Organic Corrosion Inhibitors Research Articles

Assessment of 14-(4-Nitrophenyl)-14H-dibenzo[a,j]xanthene as an effective Organic Corrosion Inhibitor for Mild Steel in 1 M HCl: Electrochemical, Theoretical, and Surface Analysis

Assessment of 14-(4-Nitrophenyl)-14H-dibenzo[a,j]xanthene as an effective Organic Corrosion Inhibitor for Mild Steel in 1 M HCl: Electrochemical, Theoretical, and Surface Analysis

Phenylurea-based corrosion inhibitor with ultra-high protection efficiency under acidic conditions

The pickling process often poses significant environmental challenges, particularly due to the addition of surface-active organic compounds to acidic solutions to inhibit corrosion on stainless steel surfaces. To minimize the generation of waste solutions and prevent excessive corrosion of stainless steel, the development of high-efficiency corrosion inhibitors for pickling solutions is of substantial practical and industrial importance. In this study, organic corrosion inhibitors prepared from aniline, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine with 1,4-phenylene diisocyanate were investigated. The structure of the resulting inhibitor films was characterized using FTIR, EDS, Mapping, and SEM, revealing good homogeneity and density, which effectively form protective layers on metal surfaces. The inhibitors exhibited excellent corrosion inhibition performance, with the protection efficiency of aniline-based inhibitors reaching 98.6 % at a concentration of 200 ppm in a 1 M HCl solution, significantly reducing the dissolution of Q235 stainless steel (Q235SS). Additionally, the relationship between inhibitor performance and molecular structure was analyzed using DFT calculations. The results demonstrate that phenylurea-based corrosion inhibitors with large π-conjugated planar structures and amine-based polar functional groups provide superior corrosion protection in HCl corrosive media.

Synthesis, Characterization, and Theoretical Calculations of a Novel Organic Corrosion Inhibitor for Mild Steel

Q235 is a carbon structural steel sheet that is widely used in the construction and engineering sectors due to its cost-effectiveness and durability. Here, a novel organic corrosion inhibitor for a Q235 sheet based on furan-thiadiazole (5-amino-2-furyl-1, 3, 4-thiadiazole, AFTZ) has been designed, successfully synthesized, and characterized in this work. Results of experimental data and theoretical calculations indicated that AFTZ has an excellent corrosion inhibition property for a Q235 sheet in 1.0 mol/L H2SO4. The highest efficiency of corrosion inhibitor tested by a weight loss experiment can reach 91.17% and an electrochemical experiment was up to 95.85% when AFTZ increased to 2 mg/mL in H2SO4 solution. The morphological characteristics of Q235 sheets with or without corrosion inhibitor showed that the target inhibitor has good corrosion inhibition performance. Quantum computation using the density functional theory method of Gaussian09 software and Fourier-transform infrared data attribute the excellent corrosion inhibition to the film-forming nature of AFTZ.

Ensemble Stacking of Machine Learning Approach for Predicting Corrosion Inhibitor Performance of Pyridazine Compounds

Corrosion is a major challenge affecting various industrial sectors, leading to increased operational costs and decreased equipment efficiency. The use of organic corrosion inhibitors is one of the promising solutions. This study applies an ensemble algorithm with a stacking method to estimate pyridazine-derived compounds corrosion inhibition efficiency. This study utilized various molecular characteristics of pyridazine compounds as inputs to predict inhibition efficiency values. After evaluating several boosting models, the stacking technique was chosen as it showed the best results. Stacking Model 6, which combines XGB, LGBM, and CatBoost as the base model with Random Forest as the meta-model, produced the most accurate prediction with an RMSE of 0.055. These findings indicate that machine learning approaches can effectively and efficiently predict corrosion inhibitor performance. This method offers a faster and more economical alternative to conventional experimental methods.

Evaluation of 14-(p-tolyl)-14H-dibenzo[a,j]xanthene as a highly efficient organic corrosion inhibitor for mild steel in 1 M HCl: Electrochemical, theoretical, and surface characterization

Corrosion of mild steel, particularly in acidic environments such as hydrochloric acid (HCl), remains a critical issue due to its impact on material durability, economic costs, and safety concerns. This study introduces 14-(p-tolyl)-14H-dibenzo[a,j]xanthene (ZM5), a novel and highly effective organic corrosion inhibitor, to mitigate this challenge. Employing advanced electrochemical techniques: electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), we evaluated ZM5’s performance in a 1 M HCl solution, revealing an impressive inhibition efficiency of 94.7 %. Surface characterization using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) further confirmed the formation of a robust protective film on the steel surface, shedding light on ZM5’s adsorption mechanisms. Complementing the experimental findings, Density Functional Theory (DFT) simulations provided theoretical insights into the anti-corrosion mechanism of ZM5, aligning well with observed results. These findings underscore ZM5's potential as a highly promising corrosion inhibitor for industrial applications, effectively enhancing the corrosion resistance of mild steel in aggressive environments.

Effect of organic corrosion inhibitors on the behaviour of repair mortars and reinforcement corrosion

Repairing concrete structures affected by reinforcement corrosion is vital to ensure their durability and safety. Organic corrosion inhibitors (OCIs) are widely used in the construction industry to prevent steel corrosion due to their effectiveness, sustainability, and health and safety benefits. However, the effects of these OCIs on different types of repair mortars have not been extensively studied. This study evaluated the fresh and hardened properties, as well as the corrosion resistance, of four types of repair mortars (polymer-modified, general cementitious, fine-grained, and alkali-activated) incorporated with two types of OCIs (amino alcohols and sodium gluconate-based) at dosages of 0.5 %, 1 %, and 2 %. Additionally, the corrosion kinetics of mortars under the influence of OCIs were analysed using the impressed current technique. The results indicated that OCIs generally enhanced workability and increased void content across all repair mortars. The amino alcohol inhibitor increased the drying shrinkage of general cementitious and fine-grained mortars by up to 33 % and 39 %, respectively, and reduced compressive strengths by 47 % and 26 %. However, it did not significantly affect water absorption. In contrast, the sodium gluconate inhibitor increased water absorption in all repair mortars but notably decreased drying shrinkage by up to 47 % in polymer-modified mortar and 66 % in alkali-activated mortar. Despite the variations in the properties of repair mortars, OCIs effectively resisted corrosion and delayed crack formation time by up to 400 %. The resistance to corrosion improved with increasing amounts of the inhibitor. The results of this study were used to develop a technical guide for the construction industry, facilitating the selection of appropriate mortar compositions to effectively repair corroded concrete structures and reduce the risk of further corrosion.

Performance and mechanism of triethanolamine-triisopropanolamine corrosion inhibitor to deterioration of reinforced concrete under the coupling effect of freeze-thaw cycles and chloride attack

The purpose of this study is to propose an efficient and economical organic triethanolamine-triisopropanolamine corrosion inhibitor (OTTCI) to reduce the corrosion of steel in reinforced concrete. The influence of OTTCI on corrosion of steel in reinforced concrete under the coupling effect of freeze-thaw cycles and chloride attack (FTCs-CA) were characterized by electrochemical impedance spectroscopy (EIS), dynamic electrode potential (PDP), mechanical properties (mass loss rate (M), compressive strength (fn) and relative dynamic elastic modulus value (Pi)), capillary water absorption (CWA), bubble spacing coefficient (BSC) and scanning electron microscope (SEM). The inhibition mechanism of OTTCI was also analyzed and summarized. The results displayed that the dosage of OTTCI delayed the degradation of reinforced concrete under FTCs-CA. After 150 cycles, the M value of specimens with 1.0 % OTTCI reduced by 66.31 % compared to that of specimens without OTTCI, the Pi value increased by 51.9 %, and the polarization resistance and corrosion inhibition efficiency reached 2744.19 Ω cm2 and 92.88 %, respectively. In addition, OTTCI significantly reduced the CWA value and porosity. After 150 cycles, the CWA and porosity with 1.0 % OTTCI decreased by 60.1 % and 54.54 % respectively. The capillary water absorption coefficient increased linearly with the increase of FTCs-CA. SEM tests illustrated that OTTCI inhibited the development of internal cracks and macropores in concrete and promoted the formation of hydrated calcium silicate gels and calcite. The application of this study not only provides a new method to alleviate the deterioration of reinforced concrete, but also offers theoretical and technical support for further investigate on the deterioration characteristics of reinforced concrete in harsh environments.

Effects of interlayer-modified layered double hydroxides with organic corrosion inhibiting ions on the properties of cement-based materials and reinforcement corrosion in chloride environment

Developing novel, environmentally friendly, and efficient corrosion inhibitors is of great significance for improving the durability of marine concrete against chloride ion erosion. This paper aims to explore the potential of layered double hydroxides (LDHs) as nanocontainers, incorporating organic corrosion inhibitors between LDHs layers to synergistically enhance their effectiveness. In this study, Mg/Al-pAB-LDH was synthesized through the interlayer modification of LDHs with an organic corrosion inhibitor, p-aminobenzoic acid (pAB), employing a calcination-rehydration method. Chloride ion (Cl−) adsorption behavior was quantitatively and qualitatively analyzed and the effect on mortar properties was investigated. The corrosion resistance of steel bars in the mortar was assessed under chloride salt simulated concrete pore solution (SCPs) and chloride salt wet-dry cycles via electrochemical tests and microscopic characterization of Mg/Al-pAB-LDH. The results demonstrate that Mg/Al-pAB-LDH efficiently captures Cl− and releases corrosion-inhibiting ions pAB, with the adsorption process conforming to pseudo-second-order kinetics and Langmuir adsorption isotherm. Mg/Al-pAB-LDH enhances the pore structure of mortar, effectively improving mechanical properties and resistance to chloride ion penetration, with the optimal effect observed at a 4 % addition rate. Mg/Al-pAB-LDH demonstrates outstanding corrosion resistance to steel bars in both SCPs and mortar. In SCPs, it serves as a corrosion inhibitor by adsorbing Cl− and releasing pAB, whereas in mortar, it functions as a corrosion inhibitor by enhancing the physical barrier effect of mortar, adsorbing Cl−, and releasing pAB. This study demonstrates the promising potential of utilizing Mg/Al-pAB-LDH as a novel corrosion inhibitor to mitigate the corrosion of steel bars in marine concrete.

2-(4-fluorobenzyl)Chromeno[2,3-c]Pyrozol-3(2H)-One as Copper Corrosion Inhibitor in HNO3: Gravimetric and Quantum Chemical Investigation Methods

The use of organic compounds as corrosion inhibitors has become a principal means of protecting metal equipment in industrial applications. This work therefore set out to evaluate the inhibiting properties of 2-(4-fluorobenzyl)chromeno[2,3-c] pyrozol-3(2H)-one for copper corrosion in 1M nitric acid solution. These properties were investigated using gravimetric method and quantum chemical calculations. Inhibition efficiency increased with temperature, inhibitor concentration and immersion time. Adsorption of this molecule on copper surface occurs according to Langmuir isotherm, while the thermodynamic parameters of absorption and kinetics prove that adsorption is spontaneous and dominated by chemisorption. Quantum chemical parameters derived from density functional theory (DFT) revealed that there is a strong interaction based on electronic exchange between the inhibitor and copper. Global and local reactivity parameters such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, energy gap, Fukui functions and dual descriptor were used to understand the molecule-metal interface and to design more appropriate organic corrosion inhibitors. Theoretical results proved to be consistent with the experimental data obtained.

An inhibitive system to mitigate the corrosion of AA2024-T3 in 3.5 wt% NaCl solution: Utilizing the synergistic effect of cerium cations and benzimidazole molecules

This study aims to improve the anti-corrosion protection performance of AA2024-T3 using the synergistic effect of organic and inorganic corrosion inhibitors in saline solution. Combining the Ce3+ cations and benzimidazole (BI) molecules was employed as the inhibitive system for the AA2024-T3. Electrochemical properties of the metallic substrate in the presence and absence of the inhibitive system were studied utilizing EIS, PD, and OCP techniques. In addition, GIXRD, ATR-FTIR, XPS, OM, FE-SEM/EDS, water contact angle, and AFM were hired to study the protection mechanism. Based on the results obtained, the inhibitive system has a synergistic effect in improving the anti-corrosion protection performance of AA2024-T3. The synergistic index for the Ce + BI system was calculated to be around 19. Also, the efficiency of the synergistic system in the simultaneous presence of Ce3+ cations and BI molecules as the corrosion inhibitor was 99.3 %, which is higher than that of other inhibitive systems. Finally, the surface analysis outcomes revealed that the inhibitive film forming on the samples' surface during the immersion of the sample in the saline solution in the presence of the inhibitive species is the main factor in boosting the anti-corrosion properties of the aluminum substrate.

Synthesis, characterization and anticorrosion performance of a new corrosion inhibitor based on cobalt- phenanthroline- p-hydroxybenzoic acid ternary complex

In this paper, a new corrosion inhibitor based on cobalt- phenanthroline- p-hydroxybenzoic acid ternary complex was synthesized. Its anti-corrosion effects on carbon steel in 0.5 M HCl were investigated by weight-loss measurements, electrochemical tests, surface analyses, and quantum chemical calculations. The results indicated that the Co-phen-phba ternary complex exhibits excellent anti-corrosion efficiencies of ∼97 % at 298 K and ∼86 % at 328 K. The excellent anti-corrosion performance of Co-phen-phba ternary complex could be attributed to the combination of inorganic and organic corrosion inhibitors. Theoretical calculations established the correlation between the structure and the anti-corrosion effect of corrosion inhibitor.

Corrosion behaviour of 110SS steel in hydrochloric acid and blended acid system at 200°C

The influence of organic acids (formic acid, acetic acid) on the corrosion behaviour of 110SS steel, a hydrogen sulphide corrosion resistant alloy steel, in hydrochloric (HCl) acid environments was studied. The corrosion rates of 110SS steels in HCl acid and blended acid were measured using the high-temperature and high-pressure corrosion tester. Scanning electron microscopy was utilised to observe the morphology of corrosion products on steel samples corroded by different acid systems, and the energy dispersive X-ray spectrometer was used to analyse the elemental composition of the corrosion products. The corrosion morphology was observed using a 3D laser scanner. The results indicated that the corrosion rate of 110SS steel in HCl acid at 200 °C was an exponential function of HCl concentration. Reducing the HCl concentration significantly decreased the corrosion rate of 110SS steel. Organic acids and corrosion inhibitors synergistically reduced the corrosion of 110SS steel in HCl acid. Adding 3 wt.% organic acid to the 15 wt.% HCl acid system further reduced the corrosion rate, with a more pronounced effect observed in the HCl–formic acid system compared to the HCl–acetic acid system. Organic acids chemically adsorbed onto the steel surface and decomposed to produce CO, which hindered the attack of hydrogen ions on the metal. The added corrosion inhibitor and intensifier Sb2O3 resulted in the formation of a compact adsorption film on the steel surface, further inhibiting corrosion. The optimal mass ratio of HCl acid to organic acid was found to be 15% to 3%.

Exploration of adsorption properties of organic corrosion inhibitors on layered double hydroxide nanosheet: A molecular dynamics simulation study

Understanding the adsorption of organic corrosion inhibitors with different functional groups on layered double hydroxide (LDH) nanosheet is crucial for the synthesis of these protective materials. In this study, the adsorption process of five deprotonated organic corrosion inhibitors—lactate (Lc), 2-hydroxybenzothiazole (2-OH-BTH), 2-mercaptoethanesulfonic acid (MS), N,N-dimethylethanolamine (DMEA), and eugenol (EG)—on LDH nanosheets was simulated. The adsorption rate, adsorption configuration, and adsorption stability between LDH nanosheet and organic corrosion inhibitors were investigated throughout the entire adsorption process. The study observed consistency in the adsorption rate and stability of these organic corrosion inhibitors in the following order: Lc > 2-OH-BTH > MS > DMEA > EG. Additionally, hydrogen bonds between the organic corrosion inhibitors and the LDH nanosheet is the primary mechanism driving adsorption. The number and stability of hydrogen bonds influenced both the adsorption rate and stability. It is noteworthy that 2-OH-BTH and DMEA have not previously been incorporated into LDH. There is potential for these two organic corrosion inhibitors to be modified for LDH, suggesting significant prospects for future research.

Effect of spinach (Spinacia oleracea) leaf extract on the aluminum (Al) as a green corrosion inhibitor in HCl medium

Green corrosion inhibitors have recently attracted much attention due to their non-toxic properties, especially plant extracts. This study used spinach leaf extract (Spinacia oleracea) as a corrosion inhibitor on aluminum in an HCl medium. Spinach leaf extract (Spinacia oleracea) was obtained by maceration method, using ethanol as the solvent, which was then distilled to purify the extract. The corrosion inhibition properties were studied by the gravimetric method. The results showed that spinach leaf extract (Spinacia oleracea) can efficiently decrease the corrosion rate of aluminum in an HCl medium, achieving a maximum efficiency of 96.7742 %. Spinach leaf extract (Spinacia oleracea) formed a protective layer on the aluminum surface via adsorption and chemisorption, thus increasing surface coverage and blocking mass transfers. As the inhibitor concentration increases, the corrosion rate decreases, and the corrosion inhibition efficiency increases. This study shows that spinach leaf extract (Spinacia oleracea) is a viable organic corrosion inhibitor option with high efficiency.

Mitigation of mild steel corrosion using Schiff base-derived inhibitors in acidic media: An experimental and theoretical study

Corrosion presents a substantial hurdle in the oil and gas industry, and corrosion inhibitors represent an economically viable strategy for control and prevention. As operating conditions in oil and gas extraction become increasingly harsh, factors such as cost, availability, and service temperature significantly influence inhibitor selection. While there is a wealth of literature on organic corrosion inhibitors, many exhibit a notable decrease in effectiveness at elevated temperatures, hindering their industrial application. To address this issue, we synthesized a novel Schiff base derivative, 1-((E)-(4-chlorophenylimino)methyl)naphthalen-2-ol (E4CMN), and investigated its effectiveness in inhibiting corrosion on Q235 immersed in a 1 M HCl. E4CMN adsorbs onto the surface by forming strong π-d interactions with Fe through the delocalized π electrons in its conjugated structure, effectively blocking the attack of corrosive particles towards the metal surface and consequently suppressing metal corrosion. Our study demonstrates that E4CMN exhibits maximum efficiencies of 96.9 % at a concentration of 250 mg L−1. Importantly, E4CMN shows insensitivity to service temperature, maintaining an 84.4 % corrosion inhibition efficiency even when exposed to 75 °C. This work provides novel insights into mechanism of inhibition of mild steel corrosion by Schiff base derivatives in acidic environments and offers valuable considerations for the development and selection of corrosion inhibitors for high-temperature applications.

Experimental, theoretical and computational studies of oxalyl dihydrazide as a novel corrosion inhibitor for mild steel in neutral saline solution

In this work, the corrosion inhibition performance and mechanism of oxalyl dihydrazide (ODH) for mild steel in neutral saline solution are in-depth studied using weight-loss and electrochemical tests, surface characterizations, theoretical calculation and computational simulations. Results indicate that ODH can act as a novel and superior mixed-type corrosion inhibitor for mild steel in neutral saline solution, its corrosion inhibition efficiency increases with the rising ODH concentration, and the optimum value reaches 88.7 % with adding 200 mg/L. Its corrosion inhibition ability becomes better with immersion time. A compact corrosion product film mainly consisting of Fe, O, N and Cl elements formed on metal surface after adding ODH. ODH molecules adsorb on metal surface in an orderly fashion to form a hydrophobic film, which is belonging to the physicochemical adsorption and obeys the Langmuir adsorption isotherm model. The corrosion inhibition process of ODH molecule on mild steel is the endothermic process, which enlarges the activation energy barrier of corrosion reactions. ODH molecule can expel the adsorbed water molecules on metal surface and form copolymers with increasing of ODH concentration, retarding the diffusion of water molecule thus protecting metal from corrosion. ODH is proved to be an effective organic corrosion inhibitor for protecting mild steel in neutral saline solution, and contributes toward research and application of easily accessible sources for organic corrosion inhibitors.

Developing a novel imine derivative as a corrosion inhibitor for Q235 carbon steel in 1 M HCl solution: Experiments and theoretical calculations

During oil and gas extraction, metals are inevitably exposed to acidic environments on a regular basis. Acid solutions, particularly hydrochloric acid, are employed in a multitude of industrial processes, including oil well acidising, steel pickling, ferroalloy pickling and acid cleaning. These applications frequently result in severe metal corrosion. To cope with corrosion, the superlative simple and effective method is to prevent corrosion inhibitors. Naphthyridinimides are not as effective as rust inhibitors, but their corrosion inhibition is significantly improved by the addition of Br ions. This thesis focuses on the synthesis of naphthylimine-type novel organic corrosion inhibitors and the corrosion inhibition mechanism, with the main content of 3,3′-(1,3,6,8-tetraoxo-1,3 6,8-tetrahydrobenzo[lmn] [3,8] phenanthroline-2,7-diyl) bis (N-ethyl -N, N-Dimethyl-1-propylamine) bromide (NDI-N-Br) on Q235 carbon steel in an acidic environment (1 M hydrochloric acid solution). The corrosion inhibition efficiencies of NDI-N-Br reached 93.53 % at 300 ppm at an ambient temperature of 298 K. The corrosion inhibitor NDI-N-Br forms a protective film on the metal surface and organizes the interaction between the metal matrix and the corrosive medium, providing a rust inhibiting effect. This thesis shows that this class of compounds can be well applied to acidic environments and provide ideas for the subsequent development of naphthylimide-based organic corrosion inhibitors.

Structure and Dynamics of Aqueous 2-Aminothiazole/NaCl Electrolytes at Electrified Interfaces.

A computational study was performed to investigate the dynamics of aqueous electrolytes containing organic corrosion inhibitors near electrified interfaces by using the constant-charge model in classical molecular dynamics simulations. The results showed that when inhibitors form films at the interface, the surface charge of the electrode causes displacement of the molecules, referred to as electroporation. The hydrophobicity of the inhibitor molecules affects both the stability of the films and their recovery time. This study highlights the value of computational investigations of the dynamics within inhibitor films as a complementary approach to the traditional focus on inhibitor-substrate interactions, leading to deeper insights into the mechanisms of corrosion inhibition mechanisms.

New approach for processing chitosan as low cost protective hybrid coating for C-steel in acid media

The novelty of this study is that it the first time blending and formulation of chitosan as a new hybrid (organometallic) protective coatings for achieving synergistic protection for carbon steel alloy during acid pickling. The role of coated silica (by 0.1 wt % stearic acid lubricant) in the improvement of coating performance was highlighted. Variable weight percentage of chitosan and silica in addition to a fixed weight percentage (35 %) of guar gum natural plant resin, 5 × 10−6 mmol (2-Hydrazinyl-6-methyl (or phenyl) −4, 5-di-H pyrimidinone) as organic corrosion inhibitors were compounding as hot melt in the presence of a low cost surfactant as an emulsifying agent improved compatibility between coating constituents. Guar gum increased coating flow during application and grafted chitosan into high molecular copolymer resin insoluble in acid media. Phosphorous acid improved coating flexibility during application by hot dipping. Hybrid coating decreased corrosion potential of carbon steel and retarded both redox reactions of corrosion acting as adsorbed mixed-type inhibitor. Percentages protection (%P) approached hundred percentage as confirmed from the agreement between impedance and polarization parameters. Guar gum plant resin and slice powder increased gloss of coating. The coated silica filled the pores and increased stiffness of coating. Super hydrophobicity of coating was confirmed by the measured contact angle above 150oC indicating good spreading of coating sample as insulating adherent surface film.

Understanding the adsorption of imidazole corrosion inhibitor at the copper/water interface by ab initio molecular dynamics

Understanding the adsorption mechanisms of organic corrosion inhibitors at metal/water interfaces is crucial for designing corrosion inhibitors. Imidazole adsorption at copper/water surfaces was investigated via ab initio molecular dynamics simulations. The adsorption energy of imidazole on copper in water is slightly more positive than that in vacuum, which is attributed to the hydrogen bond interaction between imidazole and water molecules. Imidazole adsorption changes interfacial water density and dipole distribution, disrupts hydrogen bond networks, and decreases water residence time at the interface. These characteristics are considered to be correlated to the decreased corrosion rate induced by imidazole adsorption.