Partitioning of a model corrosion inhibitor in emulsions
Knag, M.
,
Sjöblom, J.
,
Gulbrandsen, E.
Journal of dispersion science and technology, Vol. 27, no. 1 (2006), 65-75
2006
article
As the majority of corrosion inhibitors used in oil production are surfactants, they are are not only adsorbing to metal surfaces, but also at the oil/water (o/w) interface and onto dispersed solid particles. In the present work, the partitioning of cetyltrimethylammonium bromide (CTAB) between the aqueous bulk and the o/w interface is investigated. Zeta potential measurement of oil droplets at different CTAB concentrations has been utilized to study the adsorption process at the o/w interface. The CTAB reached an adsorption maximum at the critical micelle concentration. Upon dilution, the CTAB desorbed to equilibrium values within minutes. A new method has been utilized for determining the concentration of CTAB in the continuous phase of an o/w emulsion. The effects of some selected parameters were investigated in a fractional factorial experimental design, and the main effects were determined by blocking the experiments for each effect. The average loss of CTAB due to emulsification of 5% oil was found to be 0.34 and 0.24 mmol dm−3, 15 minutes and 315 minutes after emulsification, respectively. The loss of CTAB was higher for samples with an initial concentration of 3 mmol dm−3 than for those with an initial concentration of 1 mmol dm−3. Of the parameters investigated, the presence of 3% NaCl had the highest impact on the CTAB loss for the samples taken 15 minutes after emulsification, while the presence of 100 ppm MEG had the highest impact 315 minutes after emulsification. The presence of NaCl and MEG increased the aqueous concentration of CTAB. (Taylor & Francis)
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