Calix[4]pyrrole-Crosslinked Porous Polymeric Networks for the Removal of Micropollutants from Water

Calix[4]pyrrole-based porous organic polymers (P1-P3) for removing organic micropollutants from water were prepared. A bowl-shaped alpha,alpha,alpha,alpha-tetraalkynyl calix[4]pyrrole and diketopyrrolopyrrole monomer were crosslinked via Sonogashira coupling to produce a 3D network polymer, P1. P1 proved too hydrophobic for use as an adsorbent and was converted to the corresponding neutral polymer P2 (containing carboxylic acid groups) and its anionic derivative P3 (containing carboxylate anion groups). Anionic P3 outperformed P2 in screening studies involving a variety of model organic micropollutants of different charge, hydrophilicity and functionality. P3 proved particularly effective for cationic micropollutants. The theoretical maximum adsorption capacity (q(max,e)) of P3 reached 454 mg g(-1) for the dye methylene blue, 344 mg g(-1) for the pesticide paraquat, and 495 mg g(-1) for diquat. These uptake values are significantly higher than those of most synthetic adsorbent materials reported to date.

Automated summary

In this study, Calix[4]pyrrole-based porous organic polymers were prepared and proved to be effective in removing organic micropollutants from water. Among the different polymers synthesized, the anionic derivative P3 outperformed the neutral polymer P2, particularly in removing cationic micropollutants. The theoretical maximum adsorption capacity of P3 for various organic micropollutants was significantly higher than that of most synthetic adsorbent materials reported to date.