Effect of small amounts of surfactants on oil-water dispersion

Abstract

The present work reports the study of oil-water dispersions in static conditions. All experiments were carried out with a mineral oil and tap water in glass beakers with mixing of the phases. Small amounts of non-ionic surfactants were used to stabilize the emulsion systems. This simple system gives a good formation of oil-water emulsions. The objective of the present work is better understanding of emulsion behavior. The study was conducted with increasing agitation speed of impeller and different proportion of Span 80 and Tween 80. The understanding of emulsion changes with increase HLB value from 4.3 to 15 was studied on both O/W and W/O emulsion types. The emulsions, which did not show immediate separation trends, were analyzed for 72 hours with pH meter, a microscope. The unstable emulsions separated due to creaming and coalescence processes. Droplets of the short- stable emulsion were growing in size along time, what signals about coalescence. During guest’s presentation out of Mettler Toledo Company it was a great luck to use FBRM and PVM probes to confirm states made with simple measurement tools and compare the results. The results achieved with FBRM and PVM tools, also prove that the droplets sizes decrease with addition of a very small amount of surfactants and/or increase of stirring speed of an impeller.