Corrosion Inhibition Performance Research Articles

Batatas lam leaf extract as a biodegradable corrosion inhibitor for copper in 0.5 M H2SO4 solution

In this study, the Ipomoea Batatas Lam Leaf Extract (IBLE) was obtained through a pure water decoction process. To investigate the corrosion inhibition capabilities of Ipomoea Batatas Lam Leaf Extract (IBLE), a comprehensive approach encompassing electrochemical techniques, X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and theoretical calculations has been employed. The electrochemical test results demonstrate a remarkable corrosion inhibition efficiency of up to 96.7% when utilizing an 800 mg/L concentration of IBLE. As the temperature increases, IBLE can still maintain a high standard of anti-corrosion performance and the corrosion inhibition performance can even maintain more than 95% at a temperature of 315 K. Polarization curve test results demonstrate that IBLE belongs to the mixed corrosion inhibitor, which restrains both anode and cathode reactions of copper electrodes in 0.5 M H2SO4 medium. The EIS test shows that the effective inhibition of the charge transfer process by the adsorption of IBLE onto the interface of copper, as the concentration of IBLE increases, there is a notable and significant rise in it, thus showing a great corrosion inhibition property. The surface morphology test shows that the erosion of the copper surface is significantly suppressed after IBLE adsorbing on the copper surface. XPS test reveals that the active ingredients in IBLE can generate Cu–N bonds on the copper surface, producing chemisorption. Theoretical calculation results reveal that the active ingredients of IBLE have great corrosion suppression property.

Microwave-assisted fast preparation of functionalized carbon dots: The impact of ionic liquid precursor on corrosion inhibition

In this study, functionalized carbon dots were synthesized in one step from L-histidine and imidazolyl ionic liquids using an ionic liquid-assisted microwave method as green corrosion inhibitors for steel in a 1 M HCl solution. Different ionic liquid anions (CF3COO- and HSO4-) were introduced in the preparation of the carbon dots, and their microstructures and surface properties were characterized. Notably, the corrosion inhibition efficiency of the prepared CDs (assisted by CF3COO-) reached 94.2% at 5 mg‧dm−3. The corrosion inhibition behavior of CDs on mild steel in 1 M HCl was investigated through DFT calculations. Our investigation revealed that the anions of the selected ionic liquids have a certain influence on the structure of the carbon dots, which correlates with the performance of the carbon dot corrosion inhibitor. Therefore, this study provides guidance for the preparation of functionalized carbon dot corrosion inhibitors using a one-step microwave method and the selection of ionic liquids (as solvents, modifiers, and mediums for microwave conversion).

Comprehensive analysis of a thiazole-substituted corrosion inhibitor's impact on N80 carbon steel in acidic conditions: Integrating computational predictions with experimental verifications

The present investigation elucidates the effectiveness of a newly developed organic inhibitor, namely 6,6-diphenyl-2,3-dihydroimidazo[2,1-b]thiazol-5(6H)-one (PHIT) in inhibiting the corrosion of N80 carbon steel (N80-CS) in 15 wt% HCl at 303 K. An integrative approach combining theoretical insights through Density Functional Theory (DFT) and molecular dynamics (MD) simulations with empirical data derived from a suite of analytical techniques (namely, weight loss measurements, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and scanning electron microscopy (SEM)), was employed to assess the corrosion inhibition performance. The research identified the thiazolone fragment as the predominant site of activity within the PHIT molecule. According to EIS results, a significant reduction in the effective double-layer capacitance from 174 (blank) to 36.17 μF/cm2 was registered following the addition of 5 × 10−3 mol/L PHIT to the HCl medium. Moreover, at a low concentration of 10−4 mol/L, the inhibition efficiency reached a maximum of 95 %. The immersion time had a significant effect on the inhibitor's polarization resistance, peaking at 48 h (596 Ω cm2), then experiencing a minor reduction at 72 h (457 Ω cm2), in comparison to the blank measurement at 0.5 h (231 Ω cm2). Besides, the inhibitor demonstrated a high degree of effectiveness across various temperatures with a slight decrement in efficiency from 96.5 % at 303 K to 94 % at 363 K. PDP results confirmed the tested compound as an anodic-type inhibitor. These results affirmed the potential of PHIT as a highly efficacious organic inhibitor for N80-CS in acidic conditions, encouraging further development of its derivatives.

Development of a Method for Determining the Residual Life of Structural Elements with Cracks Under the Action of Load and Corrosive Environment, as well as the Application of Corrosion Inhibitors to Enhance It

A developed method for determining the lifespan of structural elements with large-scale cracks of complex geometry under the influence of long-term static loads and corrosive environments. The method is based on an appropriate computational model, which relies on the first law of thermodynamics for the elementary act of local failure (crack propagation), some fundamental principles of physical chemistry, as well as the basic principles of fracture mechanics. The advantages of this method over existing ones are substantiated. The application of the method is demonstrated through examples involving the determination of the residual life of such structural elements as torsion and a pipe with small cracks made of 45KhN2MFA steel (tempered at 470 K and 725 K) under the influence of long-term static loading and distilled water. As the cracks are considered small, we have constructed a computational model in terms of deformation parameters, including a well-known counterpart in fracture mechanics, crack opening at the crack tip δt. At the same time, based on available experimental data from the literature, it is substantiated that the application of existing linear fracture mechanics methods in stress intensity factors KI for implementing the mentioned problems, the application of existing linear fracture mechanics methods is inappropriate. To determine the residual life of structural elements using this method, it is necessary to have kinetic diagrams in coordinates of the growth rate of small cracks and the crack opening at the crack tip, which means V ∼ δt. These diagrams are constructed here using the provided formulas for determining δt and diagrams are constructed here using the provided formulas and known experimental data for 45KhN2MFA steel under the influence of distilled water and static tension. Using the mentioned method, the residual lifespans of the torsion and the pipe were calculated under the influence of long-term static loading and distilled water. Additionally, the effectiveness of water solutions of well-known inorganic corrosion inhibitors on the residual lifespan of the mentioned structural elements was verified through calculations. It was found that the residual lifespan effectively characterizes the performance of corrosion inhibitors, which can be applied in engineering practice.

Celastrus paniculatus seeds as a green corrosion inhibitor for stainless steel in H2SO4 acidic solution

Corrosion poses a significant threat to the durability and safety of metallic structures, particularly in aggressive environments such as sulfuric acid solutions. In this study, the corrosion inhibition performance of Celastrus paniculatus for steel in 0.5 M H2SO4 is investigated. Celastrus paniculatus, a natural plant extract known for its potential corrosion-inhibitive properties, is explored as a green alternative to synthetic inhibitors.The experimental methodology involves the immersion of steel specimens in 0.5 M H2SO4 solutions containing various concentrations of Celastrus paniculatus extract. Electrochemical techniques, such as potentiodynamic polarization and electrochemical impedance spectroscopy, assess corrosion inhibition efficiency. Surface analysis techniques, i.e., scanning electron microscopy (SEM), were employed to investigate the steel surfaces' morphological changes and elemental composition also Quantum Chemical Computations were conducted to find the energy levels of the Lowest Unoccupied Molecular Orbital (ELUMO) and Highest Occupied Molecular Orbital (EHOMO) and the energy gap (ΔE) between HUMO and LUMO from the optimized structure to find of which phytochemical absorb on the surface of the metal and this, we can clear that lower energy containing phytochemical will absorb more on the metal surface and have their greater efficiency. The study contributes to the development of environmentally friendly and sustainable corrosion inhibitors for steel in corrosive media, with potential applications in various industrial sectors. In metallic industries during acid cleaning or pickling processes metal undergoes acidic corrosion. This acidic corrosion can be prevented by many ways including alloying or dealloying of metals, anodic and cathodic protection or application of inhibitors. In this study, we have used the Celastrus paniculatus seed extract. Although its medicinal applications were explored but it was not used as a anticorrosive agent. So here we have determined the anticorrosive effects of Celastrus paniculatus seed in 0.5 M H2SO4 and used this as a novel and highly effective during acid cleaning.

Study on the inhibition mechanism of corrosion under inert deposit-covered X65 steel by three corrosion inhibitors

In order to solve the problem of under-deposit corrosion caused by typical inert minerals in oil and gas fields, three corrosion inhibitors with small molecular weight thiourea (TU), oil-soluble alkyl imidazoline (IM) and water-soluble thiourea imidazoline (TAI) were selected. The corrosion inhibition effect and mechanism of the them under SiO2 and CaCO3 deposit were studied by surface analysis, electrochemical analysis and theoretical calculations. The results show that TU, IM and TAI can adsorb on the metal surface through the deposits, and the corrosion inhibition efficiency is η(TAI) > η(TU) > η(IM). TU and TAI are mixed corrosion inhibitors that inhibit both the cathode and the anode reactions, and the thiourea group in TU and TAI can form coordination chemical bonds with the empty d orbital of iron atoms as electron-rich regions. Due to hydrophobic groups, the adsorption film formed by TAI on the metal surface is denser. However, it is difficult for IM to form a continuous protective corrosion inhibitor film under the two deposits, so it shows poor corrosion inhibition performance.

Pyridazine derivatives as effective anti-corrosion additives for carbon steel in 1 M HCl: Electrochemical, surface and theoretical studies

The study aimed to investigate the corrosion inhibition performance of two new pyridazine derivatives namely ((E)-2-(3-(4-(carboxymethoxy)-3-methoxystyryl)-5-(2-chlorobenzyl)-6-oxopyridazin-1(6H)-yl)acetic acid (CO6) and (E)-6-(4-hydroxy-3-methoxystyryl)pyridazin-3(2H)-one (CO39) for carbon steel (C.S) in 1M HCl by combining electrochemical techniques, surface analysis and theoretical studies. The electrochemical impedance spectroscopy (EIS) data indicated that the inhibitory efficiencies of CO6 and CO39 increased with increasing inhibitor concentration but decreased with increasing temperature, achieving 97.0 % and 95.3 %, respectively. The results of the potentiodynamic polarization (PDP) measurements show that the two pyridazine derivatives acted as mixed inhibitors. In addition, experimental studies have shown that CO6 and CO39 reduce corrosion rates by adsorbing on the steel surface following Langmuir adsorption isotherms. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) indicated that a protective layer had been developed on the surface of the carbon steel, which prevented corrosion from progressing. Quantum chemical computations and the molecular structures of the inhibitors were employed to investigate the mechanism of inhibition. The adsorption of the compounds investigated on C.S was validated by theoretical calculations including density functional theory (DFT) and molecular dynamics simulation (MDS).

Synthesis and evaluation of a new scale inhibitor: the modified epoxysuccinic acid copolymer

Polyepoxysuccinic acid (PESA) scale inhibitor is widely recognized as a green and environmentally friendly scale inhibitor. However, its functional group type is single and cannot be used for a variety of scales. Based on this, a modified epoxy succinic acid quaternary polymer scale inhibitor PEAPS was prepared by introducing a variety of functional groups. The effects of scale inhibitor dosage, temperature, and solution pH on the scale inhibition performance of CaCO3, CaSO4, BaSO4, and SrSO4 were studied. At the same time, it is compared with the commonly used oilfield scale inhibitors Polyacrylic acid (PAA), PESA, and Ethylenediaminetetramethylenephosphonic acid (EDTMP). The results show that under the optimal synthesis conditions, the scale inhibition efficiency of PEAPS scale inhibitor on CaCO3 scale and CaSO4 reaches 100%, and the scale inhibition efficiency of BaSO4 and SrSO4 can reach at least 60%. Its comprehensive scale inhibition efficiency is better than other commonly used scale inhibitors under the same test conditions, and it has certain corrosion inhibition performance through static corrosion evaluation. The crystal parameters and micro-morphology of the four scales before and after the addition of scale inhibitor were analyzed using SEM and XRD. The results showed that after adding the PEAPS scale inhibitor, the crystal structure parameters of the CaCO3 scale and CaSO4 scale changed, and the micro-morphology of the four scale crystals also changed, to achieve the purpose of scale inhibition.

Isoindigo derivatives as some potential corrosion inhibitors for mild steel in hydrochloric acid solution: Synthesis, experimental and theoretical studies

This investigation synthesized two isoindigo derivatives (IIDBr-NBr and IIDBr-MBr). These derivatives were then applied as green corrosion inhibitors for mild steel in a 1 mol L−1 HCl aqueous solution. The study investigated the corrosion inhibition performance of IIDBr-NBr and IIDBr-MBr through electrochemical and weight loss (WL) measurements, as well as surface analysis (SEM, AFM and XPS). The results showed that both IIDBr-NBr and IIDBr-MBr exhibited excellent corrosion inhibition performance (inhibition efficiency of 96.27 % for IIDBr-NBr and 96.46 % for IIDBr-MBr). Quantum chemical calculations based on density functional theory (DFT) and molecular dynamics (MD) were used to reveal the adsorption mechanisms of IIDBr-NBr and IIDBr-MBr at the steel/solution interface.

Review of nano-based smart coatings for corrosion mitigation: mechanisms, performance, and future prospects.

In response to environmental concerns about toxic corrosion inhibitors, nanomaterials have gained attention for their enhanced corrosion inhibition properties due to their high surface-to-volume ratio. This paper summarizes advancements in utilizing nanomaterials to control corrosion, exploring various preparation methods and effectiveness as inhibitors. Nano-based intelligent coatings have emerged as promising solutions, with this review examining their corrosion inhibition mechanisms, performance attributes, and future prospects. By combining nanomaterials with traditional inhibitors, synergistic effects can be achieved. Performance assessment extends to real-world scenarios, considering factors like adhesion, durability, and practical implementation across industries. Future trends include integrating real-time monitoring abilities and using environmentally conscious nanomaterials for sustainable corrosion control.

Protein-derived carbon dots as green corrosion inhibitors for carbon steel in sulfuric acid solution

At present, the development of eco-friendly corrosion inhibitors (CIs) is considered an important and attractive method for controlling the corrosion of metals in acidic media. In this study, protein-derived carbon dots (P-CDs) were prepared via hydrothermal reaction using protein as the raw material, and the corrosion inhibition performances of P-CDs for carbon steel (CS) were investigated systematically. The electrochemical test results showed that the corrosion inhibition efficiency of 500 mg/L P-CDs on CS reached 95.1 % in 0.5 M H2SO4, and the corrosion inhibition efficiency was enhanced to 98.1 % after 8 h of immersion time. The composition and characterization of P-CDs was analysed using Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet Spectroscopy (UV), X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) characterization showed that the surface of CS with P-CDs was smoother than that without P-CDs, and that P-CDs was able to adsorb on the surface of CS to form a protective layer, thereby inhibiting corrosion. Adsorption studies indicate that P-CDs form a protective layer on the surface of CS through both physisorption and chemisorption. Overall, these findings demonstrate that P-CDs exhibit superior protective effects against the corrosion of CS in 0.5 M H2SO4.

In-Depth Insight into Corrosion Inhibition Performance of Sweet Potato Leaf Extract as a Green and Efficient Inhibitor for 6N01 Al Alloy in the Seawater: Experimental and Theoretical Perspectives.

Corrosion protection of metal has become an important and urgent topic, which requires the development of an inexpensive, environmentally friendly, and highly efficient corrosion inhibitor. Herein, a sweet potato leaf extract (SPL) was obtained by a simple water-based extraction method and then as a green corrosion inhibitor for 6N01 Al alloy in the seawater was well investigated by the weight loss method and various electrochemical tests. Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopies were carried out to investigate the compositions of SPL. The findings from the potentiodynamic polarization (PDP) curves suggest that SPL functions as a typical mixed-type corrosion inhibitor. Notably, the maximum corrosion inhibition efficiency reaches 94.6% following a 36 h immersion period at 25 °C. The adsorption behavior of SPL on the Al alloy surface belongs to the Langmuir adsorption isotherm. The Gibbs free energy value illustrates that the adsorption of SPL contains both physisorption and chemisorption. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) indicate that SPL is firmly attached to the Al alloy surface by making a protective layer, which can effectively inhibit the corrosion of the Al alloy in the seawater. Furthermore, quantum chemical calculations were applied to validate the chemical adsorption and elucidate the relationship between the electronic structure of the active components in SPL and their effectiveness in corrosion inhibition.

Effect of Alkyl Chain Length on the Corrosion Inhibition Performance of Imidazolium-Based Ionic Liquids for Carbon Steel in 1 M HCl Solution: Experimental Evaluation and Theoretical Analysis.

In this study, five kinds of 1-alkyl-3-methylimidazolium bromide ([CXami]Br) ionic liquids with different alkyl chain lengths (8, 10, 12, 14, and 16) were selected as inhibitors. Then, their corrosion inhibition performances for Q235 steel in 1.0 mol L-1 HCl solution were investigated via a weight loss test, polarization curve method, and surface analysis techniques. The results show that these five imidazolium-based ionic liquids are all mixed-type inhibitors, and they can be spontaneously adsorbed onto the Q235 steel surface. The adsorption process follows the Langmuir model and involves mixed physical-chemical adsorption. Theoretical calculations confirm that the increase in alkyl chain length is conducive to the imidazolium-based ionic liquids exhibiting stronger chemical bonding abilities and forming denser adsorption films. The inhibition efficiency significantly increases below the critical micelle concentration (CMC) with an increase in alkyl chain length, and the highest inhibition efficiency is 95.17% for the [C16ami]Br inhibitor at the concentration of 0.005 mM. However, above the CMC, the inhibition efficiency is minimally affected by the alkyl chain length since all ionic liquid inhibitors have reached adsorption saturation on the steel surface.

Theoretical Study and Virtual Screening of Nitrogen‐Containing Corrosion Inhibitors Based on Quantitative Structure–Activity Relationship

AbstractNitrogen‐containing corrosion inhibitors have a wide range of promising applications, and current conventional corrosion design and evaluation methods are largely based on empirical speculation and extensive exploratory experiments. Unfortunately, these efforts are often associated with high costs, long lead times, and a lot of “blind work.” In this work, we have computationally screened the quantum chemical parameters of five nitrogen‐containing corrosion inhibitor molecules and their corrosion inhibition properties by a molecular simulation method based on density functional theory calculations. The ultimate relationship between the corrosion inhibition efficiency (IE) of an adsorbent and its quantum chemical parameters was analyzed using linear regression by comparing the various quantum mechanical parameters of each inhibitor molecule, as well as the fraction of electrons (ΔN) that are transferred to the metal surface from the chemisorbed inhibitor molecule. Five different nitrogen‐containing corrosion inhibitor molecules were screened based on structural similarity. Meanwhile, their corrosion inhibition performance was evaluated using the most relevant structure–activity equations. The results showed that the synergistic effect between the corrosion inhibition performance and the orbital energies of highest occupied molecular orbital and lowest unoccupied molecular orbital was optimal under the HF/6‐31G(d) method, and the corresponding structure–activity relationship was established. Based on these results, a specific inhibitor molecule was found to have excellent corrosion inhibition performance with a predicted corrosion IE of up to 94.12 %.

A study of pomegranate peel extract effect on corrosion inhibition performance on aluminum in HNO3 solution

Green corrosion inhibitors have an important role in reducing the corrosion rate of metals and the effects of toxic chemicals in the environment. In this study, the inhibition effect of pomegranate peel extract (PPE) with concentration of 0.5, 1, 1.5, 2, 2.5 and 3g/L on the aluminum 1050 alloy corrosion behavior in the nitric acid solution investigates using the weight loss, electrochemical techniques, scanning electron microscope (SEM), atomic force microscope (AFM), contact angle images, gas chromatography-mass spectrometer (GC-MS) analysis, fourier transform Infrared spectroscopy (FTIR) and ultraviolet radiation (UV-IR). And, the (UV-IR), (GC-MS), and FTIR results confirm the presence of many organic compounds (Containing the N, S, and O atoms), which are responsible for inhibitor performance and absorption phenomena. Meanwhile, the electrochemical impedance results (EIS) indicate that the double layer capacity decreases and the corrosion resistance (Corrosion current density (icorr) from 0.128 to 0.009mA/cm2) increases with the increase of the inhibitor concentration (The inhibition efficiency increased with increasing the inhibitor concentration from % 54.29 to the % 92.58 at (1 to 3g/L). In addition, the corrosion current density decreases with the increase of the inhibitor concentration using the potentiodynamic polarization (PDP) test. However, the corrosion rate enhances with increasing the temperature. From the other hand, quantum chemical (QC) calculation and molecular dynamics (MD) simulation perform to investigate the theory of the adsorption mechanism. According to these studies, the adsorption of PPE on the aluminum 1050 alloy surface is agreement with the langmuir isotherm and as a result it is a mixed-type inhibitor. In final the SEM and AFM results show that the corrosion rate of the aluminum 1050 alloy surface is significantly reduced after the addition of the inhibitor to the corrosive environment. Furthermore, the contact angle image shows that the inhibited aluminum surface has a hydrophobic property in an aqueous solution. And, the QC calculation and MD simulation clarify well the thin layer formation due to the good adsorption of inhibitor (PPE) on the surface of aluminum 1050 alloy in the nitric acid solution, theoretically. It is concluded that PPE will inhibit the surface of aluminum against the corrosion agents in acidic environment and can use as a green inhibitor.

Particle Properties of Air Nanobubbles and Their Inhibition Mechanism on Brass Corrosion in Recirculating Cooling Water: Effects of Concentration Ratio and Flow Velocity

AbstractThe corrosion inhibition performance of air nanobubbles (A‐NBs) is expected to address the environmental problems arising from chemical corrosion. In order to regulate the corrosion inhibition performance of A‐NBs, the particle characteristics of A‐NBs in flowing composite salt solutions are investigated, and the corrosion inhibition effect of A‐NBs under different concentration ratios and rotational speed of simulated circulating cooling water is studied. High salt concentrations significantly reduced the particle size, concentration, and zeta‐potential value of A‐NBs, thus reducing the stability of A‐NBs. The flow velocity has a slight effect on A‐NBs. The results of the weight loss and electrochemical method showed that A‐NBs achieved the highest corrosion inhibition rate of 55% under a concentration ratio of 1.5 and a rotational speed of 100 r min−1. The surface characterization of brass specimens revealed that A‐NBs facilitated the formation of Cu2(OH)2CO3 passivation film, calcium carbonate scale film, and a layer of bubbles on the surface of brass, which subsequently mitigated the erosive impact of the fluid. A‐NBs can adsorb cations and thus reduce the concentration of corrosive ions. However, the increase in concentration ratio and rotational speed impeded the formation of the bubble layer and passivation film.

Study on the corrosion inhibition performance of Schiff base corrosion inhibitor on Q235 steel

Q235 steel is widely used in industry and daily life, and it is prone to corrosion during use, especially in hydrochloric acid solution where corrosion is particularly severe. Schiff base organic compounds can significantly inhibit the corrosion of Q235 steel in hydrochloric acid solution, making them a green and environmentally friendly organic compound. This article uses aniline, octadecylamine, and glutaraldehyde as raw materials to prepare two Schiff base corrosion inhibitors, namely bisaniline Schiff base and bisoctadecylamine Schiff base (named BXFJ and SXFJ respectively). The corrosion inhibition performance and mechanism of these two Schiff base inhibitors in Q235 steel in hydrochloric acid solution were studied using weight loss method, electrochemical testing, quantum chemical theory calculation, and molecular dynamics simulation. The results of weight loss method and electrochemical testing show that in a 1mol/L HCl solution, the corrosion inhibition performance of BXFJ at a concentration of 25mg/L is higher than that of SXFJ, indicating that BXFJ can exert excellent corrosion inhibition performance in HCl environment. Density functional theory (DFT) indicates that the active sites of the two Schiff bases are C=N double bonds, and molecular dynamics (MD) further confirms that both Schiff base corrosion inhibitors can adsorb on the surface of Q235 steel.

Corrosion inhibition performance of new Schiff base cyclohexanamine derivatives on C-steel in 1 M HCl solution: Electrochemical, chemical, surface and computational explorations

Iron has many advantages, which makes it a material of great importance on the industrial level, but it is quickly affected by surrounding environmental factors that cause its corrosion. In this context, two new Schiff base cyclohexanamine derivatives (CSBs) were synthesized, characterized, and screened as corrosion inhibitors of C-steel in a 1 M hydrochloric acid solution. Specifically, they are (Z)-N-cyclohexyl-1-phenylethan-1-imine (CSB-1) and (E)-N′-cyclohexyl-N-hydroxybenzimidamide (CSB-2). 1H NMR was used to determine the structures of the new CSB molecules. The inhibition efficacies (%IE) were evaluated by combining theoretical, physical, chemical, electrochemical, and spectroscopic methods. The results confirmed that CSBs were mixed-type inhibitors and that the IE depended linearly on their concentration. The adsorption of these molecules on the metal surface is key to this role. Kinetic and thermodynamic studies indicated that they are physically adsorbed and subject the Langmuir adsorption isotherm. Using 0.001 M of inhibitor, the maximum %IEs achieved were 91.1 % for CSB-1 and 94.4 % for CSB-2, respectively, which confirms tatehat they are promising inhibitors. Surface analysis via atomic force microscopy (AFM) confirmed that the C-steel was covered in a protective layer. Several thermodynamic and kinetic parameters were calculated. DFT and Mullikan charge calculations and molecular dynamics (MD) simulations were applied to predict the effectiveness and interactions of new CSBs on the steel surface as well. Theoretical expectations correspond to the practical.

Impact of Aqueous Extract Artemisia Herba-Alba Leaves as a Green Inhibitor against Acid Activation of 2024 Aluminum Alloy

This work is part of the development of new bio-sourced corrosion inhibitors from an abundant resource that can replace conventional synthetic inhibitors that are harmful to both human health and the environment. The corrosion inhibition performance of an aqueous extract of Artemisia herba-alba on the corrosion of 2024 aluminum alloy in a 1 M hydrochloric acid solution is investigated by weight loss method, electrochemical (linear polarization, potentiodynamic polarization, and electrochemical impedance spectroscopy) and SEM techniques. The extract shows excellent corrosion-inhibiting properties on aluminium alloy with a maximum inhibition efficiency of 93% at 0.6 g/L. The adsorption of the natural extract obeys the extended Langmuir isotherm equation adsorption model for multicomponent systems. Temperature studies show that the efficiency of the extract decreases with increasing temperature and that the corrosion activation energies increase in the presence of the extract. Liquid chromatography/high resolution mass spectrometry is used to identify the chemical constituents of the natural extract, and the most abundant phytochemicals for each subclass of metabolite are investigated using density functional theory (DFT) calculations. This study paves the way for further development of a plant that is particularly abundant in the desert regions of North Africa and has until now been used mainly for food for livestock and for pharmaceutical applications.

Study on the corrosion inhibition properties of some quinoline derivatives as acidizing corrosion inhibitors for steel

In this paper, four quinoline quaternary ammonium salts were synthesized using quaternization reaction, which were benzyl quinolion (BQL), naphthylmethyl quinolinium chloride (NQL), benzyl-8-hydroxy quinolinium chloride (BHQ) and naphthylmethyl 8-hydroxy quinolinium chloride (NHQ). The corrosion inhibition properties of the quinoline derivatives as corrosion inhibitors on P110 steel in 20% HCl solution at 60°C at different concentrations were investigated by weight loss and electrochemical measurements. The results showed that as the concentration of corrosion inhibitor increases, the corrosion rate decreased and the inhibition efficiency improved. Among various corrosion inhibitors at the same concentration, their inhibition efficiencies can be ranked from lowest to highest as follows: QL(quinoline)<8-HQ(8-hydroxyquinoline)<BQL<BHQ<NQL<NHQ. The inhibitors synthesized from 1-chloromethyl naphthalene, NQL and NHQ, exhibited excellent inhibition property, in which the inhibition efficiencies reached to 99.8% and 99.9% even with concentration of 0.1%. It also demonstrated the adsorption of all inhibitors on the steel surface followed Langmuir adsorption isotherms, in which QL and 8-QH exhibited as physical adsorption, BQL and BHQ exhibited as mixed adsorption and NQL and NHQ exhibited as chemical adsorption. The inhibition mechanism of inhibitors was also investigated with scanning electron microscopy (SEM), quantum chemical analyses and molecular dynamics simulations, which proved BHQ and NHQ can facilitate an increase in electron cloud density on the benzene ring, thereby enhancing corrosion inhibition performance.