Abstract

DE LEMOS ARAUJO, Alessandro Alisson; DE BARROS NETO, Eduardo Lins; CHIAVONE-FILHO, Osvaldo  and  FOLETTO, Edson Luiz. Influence of sodium chloride on the cloud point of polyethoxylate surfactants and estimation of Flory-Huggins model parameters. Rev.fac.ing.univ. Antioquia [online]. 2015, n.75, pp.155-162. ISSN 0120-6230.  https://doi.org/10.17533/udea.redin.n75a15.

In this study, the influence of NaCl on the cloud point of polyethoxylate surfactants from the family of lauryl alcohol polyethoxylates (C₁₂EO_n) and nonylphenol polyethoxylates (NPEO_n) was investigated. Liquid-liquid equilibrium curves of the aforementioned aqueous surfactant systems with the presence of NaCl were plotted and thermodynamic parameters based on the Flory-Huggins model were obtained. The visual method was used to determine the cloud point. Solutions containing surfactant concentrations between 0.5 and 20% (by weight) and NaCl between 4.9 and 12.1% (by weight) were prepared. Salt had a salting-out effect, decreasing surfactant solubility in water. Furthermore, the cloud point decreased with an increase of NaCl concentration. The Flory-Huggins model satisfactorily described the experimental data for all surfactant + NaCl aqueous mixtures studied.

Keywords : Nonionic surfactant; cloud point; NaCl; Flory-Huggins model.

        · abstract in Spanish     · text in English     · English ( pdf )