Electrochemical Measurement and Modeling of Corrosion Inhibition Efficiency of Surfactants in Salt Solutions

In the present study, the corrosion inhibition efficiency (IE) of different mixtures of three homologous cationic surfactants, benzalkonium chlorides (ADBAC), were investigated using electrochemical measurements. There is excellent agreement between IE measured from EIS and LPR of the discussed mixture of ADBAC surfactants: C12Cl/C14Cl/C16Cl=0.70/0.25/0.05. The calculated adsorption free energy indicates that the adsorption mechanism of mixtures 0.70/0.25/0.05 is a mixed form of physisorption and chemisorption. A new critical micelle concentration (CMC) prediction model for ternary mixtures of homologous surfactants, on the basis of previous work, is developed over a wide concentration range of salt from 0.2% to 5.0% NaCl. The developed corrosion IE prediction model based on CMC prediction is an effective method that can be used for corrosion IE prediction of various mixed surfactant systems at various salt concentrations.