Enhanced removal of per- and poly-fluoroalkyl substances with porous aminated covalent organic polymer in water

This study investigated the environmental application of a positively charged aminated covalent organic polymer (ACOP) for the removal of per- and poly-fluoroalkyl substances (PFAS) from water. ACOP was synthesized via a catalyst-free Schiff base reaction, using melamine as a monomer and terephthalaldehyde as a ligand. This study aims to utilize the highly protonated surface of this amine-based polymer to adsorb PFAS. The adsorption efficiency of ACOP was investigated for six types of PFAS with varying carbon chain lengths. ACOP exhibited rapid adsorption of PFOS and PFOA, achieving significant removal within one minute and reaching equilibrium within five minutes. The adsorption process was well described by the pseudo-second-order kinetic model. Isotherm analysis revealed that the adsorption of PFOA and PFOS followed the Langmuir model. The adsorption mechanism of PFAS onto ACOP was attributed to a combination of electrostatic interactions and hydrophobic interactions. Therefore, this study demonstrates that ACOP is an effective and practical adsorbent for PFAS removal in aqueous systems. ACOP's easy synthesis, thermal stability, and excellent reusability further highlight its potential for environmental applications.