High selectivity of TiC-CDC for CO2/N2 separation

Abstract

A series of carbide-derived carbons (CDC) have been prepared starting from TiC and using different chlorine treatment temperatures (500ºC-1200ºC). Contrary to N 2 adsorption measurements at -196ºC, CO 2 adsorption measurements at room temperature and high pressure (up to 1 MPa) together with immersion calorimetry measurements into dichloromethane suggest that the synthesized CDC exhibit a similar porous structure, in terms of narrow pore volume, independently of the temperature of the reactive extraction treatment used (samples synthesized below 1000ºC). Apparently, these carbide-derived carbons exhibit narrow constrictions were CO 2 adsorption under standard conditions (0ºC and atmospheric pressure) is kinetically restricted. The same accounts for a slightly larger molecule as N 2 at a lower adsorption temperature (-196ºC), i.e. textural parameters obtained from N 2 adsorption measurements on CDC 2 must be underestimated. Furthermore, here we show experimentally that nitrogen exhibits an unusual behavior, poor affinity, on these carbide-derived carbons. CH 4 with a slightly larger diameter (0.39 nm) is able to partially access the inner porous structure whereas N 2 , with a slightly smaller diameter (0.36 nm), does not. Consequently, these CDC can be envisaged as excellent sorbent for selective CO 2 capture in flue-gas streams.

Controlling Synthesis of Polymer-Derived Carbon Molecular Sieve and Its Performance for CO2/CH4 Separation

“…The molecular sieving characters of carbon material are dictated by many factors such as the pore structure of adsorbent, kinetic diameter of adsorbate, affinity of adsorbate toward carbon surface and molecular interaction of adsorbate. It is known that pore size distribution with high portion below ultramicropore range (<0.7 nm) like featured by CMS-2 is essential to introduce good molecular sieving characters [4]. Furthermore, location and number of pore mouth (pore constriction) also plays important roles, although these parameters are difficult to be quantitatively determined.…”

“…This technique has been widely used in many chemical industries and become competitive to conventional separation process such as cryogenic distillation or absorption [3]. Due to its specific micropore structure, this porous carbon molecular sieve can provide more selective properties than conventional activated carbon in adsorbing molecule from a gaseous mixture [4][5][6]. With the micropore size in the range of molecular dimension, a small difference in size of molecules to be adsorbed will lead to a large difference in micropore diffusivities due to the activation energy required for diffusion.…”

Novel process for producing hierarchical carbide derived carbon monolith and low carbon ferromanganese from high carbon ferromanganese

“…It is found that the amount of cathode products is four times than the amount of manganese ions added initially, which implied that most of ferromanganese deposits were fed from HCMnFe. Since we supposed both manganese and iron are reduced in a divalent state, the anode and cathode current efficiency are considered to be at least 92% and 80% respectively, which are computed via combining Faraday's law and eqn (1)- (3). The lost cathode current efficiency may be attributed to the loss of the powdered product during the collection process which was mixed with molten salts.…”

129Xenon NMR: Review of recent insights into porous materials

“…Porous carbon materials with high specific surface areas and superhydrophobicity have attracted much research interest due to their potential application in various fields including adsorption/separation of gases [214], energy storage [215] and catalysis [216].…”