CO₂-Filling Capacity and Selectivity of Carbon Nanopores: Synthesis, Texture, and Pore-Size Distribution from Quenched-Solid Density Functional Theory (QSDFT)

Abstract

Porous carbons synthesized by KOH activation of petroleum coke can have high surface areas, over 3000 m(2)/g, and high CO(2) sorption capacity, over 15 wt % at 1 bar. This makes them attractive sorbents for carbon capture from combustion flue gas. Quenched solid density functional theory (QSDFT) analysis of high-resolution nitrogen-sorption data for such materials leads to the conclusion that it is the pores smaller than 1 nm in diameter that fill with high-density CO(2) at atmospheric pressure. Upon increasing pressure, larger and larger pores are filled, up to about 4 nm at 10 bar. An ideal CO(2)/N(2) selectivity of such carbon materials tends to decrease substantially upon increasing pressure, for example, from about 8-10 at 1 bar to about 4-5 at 10 bar. All in all, this work confirms the robust CO(2)-filling properties of porous carbon sorbents, their low-pressure selectivity advantages, and points to the critical role of <1 nm pores that can be controlled with activation conditions.

Amine-modified ordered mesoporous silica: The effect of pore size on CO2 capture performance

“…Therefore, developing alternative CO 2 sorbents is considered in recent years. Porous solids such as zeolites, [8,9] porous carbon [10] or metal oxides [11] are good candidates for capturing CO 2 .…”

Solid Adsorbents for Low-Temperature CO2 Capture with Low-Energy Penalties Leading to More Effective Integrated Solutions for Power Generation and Industrial Processes

“…More recently, Hu et al used a more sophisticated method (QuenchedSolid Density Functional Theory) to analyze the low-temperature N 2 adsorption data, by which high-resolution pore distributions of a series of petroleum coke-derived carbons could be obtained. This enabled conclusions to be drawn that at atmospheric pressure, high-density CO 2 filled the pores smaller than 1 nm, upon increasing pressure, larger pores are filled (up to about 4 nm at 10 bar; Hu et al, 2011). Similar conclusions have also been achieved by using Grand Canonical Monte Carlo simulation and Non-Local Density Functional Theory (NLDFT) (Martin-Martinez et al, 1995;Cazorla-Amoros et al, 1996;Vishnyakov et al, 1999;Wei et al, 2012).…”

Solid‐Waste‐Derived Carbon Dioxide‐Capturing Materials

“…[156,159] Wahby et al used petroleum pitch to prepare as eries of carbon molecular sieves through activation with KOH. They are promising raw materials because they contain ah igh fixed carbon content,l ow ash content, andl ow volatility.T herefore, they are also employed as precursorsf or producing carbon materials.…”