Simultaneous influence of uni-univalent salt aqueous solutions and sodium dodecyl sulfate surfactant on interfacial tension of toluene-water

• Published in: The Korean journal of chemical engineering Vol. 30; no. 5; pp. 1125 - 1130
• Main Authors: Saien, Javad, Moghaddamnia, Farzaneh, Mishi, Mokhtar
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.05.2013; 한국화학공학회
• Subjects: Biotechnology; Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Materials Science; Separation Technology; Thermodynamics; 화학공학; SDS; Uni-univalent Salts; Interfacial Tension; Equations of State; Toluene-water
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-013-0001-3

The simultaneous influence of NaCl, KCl and KI salts and well known sodium dodecyl sulfate (SDS) surfactant on the interfacial tension (IFT) of conventionally used chemical system of toluene-water was studied. The concentration range of salts was within (0.010 to 0.075) mol/dm 3 and of surfactant within (1.7 to 26.0)×10 −5 mol/dm 3 . SDS adsorption on interface is highly intensified in the presence of salts and IFT can reach to 67.1% of its initial value. Accordingly, the role of ions was investigated and the order of salts effectiveness was revealed as KI≫KCl>NaCl. The obtained data, with both effects, were nicely reproduced using an equation of state, based on Gibbs adsorption equation and the Langmuir isotherm. Two relevant important adsorption parameters exhibited reasonable variations. Furthermore, the general revealed linear variation of IFT with a previously defined “effective concentration” indicates the strong influence of the surfactant counterions.