Understanding the Relationship between Corrosion Inhibitor Adsorption and Surfactant Properties and Micellization: Methodology

摘要

A novel experimental methodology for investigating the relationship between corrosion inhibitor adsorption and micellization processes was developed and implemented using typical components of commercially available corrosion inhibitors for oil and gas applications (e.g., quaternary amines, imidazolines). This paper presents the methodology and approach used to characterize micellization and adsorption related parameters for an individual corrosion inhibitor components; specifically, data for a homologous quaternary amine series is presented in this manuscript. The micellization phenomenon associated with an inhibitor molecule in aqueous solutions was studied using surface tension measurements and fluorescence spectroscopy. For the same molecule, the adsorption phenomenon onto a platinum surface was studied, using quartz crystal microbalance and electrochemical methods, which included Capacitance vs potential measurements and Cyclic Voltammetry. Micellization and adsorption were found to be closely related. Free energy change associated with adsorption onto the Pt/solution interface was more negative than that associated with the micellization process. The effect of temperature on the adsorption and micellization process was also studied to provide insights into the thermodynamic constants - enthalpy and entropy changes, associated with micellization and adsorption processes. Thermodynamic data could potentially be used to help tailor corrosion inhibitor for specific and / or challenging conditions encountered in oil and gas industry. The experimental methodology was implemented to investigate different pure components of typical corrosion inhibitors at different environmental conditions (salinity and temperature). Important thermodynamic parameters such as free energy, entropy and enthalpy associated with the adsorption and micellization process were also derived from these studies. This paper will show results obtained with quaternary amine based inhibitor family.