Selective sorption of CO2 from flue gas is of critical importance in mitigating the greenhouse gas emissions and is a crucial step for CO2 sequestration and utilization. In the past years, we have developed a series of molecular basket sorbents (MBS) consisting of functional polymers immobilized in nano-porous materials, which have shown great potential as highly selective, high-capacity solid sorbent for CO2 capture. As for the real application and the design of a sorption process, beside the thermodynamic characteristics, the knowledge of sorption kinetics or dynamic behavior in a fixed bed is valuable as well. In this paper, we report our study on the kinetics for CO2 sorption over MBS using a model flue gas with 15% CO2 in He at 75 �C. Three simplified kinetic models, i.e., the pseudo-first-order, the pseudo-second-order, and the intraparticle diffusion models were used to describe the kinetic data and the rate constants were calculated. The rate parameter, k1, of the pseudo-first-order, the rate parameter, k2, of the pseudo-second-order and ki, the rate parameter for the intraparticle diffusion mechanism were compared. It was found that the pseudo-second-order sorption mechanism is predominant, which is in a good agreement with the reaction chemistry for amine and CO2 and the Langmuir sorption mechanism over MBS. In addition, the rate constant and the initial sorption rate for CO2 increased with the increase of flue gas flow rate. At the flow rate of 224 ml/min (i.e., a GHSV of 16,800 h-1), the obtained rate constant was 0.0463 g mg-1 min-1 and the initial sorption rate was as high as 10.1 mg g-1 s-1.

Kinetic study of CO<sub>2</sub> sorption over molecular basket sorbent

245th National Meeting (2013)

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Kinetic study of CO2 sorption over molecular basket sorbent

Kinetic study of CO₂ sorption over molecular basket sorbent