Porous calix[4]pyrrole-based polymers with high surface area for efficient removal of polar organic micropollutants from water.

Abstract

Herein, effort was made to construct innovative adsorbent for the removal of polar organic micropollutants (OMPs) from water. Tetra-meso resorcinol-functionalized calix[4]pyrrole (CP) featured with endo-functionalized attribute and polyphenol hydroxyl structure was crosslinked by π-electron-rich 4,4'-bis(chloromethyl)biphenyl (BCMBP) through Friedel-Crafts reaction to generate porous calix[4]pyrrole-based polymers (PCPPs) with high surface area. The porosity of the PCPPs could be tuned by adjusting the molar ratio of hydrophilic CP to hydrophobic BCMBP, and diversified binding sites were integrated together. Based on adsorption kinetics and isotherm studies, PCPP(1-16) showed rapid adsorption rate and high removal efficiency (RE) as well as advanced adsorption capacity. The REs towards the tested polar OMPs by PCPP(1-16) were all above 95% in 30 min. Compared with granular activated carbon (GAC), the rate constant of pseudo-second-order model (k₂) and adsorption capacity upon PCPP(1-16) were 8-230 times and 1.3-3.1 times greater than those by GAC. Adsorption mechanism studies confirmed the presence of multiple interactions and thermodynamic investigation revealed the spontaneous and physical adsorption nature. Besides, PCPP(1-16) showed excellent adsorption performance in real water samples at environmental levels and exhibited advanced absorption ability in flow-through mode. Accompanied by facile regeneration under eluting with methanol and cost-effective preparation, PCPP(1-16) demonstrated great potential as promising adsorbent for water treatment.