Abstract
Steel alloys are significant industrial substances, but they generally suffer severe corrosion under harsh conditions. Using inhibitors is an efficacious method to impede corrosion. So, in this study, two novel natural surfactants based on soybean oil have been synthesized by a facile route, namely, 1-(bis(2-hydroxyethyl)amino)-1-oxooctadecan-9-yl sulfate 2-hydroxyethan-1-aminium (CSM) and–N-(C2H4-OH)2; 1-(bis(2-hydroxyethyl)amino)-1-oxooctadecan-9-yl sulfate bis(2-hydroxyethyl)aminium (CSD), and their chemical structures were elucidated by physical–chemical approaches, Fourier transform infrared (FT-IR) spectroscopy, and surface activity measurements. The inhibitive effect of natural surfactants (CSM and CSD) on the C-steel corrosion in CO2-saturated 3.5% NaCl has been estimated in this investigation by electrochemical and surface analyses including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), linear polarization resistance (LPR) corrosion rate, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscope/energy-dispersive X-ray spectroscopy (FESEM/EDX) approaches. The EIS study reveals the value ofRpaugmented to an increase of 913.5 Ω cm2with a protection capacity of 96.1% at 150 ppm (CSD). The outcomes of PDP suggested that CSM and CSD are mixed-type inhibitors. XPS and FESEM/EDX analyses determined the protective film formation on a metal interface having undamaged surface morphology and more homogeneities in the occurrence of the surfactant. Moreover, the adsorption of natural surfactants on the metal substrate takes place based on the model of Langmuir isotherm. Density functional theory (DFT) calculations and Monte Carlo (MC) simulations were selected for attaining basic atomic/electronic-scale details about the prepared surfactants, which support the practical findings. This study is intended to investigate the protection of C-steel using sweet service conditions with green extract surfactants.
Highlights
Sweet corrosion has gained abundant attention in the gas and oil industry, processing, and transportation
The protective effect of two natural surfactants based on soybean oil was inspected via different morphological (XPS and FESEM/EDX) and electrochemical (PDP, LPR corrosion rate) examinations and combined with DFT calculations and Monte Carlo (MC) simulations
The diverse experimental methods were in good agreement, presenting that CSD is a superior inhibitor compared to C2H4-OH; 1-[bis(2-hydroxyethyl) amino]-1-oxooctadecan-9-yl sulfate 2-hydoxyethan-1-aminium (CSM) under the same conditions, and the protection capacities augmented with the increase in the surfactant dose, reaching the maximum values 97.6 and 98.6% in the presence of 150 ppm of CSM and CSD, respectively
Summary
Sweet corrosion (carbon dioxide corrosion) has gained abundant attention in the gas and oil industry, processing, and transportation. It is because of the common practice of using carbon dioxide-saturated H2O in oil wells to diminish pumped fluid viscosity and improve oil recovery. A significant phenomenon is that when carbon dioxide dissolves in H2O, H2CO3 (carbonic acid) is formed which is more corrosive than HCl solution under similar conditions (Ramírez-Estrada et al, 2017). Alloys of carbon steel are the most commonly used manufacturing materials for pipelines in petroleum manufacturing. They are very vulnerable to corrosion under sweet corrosion environments. A deep understanding of the action mechanism of the corrosion mitigation route is still required for reliable implementations (Hsissou et al, 2019a; Saleh et al, 2019; Hsissou et al, 2020a; Zhang et al, 2021a)
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