CO2 Adsorption by Functionalized Nanoporous Materials: A Review

This review highlights the recent advances in the development of functionalized nanoporous adsorbentsfor CO2 capture. Three main classes of materials are taken into account: zeolites, mesoporoussilicates, and metal organic frameworks (MOFs). Proper modification of the cation content of zeolites,as well as the introduction of functional groups such as amine groups into ordered mesoporoussilicates and MOFs, greatly enhance the CO2 adsorptive properties of these substrates. Specifically,cation-exchanged zeolites can be currently considered the benchmark for ordered nanoporous CO2adsorbents, finding application also on a plant scale. Amino-functionalized mesoporous silicatestend to show a high affinity toward CO2: while this could be an advantage when pushed purificationis needed, it also implies that full regeneration of the adsorbent can be achieved only by puttingits surface in contact with a completely CO2-free environment. On the contrary, similarly modifiedMOFs show higher CO2 adsorption working capacities: this potentially makes them even bettercandidates than their mesoporous inorganic homologues for a plant scale use. However, the persistinglack of reliable methods for the pelletization of both ordered mesoporous silicates and MOFscreates a care for further development efforts in the next future.