Development of group-contribution models for use in surfactant selection – case studies of single and mixed surfactant applications

Abstract

Microemulsion is the surfactant/oil/water system that is applied to many applications such as enhanced oil recovery, cleaning agents, environmental remediation and drug delivery system. To select the suitable surfactant to form an efficient microemulsion system for each specific condition and application, a systematic selection method is needed to reduce time and valuable resources that may be required in the design of an interest product. This work developed a systematic method to select suitable surfactants for a specific application based on several properties including but not limited to types of emulsion, emulsion stability, solubility and toxicology. Since not all models are available in the literature, this work developed properties models based on the molecular structure of the surfactants by using the concept of Group-Contribution (GC) based on Marrero and Gani method. One important key of surfactant properties for Hydrophilic-Lipophilic property through an Hydrophilic-Lipophilic Deviation (HLD) equation is the characterictic curvature (Cc) that indicates the hydrophobicity or hydrophilicity of a surfactant based on their molecular structure. This work developed the GC-model for prediction of characteristic curvature of anionic and nonionic surfactants to use in the HLD equation to aid in the design of surfactant formulation. Krafft point—another key property to indicate the solubility of anionic surfactant, was also modeled based on the GC concept. The application of this work was performed through case studies in the fields of enhanced oil recovery, soil remediation and detergency.