Calix4pyrrole‐based Crosslinked Polymer Networks for Highly Effective Iodine Adsorption from Water

Abstract A series of calix4pyrrole‐based crosslinked polymer networks designed for iodine capture is reported. These materials were prepared by Sonogashira coupling of α,α,α,α‐tetra(4‐alkynylphenyl)calix4pyrrole with bishalide building blocks with different electronic properties and molecular sizes. Despite their low Brunauer–Emmett–Teller surface areas, iodine vapor adsorption capacities of up to 3.38 g g −1 were seen, a finding ascribed to the presence of a large number of effective sorption sites including macrocyclic π‐rich cavities, aryl units, and alkyne groups within the material. One particular system, C4P‐BTP , was found to be highly effective at iodine capture from water (uptake capacity of 3.24 g g −1 from a concentrated aqueous KI/I 2 solution at ambient temperature). Fast capture kinetics (k obs =7.814 g g −1 min −1 ) were seen. Flow‐through adsorption experiments revealed that C4P‐BTP is able to remove 93.2 % of iodine from an aqueous source phase at a flow rate of 1 mL min −1 .