Initially, we performed solubility tests by adding 0.1 wt% of
crude oil in the O/W nanoemulsions, at room temperature. For the
nanoemulsion that presented the best solubilization of crude oil,
we did saturation tests, by adding concentrations ranging from
0.001 to 10 wt% of crude oil in the nanoemulsion.
Later, we carried out solubility tests of crude oil dispersed in
synthetic oily water by addition of the nanoemulsion in the oily
water samples in the following ratios: 1:1, 1:0.5, 1:0.2, 1:0.1,
1:0.02 and 1:0.01. The droplet size and size distribution were
measured in the Zetasizer Nano ZS. Analyzes were also made in
the S2H10 optical microscope in order to observe the behavior of
the nanoemulsion before and after adding the oil. From these
tests, we determined the saturation point of the nanoemulsion
with crude oil and selected the mixing ratio able to transform the
oily water in a colloidal dispersion. This ratio was then used as a
standard to obtain the calibration curve of crude oil in the
nanoemulsion.