Porous materials for the sorption of emerging organic pollutants from aqueous systems: The case for conjugated microporous polymers

Abstract

Emerging organic pollutants (EOPs) pose a challenge to water treatment facilities and are a potential hazard to the environment and human health. Potential ways of removing these pollutants in tertiary wastewater treatment processes to make it potable include the use of porous materials like biochar, zeolites, metal organic frameworks (MOFs), covalent organic frameworks (COFs), polymers of intrinsic microporosity (PIMs), zirconium based porous materials and, more recently, conjugated microporous polymers (CMPs). CMPs have attracted research attention owing to their porosity and π-conjugation which can easily be engineered for a wide range of applications. The synthesis of CMPs is relatively easily done through established pathways that include the Suzuki coupling, Sonogashira-Hagihara cross-coupling, Friedel-Crafts reactions, oxidative coupling, Ullmann reaction and the Yamamoto coupling. Post-synthetic functionalisation approaches have been used to obtain CMPs which have specific motifs suited for particular applications. Despite their potential, use of CMPs in removing EOPs from water has not received adequate research attention, and is therefore an area that needs research. This short communication highlights the challenges posed by EOPs, presents some of the possible porous materials that can be used for their removal, and proposes CMPs as suitable potential adsorbents. Basing on recent literature covering the period 2003–2016, the synthetic methods, properties and applications of these materials have been presented.