Reported here is a hydrogel-forming polymer network that contains a water-soluble tetracationic macrocycle. Upon immersion of this polymer network in aqueous solutions containing various inorganic and organic salts, changes in the physical properties are observed that are consistent with absorption of the constituent anions into the polymer network. This absorption is ascribed to host-guest interactions involving the tetracationic macrocyclic receptor. Removal of the anions may then be achieved by lifting the resulting hydrogels out of the aqueous phase. Treating the anion-containing hydrogels with dilute HCl leads to the protonation-induced release of the bound anions. This allows the hydrogels to be recycled for reuse. The present polymer network thus provides a potentially attractive approach to removing undesired anions from aqueous environments.
Bibliographical noteFunding Information:
The American Chemical Society Petroleum Research Fund (Grant No. 56925-ND7 to J.L.S.), the Robert A. Welch Foundation (F-0018 to J.L.S.), the National Basic Research Program (2013CB834502 to F.H.), the NSFC/China (91527301, 21434005 to F.H.), and the collaborative research grant (CRG 6 to N.M.K.) of King Abdullah University of Science and Technology are acknowledged for financial support.
ASJC Scopus subject areas
- Colloid and Surface Chemistry