Experimental investigation of emulsion formation and stability: Comparison of low salinity water and smart water effect

Effect of the presence of NaCl, Na2SO4, MgCl2 and CaCl2 as smart water with different salinity was investigated in the formation and stability of the emulsion. Three methods were used to evaluate the emulsion stability. The first method, the amount of water separated from each sample, after 14 days of emulsion preparation, was recorded and examined. Bottle test was the second method to evaluate the stability during which the emulsion samples were monitored for up to 14 days. In the third method, a microscopic image was taken from each sample, and the mean droplet area for each sample was recorded. By adding Na2SO4 to a concentration of 8000 ppm in distilled water, the most stable emulsion was obtained, which was completely stable for up to 48 h, and after two weeks of preparation of the emulsion, almost only 10% of the aqueous phase was separated from the emulsion. And the microscopic image showed that in this case, the mean droplet area is 17 μm2, which, compared to other salts in different concentrations, had the lowest amount. On the other hand, salt NaCl with a concentration of 40,000 ppm formed the most unstable emulsion, which after 14 days, almost the entire aqueous phase was separated from the emulsion. By microscopic image analysis, the average droplets area was 58 μm2 for NaCl with 40000 ppm concentration, which is the highest value compared to other samples. While seawater was used to make the emulsion, ten times diluted seawater formed the most stable emulsion.