Organic Inhibitors Research Articles

Investigation of the Inhibition Mechanism of Organic Corrosion Inhibitors on the Copper Surface by DFT study and MD simulations

AbstractSupports of the National Natural Science Foundation of China (21908017 and 21902021), the Undergraduate Innovation and Entrepreneurship Training Program Dalian University of Technology (20211014110934), the Foundation of State Key Laboratory of High‐efficiency Utilization of Coal and Green Chemical Engineering (2022‐K70), the Fundamental Research Funds for the Central Universities (DUT22LK09), the Open Foundation of Key Laboratory of Industrial Ecology and Environmental Engineering, MOE (KLIEEE‐20‐01, KLIEEE‐21‐02), and the Hefei Advanced Computing Center for this work are gratefully acknowledged.

Investigation Effect of 4-Aminophenol as a Corrosion Inhibitor for Mild Steel in Sulfuric Acid Medium

A high number of organic materials have been studied as inhibitors for corrosion in different conditions. In this paper, the effect of organic chemical (4-Aminophenol) as an inhibitor for mild steel metal corrosion was investigated in presence of sulfuric acid at different temperatures. The study was carried out using three known methods in testing corrosion process, methods of weight loss, thermometric, and polarization. The obtained results showed that when the inhibitor concentration increases, the corrosion rate decreases, and hence, the inhibition efficiency increases. Moreover, when the surface coverage at a temperature of 313 °C with organic inhibitor increases, the corrosion rate decreases as noticed in the weight loss method. For the thermometer method, the inhibitor was examined by temperature. The inhibition efficiency increases, as well as in the anodic and cathodic polarization method, where it is observed that the anodic and cathodic curves are present to measure the corrosion current and corrosion potential. As the higher the concentration of the inhibitor, the lower the current and the corrosion voltage. The reason for the effectiveness of this inhibitor is the presence of amine and phenol organic molecules in its composition, which can form a film on the metal surface and prevent corrosion from taking place.

Corrosion Inhibition Properties of Lawsone Derivatives againts Mild Steel: A Theoretical Study

Theoretical studies have been carried out using DFT, ab initio MP2 and Monte Carlo (MC) simulations of corrosion inhibitors from lawsone derivatives against carbon steel. The research focuses on studying the effect of substituent groups in the lawsone structure on the efficiency of corrosion inhibition in mild steel. Quantum chemical parameters of lawstone inhibitors in neutral and protonated conditions have been calculated. Fukui’s function analysis predicts that the active side of the inhibitor will be adsorbed on the mild steel surface. MC simulation is used to understand the adsorption patterns of lawsone compounds on metal surfaces. The organic inhibitor L-NH2 has better performance as a corrosion inhibitor for mild steel in neutral or protonated conditions.

Combined atomic-scale/DFT-theoretical simulations and corrosion protection study of AA2024-T3 in 3.5% NaCl by phenolphthalein derivatives: Surface characterization (FT-IR, FT-RAMAN, and SEM)

This work investigates the effectiveness of two organic inhibitors, CH3O-φ-OCH3 (P3) and bzO-φ-Obz (P4), in preventing corrosion of aluminum alloy 2024-T3 in a 3.5% NaCl solution. The study employs a combination of experimental and theoretical research methods to gain a comprehensive understanding of the corrosion inhibition behavior. Density functional theory (DFT) studies and molecular dynamics (MD) simulations provide atomic-level insights into the resistance mechanism and the influence of the molecular structures of P3 and P4 on corrosion inhibition. The potentiodynamic polarization experiments (PDP) confirm that the studied compounds are mixed-type inhibitors. At a concentration of 10−4 M, P3 and P4 exhibit impressive inhibition efficiencies of 87.5% and 92.5%, respectively. FTIR and Raman spectroscopy were utilized to show that an adsorbent protective layer was formed on the surface of the aluminum when it was immersed in an inhibited solution. The scanning electron microscopy (SEM) morphology analysis indicates that the presence of P3 and P4 inhibitors effectively reduces corrosion on the surface of the AAl 2024 alloy. Furthermore, energy-dispersive X-ray spectroscopy (EDS) analysis confirms the formation of a chemical particle coating on the surfaces of the Al alloy. Electrochemical impedance (EIS) measurements of total resistance bias (Rp) further demonstrate the superior corrosion resistance of the inhibitors, as the resistance increases with inhibitor concentration. These findings highlight the strengths of this work in providing a comprehensive understanding of the corrosion inhibition mechanism and the excellent performance of P3 and P4 as inhibitors for aluminum alloy 2024-T3 in a NaCl environment.

Synthesis, Corrosion Inhibition Efficiency and Adsorption Behavior of Dibenzo [a,c] Quinoxalino(2,3-I)Phenazine on Mild Steel in Acidic Medium

Designing new inhibitors and understanding the mechanisms responsible for the inhibition are required in developing techniques to prevent corrosion. A new azaacene organic corrosion inhibitor, DQP (dibenzo[a,c]quinoxalino (2,3-i)phenazine), for mild steel in an acidic medium was successfully synthesized, characterized and reported for the first time using electrochemical impedance spectroscopy (EIS) and Potentiodynamic polarization measurement techniques (PDP). Surface morphologies and average percentage by weight of elements existing in mild steel were determined by SEM-EDX. The alterations in the impedance characteristics showed that DQP inhibitor adsorbed to the surface of mild steel, resulting in the creation of a protective coating. At the maximal concentration of 2.618 x 10-5 M, the inhibition efficiency reached 98.02% demonstrating DQP effectiveness in reducing corrosion process that may occur in mild steel in HCl. However, this efficiency is weakened by increase in temperature. The PDP curve revealed that DQP functions as a mixed inhibitor but is mostly cathodic. The adsorption behavior of DQP was best supported by the Langmuir adsorption isotherm (R2 = 0.9837) while the adsorption-free energy (G0ads) ranging from -41.749 to -43.183 kJmol-1 indicate chemical adsorption on metal surface. This study demonstrates that the synthesized DQP functions admirably well as a corrosion inhibitor in HCl solution.

Supramolecular corrosion protection: Eco-friendly synthesis and efficacy of a β-cyclodextrin/o-phenylenediamine complex

BackgroundIn corrosion science, organic inhibitors were widely used to protect the metal from corrosion. However, the greenness and effectiveness are a problem for organic inhibitors. Therefore, environmentally friendly and cost-effective corrosion inhibitors are important tasks in the material and engineering sciences. The solubility of organic inhibitors are also problem. In this work, these solutions were tried to solve. MethodsIn this research work, the green supramolecular complex (β-CD/o-PhDA) was first synthesized from the β-cyclodextrin (β-CD) and o-phenylenediamine (o-PhDA). The structure, physical interactions and structural changes of β-CD/o-PhDA were confirmed by the FT-IR, 1H NMR and Raman spectroscopic results. Main findingsIt was found that the supramolecular system of β-CD/o-PhDA was more stable with the van der Walls and hydrophobic interactions. The corrosion inhibition performance of β-CD/o-PhDA on the St20 steel corrosion in 0.5 M hydrochloric acid (pH=0.3) was first investigated by various experimental and theoretical investigations. It is indicated that the corrosion protection of β-CD/o-PhDA was over 95–96% in the aggressive solutions. The β-CD/o-PhDA formed the thin defender layer on the metal surface by the formation of NFe and FeO bonds. The protonation process affects the corrosion inhibition of the host-guest complex on the metal surface. The adsorption energies of β-CD/o-PhDA on the metal surface are more negative and depend on the adsorption positions. The β-CD/o-PhDA acts as a mixed type of corrosion inhibitor. The β-CD/o-PhDA was suggested as good water soluble, low-cost, stable and green protective agent for the acidizing-scaling processes in the chemical industries.

A combination of machine learning model and density functional theory method to predict corrosion inhibition performance of new diazine derivative compounds

This study proposes a novel approach that combines machine learning (ML) and density functional theory (DFT) methods to construct a quantitative structure-properties relationship (QSPR) model for diazine derivatives as anti-corrosion inhibitors. A dataset is constructed by combining three existing diazine isomer datasets to represent diazine compounds. Thirty-two different ML algorithms were implemented on the dataset, and the gradient boosting regressor (GBR) model was identified as the best predictive model for diazine and each isomer dataset based on the coefficient of determination (R2) and root mean square error (RMSE) metric values. This consistency was also observed when the GBR model was implemented on four other diazine derivatives, resulting in high corrosion inhibition efficiency (CIE) values ranging from 85.02 % to 94.99 %. The DFT calculations for these derivatives also showed strong adsorption energies ranging from − 4.41 to − 6.09 eV, in line with the CIE trend obtained from the ML prediction. This novel approach can provide insights into the properties of prospective organic corrosion inhibitors prior to experimental investigations, which could accelerate the development of new and effective organic corrosion inhibitors.

Anticorrosive properties of aqueous Cichorium intybus seeds extract as a sustainable-green inhibitor for aluminum corrosion in hydrochloric acid solution: An experimental and DFT/MC/MD theoretical approach

The inhibitory effect of Cichorium intybus seeds (C. Intybus) on the corrosion behavior of Al 7075 alloy was evaluated in a 1 M HCl acid solution using chemical and electrochemical methods. The adsorption process was proved using FTIR, UV-Vis, Fluorescence, SEM, EDX, AFM, and contact angle measurements. The results reflect that C. Intybus provided excellent protection, and all measurements showed that the inhibition performance of extracts increased by increasing the concentration to reach 93.67% at 12% v/v. Furthermore, this substance functioned as a mixed-type inhibitor to obstruct the anodic and cathodic active sites on the surface of the metal. The study outcomes matched the monolayer Langmuir isotherm, and the calculated adsorption free energy and activation energy reflect that the inhibition mechanism featured the physisorption process. The computational studies were used to provide further confirmation of the adsorption mechanism and to find out how organic inhibitor molecules interact with metal surface using Density Functional Theory (DFT) with Lee/Yang/Parr (B3LYP) level, 6–311 + + G(d,p) as the basis function set calculation, Monte Carlo (MC), and Molecular Dynamic (MD) simulations. The findings showed good agreement with both the experimental and theoretical results. One of the important findings of this work is the possibility of using C. Intybus as a greener alternative and environmentally friendly resource for corrosion inhibition in an acidic medium.

Research Progress on Types and Mechanism of Common Organic Corrosion Inhibitors

In this paper, several kinds of common organic corrosion inhibitors, such as heterocyclic, aldehydes and ketones, organic phosphonic acid, are introduced. The development prospects and application limitations of some corrosion inhibitors are discussed and pointed out. There are also studies have shown that usually two or more corrosion inhibitors are combined or better than a single corrosion inhibitor. Taking the effect as the introduction point, the mechanism of action of organic corrosion inhibitors is generally recognized. Finally, the future research direction of organic corrosion inhibitors is prospected.

Efficient anaerobic digestion of hydrothermal carbonization wastewater via an innovative multistage anaerobic hythane reactor (MAHR): Organic conversion and microbial evolution

Seeking continuous treatment of downstream wastewater is a desperate requirement for the scale-up of hydrothermal technology. In this study, a novel multistage anaerobic hythane reactor (MAHR), which was constructed with an internal downflow biofilter bed and an external up-flow sludge bed, was used to dispose of hydrothermal carbonation wastewater (HTCWW), a by-product of the hydrochar preparation process of microalgae. To verify the performance of MAHR for the actual complex wastewater treatment, a conventional up-flow anaerobic sludge bed reactor (UASB) was used as a comparison. The two reactors were both operated independently in parallel with a hydraulic retention time (HRT) of 12 h and an organic load rate (OLR) of 20 g SCOD/L/d. Both MAHR and UASB achieved 84% COD removal rate and 7.0 ± 0.6 and 5.5 ± 0.3 L/L/d of methane production rate, respectively, when the proportion of HTCWW was increased to 100% of the original wastewater. Specifically, the hythane-producing area (MH) of MAHR was gradually transformed into methane producing area in the process of feeding HTCWW. High-performance liquid chromatography (HPLC) analysis revealed that more small molecule compounds including organic acids and inhibitors were degraded in MAHR. Fourier transform ion cyclone resonance mass spectrometry (FT-ICR MS) analysis demonstrated that more soluble proteins and lipids were degraded to some extent, while the lignin and condensed aromatic compounds increased especially in UASB. A dramatic change was observed in the dominating microbial communities in MAHR and UASB from the Streptococcaceae associated with carbohydrates degradation to the Renkenellaceae involved in both proteins and carbohydrates degradation. At the archaeal level, hydrogenotrophic methanogens replaced acetoclastic methanogens. Redundancy analysis (RDA) further verified the relationship between dominant functional communities and the anaerobic digestion performance of the reactors. The above results indicate that MAHR is a promising configuration for the anaerobic valorization of hydrothermal wastewater.

Temporal Aspects of Corrosion Inhibition on Copper, Silver, and Copper-Silver Alloys: An Electrochemical Impedance Spectroscopy Study

Electrochemical impedance spectroscopy (EIS) was utilized to delve into the corrosion inhibition of eutectic Cu-Ag alloy and its components (Cu and Ag) in an aqueous, aerated 0.1 M KNO3 solution. This alloy plays a major role in the water cooling of central processing units in data storage centers. Two organic inhibitors, namely, 1,2,3-benzotriazole (BTA) and 2,5-dimercapto-1,3,4-thiadiazole (DMTD), were utilized in this study. The corrosion inhibition slowly evolved over time as diagnosed by an increase in the charge transfer impedance and the gradual tendency of the Nyquist profiles to arc toward the real axis. This trend was attributed to the gradual formation of organometallic passivation layers. The EIS data underlined the specific affinity of BTA and DMTD toward the Cu and Ag surfaces, respectively. A transition of the double-layer equivalent circuit element from ideal capacitance to a constant phase element was observed for the alloy compared to the pure metals. This was attributed to the heterogeneity induced by Cu-rich and Ag-rich phases in the alloy and by the formed oxides/protective film on the alloy surface. The EIS study demonstrated that both BTA and DMTD can provide sufficient corrosion inhibition to Cu-60Ag alloy with DMTD being significantly more effective.

Review on anti-corrosion properties of expired antihypertensive drugs as benign corrosion inhibitors for metallic materials in various environments

Discovering new classes of organic corrosion inhibitors, such as expired drugs, can provide cheaper, low-toxic, and highly efficient alternatives to the toxic organic counterparts that serve as an efficient recycling or disposal strategy. Antihypertensive drugs constitute one of the cheapest classes of drugs, globally, and have been reported as highly effective corrosion inhibitors for a variety of metallic materials in various corrosion environments. The corrosion inhibition mechanism of these drugs, generally, involves the adsorption on the metallic surfaces and the formation of a protective organic film that retards the attack of substrates by corrosive entities in the media. The drug molecular structure usually contains π-bonds, phenyl rings, and polar functional groups (such as –NH2, –OH, –CN, and −Cl) which influence the electron density within the inhibitor framework and also facilitate adsorption of the drug on the metal surface. Generally, most antihypertensive drugs act as mixed-type inhibitors and usually obey Langmuir adsorption isotherm revealing physisorption adsorption mechanisms except telmisartan, losartan potassium, and atenolol when used in nitric acid. The reported inhibition efficiency of the drugs is generally above 90% with spironolactone having the highest efficiency of 98.1% at 30 °C.

A study on Jordanian green natural agro-wastes as potential inhibitors of mild steel corrosion in HCl solution

Mild steel is one of the most widely used materials in different engineering applications due to its mechanical properties, high availability and low cost. However, the exposure of the steel to acids such as hydrochloric acid (HCl) accelerates its corrosion rate. Green organic corrosion inhibitors are among the most effective materials for reducing the mild steel corrosion rate in an acidic medium. These inhibitors are environmentally accepted, easy to extract and non-toxic. This study investigated the feasibility of using different green Jordanian natural agro-wastes as green organic corrosion inhibitors and determined the efficiency of these inhibitors at different concentrations at room temperature. A potentiodynamic polarization test was performed in two sets of runs; the first set of runs was used to screen ten extracted green inhibitors and choose three based on their highest efficiency. In the second set of runs, the test was performed only on the highest-efficiency inhibitors selected from the first run. A weight loss test and Fourier transform infrared spectroscopy were also performed on the selected inhibitors. Based on the results of the tests, the green zucchini (Cucurbita pepo) leaf extract, oak (Quercus) leaf extract and okra (Abelmoschus esculentus) leaf extract were selected as inhibitors.

Synthetic Organic Molecules as Metallic Corrosion Inhibitors: General Aspects and Trends

Organic molecules are gaining special attention over the last years in the corrosion area thanks to their general low achievable cytotoxicity, structural versatility, and environmentally friendly obtainment methods. Under those approaches, synthetic organic motifs have attracted the interest of researchers due to their variated methods of obtention through molecular manipulation via diverse chemical reactions, allowing the production of adequately planned structures or repurposing their original application in the case of drugs. This review summarizes general aspects that are desired in organic molecules as corrosion inhibitors, presenting selected works published in the 2022–2023 period and emphasizing the importance of finding novel and different organic corrosion inhibitors. Patents were not considered in this review. Scifinder, Google Scholar, and Web of Science were employed as databases. Mathematical and analytical methods involved in the search for corrosion inhibitors are out of this review’s scope.

A comprehensive assessment of carbon steel corrosion inhibition by 1,10-phenanthroline in the acidic environment: insights from experimental and computational studies.

1,10-Phenanthroline (PHN) is a nitrogen-containing heterocyclic organic compound that is widely used in a variety of applications, including chemosensors, biological studies, and pharmaceuticals, which promotes its use as an organic inhibitor to reduce corrosion of steel in acidic solution. In this regard, the inhibition ability of PHN was examined for carbon steel (C48) in a 1.0M HCl environment by performing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), mass loss, and thermometric/kinetic. Additionally, scanning electron microscopy (SEM) was used to examine the surface morphology of C48 immersed in 1.0M HCl protected with our inhibitor. According to the PDP tests, increasing the PHN concentration resulted in an improvement in corrosion inhibition efficiency. Besides, the maximum corrosion inhibition efficiency is about 90% at 328K. Furthermore, the PDP assessments demonstrated that PHN functions as a mixed-type inhibitor. The adsorption analysis reveals that our title molecule mechanism is due to physical-chemical adsorption, as predicted by the Frumkin, Temkin, Freundlich, and Langmuir isotherms. The SEM technique exhibited that the corrosion barrier occurs due to the adsorption of the PHN compound through the metal/1.0M HCl interface. In addition, the computational investigations based on a quantum calculation using density functional theory (DFT), reactivity (QTAIM, ELF, and LOL), and molecular-scale by Monte Carlo (MC) simulations confirmed the experimental results by providing further insight into the mode of adsorption of PHN on the metal surface, thus forming a protective film against corrosion on the C48 surface.

Utilization of Rice Straw Extract as Corrosion Inhibitor to Decreasing Effect of Elevation on CS Pipeline using Olga Simulator

In many infrastructure of oil and gas industries, corrosion is one of the most problems that often occur, especially in pipelines. Corrosion is caused by an electrochemical reaction between material surface and corrosion fluid. This problem will affect the economy, safety, and conservation. In this case, we should give a solution such as a method or tools to minimize corrosion’s effect so, it can improve safety and minimize the potential problems caused by corrosion and loss more cost. One of the ways is using organic corrosion inhibitors such as biomass agriculture waste and plant extract. A corrosion prediction model can be used to predict the corrosion rate such as NORSOK and de Waard models. Both methods are available in Olga Simulation software by Schlumberger that were used in this paper. Some of the parameters that influence corrosion were also tested: Evaluation of 1°, 2°, 3°, 4 °, and 5° of pipeline elevation to corrosion rate. Meanwhile, 31.71% of rice straw extraction (RSE) with 75% IE was used as a corrosion inhibitor compared with 30% of mono-ethylene glycol with 26% IE and 38.97% of lignin with 61% IE to determine the period of pipeline per year and to design of the pipeline. RSE that contains lignocellulose was able to give higher efficiency to decreasing corrosion. Moreover, this organic inhibitor give low cost. Therefore, this biomass would be potential as an alternative inhibitor rather than a commercial corrosion inhibitor with high cost.

Theoretical investigation of the performance of benzimidazole derivatives as mild steel organic corrosion inhibitors in acidic environments.

The efficiency of various benzimidazole derivatives as mild steel corrosion inhibitors in HCl and H2SO4 medium was evaluated using quantum chemical methods. The AM1 semi-empirical method and Density Functional Theory (DFT) at the B3LYP/6-31G* level were used. The orbital energies (EHOMO and ELUMO), Separation Energy (ELUMO-EHOMO), Dipole moment (µ), Log P, Polarizability, molecular volume, molecular weight, Hardness (η) and Softness (S) are the computed quantum chemical characteristics linked to inhibitory efficiency. There was a strong link between quantum chemical parameters and experimental inhibition efficiency. The findings revealed that the Inhibition Efficiency was linked to a number of quantum chemical factors. The 2-mercaptobenzimidazole derivative had a higher Inhibition Efficiency (IE) than the other benzimidazole derivatives, according to the results.

Analysis of Corrosion in Production Tubing Using Monoethylene Glycol and Red Ginger as Inhibitors

The production system for industrial oil and gas is susceptible to corrosion, which must be controlled in order to sustain production and well direct as the production of tubing is the initial point of contact with the corrosion fluid and material agent. A chemical reaction between corrosive materials and fluids results in corrosion. Due to its mechanical characteristics, stainless steel has a wide range of uses in the building, chemical, and structural sectors. To combat corrosion issues, several chemical inhibitors are used, and numerous studies are actively working to develop organic inhibitors. Rhizome ginger is an organic component that has a high phenol antioxidant content and antioxidant compound, making it useful for corrosion issues. In this study, the effect of monoethylene glycol and ginger extract inhibitors on corrosion was reviewed. The corrosion rate was computed using an olga simulator, and the influence of the inhibitor on the rate of corrosion and the effectiveness of the inhibitors was examined.

New pyrazole derivative as effective corrosion inhibitor for carbon steel in 1 M HCl: Experimental and theoretical analysis

Corrosion inhibition is an extensive field of study, and its progression is gaining traction among researchers. This paper describes a study to synthesize and characterize a novel class of organic corrosion inhibitor called (3, 5-dimethyl-1H-pyrazol-1-yl) (4-((4-chlorobenzy-lidene) amino) phenyl) methanone) (DPCM). The structure of DPCM was determined using FTIR, 1H NMR and 13C NMR techniques. The effectiveness of DPCM was tested on carbon steel in 1 M HCl using electrochemical and weight loss methods, and it was found that the inhibition efficiency increased with increasing temperature and DPCM concentration. The highest inhibition efficiency of 89.5% was achieved at 60 °C and 400 ppm DPCM. The inhibition action of DPCM molecules was achieved by blocking the metal surface by means of the adsorption of inhibitor molecules obeying the Langmuir adsorption isotherm. Adsorption-free energy indicates a spontaneous chemical adsorption process. The polarization test results clarified a mixed effect of DPCM on anodic and cathodic reactions. Electrochemical impedance spectroscopy indicated an increase in metal resistance in the presence of an inhibitor. The formation of a protective layer was confirmed by SEM and AFM analysis. Density functional theory (DFT) simulation has been used to determine the relationship between molecular configuration and their inhibition efficiencies.

Chloride threshold determination of hybrid inhibitor immersed in simulated concrete pore solution

The hybrid inhibitor performs excellently compared to either organic or inorganic inhibitor individually. In the present studies, a fixed amount i.e. 2 wt% l-arginine (LA) and 0.25 wt% trisodium phosphate dodecahydrate (TSPDH) is considered as hybrid inhibitor and its chloride threshold is determined by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) in simulated concrete pore solution and the formed passive films are characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy after 240 h of immersion. The chloride threshold of this hybrid inhibitor is 6 wt% NaCl, i.e., C3 until 216 h of immersion, whereas if the amount is increased, the steel rebar leads to corrode severely. 5 wt% NaCl containing sample, i.e., C2 exhibits the noble OCP, highest impedance, and lowest passive current density attributed to the consumption of all zwitterion and phosphate ions in the formation of P-zwitterion-(Cl)-Fe, zwitterion-(Cl)-Fe and FePO4 complexes with NaCl, whereas lower or higher than this amount of NaCl, the Cl- ions either lesser or greater to be formed these complexes.