Cross-Linked Supramolecular Polymer Based on Calix[4]pyrrole-Decorated Pillar[5]arene and Its Application in Micropollutant Removal

Abstract

A calix[4]­pyrrole-decorated pillar[5]­arene was synthesized via azide-alkyne “click” chemistry and used to prepare a cross-linked supramolecular polymer in chloroform based on the anion recognition ability of calix[4]­pyrrole. Complexation experiments revealed that while one of the cross-linkers, terephthalate anion, was not able to form strong complexation, suberate anion was found to act as a suitable cross-linker. Supramolecular polymerization and performance of monomers were monitored with a combination of techniques including 1H-, diffusion-ordered 1H NMR spectroscopy experiments, viscosity, and SEM analyses. Thermo and competing anion responsiveness of the cross-linked supramolecular polymer were also shown by means of 1H-NMR analyses and viscosity measurements. Micropollutant removal ability of the cross-linked supramolecular polymer in solid and gel forms was also investigated by using methylene blue, methyl violet 2B, and rhodamine B as surrogate pollutants, and UV/Vis experiments revealed that while the solid form of the supramolecular polymer performs better in the case of methylene blue and methyl violet, its gel form provides slightly better removal efficiency for rhodamine B.

Linking Nitrogen-Rich Pillar[5]arene to Hyper-Cross-Linked Polymers for Efficient and Simultaneous Capture of Iodine and Methyl Iodide

“…39,40 The Raman spectrum of I 2 @ P [5]A-TPTA12 (Figure 5c) contained peaks at 165.8 and 107.3 cm −1 , which should be ascribed to the stretching vibrations of I 5 − and I 3 − , respectively. These results were consistent with the results reported previously, 29,34 indicating that adsorption was chemically controlled and charge-transfer interactions occurred between I 2 and the active sites. In the N 1s XPS spectra of P[5]A-TPTA12 (Figure 5d), the peaks at 400.1 and 398.8 eV, assigned to sp 3 N and triazine N, shifted to 401.3 and 399.0 eV, respectively, after the adsorption of I 2 , further indicating the occurrence of charge transfer between I 2 and various N species of P[5]A-TPTA12.…”

Indium-based quantum dots trapped in solid-state matrices: a one-pot synthesis, thermoresponsive properties, and enhanced micropollutant removal

“…8–12 Additionally, specifically modified cross-linked structures have been proposed as potential agents for removing dyes due to their insoluble, solid, and porous nature. 45 In our study, In 2 S 3 , ZnIn 2 S 4 , and Cu:ZnIn 2 S 4 SSQDs were employed as removal agents to eliminate several different cationic and anionic dyes from their aqueous solutions. Methylene blue, methyl violet 2B, and rhodamine B were selected as cationic dyes, while methyl orange and sodium fluorescein were chosen as anionic dyes.…”

Tailoring fluorescent ZIF-8 nanostructures through calix[4]pyrrole modification: tunable size and enhanced organic micropollutant removal capacity

“…In the case of BCCP ZIF-8(I), where the BCCP concentration was higher, the removal efficiencies were 96% for MB and 60% for MV (see ESI† for calculation of removal efficiencies). These results highlighted that BCCP modification entirely transformed the characteristics of ZIF-8 with respect to the high affinity of calix[4]pyrrole to MB and MV, 29 allowing the adjustment and customization of ZIF-8's organic micropollutant removal properties to suit various pollution scenarios in different environments.…”