Conjugated microporous polymer chitosan hybrid materials for enhanced pollutant removal

Abstract

Highly tailorable adsorbents are the key to addressing specialized pollution problems, such as the release of pharmaceuticals into our wastewaters. Conjugated microporous polymers (CMPs) pose a platform with modifiable functionality and pore system, allowing pollutant-customized adsorption. Herein novel phenanthren-dione based monomers are coupled to triethynylbenzene (TEB) forming new CMPs. These are compared with two literature-known, also TEB based CMPs regarding their adsorption properties towards the model drug diclofenac. To improve the handleability and enhance the adsorption the CMPs are integrated into chitosan gel beads, enabling simple removal using a sieve. The drying process of the beads turned out to significantly influence the swelling. Vacuum-dried beads exhibited 4–8 times higher water uptake than air-dried beads. Further, it proved beneficial to use hexanoyl modified chitosan as hybrid matrix, since it shows even further improved swelling capabilities, leading to a facilitated diffusion of the diclofenac through the chitosan matrix. This resulted in a notable enhancement of the adsorption efficiency of the CMPs, while concurrently exerting control over the adsorption process through the customization of swelling properties.