Synergistic inhibition effect of novel counterion-coupled surfactant based on rice bran oil and halide ion on the C-steel corrosion in molar sulphuric acid: Experimental and computational approaches

The counterion-coupled surfactant (RBOS-12) based on rice bran oil is synthesized, characterized, and evaluated as a new inhibitor for carbon steel corrosion. The inhibition, and synergistic effect performance of individual RBOS-12, and that is combined with chloride ions on the corrosion of carbon steel in a molar sulphuric acid medium at 30-60 +/- 1 degrees C has been examined using open circuit potential-time, linear polarization resistance (LPR) corrosion rate, impedance spectroscopy (EIS), potentiodynamic polarization (PDP), surface topology (Field emission-scanning electron microscopy/Energy dispersive X-ray analysis (FE-SEM/EDS), X-ray diffraction (XRD) and UV-vis spectroscopic studies), density functional theory (DFT) and molecular dynamics (MD) simulations. Experimental findings exhibited that the inhibition capacity of individual RBOS-12 is 95.5% at the concentration of 1.0 x 10(-3) M. Synergistic inhibition effect was observed between the RBOS-12 surfactant and the Cl- ion additives, with the maximum corrosion inhibition capacity as high as similar to 99.1% at 1 x 10(-5) M RBOS-12 + 0.1 M Cl- ions. The individual RBOS-12 and RBOS-12/Cl- system get adsorbed onto the metal interface through mixed categories of adsorption mainly with the chemisorption. Meanwhile, the adsorption mode follows the Langmuir isotherm model. FE-SEM/EDS and XRD investigates approve the protective and adsorption capabilities of the individual RBOS-12 and RBOS-12/Cl- inhibitor systems. UV-vis spectroscopic analysis display that the additive interacts with metal in H2SO4 medium to form Fe-inhibitor complexes. DFT calculations and MD simulations further support the empirical outcomes. The findings exhibited that the prepared RBOS-12/Cl-system can be used as economic, eco-friendly, and efficient corrosion inhibitor with good anticorrosion properties for metals in acidic environments. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study found that the RBOS-12 surfactant has an inhibition capacity of 95.5% at a concentration of 1.0 x 10(-3) M, and when combined with chloride ions, the corrosion inhibition capacity can be as high as 99.1%. The RBOS-12/Cl- system adsorbs onto the metal interface through mainly chemisorption, showing good corrosion inhibition properties.