CO<SUB>2</SUB> Adsorption by Functionalized Nanoporous Materials: A Review

Abstract

This review highlights the recent advances in the development of functionalized nanoporous adsorbents for CO2 capture. Three main classes of materials are taken into account: zeolites, mesoporous silicates, 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 mesoporous silicates and MOFs, greatly enhance the CO2 adsorptive properties of these substrates. Specifically, cation-exchanged zeolites can be currently considered the benchmark for ordered nanoporous CO2 adsorbents, finding application also on a plant scale. Amino-functionalized mesoporous silicates tend to show a high affinity toward CO2: while this could be an advantage when pushed purification is needed, it also implies that full regeneration of the adsorbent can be achieved only by putting its surface in contact with a completely CO2-free environment. On the contrary, similarly modified MOFs show higher CO2 adsorption working capacities: this potentially makes them even better candidates than their mesoporous inorganic homologues for a plant scale use. However, the persisting lack of reliable methods for the pelletization of both ordered mesoporous silicates and MOFs creates a care for further development efforts in the next future.

Biomass Waste Carbon Materials as adsorbents for CO2 Capture under Post-Combustion Conditions

“…On the other hand, activated carbon materials are usually adversely compared in terms of CO2 adsorption capacity and/or selectivity. Nevertheless, it has been proven that adsorption capacity and selectivity toward CO2 are strongly dependent on the porous structure and chemical surface of the adsorbent (Ruthven, 1984;Marsh and Rodríguez-Reinoso, 2006;Shafeeyan et al, 2010;Gargiulo et al, 2014). Specifically, it has been reported that at low CO2 partial pressures and room temperature, CO2 adsorption capacity is intrinsically related to micropores, although some discrepancies can be found in the literature.…”

Solid mesostructured polymer–surfactant films at the air–liquid interface

“…Other possible applications could include heavy ion removal or an 17 environmental absorbent. [75,81,82] Perhaps the most interesting potential use of the films is in drug 18 delivery. It has already been shown how small amounts of hydrocarbons or alcohols can be incorporated into 19 micelles within the polymer-surfactant films.…”

Polyethylenimine-incorporated zeolite 13X with mesoporosity for post-combustion CO2 capture

“…In this work, we synthesized a hierarchical zeolite X with mesoporosity (Meso-13X) and attempted to make use of the mesoporosity to incorporate increased and better dispersed amine species inside its pore structure. Polyethylenimine (PEI) was chosen as the amine source, which was found to greatly enhance CO 2 capture when supported on mesoporous silica [18][19][20][21][22][23]. The effectiveness of PEImodified Meso-13X (Meso-13X-PEI) as a CO 2 adsorbent was tested in terms of its adsorption capacity, selectivity and stability.…”