Bitumen emulsification using a hydrophilic polymeric surfactant: Performance evaluation in the presence of salinity

In the present study, bitumen was dispersed in the aqueous solution of PVA (Poly Vinyl Alcohol) containing dissolved salt (NaCl). The stability and rheological property were studied to evaluate the characteristics of the dispersion system under the influence of salt. Under an isothermal condition (temperature of 20 °C), it was observed that the stability of bitumen-in-water emulsion containing 50% bitumen content, was increased by the dissolution of 0.5% w/w salt in the aqueous phase while at the salt content of 1% w/w and above, the stability of emulsion was decreased. In addition, the tolerance of the chemical to salinity was confirmed since the surface tension of the aqueous solution and the particle size of emulsions were not significantly affected at the level of salinity considered in this study. Moreover, analysis of the rheological property indicated that, the emulsions behave as non-Newtonian pseudoplastic (shear thinning) fluid regardless of the salt content. The apparent viscosity of emulsion was not significantly affected at up to salinity level of 1.0% w/w; while the salt content of 2% w/w and 3.5% w/w increased the apparent viscosity of emulsion.