Surface modification induced enhanced CO sorption in cucurbit[6]uril, an organic porous material.

The CO adsorption properties of an organic macrocycle, cucurbit[6]uril (CB[6]), have been evaluated through experimental and theoretical studies. Quantum mechanical calculations show that CB[6] is capable of adsorbing the CO molecule selectively within its cavity relative to nitrogen. Adsorption experiments at 298 K and at 1 bar pressure gave a CO adsorption value of 1.23 mmol g for the unmodified material. Significant enhancements in the CO adsorption capacity of the material were experimentally demonstrated through surface modification using physical and chemical methods. Ethanolamine (EA) modified CB[6] provided an excellent sorption selectivity value of 121.4 for CO/N at 323 K and is unique with respect to its discrimination potential between CO and N. The chemical nature of the interaction between CO and amine is shown to be the primary mechanism for the enhanced CO absorption performance.