Untitled - Technische Universiteit Eindhoven

42 3. Interfacial effects during reactive transport3.5 ConclusionThe mass transfer of TMOS in a two-phase bulk system, from the oleic to the aqueousphase, gives rise to a moving interface between the phases. Experiments were previouslydone using MRI to characterize the mass transfer and gel reactions. In this chapter, theMRI images were analyzed in detail. In each image the interface was identified through animage analysis procedure. By optimizing and matching the solution of a calculated modelinterface, assuming quasi-static conditions, the interfacial tension was determined. Theinterfacial tension in the two-phase system increases during the reactive mass transfer,which is clearly observed in the experiments with the high initial TMOS fraction of 0.40.The change in IFT is less pronounced in the experiments with the lower initial TMOSfraction of 0.20. A verification experiment was done, with an initial TMOS concentrationof 0.40, using a ring tensiometer. The trend of increasing IFT during the mass transferwas found with both methods.