A tailored polymer with enhanced electrosorption capability for efficient ammonium removal

Abstract

Capacitive deionization (CDI) is rapidly gaining recognition as a highly auspicious technology for water purification and effluent treatment. At the core of CDI technology reside electrode materials, which perform a pivotal function in the removal of contaminants through electrosorption process. While organic compounds present a vista of sustainable synthesis and versatile molecular architectures, their proclivity for dissolution in aqueous solutions and the paucity of redox-active sites pose significant hurdles to their implementation in CDI electrodes. Herein, this work presents the successful engineering of a novel polymer, designated as PATQ, through a facile one-step polymerization process utilizing aminoanthraquinone (ATQ) as the monomer. The strategic incorporation of abundant and readily available C=O redox-active sites, coupled with the meticulous construct of a conjugated framework to ensure high structural stability, endows the PATQ polymer with remarkable capabilities as an electrode material for NH₄⁺ electrosorption. This exceptional performance is corroborated by electrochemical measurements and in-situ Raman spectroscopy. Furthermore, a high-efficiency hybrid CDI device has been created, showcasing a notable NH₄⁺ removal capacity of 101.5 mg/g and a rapid removal rate of 6.18 mg/g min⁻¹, along with energy recovery features. Therefore, this work paves the way for efficient, sustainable and cost-effective water purification technologies.