Rui Afonso, Sofia Félix and Adélio Mendes

DOI: http://dx.doi.org/10.15379/2410-1869.2017.04.01.02

The reaction kinetics of CO₂ with amines is usually studied using a stirred-cell reactor. This involves the construction of a sensitive and cumbersome apparatus, used through a lengthy and complicated experimental procedure. In this work, the feasibility of using an alternative method is assessed, based on the permeation of CO₂ through a membrane contactor into the amine-containing solution. A hollow fibre module of polydimethylsiloxane dense layer supported on a porous polyetherimide layer was initially tested, but membrane resistance to CO₂ permeation was too large to allow liquid resistance to be dominant, and thus the kinetic parameters of the solution could not be determined. A membrane with lower resistance was then used, a porous polytetrafluoroethylene (PTFE) flat-sheet membrane, which did allow for liquid resistance to be dominant, and thus permitted the calculation of kinetic parameters in the reaction system.

The kinetic constants calculated from the data obtained with the permeation experiments performed with the PTFE membrane were compared with results reported in the literature. The two sets of results show differences, although the general concentration dependence trends were similar. Similar differences have previously been observed between works of different authors, and so the method tested should be considered viable