Adsorption of CO₂, CH₄, CO₂/N₂ and CO₂/CH₄ in novel activated carbon beads: Preparation, measurements and simulation

Abstract

Abstract A series of high performance carbonaceous mesoporous materials: activated carbon beads (ACBs), have been prepared in this work. Among the samples, ACB‐5 possesses the BET specific surface area of 3537 m 2 g −1 and ACB‐2 has the pore volume of 3.18 cm 3 g −1 . Experimental measurements were carried out on the intelligent gravimetric analyzer (IGA‐003, Hiden). Carbon dioxide adsorption capacity of 909 mg g −1 has been achieved in ACB‐5 at 298 K and 18 bar, which is superior to the existing carbonaceous porous materials and comparable to metal‐organic framework (MOF)‐177 (1232 mg g −1 , at 298 K and 20 bar) and covalent‐organic framework (COF)‐102 (1050 mg g −1 at 298 K and 20 bar) reported in the literature. Moreover, methane uptake reaches 15.23 wt % in ACB‐5 at 298 K and 18 bar, which is better than MOF‐5. To predict the performances of the samples ACB‐2 and ACB‐5 at high pressures, modeling of the samples and grand canonical Monte Carlo simulation have been conducted, as is presented in our previous work. The adsorption isotherms of CO 2 /N 2 and CO 2 /CH 4 in our samples ACB‐2 and 5 have been measured at 298 and 348 K and different compositions, corresponding to the pre‐ and postcombustion conditions for CO 2 capture. The Dual‐Site Langmuir‐Freundlich (DSLF) model‐based ideal‐adsorbed solution theory (IAST) was also used to solve the selectivity of CO 2 over N 2 and CH 4 . The selectivities of ACBs for CO 2 /CH 4 are in the range of 2–2.5, while they remain in the range of 6.0–8.0 for CO 2 /N 2 at T = 298 K. In summary, this work presents a new type of adsorbent‐ACBs, which are not only good candidates for CO 2 and CH 4 storage but also for the capture of carbon dioxide in pre‐ and postcombustion processes. © 2011 American Institute of Chemical Engineers AIChE J, 2011