A PREDICTIVE NUMERICAL THERMODYNAMIC MODEL OF MIXED NONIONIC SURFACTANT SORPTION IN NATURAL SYSTEMS - 2 - APPLICATION TO BROADLY DISTRIBUTED MIXTURES

Because most commercially available surfactants consist of mixtures of surfactant components, an understanding of mixed surfactant sorption behavior in the presence of natural materials may be essential for opt imal design of surfactant-based industrial processes or environmental remediation applications. This paper demonstrates the application of a new numerical thermodynamic model to the prediction of the mixed sorp tion behavior of broadly distributed nonionic surfactant mixtures. The model is found to provide excellent agreement with experimental obser vations for two different ethoxylated nonionic surfactant mixtures, on e containing 41 components. In addition, the model is demonstrated to be able to qualitatively and quantitatively duplicate the influence on mixed sorption of variation in sorbent surface area. Procedures for d etermining model parameters for broadly distributed surfactant mixture s are discussed, and applications for the model are described. Tabulat ed model parameters that can be used to predict sorption of ethoxylate d nonylphenol surfactants to silica are presented. Procedures for appl ying these parameters to the prediction of the sorption of ethoxylated nonylphenol mixtures on other natural silicate materials are discusse d. (C) 1998 Academic Press.