Rapid and Efficient Removal of Diverse Anionic Water Contaminants Using a Guanidium-Based Ionic Covalent Organic Network (iCON)

The use of ionic porous materials for the detoxification of water has been receiving widespread research attention since the last decade. Such materials are associated with attractive features such as a facile synthetic route, easy scalability, and excellent performance in the removal of pollutants from wastewater. To further enrich the literature on ionic porous materials as superior adsorbents, this work describes the construction of an ionic covalent organic network (iCON-5) using Schiff-base polycondensation of triamminoguanidium chloride and 4,4′,4″-((1,3,5-triazine-2,4,6-triyl)tris(oxy))tribenzaldehyde. The resulting polymeric framework exhibits good physicochemical stability. The presence of exchangeable chloride counteranions in the polymeric network ensures the efficient capture of various anionic pollutants from wastewater. The iCON-5 displays a good uptake capacity toward a wide range of inorganic/organic species (CrO42–, TcO4–, I3–, diclofenac, and picrate) that are proclaimed water pollutants. In addition, iCON-5 is easy to regenerate and can be reused at least 5 times without significant compromise in uptake capacities. Furthermore, the cationic network is competent in the extraction of anionic pollutants from systems mimicking real-world samples (such as pollutant-spiked tap water, seawater, river water, lake water, and pond water). Thus, iCON-5 has the desired characteristics anticipated in a porous adsorbent for the sequestration of various anionic contaminants from wastewater.