Maximum Inhibition Efficiency Research Articles

Enhancing corrosion resistance in HCl environments: Comparative efficacy of a conjugated 3ph-Schiff base versus benzotriazole

This research addresses the need for effective corrosion inhibitors in industrial applications, evaluating the performance of 4-nitro-2-(((1E,2E)-3-phenylallylidene)amino)aniline (noted as 3ph-Schiff base) as a corrosion inhibitor in comparison to benzotriazole (BTA) in a high-concentration 3 M HCl environment. Unlike studies conducted in lower concentrations (e.g. 0.1 and 1 M), this study aims to assess inhibitor performance under more aggressive conditions. Rigorous methods, including Tafel polarisation, electrochemical impedance spectroscopy (EIS), and mass loss measurements, revealed variations in inhibition efficiency (IE). Polarisation data indicated that 3ph-Schiff base at 0.3% (approximately 8.96 mM) achieved a maximum IE of 99.5%, surpassing BTA at the same concentration (approximately 25.2 mM), which recorded an IE of 96.9%. Meanwhile, EIS analysis yielded slightly lower IE values, with 3ph-Schiff base reaching 90.21% and BTA 67.39%, reflecting the complementary nature of these methods. The corrosion inhibition mechanism of 3ph-Schiff base is attributed to strong adsorption on the metal surface, where amino (NH2) and nitro (NO2) groups promote stable complex formation with metal ions, enhancing electron donation and forming a protective layer that blocks corrosive agents. Scanning electron microscopy and elemental mapping confirm uniform nitrogen and carbon surface coverage, integral to the protective layer. This layer acts as both a physical barrier and an electrochemical passivator, effectively reducing anodic and cathodic reactions. The combined effects of adsorption, physical blocking and passivation underscore the 3ph-Schiff base's superior performance as a corrosion inhibitor in acidic environments.

Green synthesis of polymeric surfactants from recycling of plastic waste for applications on steel protection in the petroleum industry

ABSTRACT Green synthesis of four novel nonionic polymeric surfactants: from the recycled product of poly (ethylene terephthalate) plastic waste for application in corrosion protection of carbon steel. In this respect, PET waste was subjected to aminolysis and glycolysis via a reaction with Trimethylenediamine (TEDA) and Tri ethylene glycol (TEG) in the presence of suitable catalysts. The prepared materials were characterized by FT-IR, 1HNMR, and elemental analysis. It was evaluated as a corrosion inhibitor for steel (type-X60) used in the petroleum industry in the marine environment. Chemical, analytical, and electrochemical techniques were used for the evaluation of the corrosion inhibition efficiency of the prepared polymeric surfactants. The effect of concentration and temperature was studied. The maximum inhibition efficiency (IE) of 96% at an inhibitor concentration of 200 ppm and a temperature of 303 K. The glycoside and amide products were compared, the efficiency of amide products (96%) was higher than the efficiency of glycoside products (91%). According to potentiodynamic polarization data, the prepared surfactant boosts polarization resistance and inhibition performance by adsorbing on the metal/electrolyte interface. The surface morphology of steel was examined using SEM. A protective coating of inhibitor molecules forms on the steel surface.

Punica granatum peel powder and extract as green inhibitor for TMT in 1M HCl: an experimental and response surface model

ABSTRACT The construction industry widely uses TMT bars. However, its corrosion is a major challenge for civil engineers. Green corrosion inhibitors in place of inorganic inhibitors are one of the effective ways to prevent the corrosion which results sustainable solution. Researchers have not explored the corrosion mitigation of TMT bars with Punica granatum. Its peel (agro-waste) as a green inhibitor for TMT bars in powder/extract form exposed to 1M HCl was investigated through gravimetric and electrochemical studies using TMT bars of 8 mm diameter, 30mm, and 5 mm length respectively. The experimental work used five different concentrations of peel powder, ranging from 3.5 g to 17.5 g, and peel extract from 15 ml to 75 ml. The corrosion analysis yielded a maximum inhibition efficiency of 86.64% for powder and 83.32% for extract. Qualitative screening identified the presence of phytochemicals. The UV-Vis and FTIR spectra before and after corrosion define the chemisorption process, confirming the formation of protective layers on the bars. Steel admixed with inhibitor showed a smooth surface with fewer cracks/pits after corrosion through AFM and FE-SEM. The weight loss results were modeled using the response surface method and obtained R2 as 0.9016 (powder) and 0.9001 (extract).

Euphorbia neriifolia extracts as green corrosion inhibitors for aluminium in hydrochloric and nitric acid media

Among the new, significant approaches for preventing corrosion in contemporary culture is using green corrosion inhibitors, which lower corrosion rates to an acceptable level with minimal negative effects on the environment. This area of investigation has witnessed substantial advancements from the environmental sustainability perspective. This study investigates the corrosion inhibition potential of Euphorbia neriifolia extracts on aluminium in various concentrations of hydrochloric acid (HCl) and nitric acid (HNO₃) using weight loss, thermometric methods, and Field Emission Scanning Electron Microscopy (FESEM) analysis. The weight loss method revealed maximum inhibition efficiencies of 94.92% and 92.62% for the stem extract at a concentration of 0.7% in 1 M HCl and 1 M HNO₃, respectively. The Langmuir adsorption isotherm indicated a strong linear relationship between surface coverage and inhibitor concentration, suggesting favorable monolayer adsorption on the aluminum surface. Thermometric analysis confirmed the efficacy of the extracts, with a significant reduction in corrosion rates from 157.89 mm/yr in the absence of inhibitors to 0.0099 mm/yr with the optimal concentration of stem extract in 1 M HCl. FESEM images illustrated a marked difference in surface morphology, revealing a smooth, intact surface in the presence of the extracts compared to rough, pitted surfaces in the control samples exposed solely to acidic environments. This work demonstrates the high efficacy and potential modes of action through adsorption of Euphorbia neriifolia extracts, drawing attention to their intriguing use as environmentally benign corrosion inhibitors. The results offer a new, biodegradable substitute for traditional synthetic inhibitors and add to the expanding corpus of research supporting sustainable corrosion management techniques.Graphical

Electrochemical and Gravimetric Investigation of the Corrosion Inhibition Performance of Clindamycin for Mild Steel in Acidic Media

The corrosion inhibition performance of clindamycin for mild steel in 2.0 M H2SO4 has been studied using gravimetric and electrochemical methods. The results showed that the clindamycin inhibited mild steel corrosion in 2.0 M H2SO4 solution. The inhibition efficiency was found to increase with an increase in the concentration of clindamycin and decrease with an increase in the temperature. The maximum inhibition efficiency was obtained at 303 K (91.1%). Potentiodynamic polarization results reveal that clindamycin is a cathodic-type corrosion inhibitor lower concentrations and an anodic-type corrosion inhibitor at higher concentrations. The experimental data fitted the Langmuir adsorption isotherm and the adsorption of clindamycin was found to be spontaneous. The values of activation energy and Gibb’s free energy were found within the range of limits expected for the mechanism of physical adsorption.

Corrosion inhibition effects of celery (Apium graveolens) seeds extract on carbon steel in acid medium

The present study highlights the inhibition performance of celery seeds (CS) extract on carbon steel immersed in 1M HCl, using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. This extract is selected due to biodegradable, renewable, and foremost aspect, is safe towards both the human being and environment. The studied inhibitor was easily extracted by using a simple aqueous extraction procedure. The experimental results show that the investigated inhibitor can effectively retard the corrosion process that occurs to carbon steel in hydrochloric acid solution. Electrochemical impedance spectroscopy (EIS) spectra showed that inhibition efficiency increases with the increasing of (CS) extract concentration. Among the studied inhibitor showed maximum inhibition efficiency of 96,86% at 250 ppm. Polarization curves indicate that (CS) extract acted as mixed type of inhibitors with a predominant effect on the anodic reactions. Basic calculations for the adsorption studies were also carried out. The adsorption of the extract onto carbon steel surface followed the Langmuir adsorption isotherm.

An extensive analysis of isoindigotin derivatives as effective corrosion inhibitors for mild steel in acidic corrosive environments: An electrochemical and theoretical investigation

Isoindigo and its derivatives are frequently employed as active ingredients in pharmaceuticals and in solar cells, largely due to their distinctive structural characteristics, which render them a green substance. The utilization of its polymers as efficacious corrosion inhibitors for the safeguarding of mild steel exhibits considerable promise. In order to achieve this, a green and highly efficient isoindigo polymer (E)-7-(9,9-bis(3-(dimethylamino) propyl)-9H-fluoren-2-yl)-1,1′-bis(3-(dimethylamino) propyl)-[3,3′-biindolinylidene]-2,2′-dione (PIIDN-FN) was synthesized using a simple one-step polymerization reaction and subsequently employed as a corrosion inhibitor for the first time. In this work, its ability to inhibit the corrosion of Q235 when added to 1 M HCl medium was the subject of corresponding electrochemical tests and surface analyses (including SEM, AFM and XPS etc.). The results implied that PIIDN-FN was able to achieve a maximum inhibition efficiency of 94.52 % at a concentration of 100 mg L−1, and the inhibition efficiency was still close to 90 % even at a high temperature of 328.15 K. Moreover, the PDP results indicated that PIIDN-FN is a hybrid corrosion inhibitor, and it was determined that the adsorption of the material onto the carbon steel surface conformed to the Langmuir isotherm model. Furthermore, quantum chemical calculations (QC) based on density functional theory (DFT) and molecular dynamics simulations (MD) facilitated the elucidation of the inhibition mechanism. The findings of the theoretical investigation suggest that PIIDN-FN adsorbs as a film on the surface of mild steel due to its conjugated structure, forming a complex with iron and thereby providing effective protection for carbon steel.

A sustainable approach for the corrosion control of mild steel using Cocous nucifera gum: An electrochemical investigation

The study of corrosion inhibition on mild steel (MS) in an acid medium (1 M HCl) solution was performed using a crude extract of Cocousnucifera gum (CNG). Cocousnucifera develops gum exudates on its palm, the exudate process occurs mainly after some physical or microbiological injuries and is formed on the fruit of the palm. The gum was utilized to study the corrosion inhibition of MS by electrochemical and surface studies. The characterization of the crude gum was done by Fourier transform infrared spectroscopy (FT-IR) which revealed the presence of several active components (aromatic and oxygen-containing functional groups) in its structure. The electrochemical studies resulted in the maximum inhibition efficiency value of 75.64 % at the highest inhibitor concentration of 4000 ppm at 308 K. It was inferred that both the anodic dissolution of the metal and cathodic hydrogen evolution were effectively decreased in the presence of Cocous nucifera gum extract, revealing that inhibitor is of mixed type. From the adsorption studies, it was found that the best fit with R2 ∼ 0.9 followed Langmuir adsorption isotherm indicating the monolayer adsorption of the inhibitor on the metal surface. Gibb’s free energy of adsorption values was found <−20 kJ/mol, a characteristic of predominant physical adsorption. To support the electrochemical data SEM (scanning electron microscopy), AFM (Atomic force microscopy), and X-ray diffraction analysis were performed and these are in good agreement.

Improvement of Electrochemical Performance with Cetylpyridinium Chloride for the Al Anode of Alkaline Al-Air Batteries.

Aluminum-air batteries (AABs) are considered among high-power battery systems with various potential applications. However, the strong self-corrosion of Al in alkaline electrolytes negatively affects its Coulombic efficiency and significantly limits their large-scale application. This work presents the use of cetylpyridinium chloride (CPC) as an inexpensive and environmentally benign electrolyte additive in alkaline AABs. Hydrogen evolution test, electrochemical measurement, and surface analysis techniques were used to investigate the inhibition effects of CPC additive for the Al anode. The potentiodynamic polarization data indicated that the effectiveness of the CPC in inhibiting corrosion increased proportionally with higher CPC concentration. The maximum inhibition efficiency of 53.6% was achieved at a CPC dosage of 5 mM. The hydrogen evolution experiment revealed that the rate of hydrogen evolution decreased from 0.789 mL cm-2 min-1 for the pristine NaOH solution to 0.415 mL cm-2 min-1. The combination of X-ray photoelectron spectroscopy (XPS) and ab initio molecular dynamics (AIMD) provides conclusive evidence that CPC may adhere to the surface of Al and create a protective film. These findings indicate that CPC is successful in preventing the self-corrosion of the Al anode. Additionally, the Al anode has improved electrochemical characteristics, including a high specific capacity of 2041 mAh g-1 and a high energy density of 2874 Wh kg-1. This work focuses on the inhibition of self-corrosion of Al and provides novel insights for the design and development of effective additives for AABs.

Green Corrosion Inhibition of Mild Steel in 1.0 M HCl Using Myrtus Communis Essential Oil: Experimental and Theoretical Investigations

AbstractThis study investigates the green corrosion inhibition of mild steel in 1.0 M HCl using Myrtus communis essential oil (EOMC). Experimental and computational methods were combined to evaluate the corrosion inhibition effectiveness of EOMC. Weight loss measurements and electrochemical techniques, demonstrated that EOMC achieves a maximum corrosion inhibition efficiency of 94.81% at a concentration of 400 ppm of MCEO extract. The icorr significantly decreased from 983 µA/cm2 in the 1.0 M HCl solution to 51 µA/cm2 at 10−3 M, demonstrating the inhibitor's effectiveness. Polarization studies suggested mixed‐type inhibition, affecting both anodic and cathodic reactions, supported by changes in Tafel slopes. The Rct reached 462 Ω cm2 at 400 ppm of EOMC, enhancing the steel's protective capability. Higher temperatures increased the corrosion rate, with icorr values rising from 51 µA/cm2 at 298 K to 501 µA/cm2. Surface analysis using scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM‐EDX) confirmed the formation of a protective layer on the steel surface in the presence of EOMC. Additionally, density functional theory (DFT) calculations and molecular dynamics (MD) simulations provided further insights into the adsorption behavior of the EOMC molecules on the MS surface, revealing that the inhibition process involves both physisorption and chemisorption mechanisms.

Revitalizing sumatriptan: transforming expired medication into a potent solution for corrosion control in acidic environments

The concerns regarding pharmaceutical waste, particularly expired drugs have prompted the exploration of their alternative applications. This research highlights the potential of repurposing expired pharmaceuticals as eco-friendly corrosion inhibitors for their industrial applications. An expired drug sumatriptan was investigated for its anticorrosive properties on MS in 1 M HCl medium. Electrochemical techniques, including potentiodynamic polarization and electrochemical impedance spectroscopy, were employed to evaluate the inhibition efficiency and complemented by surface characterization studies (SEM, EDAX, CA and AFM). The results demonstrated that sumatriptan acts as an effective mixed-type inhibitor, achieving maximum inhibition efficiencies of 94.51% and 93.85% from PDP and EIS studies respectively for 500 ppm at 318 K. The adsorption of sumatriptan on the metal surface followed the Langmuir isotherm having an R2 value of ∼1, suggesting a physical adsorption behaviour with Δ G° values ranging from −16.286 to −21.518 kJ mol−1. The results demonstrate the effectiveness of sumatriptan as a corrosion inhibitor and the potential of repurposing expired pharmaceuticals as eco-friendly and sustainable alternatives.

Exploring the bio-inspired corrosion inhibition properties of eco-friendly Limonia acidissima leaves extract for mild steel in acidic media: Computational, electrochemical and spectroscopic insights

This study investigates the corrosion inhibition properties of Limonia acidissima leaves extract (LALE) on mild steel in a 1.0 M HCl medium. Utilizing mass loss measurements, potentiodynamic polarization, AC impedance spectroscopy, and surface characterization methods like SEM, AFM, UV–Vis, and fluorescence spectroscopy, the study reveals significant findings. The maximum inhibition efficiency of LALE was attained to be 92.26 % at a 1.0 % concentration. Potentiodynamic polarization studies show a marked decrease in corrosion current density (Icorr) from 3.102 × 10–3 A/cm² for the blank solution to 3.165 × 10–4 A/cm² with 1.0% LALE, indicating mixed-type inhibition. AC impedance measurements show an increase in charge transfer resistance (Rct) from 2.1410 Ω in the blank solution to 8.6580 Ω with 1.0% LALE, and a decrease in double-layer capacitance (Cdl) from 7.757 × 10–7 μF/cm² to 1.926 × 10–7 μF/cm², suggesting the formation of a protective film. SEM and AFM analyses confirm that LALE-treated steel surfaces are smoother with fewer pits and cavities compared to untreated steel. Furthermore, DFT analysis complemented well with the empirical findings. This research highlights the potential of plant extracts in industrial applications for corrosion protection, contributing to the growing body of knowledge on sustainable corrosion inhibitors and offering practical insights for future research and application in various corrosive environments.

Predictive Modeling and Adsorption Behavior, Kinetics, and Thermodynamic Studies of &lt;i&gt;Anthocleista grandiflora &lt;/i&gt;Leaf Extract for Corrosion Inhibition of Carbon Steel in Seawater

This study investigates the corrosion inhibition performance of Anthocleista grandiflora leaf (AGL) extract on carbon steel in seawater, considering the effects of temperature, immersion time, and inhibitor concentration. Predictive modeling, adsorption behavior, and the kinetics and thermodynamics of the inhibition process were examined. The weight loss technique,characterization techniques combined with response surface methodology (RSM), revealed that the AGL extract follows the Langmuir adsorption model, exhibiting physical adsorption with ΔG values between −16.24 to −15.49kJ/mol, indicating spontaneous and endothermic inhibition. The thermodynamic parameters entropy (−198.87 to −52.58 J/mol), enthalpy (20.42 to 53.42 kJ/mol), and activation energy (13.68 to 56.32 kJ/mol further support this. The corrosion reaction follows first-order kinetics, with the half-life decreasing as the rate constant and extract concentration increase.The SEM images revealed that the AGL extract formed a protective surface layer on the mild steel, effectively preventing pitting. This protective effect became more pronounced as the concentration of the extract increased. RSM optimization identified optimal conditions for maximum inhibition efficiency (98.70%) and corrosion rate (0.058 mm/y) at 800 ppm, 303 K, and 45 days, with a prediction accuracy of 95%, making it suitable for application in the oil and gas industry.

Ruta graveolens Plant Extract as a Green Corrosion Inhibitor for 304 SS in 1 M HCl: Experimental and Theoretical Studies

This study evaluated the corrosion inhibitory effects of Ruta graveolens leaf extract for 304 stainless steel in 1 M HCl. The analysis of the leaf extract using HPLC indicated that the primary compounds present in the leaf extract were rutin, caffeic acid, p-coumaric acid, and apigenin. The inhibition efficiency (IE%) of the extract was studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and computational simulation (density functional theory, DFT). The effects of the inhibitor concentration and solution temperature were investigated. The results indicated that the IE% increased for increasing concentrations of the extract, while the reverse was true with increasing temperatures. At 25 °C and a 600 ppm extract concentration, the results indicated a maximum inhibition efficiency of 95%, 98%, and 96% by weight loss, potentiodynamic polarization, and EIS techniques, respectively. SEM observations showed a significant change in the surface morphology of the 304 SS with and without the addition of the inhibitor compound. At all temperatures, the adsorption of the inhibitor components onto the 304 SS surface was found to follow the Langmuir isotherm model, and the inhibition process was governed by physical adsorption. Furthermore, chemical interactions between the inhibitor and the 304 SS steel surface were elucidated via density functional theory (DFT) calculations.

ASSESSMENT OF NEWLY SYNTHESIZED SALICYLALDEHYDE-BASED SCHIFF BASES AS CORROSION INHIBITORS FOR CARBON STEEL IN AQUEOUS ENVIRONMENT

A novel and eco-friendly approach for synthesizing two salicylaldehyde-based Schiff bases (2HPP and BHBD) in aqueous environments has been successfully conducted. These synthesized Schiff bases were subjected to a range of physicochemical analyses, including CHNS elemental analyses, molar conductivity measurements, and spectroscopic techniques like IR, electronic, 1HNMR, and mass spectra, to ascertain their properties. The research also involved investigating the inhibitory properties of these Schiff bases against mild steel corrosion in hydrochloric acid solutions at a temperature of 30°C. The results obtained from this study revealed the remarkable inhibitory potential of 2HPP and BHBD on mild steel corrosion in HCl solution. The inhibition efficiency was found to increase with increasing concentration, ultimately reaching an impressive maximum inhibition efficiency of 91.50% and 94.54 % for 2HPP and BHBD, respectively. The adsorption behavior of 2HPP and BHBD followed the Langmuir isotherm, indicating a favorable interaction with the metal surface. Moreover, the investigations included the use of quantum chemical parameters, which were computed utilizing the Density Functional Theory (DFT) method. These calculations included energy gap assessments, which lent support to the excellent inhibiting performance of both Schiff basses. However, BHBD appeared to be a more efficient inhibitor than 2APP.

Mitigation effect of a biodegradable surfactant N,N,N-trimethyl-2-(((hexadecyloxy)carbonyl)oxy)ethan-1-aminiumiodide for mild steel corrosion in 5% HCl: Experimental and theoretical insights

A cleavable cationic surfactant having carbonate linkage, N,N,N-trimethyl-2-(((hexadecyloxy)carbonyl)oxy)ethan-1-aminiumiodide referred to as THC was synthesised and characterized employing elemental analysis, FT-IR (Fourier Transform Infrared Spectroscopy), 1H NMR (Nuclear Magnetic Resonance) and 13C NMR. The extent of corrosion inhibition of THC was for the first time studied experimentally and theoretically on mild steel (MS) substrate in 5 % HCl solution at temperatures 303, 313, 323, 333, 343, 353 K. Experimental investigations include gravimetric analysis, potentiodynamic polarization (PDP) and electrochemical impedance analysis (EIS). THC provided maximum inhibition efficiency of 93.2 % at concentration of 1×10−4 M at 303 K which was further raised to 98.1 % at 353 K. PDP studies reveal that given surfactant is mixed type inhibitor. Surface studies such as contact angle measurement, AFM (Atomic Force Microscopy), SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-ray Analysis), and XPS (X-ray Photoelectron Spectroscopy) were employed to justify the adsorption of inhibitor molecules on MS surface. Furthermore, biodegradability test on THC was done to support the environment friendly nature of the surfactant.

Preparation and Performance Study of Zinc Dibenzyl Dithiocarbamate Self‐Assembled Film on Electrodeposited Cu–Ni Alloy Surface

ABSTRACTThis study developed a green and efficient surface protection method for Cu–Ni alloys. A zinc dibenzyl dithiocarbamate film was prepared on the surface of electrodeposited Cu–Ni alloys using the self‐assembly method to improve the material's corrosion resistance in seawater. The influence of zinc dibenzyl dithiocarbamate concentration and self‐assembly time on the corrosion resistance of the self‐assembled films was investigated through electrochemical testing. The findings revealed that at a zinc dibenzyl dithiocarbamate concentration of 10 mmol/L and a self‐assembly time of 20 min, the self‐assembled film exhibited the most robust corrosion resistance, achieving a maximum corrosion inhibition efficiency of 97.70%. The self‐assembly and adsorption mechanism of zinc dibenzyl dithiocarbamate were explored using molecular dynamics simulations and adsorption isotherms. The protective effect of self‐assembled films was visually observed through salt spray testing. Zinc dibenzyl dithiocarbamate self‐assembled film technology has high application prospects in the field of marine anti‐corrosion.

Unlocking the power of Dryopteris filix mas extract: A green solution for corrosion inhibition in A210Gr carbon steel in acidified 3% wt. NaCl environment

This study investigates the corrosion inhibition effectiveness of Dryopteris filix-mas L. (DFM) extract for A210Gr carbon steel in a 3 % NaCl solution. The DFM ethanolic extract was successfully prepared and comprehensively characterized using a combination of spectroscopic and physicochemical techniques, including HPLC, FTIR, and NMR (1H and 13C). These analyses confirmed the presence of key phenolic compounds, with Quercetin-3-O-diglucoside (Q3ODG) being the major component, comprising 82.14 % peak area as identified by HPLC. The extract, obtained via an economical ethanol extraction method, exhibited a maximum inhibition efficiency up to 88 % at a concentration of 400 ppm, as determined through electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), potentiodynamic polarization (PDP), and weight loss measurements. Temperature studies revealed a drop in efficiency to 70.14 % at 323 K, indicating a temperature-sensitive inhibition mechanism. Extended immersion times led to a slight decrease in efficiency due to partial desorption, though significant protection remained after 72 h. The primary corrosion inhibition mechanism was determined to be physisorption, following the Langmuir isotherm model, with a ΔGads0 value of − 24.02 kJ/mol, indicating a spontaneous adsorption process. Thermodynamic analysis revealed an increase in Ea from 22.11 kJ/mol (blank) to 56.61 kJ/mol (400 ppm), confirming the formation of a strong protective barrier. Surface characterization techniques, including FTIR, XRD, SEM, and AFM, further confirmed the presence of a protective film rich in polar organic compounds. Complementary Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) studies provided detailed insights into the molecular interactions, highlighting the key role of hydrogen bonding and van der Waals forces in the adsorption of Q3ODG onto the steel surface. These findings underscore the potential of DFM extract as an effective and sustainable corrosion inhibitor, advancing the application of biocompounds in corrosion control and encouraging further exploration of their industrial applications and environmental benefits.

Synthesis, structural characterization, thermal analysis and anticorrosion properties of novel AZO-based imidazo[1,2-a]pyridine derivatives: Experimental study and theoretical approaches

In this study, innovative AZO-based imidazo[1,2-a]pyridine derivatives were synthesized using simple and efficient synthetic approach enabling large-scale production. Thermal analysis highlights their suitability for potential applications requiring resistance to moderate temperatures. These compounds were investigated as corrosion inhibitors for MS in a 1 M HCl-medium. Corrosion inhibition studies, including weight loss, PotentioDynamic polarization and electrochemical impedance spectroscopy methods, revealed that AZOs exhibited maximum corrosion inhibition efficiencies reaching 96.13 % and 94.07 %, respectively, at a concentration of 10−3 M and a temperature of 298 K, with both compounds acting as mixed-type inhibitors. The study also delved into the influence of temperature and immersion time on inhibitory performance, revealing stable inhibition within the temperature range of 298–328 K. The calculated standard free energy of adsorption was −42.06 and −40.62 kJ/mol for AZO 1 and AZO 2, respectively, suggesting mixed-type adsorption, with adsorption behavior following the Langmuir isotherm. Morphological analysis through SEM and AFM, showed a reduction in surface roughness in the presence of the inhibitors, while water contact angle measurements indicated a significant increase in surface hydrophobicity. UV–visible and FT-IR analyses confirmed the interaction of AZOs with the MS surface, suggesting the formation of a protective layer composed of adsorbed AZO molecules. Furthermore, computational investigations employing DFT, Monte Carlo, and Molecular Dynamic simulation revealed the formation of coordinate bonds between the studied inhibitors and the metal surface, confirming adsorption on the metallic surface. These findings align well with experimental outcomes, and a possible corrosion inhibition mechanism process was discussed.

Solanum tuberosum leaf extract as an eco-friendly corrosion inhibitor for Q235-steel in HCl medium: Experimental and theoretical evaluation

Solanum tuberosum leaf extract (STLs), used as a biodegradable corrosion inhibitor, was prepared to mitigate the corrosion rate of Q235 steel in HCl medium. The active inhibitory components existing in STLs were tracked by Fourier transform infrared spectroscopy. Electrochemical measurements, morphological characterization and contact angle tests were combined to evaluate the anti-corrosion performance of STLs at various concentrations and different temperatures, and the results show that the addition of STLs can evidently magnify the charge transfer resistance, expand the double layer capacitance at electric/solution interface, and simultaneously reduce the corrosion current density of Q235 steel in HCl medium with the maximum inhibition efficiency of 91.89 %. The adsorption behavior of STLs on steel was investigated using X-ray photoelectron spectroscopy and adsorption models. It is revealed that the molecules of STLs spontaneously bind to the substrate through chemical and physical action, forming a protective layer to block the diffusion pathway of harsh ions. Furthermore, theoretical calculations confirm that Solanum tuberosum leaves components were adsorbed on steel substrates through donor-acceptor interactions.