Mass transfer characterization in forward and back extractions of lysozyme by AOT-isooctane reverse micelles across a flat liquid-liquid interface

摘要

The mass transfer rates in lysozyme extraction between an aqueous KCl solution and an bis (2-ethyl) sodium sulfosuccinate (AOT)-isooctane reversed micellar solution were investigated using a stirred cell with a flat liquid-liquid interface. The forward extraction rates from 0.1 kmol m~(-3) KCl solution of pH 6.5 to a reversed micellar phase are controlled by the diffusion in the aqueous film and the solubilization at the interface. The solubilizing rate constant, k_(fs), increases from 3.57*10~(-5) to 1.43*10~(-4) m s~(-1) in proportion to AOT concentration of 0.05 to 0.2 kmol m~(-3). Forthe back extraction of lysozyme from the reversed micellar phase to an aqueous solution of higher KCl concentration,the rate-determining step is the release process at the interface. The releasing rate constant, k_(bd),decreases with an increase of AOT concentration and is also two orders smaller than the k_(fs) values. The back extraction rates are therefore very slow compared to the forward extraction rates.