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CO 2 Adsorption on Supported Molecular Amidine Systems on Activated Carbon
Author(s) -
Alesi W. Richard,
Gray McMahan,
Kitchin John R.
Publication year - 2010
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201000056
Subject(s) - amidine , adsorption , activated carbon , chemistry , carbon fibers , combinatorial chemistry , chemical engineering , organic chemistry , materials science , engineering , composite number , composite material
The CO 2 capture capacities for typical flue gas capture and regeneration conditions of two tertiary amidine N ‐methyltetrahydropyrimidine (MTHP) derivatives supported on activated carbon were determined through temperature‐controlled packed‐bed reactor experiments. Adsorption–desorption experiments were conducted at initial adsorption temperatures ranging from 29 °C to 50 °C with temperature‐programmed regeneration under an inert purge stream. In addition to the capture capacity of each amine, the efficiencies at which the amidines interact with CO 2 were determined. Capture capacities were obtained for 1,5‐diazo‐bicyclo[4.3.0]non‐5‐ene (DBN) and 1,8‐diazobicyclo[5.4.0]‐undec‐7‐ene (DBU) supported on activated carbon at a loading of approximately 2.7 mol amidine per kg of sorbent. Moisture was found to be essential for CO 2 capture on the amidines, but parasitic moisture sorption on the activated carbon ultimately limited the capture capacities. DBN was shown to have a higher capture capacity of 0.8 mol CO 2 per kg of sorbent and an efficiency of 0.30 mol CO 2 per mol of amidine at an adsorption temperature of 29 °C compared to DBU. The results of these experiments were then used in conjunction with a single‐site adsorption model to derive the Gibbs free energy for the capture reaction, which can provide information about the suitability of the sorbent under different operating conditions.