Eco-friendly Corrosion Inhibitor Research Articles

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.

Sterilized Chicken Feather as Eco-friendly Corrosion Inhibitor for Mild Steel in a Water- Based Drilling Mud – Gravimetric and FTIR Assessment

This research evaluated the corrosion performance of mild steel in sterilized and unsterilized alkaline mud corroding systems using chicken feather powder (CFP) obtained through the usual hydrolysis and acid neutralization protocol. Insightfully, gravimetric analysis revealed that bacterial infestation of the unsterilized environment caused its corrosion performance to be lower at 10.3% while the sterilized counterpart stood at 49% at 92 days of exposure to the environments respectively. The functional groups, C=N, O=C=O, H-C=O etc, revealed by FTIR to be present in the protein saturated feather were overwhelmed by microbial activities rendering them inactive to perform as inhibitors.

Insight into the Corrosion Inhibition Performance of Pistia stratiotes Leaf Extract as a Novel Eco-Friendly Corrosion Inhibitor for Mild Steel in 1 M HCl Solution

In this research, the Pistia stratiotes leaf (PSL) extract was evaluated as a green corrosion inhibitor for the corrosion of mild steel in 1 M HCl using electrochemical measurements and surface characterization. Electrochemical impedance spectroscopy (EIS) spectra showed that the inhibitory activity of the phytochemical compounds enhanced with increasing concentration up to 400 ppm, which was reflected in the increase in the charge transfer resistance and double-layer capacitance. Regarding the effect of immersion time, EIS results indicated that the persistence of the PSL extract was between 4 h and 8 h of exposure time. From polarization curve (PCC) results, the best performance of the corrosion inhibitor was achieved at 400 ppm with an inhibition efficiency of 93.7%. The PSL extract acted as a mixed-type corrosion inhibitor. The adsorption of the phytomolecules on the metal surface obeyed the Langmuir isotherm through a mixed mechanism (physical and chemical interactions) dominated by physisorption. Scanning electron microscopy (SEM) examinations and energy-dispersive X-ray spectroscopy (EDS) elemental analysis of the corroded samples confirmed the anticorrosive protection of the PSL extract. Chemical characterization of the PSL extract by GC-MS revealed the presence of phytol, steroids, and aromatic and long-chain unsaturated fatty acid esters, in order of abundance. Chemical quantum calculations by DFT allowed for determining that the phthalic acid, di(2-propylpentyl) ester compound has the most significant potential to act as the main active component in corrosion inhibition activity.

Sonophotopythochemical Functionalization of Graphene Oxide - Al - Zn Bimetal Nanocomposite for Corrosion Inhibition

The corrosion performance of steel in the marine environment has been a primary concern of engineers and garnered significant interest due to its industrial significance. To address this concern, the incorporation of green corrosion inhibitors as coating materials in mild steel has been extensively studied recently. This paper explores the synthesis of graphene doped with bimetal aluminum-zinc (GO-Al-Zn) nanocomposites via sonophoto-phytochemical functionalization using Chayote (Sechium edule) leaf extract as the doping agent to produce a corrosion inhibitor. The synthesized nanocomposites were characterized using FTIR, SEM-EDS, XRD, and TEM. The optimal nanocomposite, with a 55% Al - 45% Zn ratio, demonstrated successful bio-reduction, good dispersion, reduced particle size, and a rhombohedral crystal structure. When incorporated into an epoxy coating and applied to mild steel, the GO - 55% Al - 45% Zn coating achieved a high corrosion inhibition efficiency of 98.06% (gravimetric method) and 98.45% (electrochemical method) in 3.5 wt% NaCl solution. This study highlights the promising potential of GO - 55% Al - 45% Zn nanocomposite as an eco-friendly corrosion inhibitor. Future research should explore optimizing the functionalization process and exploring long-term environmental stability.

Ginger powder as sustainable and eco-friendly corrosion inhibitor for the protection of steel reinforcement bars

In the present studies, ginger powder has been used as an eco-friendly admixture for the cement mortar. Different amounts i.e. 0 wt% (M1), 0.10 wt% (M2), 0.25 wt% (M3) and 0.50 wt% (M4) ginger powder was mixed in the cement mortar (M1) and assessed the durability. The ginger powder with 0.50 wt% (M4) improves the compressive strength by 17 % owing to the water reducing capability, which enhance the hydration reaction and fill the pore matrix of the cement mortar. The active ingredient of ginger powder i.e. shogaol adsorbs on the steel rebar surface through leaching mechanism by interaction of oxygen (O) and п-electrons with iron (Fe) and provide corrosion protection at longer duration of continuous immersion in 3.5 wt% NaCl solution. Following 173 d in a 3.5 wt% NaCl solution, the M4 sample exhibits 82.10 % corrosion inhibition efficiency. Therefore, it is suggested that ginger powder could be a potential eco-friendly admixture to be used in construction industries to get high durability performance in the coastal areas.

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.

Eco-friendly corrosion inhibition of copper in NaCl media using Perseana americana extract: Insights from quantum and electrochemical studies

Corrosion of copper in saline environments, particularly in 3.5% sodium chloride (NaCl) solutions, poses significant challenges across various industries, leading to substantial economic losses and safety concerns. Traditional corrosion inhibitors, often synthetic and toxic, raise environmental issues that necessitate the exploration of sustainable alternatives. This study investigates the use of Perseana americana extract (PAE) as an eco-friendly inhibitor for copper corrosion, demonstrating an impressive inhibition efficiency of 96.53% at an optimal concentration of 300 mg/L. Electrochemical assessments, including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), reveal that PAE functions as a mixed-type inhibitor, significantly reducing the corrosion current density (icorr) from 3.59 × 10⁻⁵ A/cm2 (without inhibitor) to 1.83 × 10⁻⁵ A/cm2 at 100 mg/L, and further to 0.12 × 10⁻⁵ A/cm2 at 300 mg/L. The adsorption behavior of PAE on the copper surface adheres to the Langmuir isotherm model, indicating monolayer adsorption with a Gibbs free energy of adsorption (ΔGads) of −18.84 kJ/mol, suggesting a predominantly physisorption mechanism. Additionally, Monte Carlo simulations confirm strong interactions between PAE molecules and the copper surface, with the highest adsorption energy recorded for phloretin at −3778.338 kcal/mol, highlighting the extract's potential as a green alternative to conventional inhibitors. This research underscores the viability of utilizing natural plant extracts for effective corrosion control, contributing to more sustainable practices in metal protection.

Eco-friendly Chlorella vulgaris extracts for corrosion protection of steel in acidic environments

This study evaluates the potential of Chlorella vulgaris sp. extracts as eco-friendly corrosion inhibitors for API 5L 42 Steel in a 1M HCl acidic environment, offering sustainable alternatives for industrial applications. Two corrosion inhibitors were obtained through solvent extraction methods: M1 (methanol) and M2 (methanol/chloroform). The extracts were characterized using infrared spectroscopy, the analysis revealed hydroxyl, methyl and vinyl groups as the most representative. The effect of corrosion inhibition was study by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results show significant reductions in corrosion current density and increases in charge transfer resistance, with M2 achieving the highest protection efficiency of 91.20 % and a charge transfer resistance of 501.80 Ω at a 120 ppm concentration, while M1 reached 88.22 % efficiency with a charge transfer resistance of 102.30 Ω. Uv–Vis measurements were performed to determine the electronic transitions of the metal-inhibitor system for each of the extracts. ANOVA highlighted the significant influence of biomass concentration on corrosion resistance. The adsorption of M1 and M2 extracts on the carbon steel surface obeyed the Langmuir isotherm and Gibbs free energy calculations indicated a physisorption mechanism for both extracts. Surface morphology analysis by Scanning electron microscope (SEM) revealed less pitting and reduced surface roughness as inhibitor concentration increased. These findings underscore the potential of Chlorella vulgaris extracts, particularly M2 at 120 ppm, as effective and sustainable corrosion inhibitors for steel in acidic environments.

Fabrication and Characterization of Graphene Oxide – Cadmium Sulphide Nanocomposite Coating for Corrosion Inhibition of Mild Steel Specimen

Abstract The oil and gas sector play a significant role in the Sultanate of Oman’s economic growth and contribute major revenue. Corrosion is a global concern and that strongly affects the industrial sectors. The corrosion problems in oil pipelines would be successfully resolved by means of novel control techniques. This research focused on the fabrication of Graphene oxide (GO) - Cadmium sulphide (CdS) nanocomposite for controlling corrosion in mild steel specimen. Graphene oxide was synthesized from Alovera extract by carbonization process. GO - CdS nanocomposite was prepared and deposited on a mild steel pipe by self-assembly technique. The coated material was used for stability studies at varying pH conditions and exposure period followed by corrosion studies. The testing methods adopted are Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Energy Dispersive X-Ray analysis (EDX), and Fourier Transform Infrared Spectroscopy (FTIR). Wet/Dry test and Atmosphere tests were conducted to examine the performance of coating material towards corrosion. The atomic force microscope (AFM) operated in non-contact mode was used to study surface topology of the coated specimen. From the outcome of the corrosion studies, it was established that the GO- CdS Nano composites thin film acted as an ecofriendly corrosion inhibitor to enhance the lifespan of the mild steel pipe. This novel research is aligned with the United Nations Sustainability Goals (UNSD - 9: Industry, Innovation and Infrastructure & UNSDG 12 – Responsible consumption and production) and Oman vision 2040. The results from the study validates that the GO - CdS thin films coated on mild steel pipe could be a viable solution to corrosion issues in oil pipelines owing to their good film stability, minimum film thickness, high durability, and ecofriendly approach.

Cucumber peel extract as an eco-friendly corrosion inhibitor for low-carbon steel in sulfuric acid

Cucumber peel extract as an eco-friendly corrosion inhibitor for low-carbon steel in sulfuric acid

Exploring the Effectiveness of 3-Chloro-4-morpholin-4-yl-1,2,5-thiadiazole as a Eco-Friendly Corrosion Inhibitor for Mild Steel in HCl Solution: Experimental and DFT Analysis

Corrosion is a significant issue in many industries, particularly where metals are exposed to harsh chemical environments. This study investigates the efficacy of 3-Chloro-4-morpholin-4-yl-1,2,5-thiadiazole (CMTD) as a corrosion inhibitor for mild steel in 1 M HCl solution across a temperature range of 303–333 K. Using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization techniques, the inhibition efficiency of CMTD was evaluated at different concentrations and temperatures. The results show that CMTD achieves a maximum inhibition efficiency of 96.8% at a highest inhibitor concentration, even at elevated temperatures. The adsorption of CMTD on the mild steel surface follows the Langmuir adsorption isotherm, with a calculated free energy of adsorption (ΔGads) of -39.5 kJ/mol, confirming a spontaneous chemisorption process. Quantum chemical Density Functional Theory (DFT) studies further elucidated the relationship between CMTD's molecular structure and its inhibition efficiency. Key parameters, including the energy gap (Egap = 3.551 eV), highest occupied molecular orbital (EHOMO = -6.317 eV), and lowest unoccupied molecular orbital (ELUMO = -2.766eV), were calculated to understand CMTD's reactivity. Additionally, global reactivity descriptors such as chemical hardness (η), electronegativity (χ), and the electron fraction transferred (ΔN) from CMTD to the iron surface were analyzed. These findings suggest that CMTD is highly effective in preventing corrosion and can be applied in industries where mild steel is exposed to acidic environments, such as in petrochemical and industrial cleaning processes.

Biopolyurethane coatings with silica-titania microspheres (MICROSCAFS®) as functional filler for corrosion protection

In this work, we studied a biopolyurethane (BioPU) coating derived from a bio-based polyol and isocyanate for the protection of carbon steel against corrosion. The direct utilization of polyols obtained from raw biomass represents a novelty in polyurethane coatings production. The protective properties of these coatings were enhanced by incorporating unique silica-titania (ST) MICROSCAFS®, which are microspheres exhibiting interconnected macro- and mesoporosity. They were loaded with tannic acid (TA), an eco-friendly corrosion inhibitor. Confirmation of TA loading into the ST carriers (therefore called ST\\TA) was achieved through Attenuated total reflectance - Fourier-transform infrared spectroscopy (ATR-FTIR) and Thermogravimetric (TG) analyses. TG analysis revealed that ST\\TA particles contain approximately 34 wt% TA, and their average particle diameter is approximately 25 ± 5 μm, observed by SEM. The TGA shows slightly improved thermal resistance of the coatings modified with the filler MICROSCAFS®. Furthermore, it was observed that the fillers strengthened the coating hardness without negatively affecting the adhesion strength. Electrochemical Impedance Spectroscopy (EIS) results demonstrated that all modified coatings exhibited very good to excellent resistance in mild corrosive environments. The coatings maintained a high impedance modulus (|Z|) at low frequencies and phase angle values close to −90° across a wide frequency range, over an immersion period of 80 days in a 0.05 M NaCl solution. After 80 days of immersion, the best coating, BPU-ST\\TA, displayed |Z| of 3 × 1010 Ω cm2. Scanning Vibrating Electrode Technique (SVET) analysis revealed the inhibitory behaviour of TA. For the BPU-ST\\TA sample, inhibition of both anodic and cathodic activities was clearly visible, with a significant reduction of the current densities starting at 1 h and up to at least 24 h of immersion. In summary, the BioPU coatings modified with tannic acid-loaded MICROSCAFS® exhibit improved barrier properties and notable corrosion inhibition capacity in mild corrosive environments.

Millettia aboensis leaves extract as eco-friendly corrosion inhibitor for mild steel in acidizing solution: From experimental to molecular level prediction

The development of environmentally friendly corrosion inhibitors is becoming more popular since conventional inhibitors are poisonous and non-biodegradable. The anti-corrosive effectiveness of Millettia aboensis leaves extract (MALE) has been assessed in this study using several methods, such as electrochemical measurements, X-ray Photoelectron spectroscopy and scanning electron microscopy on mild steel in acidic solution. Gas chromatography-mass spectrometry (GC-MS) analysis was combined with qualitative and quantitative phytochemical analysis to identify the phytochemicals linked to the activity of the Millettia aboensis extracts and identified key phytoconstituents such as Hexanedioic acid, Phenol derivatives, Octadecanoic acid, and Linolenic acid, which play significant roles in the extract's inhibitory performance. The results showed that the inhibition efficiency (IE%) improved to 88.6 % with the addition of inhibitor concentration from 0.1 g/L to 3.0 g/L and that the corrosion rate drastically reduced from 56.91 mpy to 16.09 mpy. Furthermore, at a greater concentration (3.0 g/L), the Rct values rose from 61.42 Ω cm2 to 176.3 Ω cm2 thus, indicating that the inhibitor molecules were forming a protective film over the metallic surface. Scanning Electron Microscopy (SEM) provided visual evidence of surface morphology, revealing a smoother surface in the presence of the inhibitor, indicative of the protective film formed by the adsorption of organic molecules onto the steel surface. Theoretical calculations using the ωB97XD functional and def2svp basis set further supported the experimental findings, showing that the protonated form of C21H36O4 exhibited the highest interaction energy, correlating with its superior inhibition efficiency on the metal surface.

Experimental and theoretical study of two Salen-type Schiff bases: green synthesis, characterization, corrosion inhibition efficiency, and biological activity

As eco-friendly corrosion inhibitors, antioxidants, and antibacterial agents, this study assesses 1,3-bis(2-hydroxybenzylidene) thiourea (B1) and 1,3-bis(2-hydroxybenzylidene) urea (B2), two new Schiff bases, on their performance in these areas. We successfully synthesized these Schiff bases in just 15 minutes using an environmentally friendly approach, and the yield was rather good, ranging from 69.8% to 87.53%. When compared to B2, B1 showed more effective corrosion inhibition and better antioxidant activity. Both chemicals were highly effective against microbes, while B1 was particularly effective against Aspergillus. B. We measured the weight loss to examine the corrosion inhibition impact of XC48 carbon steel in 1M HCl. The findings revealed that at the ideal concentration of 5.10–4 M, the estimated IE% of the Schiff bases was 63.8% for B2 and 87.28% for B1. This study employed the Langmuir isotherm model to determine a number of thermodynamic and kinetic characteristics, all of which pointed to a physical adsorbed state. Promising electrical characteristics and robust adsorption on metal surfaces for B1 were corroborated by theoretical investigations employing density functional theory (DFT) and molecular dynamics (MD) simulations. Both the theoretical and practical aspects align with one another.

Optimization, molecular dynamics and quantum parameters simulations of Zingiber officinale rhizome as a green corrosion inhibitor

This study combines experimental and theoretical approaches to investigate ginger root extract (GRE) as an eco-friendly corrosion inhibitor for mild steel in acidic environments at temperatures ranging from 303 to 333 K. Experimental techniques, including weight loss measurements, were used to assess the inhibiting performance and adsorption behavior of GRE, while GC-MS, FT-IR, and UV–visible spectrophotometric methods provided further characterization. Results indicated that the inhibition efficiency of GRE increased with higher concentrations and decreased with temperature, highlighting its potential to effectively prevent corrosion in H2SO4 medium. GC-MS analysis identified four major phenolic compounds—6-gingerol, 6-isoshogaol, zingerone, and vanillyl glycol—and two secondary metabolites, α-Farnesene and β-Bisabolene. Among these, 6-gingerol, the most active and abundant constituent, was selected for computational studies. Optimal corrosion inhibition of 81.3 % was achieved at 303 K with a GRE concentration of 10 g/L for 1 h. Thermodynamic activation parameters suggested a temperature-dependent process, and alignment with the Langmuir isotherm indicated a physical adsorption mechanism. Quantum chemical calculations for 6-gingerol revealed highest occupied molecular orbital energy (EHOMO) and lowest unoccupied molecular orbital energy (ELUMO) values of -6.286 eV and -0.366 eV, respectively, in its protonated state, and -8.338 eV and -0.247 eV, respectively, in its neutral state. Molecular simulations showed a binding affinity of -4.736 kJ/mol between 6-gingerol and the steel surface, supporting the experimental findings and underscoring the potential of GRE as an effective corrosion inhibitor.

Exploration on the corrosion inhibition performance of Salvia miltiorrhiza extract as a green corrosion inhibitor for Q235 steel in HCl environment

Salvia Miltiorrhiza, extensively distributed and commonly employed as a traditional Chinese medicinal herb, has garnered significant attention. In this study, the Salvia Miltiorrhiza extract (SME) was prepared by one-step water extraction method, and was firstly used as a novel corrosion inhibitor for Q235 steel in 1 mol/L HCl solution. As identified via liquid chromatography-mass spectrometry, the findings reveal that Salvianic acid A, tanshinone II A, danshenxinkun D, dihydrotanshinone, and methylene tanshinquinone are the primary constituents of SME. The optimum corrosion inhibition efficiency reached 92.8 % at 200 mg/L and maintained at 90.4 % after 72 h. Based on in-situ scanning vibration electrode technology (SVET) monitoring, the adsorption of inhibitor molecules on metal surface greatly retarded the propagation of localized corrosion. AFM examination of the corroded surface reveals that the samples supplemented with SME exhibit a smoother surface compared to the blank group. The force curve graph for the SME-added group demonstrates a more evenly distributed point array and an elevated average adhesion force, indicating that the addition of SME improves the corrosion resistance of the metal surface. XPS characterization illustrated that SME interacted with iron ions to form insoluble precipitate. This work investigated the application of SME as an eco-friendly corrosion inhibitor for carbon steel in acidic medium, providing a new approach for the high value-added utilization of Salvia Milliorrhiza.

Green chemistry approach to corrosion prevention: Saccocalyx satureioides as an effective inhibitor for C45 steel in acidic medium (HCl)

Carbon steel's corrosion in harsh, acidic environments presents significant challenges to industrial use. While traditional inhibitors are effective, they often raise environmental and sustainability concerns. This study explores the potential of Saccocalyx satureioides extract (S. Satureioides) as an environmentally Eco-friendly corrosion inhibitor for protecting carbon steel 45 in a highly corrosive 0.5 M HCl solution. The organic components of the sample were identified using phytochemical screening, LC-MS analysis, and ATR-FTIR spectroscopy. The main compounds detected were coumaric acid (68.10%), 4-methoxybenzoic acid (15.15%), and kaempferol (11.36%). Weight loss measurements demonstrated that the S. Satureioides extract had a highly effective anti-corrosion capability, achieving an inhibitory efficiency of around 96.93% at a concentration of 3 g.L-1 at a temperature of 25°C after 360 hours of immersion. This significantly reduced the corrosion rate from 0.1721 mg.cm−2.h−1 to 0.0053 mg.cm−2.h−1. The adsorption isotherms indicated that the adsorption of S. Satureioides molecules onto the steel surface followed the Langmuir model, exhibiting a high correlation coefficient of 0.9958. The negative value of the adsorption free energy ( = -17.162 kJ mol-1) indicates that the physisorption interactions occurred spontaneously. The SEM/EDX analysis revealed that the steel surface exhibited reduced damage due to the inhibitor's protective coating formation. This research not only significantly contributes to corrosion science filed but also provides crucial support for global efforts to promote sustainable industrial practices, with potential applications in various industries worldwide.

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.

Eco-friendly corrosion inhibitor of Q235 carbon steel in 1.0 M HCl by Isatin/Chitosan Schiff base

This study presents the synthesis of an eco-friendly and green Schiff base, namely Isatin-Cs Schiff base corrosion inhibitor for Q235 carbon steel in 1.0 M HCl corrosion solution. Fourier-transformed infrared FT-IR and 1H NMR was utilized to characterize the prepared Isatin-Cs Schiff base corrosion inhibitor. The inhibition performance in 1.0 M HCl solution was investigated via classic weight loss at various temperatures, potentiodynamic polarization (PPD), and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy SEM, X-ray photoelectron spectroscopy XPS, and water contact angle methods are used to analyze the surface morphology of Q235 carbon steel. The polarization measurements indicate that the corrosion inhibitors act as mixed type. Moreover, the weight loss studies show that the efficiency of inhibitor increases with the concentration of inhibitor to reach a maximum efficiency of 88.4 % with 250 ppm at 25 °C. Nevertheless, increasing temperature has negative effect on the efficiency of the Isatin-Cs inhibitor. The Langmuir isotherm Unveil that Isatin-Cs adsorption on Q235 carbon steel is mediated via physi/chemi-sorption. Based on SEM and XPS analyses Isatin-Cs forms stable protective film on Q235 carbon steel. The DFT results complemented the experiments results, both observed the effectiveness of inhibitor adsorption.

Eco-friendly corrosion inhibition of steel using phenolic compounds from Cynara syriaca

This study evaluates the corrosion inhibition performance of the n-butanol (n-BuOH) fraction derived from Cynara syriaca on mild steel in acidic environments. The n-BuOH fraction achieved up to 94 % inhibition at 500 ppm, as assessed through gravimetric analysis, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). Key phenolic compounds, including kaempferol, naringenin, myricetin, chlorogenic acid, and quercetin, were identified by UPLC-MS/MS. These compounds form stable flavonoid-metal complexes, as confirmed by UV–Vis spectroscopy. FT-IR and SEM-EDS analyses revealed the formation of protective coatings and interactions with the steel surface. Polarization curves indicate that the n-BuOH fraction acts as a mixed-type inhibitor, predominantly affecting the anodic reaction. The inhibition efficiency decreased from 93.89 % to 73.43 % with increasing temperatures. Thermodynamic analysis showed an increase in activation energy (Ea = 58.20 kJ/ mol) and a positive ΔH value of 56.17 kJ/mol, which can be attributed to the increased thickness of the double layer, enhancing the activation energy of the corrosion process. A Gibbs free energy (ΔG0ads) value of −25.48 kJ/mol confirms that the adsorption process is spontaneous and involves both physisorption and chemisorption. pKa analysis identified specific adsorption sites. This research underscores the potential of the n-BuOH fraction as a novel, eco-friendly corrosion inhibitor, offering valuable insights for sustainable corrosion control strategies.