Aqueous phase behaviour of surfactant and its application in cloud-point extraction

Abstract

AbstractSolubilization behavior of hydrophobic organic compounds (HOCs) by selected nonionic surfactants such as Tergitol 15-S-7, Neodol 25-7 and Tergitol 15-S-9 was studied. Micelle-water partition coefficients of HOCs were correlated with their octanol-water partition coefficients to find out solubilization power of selected nonionic surfactants along with their hydrophobicity. The change in hydrodynamic radius and aggregation number of micelles with temperature was measured by the dynamic and static laser light scattering techniques.Cloud point temperature of selected nonionic surfactants was studied together with the effect of added electrolytes on their cloud points not only to optimize the preconcentration factor but also to facilitate the experiment at room temperature. A simple but practical cloud-point extraction (CPE) technique was developed to extract trace amount of HOCs from aqueous sample. CPE experiment was conducted at room temperature (22A?C) by adding small amount of salt to micellar solution. Recoveries efficiencies were found ranging from 72% to 103%. The effect of the molecular structures and the HLB values of the surfactants as well as salts on recovery of HOCs were studied.