Theoretical and experimental insights into the C-steel aqueous corrosion inhibition at elevated temperatures in 1.0M HCl via multi-carbonyl Gemini cationic surfactants

Abstract

Despite corrosion being an inevitable process, researchers strive to control corrosion. In this study, our goal was to prepare two amido Gemini cationic surfactants, LAPG and MAPG, each with different alkyl chains and multiple carbonyl groups as rich electronic rich centers. We aimed to evaluate these surfactants as potential corrosion inhibitors for carbon steel (CS) in 1M HCl at temperatures of 25-55 ± 0.1°C. In theoretical investigations, DFT parameters and Mont Carlo simulation were run to predict the adsorption affinity and reactive sites of the LAPG and MAPG molecules. Their efficacy was investigated experimentally considering weight loss and electrochemical techniques. The Tafel polarization revealed that at 0.1mM of LAPG and MAPG, the corrosion current density (i corr) of CS was reduced to the lowest extent (75.56 and 53.82μAcm-2) compared to 529.3μAcm-2 in the absence of the inhibitors. EIS data suggests the enhancement of the thickness of the adsorbed layers of the studied compounds from the decrease of the double-layer capacitance C dl values. The Langmuir isotherm explained the adoption phenomena of these compounds at 25-55 ± 0.1°C. Activation and adsorption thermodynamic parameters predicted the chemisorption behavior of these molecules onto the steel surface. AFM and XPS tools confirm the CS surface protection due to these inhibitors' adsorbed layer. A parallel study showed the superiority of these corrosion inhibitors in HCl compared with those reported earlier, making these compounds highly promising corrosion inhibitors, especially in high-temperature acidic environments.