High‐Surface‐Area Carbon Molecular Sieves for Selective CO₂ Adsorption

Abstract

A series of carbon molecular sieves (CMSs) has been prepared, either as powders or monoliths, from petroleum pitch using potassium hydroxide as the activating agent. The CMS monoliths are prepared without the use of a binder based on the self-sintering ability of the mesophase pitch. Characterization results show that these CMSs combine a large apparent surface area (up to ca. 3100 m(2) g(-1)) together with a well-developed narrow microporosity (V(n) up to ca. 1.4 cm(3) g(-1)). The materials exhibit high adsorption capacities for CO(2) at 1 bar and 273 K (up to ca. 380 mg CO(2) g sorbent(-1)). To our knowledge, this is the best result obtained for CO(2) adsorption using carbon-based materials. Furthermore, although the CO(2) adsorption capacity for activated carbons has usually been considered lower than that of zeolites, the reported values exceed the total amount adsorbed on traditional 13X and 5A zeolites (ca. 230 mg and 180 mg CO(2) g sorbent(-1), respectively), under identical experimental conditions. Additionally, the narrow pore openings found in the CMS samples (ca. 0.4 nm) allows for the selective adsorption of CO(2) from molecules of similar dimensions (e.g., CH(4) and N(2)).

Sustainable biomass-based carbon adsorbents for post-combustion CO2 capture

“…At 25 ˚C, the CO 2 adsorption capacity of carbons AS and OS is between that of Brightblack TM at 20 and 30 ˚C, which is a carbon adsorbent specifically developed by ATMI Inc. to maximise CO 2 adsorption [35]. The CO 2 adsorption capacity is also above that reported for high-surface-area carbon molecular sieves prepared from petroleum mesophase pitch (VR-5-M in Table 4), which not long ago were claimed to be the best result ever obtained for CO 2 adsorption with carbon-based materials [36]. Comparing carbons OS and AS, it can be seen that the adsorption capacity at 15 kPa of AS is above that of OS (Table 4).…”

High selectivity of TiC-CDC for CO2/N2 separation

“…In any case, the total amount adsorbed of methane and nitrogen slightly increases for sample TiC-CDC-700, the amount adsorbed being mainly nil for the samples synthesized above this temperature. The larger adsorption of methane compared to nitrogen is completely opposite to the typical behavior observed in the literature for carbon molecular sieves, which is defined based on kinetic considerations [33]. The observed behavior on the carbide-derived carbon molecular sieves allows for a large CO 2 /N 2 selectivity (within the accuracy of the equipment ∞) compared to conventional carbon molecular sieves, except sample CDC-700.…”

“…This higher mobility during the 13 carbide-derived carbon network formation is supposed to be responsible for the aforementioned described effects. 14 Recent analysis described in the literature has shown that carbon materials are excellent candidates for CO 2 capture both at atmospheric and high pressure [1,2,26,33]. Taking into account that an optimum carbon for CO 2 capture requires the presence of a welldeveloped narrow microporosity (pores below 0.8 nm for atmospheric pressure studies), carbide-derived carbons can be anticipated as excellent candidates in terms of adsorption capacity and selectivity towards molecules of similar molecular dimensions.…”

Structurally Designed Synthesis of Mechanically Stable Poly(benzoxazine-co-resol)-Based Porous Carbon Monoliths and Their Application as High-Performance CO2 Capture Sorbents

“…They exhibit a larger adsorption capacity for CO 2 at high pressures but lower at low relative pressures. 10,11 In order to improve their CO 2 sorption performance, especially at low pressures, amine groups have been introduced into the porous carbons, by either postmodification or copolymerization of amine-containing precursors. 12,14À16 For example, the monoethanolamine impregnated activated carbons show enhanced CO 2 capacity (75 mg g À1 ) at 75°C and 1 bar as compared to the parent support (31 mg g À1 ).…”