Calix[4]pyrrole‐based Crosslinked Polymer Networks for Highly Effective Iodine Adsorption from Water

A series of calix[4]pyrrole‐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)calix[4]pyrrole 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, C[4]P‐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 C[4]P‐BTP is able to remove 93.2 % of iodine from an aqueous source phase at a flow rate of 1 mL min −1 .