] whereas the presence of an electron-rich building block in the polymeric skeleton [81][82][83] and accumulation of a large number of N atoms in the material helps in increasing the photocatalytic performance. 82,84 Strategic incorporation of different binding sites into the polymeric network and the electron-rich moiety might contribute towards the selective capture of anionic pollutants and enhance the material's photocatalytic performance.…”

Rational Design of High-Performance Cationic Organic Network Adsorbents

“…Similarly, the adsorption capacities of CON-LDU4 and CON-LDU5-SiO 2 for CrO 4 2– were calculated as 222 and 129 mg g –1 , respectively (Figure S10), indicating the better accessibility of CON-LDU5 . As illustrated in Figure d, the capacity of CON-LDU5 surpasses those of most other comparable adsorbents. ,,− Additionally, the adsorption efficiency of CON-LDU5 at the low concentrations of CrO 4 2– aqueous solutions was evaluated. As shown in Figure S13, the adsorption percentages are nearly 100% when the K 2 CrO 4 aqueous solutions were used with concentrations of 100, 50, and 10 ppm, revealing CON-LDU5 is an effective adsorbent.…”

An excited-state intramolecular proton-transfer responsive nanoscale MOF for dual sensing of water and chromate ions

“…[37][38][39] The intrinsic porous structure and good guest binding properties could enable the access of water molecules to the chromophores; in addition to this, high stability and easy processability of the framework account for their reusability as chemosensor materials. MOF-based luminescent chemosensors have also attracted immense research interest in the detection of trace amounts of cationic [6][7][8]40 and anionic [41][42][43][44][45][46][47][48][49][50][51] contaminant analytes. The excellent structural tunability of these systems enables the incorporation of Lewis acidic/basic sites into the framework, which can essentially bind to the analytes.…”