Corrosion Inhibition Behavior Research Articles

2-Amino-6-methylbenzothiazole as corrosion inhibitor for low carbon steel in acidic solution: Experimental and theoretical studies

The corrosion susceptibility of S235 steel samples in 1 M HCl solution, with and without addition of 2-amino-6-methylbenzothiazole (AMBT) was evaluated using weight loss (WL), chronopotentiometry, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PD) techniques. The corrosion inhibition efficiency of AMBT was investigated at 298 to 318 K, with and without addition of 0.5 wt% KI. The highest corrosion inhibition efficiency (i.e. 83.30 %) was achieved upon addition of 5 mM AMBT. PD curve measurements after 24 h immersion revealed that AMBT behaves as a mixed-type inhibitor, predominantly affecting the cathodic corrosion reaction. Thermodynamic calculations showed that AMBT adheres to the Langmuir adsorption isotherm. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) was used to confirm the adsorption of AMBT, while its influence on the morphology of the S235 steel samples was also investigated by scanning electron microscopy (SEM). Density Functional Theory (DFT) calculations, along with Monte Carlo (MC) and Molecular Dynamics (MD) simulations, were employed to investigate AMBT’s corrosion inhibition behaviour at the molecular level. The simulations confirmed that AMBT strongly adsorbs on the Fe(110) surface through a combination of physisorption and chemisorption mechanisms. This study offers detailed insights into AMBT’s effectiveness as a corrosion inhibitor

Corrosion Inhibition and Adsorption Behaviour of Centrosema pubescens Leaf Extract for Copper in HCl Solution

Study’s Excerpt In this study, Centrosema pubescens leaf extract (CPE) has been confirmed as eco-friendly and efficient green inhibitor for copper corrosion in hydrochloric acid. Detailed thermodynamic analysis, revealed that CPE adsorption follows a Freundlich isotherm model. SEM-EDX and FTIR characterizations confirmed the formation of a protective layer confirming the potentials of the plant extracts in sustainable corrosion prevention. Full Abstract The anti-corrosion behaviour of Centrosema pubescens leaf extract (CPE) on copper in 1.5 M hydrochloric acid was investigated using weight loss method at different temperatures, followed with scanning electron microscopy (SEM) surface characterization connected with energy dispersive X-ray spectroscopy (EDX). The Fourier transform infrared spectrum of CPE was obtained. CPE inhibition effectiveness depends on the temperature and its concentration. CPE restrains the copper corrosion with 94.26 % inhibition efficiency at 1.0 g/L of CPE and at 303 K. For the CPE-inhibited system, a higher activation energy (Ea) value (range of 31.09 to 38.70 kJmol-1) compared to 20.34 kJmol-1 of the blank solution was obtained. The reaction process is spontaneous and endo thermic, as indicated by the ΔH, ΔS and ΔG values calculated. CPE adsorption behaviour fitted best into Freundlich isotherm.

Corrosion Inhibition Behaviour of Calf Thymus Gland DNA on Mild Steel in 10% Sulphamic Acid

Corrosion Inhibition Behaviour of Calf Thymus Gland DNA on Mild Steel in 10% Sulphamic Acid

Synergistic inhibition effect of Chlorella sp. and benzotriazole on the corrosion of Q235 carbon steel in alkaline artificial seawater

The interaction of microalgae on the reinforced concrete with corrosion inhibitor is not well understood. Moreover, the inhibition role of microalgae on corrosion has been reported in recent years. In this study, the corrosion inhibition behavior of Q235 carbon steel (CS) due to the presence of Chlorella sp. and benzotriazole (BTA) in alkaline artificial seawater was investigated by means of weight loss, electrochemical measurements including open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization curves, and surface analysis including scanning electron microscopy, energy dispersion spectrometer, and X-ray photoelectron spectroscopy. The results of reduced corrosion rates in the algae-BTA system demonstrated that Chlorella sp. could facilitate the corrosion inhibition efficiency of BTA on the CS specimens. Moreover, polarization measurement showed the algae-BTA system had a mixed-type corrosion inhibition effect. The mechanisms of inhibition were proposed to be the precipitation of iron complexes such as Fe-BTA-EPS and Fe-BTA and iron compounds on the steel surface in the presence of the microalgae and BTA–. This study highlights the application of CS corrosion control by combining biological and chemical approaches that can be used for future research and practice, rather than purely chemical approaches.

Surface functionalization of XC18 steel using a new transition metal complex for remarkable corrosion performance: Empirical and theoretical studies

Synthesis of transition metal complexes (TMC) having specific characteristics is advantageous for combining their organic and inorganic properties, to help prevent metals from corrosion. In this study, the corrosion inhibition behavior of [N, N′-bis(salicylidene)-2,2-dimethyl-1,3-propanediaminato] copper (II) (CuL) on the surface of XC18 steel surface immersed in 1.0 M HCl was investigated. The thermodynamic and kinetic corrosion parameters were determined using the mass loss (ML) and electrochemical measurement methods. CuL exhibited a good corrosion inhibition efficiency of 96.72 %. The adsorption behavior of CuL followed the Langmuir isotherm model, indicating both physical and chemical interactions. Morphological structural analysis demonstrated that CuL formed a protective film between the surface of XC18 steel and the corrosives elements, thus confirming its adsorption onto XC18 steel surface. Theoretical calculations were consistent with the experimental findings, thereby confirming that the adsorption of CuL onto the steel surface comprises both physisorption and chemisorption processes. These calculations elucidate the specific bonding nature and emphasize the significant inter- and intra-molecular interactions that enhance the stability and adsorption capability of the CuL inhibitor. The successful formation of a protective layer on the surface of XC18 steel using a TMC signifies exciting prospects for the development of advanced materials with diverse applications.

Corrosion mitigation of carbon steel in sulfuric and hydrochloric acid solutions by Syzygium polyanthum (Wight) Walp. leaf extract

It is widely recognized that corrosion has been a persistent issue throughout human history. Over time, various effective strategies have been suggested and successfully employed to combat this problem. Among them, the utilization of inhibitors stands out as a promising, versatile, and easily applicable method. Considering the drawbacks associated with previous substances such as environmental concerns and high operational expenses, plant extracts have emerged as an effective alternative. In there, Syzygium polyanthum (Wight) Walp. stands out as a popular species characterized by a high concentration of polar compounds that is crucial for the formation of a protective film layer on carbon steel. Consequently, this work centers on investigating the corrosion inhibition behavior of Syzygium polyanthum (Wight) Walp. leaf water-extract (SPWE) for carbon steel in different solutions, including 1.0 M HCl, 0.5 M H2SO4, and co-volume acidic mixture, by employing electrochemical and surface techniques. The findings reveal that 2000 ppm of SPWE proved inhibition efficiency exceeding 94.24, 66.27, and 95.02% (estimated by Tafel extrapolation) for carbon steel in 1.0 M HCl, 0.5 M H2SO4, and acidic mixture solutions, respectively. High inhibition performance was also ensured by high polarization resistances (Rp) observed on electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR). Increasing corrosion resistance could be due to the protective layer formed on the inhibited samples, while severe corrosion occurred on the uninhibited steel due to extensive damage across the entire surface. Hence, the study underscores the noteworthy impact of chloride and sulfate ions on corrosive inhibition process of SPWE.

Effect of cetyl pyridinium chloride on corrosion inhibition of mild steel in acidic medium

The corrosion inhibition behavior of cetyl pyridinium chloride (CPC) on mild steel (MS) in 0.5 M H2SO4 solution was examined using weight loss and potentiodynamic polarization method. Different concentrations of CPC (0.000192 M, 0.0038 M, 0.0057 M and 0.0077 M) was used to find the balanced CPC in the acid solution. Among them, 0.000192 M and 0.0077 M of CPC solution showed a corrosion rate of 8.23×10−3, 3.52×10−5 (mm/Year), and the inhibition efficiency of 89.94 % and 96.23 %, respectively, which is lower than the pure acidic solution (0.5 M H2SO4). Furthermore, the experimented MS surfaces were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and Atomic Force Microscopy (AFM). FESEM and AFM studies demonstrated the corrosion attack on the MS surface, which is relatively less as compared to the only acid-exposed surface. The SEM-EDX analysis indicates the presence of nitro-group on the MS surface, which might be due to the contribution of pyridinium protonation of CPC. This phenomenon might enhance the corrosion resistance on the MS surface.

Anti-corrosion design of layered zirconium-based metal–organic frameworks (Zr-MOF) enhanced epoxy nanocomposite coatings

In this work, two-dimensional UiO-67 nanosheets are successfully modified on graphene oxide (GO). The synthesized GO@2D-UiO-67 composite not only exhibits the electrical insulation characteristics of Zr-MOF, but also leverages the passive barrier effect of its 2D layered structure to prepare a highly anticorrosive epoxy coating. Electrochemical measurements reveal that the impedance modulus of the GO@UiO-67/EP composite coating remain two orders of magnitude higher than that of the pure EP coating even after 28 days of immersion in 3.5 wt% NaCl solution. This good long-term anti-corrosion performance could derive from the enhanced crosslinking density of composite coating due to the incorporation of GO@UiO-67 nanosheets. Furthermore, the shielding effect of layered structure and the corrosion inhibition behavior of organic ligands are proved to improve the corrosion resistance properties of composite coating. This research fills the application void of two-dimensional Zr-MOF composites in resin coatings, as well as serves as a forward-looking initiative to enhance the long-term corrosion protection of epoxy resin coatings.

In-depth study of a newly synthesized imidazole derivative as an eco-friendly corrosion inhibitor for mild steel in 1 M HCl: Theoretical, electrochemical, and surface analysis perspectives

The present study is concerned with the corrosion inhibition and adsorption behaviour of a series of novel imidazole derivatives. The compounds under investigation are 5,5-diphenyl-3-propyl-2-(propylthio)-3,5-dihydro-4 H-imidazol-4-one (AM3) and 3-allyl-2-(allylthio)-5,5-diphenyl-3,5-dihydro-4 H-imidazol-4-one (AM6). The objective of this study is to evaluate the efficacy of 5,5-diphenyl-3,5-dihydro-4 H-imidazol-4-one (AM6) as a corrosion inhibitor on mild steel immersed in a 1.0 M hydrochloric acid medium. This comprehensive study assesses the efficacy of these derivatives through a range of electrochemical and spectroscopic analysis techniques. Additionally, polarisation curves, electrochemical impedance spectroscopy and advanced computer simulations were employed to evaluate the efficacy and inhibition mechanism of imidazole derivatives, thereby facilitating a more profound understanding of their anticorrosive capacity. The results obtained from potentiodynamic polarisation (PDP), electrochemical frequency modulation (EFM) and electrochemical impedance spectroscopy (EIS) measurements demonstrate that the inhibition efficiency increases with increasing imidazole derivative concentration. Conversely, an inverse relationship is observed between inhibition efficiency and temperature. The thermodynamic parameters ΔG°_ads and ΔH°_ads corroborate the conclusion that the adsorption process is predominantly chemical in nature. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) were employed to characterise the surface morphology. The maximum protection afforded by imidazole derivatives was 95.2 % and 93 % for compounds AM3 and AM6, respectively. Polarisation curves indicated that imidazole derivatives exhibited mixed inhibition behaviour. Surface analysis demonstrated that imidazole derivatives were effectively adsorbed onto the carbon surface, thereby significantly reducing acid damage. This finding was corroborated by DFT calculations, as well as Monte Carlo (MC) and molecular dynamics (MD) simulations. These simulations provided a comprehensive insight into the adsorption of imidazole and its protonated form onto the carbon surface, offering valuable insight into the corrosion inhibition mechanism.

Syzygium polyanthum (Wight) Walp. leaf extract as a sustainable corrosion inhibitor for carbon steel in hydrochloric acidic environment

This study focuses on an investigation of the corrosion inhibition behavior of Syzygium polyanthum (Wight) Walp. leaf extract (SPWE) of carbon steel in 1.0 M hydrochloric acid medium. Electrochemical methods demonstrated a corrosion inhibition efficiency of 94.65 ± 0.94 % when 2000 ppm extract is added to the corrosive solution. Furthermore, surface analysis results indicated that with the absence of an inhibitor, the steel surface suffered severe corrosion, while the corrosion density was slow, and a film was observed on the surface after applying the SPWE into a corrosive environment. The film formed by the chemical and physical adsorption of compounds such as polyphenol, flavonoid, alkaloid, and tannin onto the carbon steel surface has been qualitatively and quantitatively analyzed in this study. Notably, increased immersion time and reaction temperature led to significant desorption of molecules, reflecting characteristic of physical adsorption. However, the corrosion inhibition efficiency of SPWE remained effective, particularly within the temperature range of 25–35 °C. Therefore, this study provides an efficient inhibitor for carbon steel corrosion in 1.0 M hydrochloric acidic environment that could be possibly added to the corrosion inhibitor system.

Menadione sodium bisulfite as an efficient anti-corrosion additive for mild steel in acid corrosion: Electrochemical, surface morphological and theoretical studies

The corrosion inhibition behavior of Menadione Sodium Bisulfite (MSB) in 1.0 M HCl medium was evaluated using weight loss, electrochemical techniques (Tafel polarisation and Electrochemical impedance spectra), surface analysis (SEM and EDX), Density Functional Theory (DFT), Noncovalent interaction- Reduced Density Gradient (NCI-RDG) and Monte Carlo (MC) simulation techniques. Weight loss measurement showed that as inhibitor concentration increased, the corrosion rate decreased which means that a protective film formed on the metal surface. At 300 ppm, the inhibitor showed a maximum inhibition efficiency of 89.7 %. Tafel polarisation studies indicate that the inhibitor is mixed-type in nature. The inhibitor adsorption on the mild steel is the best fit for the Langmuir isotherm model. As the weak interaction of sodium and oxygen in the inhibitor molecules, the inhibitor exhibits two distinct equilibrium behaviors. (i) inhibitor with sodium (solid-state) and inhibitor without sodium (in liquid-state). These two behaviors were theoretically investigated using DFT and MD simulation studies. The inhibitor and metal interaction is further supported using these theoretical studies. The electron population of the inhibitor was analyzed using molecular electrostatic potential, NCI-RDG, Fukui function, and natural bond orbital analysis. These studies further give an understating of the inhibitor and metal interactions.

Zea mays bracts extract as an eco-friendly corrosion inhibitor for steel in HCl pickling solution: Experimental and simulation studies

Active phytochemicals with unique electron structures can adsorb on metal surfaces and effectively mitigate metal corrosion. Recently, plant extracts have garnered significant attention as green and renewable corrosion inhibitors. In this study, the abundant agricultural byproducts, namely Zea mays bracts, were used as the extract raw materials, and Zea mays bracts extract (ZMBE) was served as an eco-friendly corrosion inhibitor for mild steel (MS) in 1 M HCl pickling solution. The organic substances in ZMBE were analyzed via ultra-high performance liquid chromatography- quadrupole time-of-flight mass spectrometry (UPLC-QTFMS). The interaction between the active functional groups and MS was investigated using Fourier transform infrared (FT-IR) and ultraviolet–visible (UV–visible) spectroscopy and X-ray photoelectron spectroscopy (XPS). The corrosion inhibition behavior was scrutinized through potentiodynamic polarization (PDP) curves and electrochemical impedance spectroscopy (EIS). The results show that functional groups such as aromatic rings, double bonds, and hydroxyls successfully adsorb on the MS surface to form the protective films. ZMBE exhibits a mixed-type corrosion inhibition with a “geometric coverage” effect. The corrosion inhibition efficiency (η) increases with ZMBE concentration and solution temperature, the optimum η with 5.0 g·L−1 ZMBE at 318 K is 96.2 %. The adsorption of active ingredients follows the Langmuir and El-Awady isotherms. Density functional theory (DFT) and molecular dynamics (MD) simulations prove the synergistic effect of complex components in ZMBE and the corrosion inhibition mechanism. ZMBE is a promising acid pickling corrosion inhibitor with broad application prospects.

Corrosion inhibition performance of RNC-n on aluminum alloy surface in alkaline solution

The corrosion inhibition behavior of glycine surfactants with different carbon chain lengths (RNC-n, n = 8, 12, 14) of AA2024-T3 aluminum alloy in 0.01 mol·L−1 NaOH solution was investigated. The weight loss and electrochemical methods, XPS, SEM/EDS techniques, quantum chemical calculations, and molecular dynamics simulations were used for studying the corrosion inhibition properties, adsorption behavior, and corrosion inhibition mechanism. When the maximum solubility of 0.01 mol·L−1 was achieved, the inhibition effectiveness of RNC-8 reached 90.55 %. Both RNC-12 and RNC-14 exhibited inhibitory efficiencies of 92.81 % at 0.005 mol·L−1 and 91.83 % at 0.0005 mol·L−1. RNC-n was shown to be an anodic corrosion inhibitor, since its impact on the anodic reaction was larger than on the cathodic one. RNC-n was able to successfully adsorb on the aluminum surface and form a protective film, which hindered further corrosion damage of the aluminum by the alkaline solution. In addition, the adsorption sites of RNC-n molecules were analyzed, and it was found that the adsorption sites of the corrosion inhibitor were mainly in the carboxyl group. Therefore, this paper can provide some theoretical support for the protection of aluminum alloys against corrosion in alkaline medium.

Comprehensive Investigation of the Adsorption, Corrosion Inhibitory Properties, and Quantum Calculations for 2-(2,4,5-Trimethoxybenzylidene) Hydrazine Carbothioamide in Mitigating Corrosion of XC38 Carbon Steel under HCl Environment.

This study investigates the inhibitory effects of 2-(2,4,5-trimethoxy benzylidene) hydrazine carbothioamide (TMBHCA) on the corrosion of carbon steel in a 1 M HCl solution across various concentrations. The assessment employs a comprehensive approach, combining gravimetric analysis, potentiodynamic polarization tests, and electrochemical impedance spectroscopy (EIS). Additionally, scanning electron microscopy (SEM) and quantum chemical calculations are employed to provide a thorough understanding of the corrosion inhibition mechanism. The influence of exposure time on mild steel corrosion is systematically examined. Results reveal a remarkable reduction in the corrosion rate of steel, with TMBHCA demonstrating its highest inhibition efficiency of 97.8% at 200 ppm. Potentiodynamic polarization studies characterize TMBHCA as a mixed-type inhibitor, while Nyquist plots illustrate increased charge transfer resistance and decreased double-layer capacitance with escalating TMBHCA concentrations. Consistency between weight loss measurements and electrochemical findings further validates the efficacy of TMBHCA as a corrosion inhibitor. SEM images substantiate and visually support the obtained results. An immersion test conducted at 25 °C over 28 days showcases a notable enhancement in TMBHCA efficiency (IE%) from 45.16% to 92.43% at 200 ppm as the immersion period progresses from 1 day to 28 days. This improvement is attributed to the augmented adsorption of inhibitor molecules on the steel surface over time. These comprehensive findings significantly contribute to our understanding of TMBHCA's corrosion inhibition behavior, emphasizing its potential as a highly efficient corrosion inhibitor for diverse industrial applications.

Prolonged corrosion protection via application of 4-ferrocenylbutyl saturated carboxylate ester derivatives with superior inhibition performance for mild steel

A series of 4-ferrcenylbutyl carboxylate esters with different alkyl chain length (C2-C4) of carboxylic acids were synthesized using Fe3O4@SiO2@(CH2)3-Im-bisEthylFc[I] nanoparticles as catalyst and have been characterized with FT-IR, 1H NMR, and 13C NMR. Ferrocenyl-based esters were used as corrosion inhibitors of mild steel in the 1M HCl solution as corrosive media. The corrosion inhibition efficiency of the synthesized ferrocenyl-based esters has been assessed by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The 4-ferrocenylbutyl propionate showed a more effective corrosion inhibition behavior among the studied esters with 96% efficiency after immersion in the corrosive media for 2 weeks. The corrosion inhibition mechanism is dominated by formation of passive layer of inhibitor on the surface of the mild steel by adsorption. Moreover, the adsorption characteristics of 4-butylferrcenyl carboxylate esters on mild steel were thoroughly explored using density functional theory calculations. It was found that the Fe atoms located around the C impurity in the mild steel are the most efficient and active sites to adsorb 4-butylferrcenyl carboxylate esters.

Unraveling the corrosion inhibition behavior of prinivil drug on mild steel in 1M HCl corrosive solution: insights from density functional theory, molecular dynamics, and experimental approaches.

The deterioration of mild steel in an acidic environment poses a significant challenge in various industries. The emergence of effective corrosion inhibitors has drawn attention to studies aimed at reducing the harmful consequences of corrosion. In this study, the corrosion inhibition efficiency of Prinivil in a 1M HCl solution through various electrochemical and gravimetric techniques has been investigated for the first time. The results demonstrated that the inhibition efficiency of Prinivil expanded from 61.37% at 50ppm to 97.35% at 500ppm concentration at 298K. With a regression coefficient (R 2) of 0.987, Kads value of 0.935 and Ea value of 43.024kJ/mol at 500ppm concentration of inhibitor, a strong affinity of Prinivil for adsorption onto the metal surface has been significantly found. Scanning electron microscopy (SEM) and contact angle measurement analyses further support the inhibitory behavior of Prinivil, demonstrating the production of a defensive layer on the surface of mild steel. Additionally, molecular dynamics (MD) and Monte Carlo simulations were employed to investigate the stability and interactions between Prinivil and the metallic surface (Fe (1 1 0)) at the atomic level. The computed results reveal strong adsorption of Prinivil upon the steel surface, confirming its viability as a corrosion inhibitor.

Corrosion Inhibition Properties of Corrosion Inhibitors to under-Deposit Corrosion of X65 Steel in CO2 Corrosion Conditions.

Under-deposit corrosion is widely present in the pipelines of oil and gas production, causing significant corrosion damage. In this paper, a novel electrochemical cathodic-polarization method was carried out to accelerate the formation of CaCO3 scale on a X65 steel surface in a simulated solution containing scaling ions. Subsequently, pre-scaled X65 steel was placed in a high temperature and pressure autoclave to conduct corrosion weight-loss experiments and in situ electrochemical measurements. The study mainly compared the corrosion inhibition behavior of four quaternary ammonium salt corrosion inhibitors, pyridinium quaternary salt (BPC), quinolinium quaternary salt (BQC), 8-hydroxyquinolinium quaternary salt (BHQ) and pyridinium (1-chloromethyl naphthalene) quaternary salt (1-CPN), in a simulated oilfield scale under corrosive conditions. The results of the weight-loss experiments demonstrated that the inhibition efficiencies of the corrosion inhibitors from high to low were as follows: 1-CPN < BHQ < BQC < BPC. The in situ electrochemical measurements showed that the immersion time and type of corrosion inhibitor had a pronounced influence on the corrosion and corrosion inhibition behavior of X65 steel with CaCO3 coating. It was also proved using both EIS and PC that 1-CPN shows the best inhibition performance in all. Lastly, the inhibition mechanism of corrosion inhibitors at under-deposit conditions was analyzed via a surface morphology observation of SEM.

Effect of Cation Types on the Steel Corrosion Inhibition Behavior of Calcined Layered Double Hydroxides in Saturated Calcium Hydroxide Solution

Effect of Cation Types on the Steel Corrosion Inhibition Behavior of Calcined Layered Double Hydroxides in Saturated Calcium Hydroxide Solution

CORROSION INHIBITION BEHAVIOUR OF CUSTARD APPLE LEAVES AND ACACIA CONCINNA EXTRACT ON MILD STEEL IN ACIDIC MEDIA: ADSORPTION AND THERMODYNAMIC STUDY

Custard apple leaves extract (CALE) was tested to evaluate corrosion inhibition efficiency for mild steel under acidic medium. The test metal substrate was collected over a period of 24 hr of contacting with acid to determine the corrosion inhibition efficiency (CIE) and corrosion rate (CR) using the Gravimetric analysis. The findings of the study were applied to examine the adsorption behavior and thermodynamic characteristics for CALE as a potential corrosion inhibitor in acidic environment. Mild steel exhibited the highest corrosion rate in the absence of a corrosion inhibitor in a 0.5 M sulphuric acid solution. However, the rate of corrosion was observed to decrease gradually with increase in CALE concentration (0.4–2.0 g/l). The similar trend was noted at the experimental temperature range of 298-328 K. Adsorption behavior was investigated using the Langmuir, Temkin, Freundlich, and Flory Huggins adsorption isotherm models. The Temkin adsorption isotherm model provides the best fit to the experimental data. Besides, the negative values of Gibb’s free energy of adsorption (ΔGad) reveal strong evidence for the spontaneous nature of CALE adsorption on mild steel surface. The increase in activation energy (Ea) from 35.05 kJ/mol in the blank test solution to 68.03 kJ/mol at 2.0 g/l concentration of CALE indicates the formation of a protective film of inhibitor molecules on the metal surface. Adsorption enthalpy values (∆H=31.28-73.79 kJ/mol) over the concentration range (0-2.0g/l of CALE) implies physical adsorption, whereas negative entropy values (ΔS) suggests free movement of inhibitor molecules in the bulk solution. Additionally, a synergistic effect was demonstrated in lowering the corrosion rate by combining Acacia concinna extract (ACE, 0.1-0.3 g/l) with CALE, thereby enhancing the overall corrosion inhibition efficiency. For citation: Jitendra Kisan Shinde, Ravindra Gulab Puri, Pawan Devidas Meshram, Rajkumar Shankarrao Sirsam Corrosion inhibition behaviour of Custard apple leaves and Acacia concinna extract on mild steel in acidic media: adsorption and thermodynamic study. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 119-126. DOI: 10.6060/ivkkt.20246707.7038.

Synergistic inhibition of Mikania micrantha extract with iodide ion on the corrosion of cold rolled steel in trichloroacetic acid medium

The corrosion inhibition behavior of Mikania micrantha extract (MME) and iodide ion in a synergistic system consisting of 0.10 M trichloroacetic acid (Cl3CCOOH, TCA) on cold rolled steel (CRS) materials and its mechanism was fully investigated by weightlessness, electrochemical, and surface analysis measurements. The results show that MME/I− performs higher inhibition than either MME or I− with a peak inhibition efficiency of 96.3 %. The adsorption of MME, I− and MME/I− on CRS follow with Langmuir isotherm. MME/I− retards both anodic and cathodic reactions. With the MME/I− complex inhibitor, the capacitance arc radius reaches a maximum. The results of scanning electron microscopy (SEM), atomic force microscopy (AFM), and confocal laser scanning microscopy (CLSM) showed that there were obvious adsorbent films on the surface of the suppressed CRS. Compositional analysis of surface adsorbates on CRS by X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (TOF-SIMS) revealed that the main components of the adsorption film on the surface of CRS contained a large number of polar compounds, notably the formation of chemical bonds by iron atoms.