Resorcinarene Cavitand Polymers for the Remediation of Halomethanes and 1,4-Dioxane

Executive summary: Porous resorcinarene-containing polymers are used to remove halomethane disinfection byproducts and 1,4-dioxane from water.

Disinfection byproducts such as trihalomethanes are some of the most common micropollutants found in drinking water. Trihalomethanes are formed upon chlorination of natural organic matter (NOM) found in many drinking water sources. Municipalities that produce drinking water from surface water sources struggle to remain below regulatory limits for CHCl₃ and other trihalomethanes (80 mg L^–1 in the United States). Inspired by molecular CHCl₃⊂cavitand host-guest complexes, we designed a porous polymer comprised of resorcinarene receptors. These materials show higher affinity for halomethanes than a specialty activated carbon used for trihalomethane removal. The cavitand polymers show similar removal kinetics as activated carbon and have high capacity (49 mg g^–1 of CHCl₃). Furthermore, these materials maintain their performance in real drinking water and can be thermally regenerated under mild conditions. Cavitand polymers also outperform activated carbon in their adsorption of 1,4-dioxane, which is difficult to remove and contaminates many public water sources. These materials show promise for removing toxic organic micropollutants and further demonstrate the value of using supramolecular chemistry to design novel absorbents for water purification.