An Overview of Molecular Dynamic Simulation for Corrosion Inhibition of Ferrous Metals

Surfactants as biodegradable sustainable inhibitors for corrosion control in diverse media and conditions: A comprehensive review

BACKGROUND

Corrosion is a challenging and potentially harmful process that involves the continuing, impulsive deterioration of metallic structures via reactions involving environmental components and electro- or chemical processes. To inhibit corrosion, various additives are added. Traditional additives, on the other hand, contain environmentally hazardous substances. Surfactants are less expensive, easier to manufacture, and have high inhibitory efficacy and low toxicity compared to standard corrosion inhibitors. They are often employed as corrosion inhibitors to protect metallic materials against corrosion.

METHODS

Surfactant molecules' amphiphilic nature promotes adsorption at surfaces such as the metal/metal oxide-water interface. Surfactant adsorption on metals and metal oxides forms a barrier that can prevent corrosion.

SIGNIFICANT FINDINGS

This review of surfactants as corrosion inhibitors aims to offer a systemic evaluation of various surfactant physical and chemical properties, surfactant influence in corrosion inhibition, and surfactant used in corrosion inhibition that can be used to enhance the efficacy of surfactant use as corrosion inhibitors in a variety of environments. The effect of several parameters on the potential to suppress corrosion of surfactant molecule series is also discussed here.

Corrosion Inhibition of Azo Compounds Derived from Schiff Bases on Mild Steel (XC70) in (HCl, 1 M DMSO) Medium: An Experimental and Theoretical Study

The inhibitory activity of three prepared azo compounds derived from Schiff bases, namely, bis[5-(phenylazo)-2-hydroxybenzaldehyde]-4,4'-diaminophenylmethane (C1), bis[5-(4-methylphenylazo)-2-hydroxybenzaldehyde]-4,4'-diaminophenylmethane (C2), and bis[5-(4-bromophenylazo)-2-hydroxybenzaldehyde]-4,4'-diaminophenylmethane (C3), against corrosion of steel type XC70 in (HCl, 1 M DMSO) medium was investigated experimentally by electrochemical measurements and theoretically using density functional theory (DFT). The correlation between corrosion inhibition and concentration is direct. The maximum inhibition efficiency at 6 × 10^-5 M for the three azo compounds derived from Schiff bases was 64.37, 87.27, and 55.47% for C1, C2, and C3, respectively. The Tafel curves indicate that the inhibitors follow a mixed but predominantly anodic inhibitor system and have a Langmuir isothermal adsorption process. The observed inhibitory behavior of compounds was supported by DFT calculation. It was also found that there was a strong correspondence between the theoretical and experimental results.

Insight into the corrosion mitigation performance of three novel benzimidazole derivatives of amino acids for carbon steel (X56) in 1 M HCl solution

Three new organic molecules having a benzimidazole base were synthesized and used for the protection of carbon steel (X56) against corrosion in 1.00 M HCl solution. The protection against corrosion was assessed by electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). In addition, the electronic and molecular structure of the synthesized molecules were computationally investigated and correlated to corrosion inhibition. Global reactivity descriptors, molecular orbitals (FMO and NBO) and local reactivity descriptors (molecular electrostatic potential map and Fukui functions) were discussed. The results showed a maximum protective efficiency range between 95% and 98% indicating high corrosion inhibition. Moreover, all molecules were able to combat the cathodic as well as anodic reaction simultaneously, revealing a mixed-type resistance. SEM and EDX verified effective adhering film formation to the metal surface. In accordance, the theoretical calculations showed effective electron reallocation from the organic film to the X56 c-steel surface. Furthermore, the adsorption annealing calculations revealed that structural layers of these molecules hold parallel and close to the metal surface with adsorption energy from 249.383 to 380.794 kcal mol^-1, showing strong inhibitor-metal contact.

Interactions study of 1,2,4-triazole derivatives in acid medium using molecular dynamics

We investigated the interaction of some 1,2,4-triazoles derivatives: 4-amino-3-methylthio-5-phenyl-4H-1,2,4-triazole 1, 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol 2 A, 4-amino-5-phenyl-2H-1,2,4-triazole-3-thione 2B, and 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol 2 C (respectively MTE 1, TL 2 A, TN 2B and TL 2 C) using the molecular dynamics simulation. First, we employed this method to predict the total energies in vacuum and in solutions (water and acid media). Then, we calculated the MD parameters: interaction energies and angle parameters. We have also evaluated the conformations of these molecules in gas and in solutions. Next, we compared the calculated results in water with those in acid solution. Our simulated results prove that the presence of intermolecular hydrogen bond increases the interaction energies in the tautomer thione 2B. We confirm that the TN 2B reaches its high stable conformation state in the solution environment. The calculations confirm that the compound MTE 1 has a spatial conformation state and shows high interaction energy in acid medium. Our molecular dynamics results complete very well our quantum chemical calculations. Communicated by Ramaswamy H. Sarma.

Corrosion Inhibition Properties of Phenyl Phthalimide Derivatives against Carbon Steel in the Acidic Medium: DFT, MP2, and Monte Carlo Simulation Studies

The effectiveness of phenyl phthalimide and its derivatives at preventing corrosion of carbon steel has been tested experimentally using gravimetric and electrochemical measurements. However, experimental studies have not thoroughly explained the structural patterns and coating mechanisms of phenyl phthalimide and its derivatives during corrosion inhibition. In this study, the density functional theory (DFT), ab initio MP2, and Monte Carlo simulation are applied to study phenyl phthalimide (PP) and its derivatives as corrosion inhibitors of carbon steel. The geometry, quantum parameters, and reactive site of the inhibitors were determined by DFT and ab initio MP2 methods. The real environment conditions of corrosion inhibition in the solution phase can be replicated by the Monte Carlo simulation. The corrosion inhibition efficiency of phthalimide derivatives is PP-OCH₃ > PP-CH₃ > PP-H > PP-Cl > PP-NO₂. The theoretical study is consistent with previously reported experimental results.

Review on the Recent Development of Fatty Hydrazide as Corrosion Inhibitor in Acidic Medium: Experimental and Theoretical Approaches

In recent years, numerous research work has been conducted in order to find the most practical and cost-effective solution for corrosion issues in the oil and gas industry. Several studies have revealed that fatty hydrazide derivatives are the most suitable corrosion inhibitor for the application in the said industry. These compounds can also act as effective corrosion inhibitors in acidic medium with inhibition efficiency greater than 95%. This review summarizes and discusses the recent corrosion inhibitor development in acidic media from 2017 until 2021, focusing on fatty hydrazide derivatives. The significant findings and mechanisms of inhibition have been elucidated. In addition, intake on the computer simulation studies of fatty hydrazide inhibition properties is also included in this review. Finally, some suggestions for future research on corrosion inhibitors have been recommended.

Anti-Corrosion Behavior of Olmesartan for Soft-Cast Steel in 1 mol dm−3 HCl

This study discusses the effects of temperature on corrosion inhibition for soft-cast steel by the pharmaceutically active drug olmesartan in 1 mol dm−3 HCl. The sufficient number of electron-rich elements and non-bonding π electrons in its structure favored a good capability for coating onto the electron-deficient steel surfaces. Theoretical and electrochemical measurements were carried out at the temperature region of 303 K to 333 K. Therefore, the experiment suggests that the inhibition efficiency of olmesartan increases with its increasing concentrations due to the adsorption. Additionally, even at a higher temperature of 333 K, the inhibitor molecules attain their stability towards corrosion resistance of steel surfaces. The adsorption of inhibitors on steel surfaces is spontaneously found to include the mixture of physisorption and chemisorption, and it obeys Temkin’s adsorption isotherm model. Theoretical and computational considerations were made using quantum chemical parameters and molecular dynamics simulations, which confirmed that the olmesartan has a suitable corrosion inhibitive capability intended for soft-cast steel in 1 mol dm−3 HCl. Additionally, scanning electron microscopic measurement was used to obtain a visual idea of the inhibitive action of the inhibitor attained by forming an adsorbed protective layer onto the steel surfaces. The minute concentration of olmesartan of about 10–50 ppm shows high inhibition efficiency of ~80%, even at elevated temperatures.