Publication Date:
2017-06-08
Description:
The kinetics of adsorption of CO 2 on solid sorbents based on polyethyleneimine/mesoporous silica (PEI/MPS) was studied by following the mass gain during CO 2 flow. The desorption kinetics was also investigated. A linear (PEI-423) and a branched (PEI-10k), both with similar nitrogen contents, were chosen for this study. The solid sorbents were synthesized by impregnating the PEI materials into MPS foam. The kinetics of adsorption was fitted with a double exponential model in which the first exponential component describing the surface adsorption and the second one for the diffusion of CO 2 into the silica pores. On the other hand, the desorption process obeyed a simple first order kinetics. The activation energy of desorption off PEI-423 was lower than that of PEI-10k, presumably, because the first imine is linear but the latter is branched, thus needed more energy to have its nitrogen well exposed to CO 2 . In an attempt to increase the CO 2 sorption capacity, the MPS was first treated by non-ionic surfactant materials prior to impregnation with PEI. The surfactants treatment enhanced the CO 2 sorpitivity by ~ 10% due to accelerating the kinetics of surface adsorption; revealing that the surfactant assisted the dispersion of the PEI onto the MPS surface. The surfactant effect was not only limited to improving the sorption capacity, but also lowered both the maximum sorption temperature and the desorption activation energies.
Print ISSN:
0930-7516
Electronic ISSN:
1521-4125
Topics:
Chemistry and Pharmacology
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Process Engineering, Biotechnology, Nutrition Technology
