Copper corrosion in acidic environments remains a significant challenge in industrial applications, and the development of efficient, environmentally friendly corrosion inhibitors is highly desirable. In this study, the corrosion inhibition performance of Acer palmatum Thunb. leaf extract (APE) for copper in 0.5 M H2SO4 solution was investigated using electrochemical measurements, and surface characterisation, while phytochemical analysis and theoretical calculations were employed to elucidate the inhibition mechanism. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements demonstrated that APE exhibited excellent inhibition performance, achieving maximum inhibition efficiencies of 96.6% and 96.9%, respectively, at an optimum concentration of 700 mg/L at 298 K. Surface characterisation by scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS) revealed the formation of a protective adsorption layer on the copper surface after APE treatment. X-ray photoelectron spectroscopy (XPS) analysis further confirmed the interaction between the functional groups of APE constituents and the copper substrate, indicating chemical adsorption in the protective film formation. Ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS) identified the major phytochemicals present in APE. At the same time, molecular dynamics (MD) simulations demonstrated the spontaneous adsorption of these active compounds onto the copper surface. The findings provide molecular-level insights into the corrosion-inhibition mechanism of APE and highlight its potential as a sustainable, effective green corrosion inhibitor for copper protection in acidic media.

This work explored the corrosion inhibition effect of Portulaca oleracea L. extract (POLE). The inhibition effect of POLE on copper in 0.5 mol/L H2SO4 solution. Fourier transform infrared spectroscopy (FTIR) and liquid chromatography − mass spectrometry (LC − MS) analysis confirmed that the main plant components in POLE were Betaine, L-Phenylalanine, Malic acid, Choline, L-Isoleucine, DL-Tryptophan, Azelaic acid and 3-Hydroxybenzoic acid. Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), quantum chemical calculation (QC) and molecular mechanics simulation were used to study the corrosion resistance of POLE in the presence and absence of POLE. The results showed that the corrosion inhibition rate of POLE on copper in H2SO4 solution reached 85%. SEM and AFM analysis confirmed that the copper surface was smoother when POLE was added to the aggressive solution. The dipole moments, Mulliken charges and Fukui parameters of the eight main molecules found in POLE were determined by theoretical calculations. The results show that POLE has the effect of inhibiting corrosion.

The corrosion inhibition of mild steel (MS) in 5% HCl by L-leucine methyl ester hydrochloride (LMEH) was studied using weight loss measurement, electrochemical analysis, FTIR, SEM, and AFM studies. LMEH showed a moderate optimum inhibition efficiency of 74.74% at 1.4 & times; 10-& sup3; M at 30 degrees C, which marginally improved to 78.5% on raising the temperature to 60 degrees C. To enhance LMEH's effectiveness, three biodegradable cationic Gemini surfactants namely ethane-1,2-diyl bis(N,N-dimethyl-N-alkylammoniumacetoxy)dichloride) referred to as m-E2-m (where m = 12, 14, and 16 defining the number of carbons in the hydrophobic part and E2 is diester group in Gemini's spacer part) were added at a very low concentration, i.e. 1 & times; 10-8 M. The addition of m-E2-m to LMEH caused a significant improvement in inhibition efficiency; the order of effectiveness being 12-E2-12 (97.9%) < 14-E2-14 (98.10%) < 16-E2-16 (98.90%), reflecting the impact of increase in hydrophobic chain length. Synergistic interactions, confirmed by the Aramaki-Hackerman equation (synergistic parameter approximate to 1), led to enhanced performance. Adsorption of inhibitors followed the Langmuir isotherm, and electrochemical studies showed increased polarization resistance and reduced double-layer capacitance, indicating better protection. FTIR analysis confirmed the involvement of functional groups in LMEH in the inhibition mechanism, while AFM and SEM studies provided information on the surface morphology, collectively offering insights into the inhibition process.

This research investigates the synergistic corrosion inhibition effect of a system comprising Styphnolobium japonicum (L.) Schott extract (SE), thiourea (TU), and cetyltrimethylammonium bromide (CTAB) collectively termed STC on mild steel (MS) in H2SO4 solution. The optimal concentration of SE (500 mg/L), TU (100 mg/L), and CTAB (1000 mg/L) yielded a maximum inhibition efficiency of 96.07 % at 313 K and 90.35 % after 8 h immersion. In H2SO4 containing STC, a protective film forms on the MS surface, giving a much higher charge transfer resistance (Rct) than in H2SO4 alone. However, as temperature increases, the film deteriorates, causing a sharp drop in Rct and a consequent decrease in inhibition performance. Tafel analysis indicates that STC acts as a mixed-type inhibitor, reducing both anodic and cathodic reactions. However, increasing temperature raises icorr and lowers inhibition efficiency. Analyses of the radial distribution function (RDF) data confirm that the interaction between STC and MS is chemisorption. In addition, the movement behaviors of H2O, H3O+and SO4 2-are explored using the mean square displacement (MSD) method.

The fact that numerous industries rely heavily on metals underscores the need to address corrosion as a common and costly process. Conventional corrosion inhibitors (CIs) have been employed to mitigate metal degradation and associated economic losses. However, their environmental and health hazards have driven a global shift toward sustainable alternatives. This review critically examines green corrosion inhibitors (GCIs), focusing on their sources, mechanisms, performance, and industrial applicability. Derived from natural compounds such as plant extracts, essential oils, amino acids, and biopolymers like starch, cellulose, lignin, and gums, GCIs are categorized based on their chemical nature, adsorption behaviour, and inhibition mechanisms consistent with green chemistry principles. This review also notes the practical challenges of implementing GCIs, namely synthesis, standardization, operational efficiency, and compliance with national regulations, as well as advances in hybrid (natural + synthetic) corrosion inhibitors and predictive modelling. Furthermore, GCIs are evaluated against key Sustainable Development Goals (SDGs), with applications spanning the oil and gas, water treatment, construction, and marine engineering sectors. The review also identifies key weaknesses of GCIs, such as inherent variability, limited solubility, and challenges in large-scale production. Future directions include chemical modifications to enhance performance, blending low concentrations of GCIs with CIs to develop synergistic formulations, and utilizing molecular data to advance a rational design approach. In summary, this directive review pulls together interdisciplinary knowledge to enhance the rational process of developing and implementing eco-friendly approaches to mitigate corrosion.

Mild steel is prone to corrosion due to environmental factors like humidity, O2, salt, pH, and pollutants. Corrosion inhibitors offer a practical solution to this problem. This study involved synthesising protein-based carbon dots from waste oyster meat via a hydrothermal reaction. These CDs were subsequently modified with stearic acid to enhance their hydrophobicity. Unmodified and modified CDs were tested for their corrosion inhibition properties using weight loss and electrochemical measurements in 0.5 mol/L H2SO4. The findings showed that the modified CDs achieved a corrosion inhibition efficiency of up to 93.19% at 100 mg/L. This improvement is attributed to the enhanced hydrophobicity of the modified CDs, which enables them to form a more effective protective film. The research emphasises the potential of modified CDs as a promising approach for the high-value utilisation of waste resources and the development of corrosion inhibitors from biomass sources.

The present study investigates the corrosion inhibition performance of a Cu-metal-organic framework (Cu-MOF) functionalized with bay leaf-derived carbon dots (MOF@CDs) for Q235B steel in 1 M HCl solution. The electrochemical tests (open circuit potential, potentiodynamic polarization curves, and electrochemical impedance spectroscopy) results demonstrated that the MOF@CDs could effectively inhibit steel corrosion, characterized by shifting the corrosion potential in the negative direction and decreasing the corrosion current density with the increase of the inhibitor concentration. The MOF@CDs function as an effective mixed-type corrosion inhibitor, primarily suppressing the anodic dissolution process while also hindering cathodic hydrogen evolution. Surface characterization using Fourier transform infrared spectroscopy (FTIR) confirmed the adsorption of MOF@CDs onto the steel surface through interactions involving hydroxyl, carboxyl, and aromatic groups. UV-vis spectroscopy further confirmed the adsorption behavior of MOF@CDs on the steel surface by suggesting the complexation between the metal and inhibitor. The presence of bay leaf-derived CD components in the MOF structure enhanced its corrosion inhibition capability, as the polyphenolic and oxygen-rich constituents facilitated strong surface interactions. Additionally, atomic force microscopy (AFM) demonstrated a substantial reduction in surface roughness after inhibitor adsorption, highlighting the protective barrier formation.

Helical strands are widely used in engineering applications owing to their superior tensile strength and exceptional deformation flexibility. During service, these cables are frequently subjected to axial tension and cyclic bending loads. Consequently, their hysteretic bending behavior under axisymmetric loading has attracted significant research interest. Nevertheless, prevailing theoretical models inadequately account for strand configurations in characterizing the transmission of radial contact forces. To address the limitations of existing models, this work develops a refined formulation for interlayer radial contact force transmission that explicitly accounts for the effects of strand configuration. Based on the improved formulation, novel analytical expressions for radial contact forces and the limit function of the nonlinear component of wire axial forces are derived. Finally, comparative evaluations between the proposed model and existing models are systematically conducted under varying lay angles and strand strains. Numerical validation reveals that the proposed model induces substantial modifications to both radial contact forces and the nonlinear component of wire axial force. Furthermore, theoretical derivations confirm that the selection of the dependent variable does not affect the mathematical expressions governing the limit domain of wires.

In dynamic corrosive environments, achieving precise control over inhibitor release and sustained corrosion protection remains a critical challenge. Herein, a pH- and magnetic dual-responsive core-shell composite (MSTE/Fe3O4@CS) was synthesized via emulsion cross-linking. The composite is composed of Melica scabrosa Trin. extract (MSTE) and Fe3O4 nanoparticles as the core, with chitosan (CS) forming the protective layer. The material showcased a distinct core-shell architecture and reached a 25.72% loading with a 64.3% encapsulation efficiency. Its pH-responsive release behavior, fitting the Korsmeyer-Peppas kinetic model, showed significantly faster MSTE release in acidic environments (pH 1-3) compared to neutral conditions. Electrochemical and weight loss tests showed MSTE/Fe3O4@CS reached 81.8% inhibition in 1 M HCl in the absence of an external magnetic field (MF OFF). In the presence of an external magnetic field (MF ON), this efficiency significantly increased to 93.19%. Magnetic field-enhanced composite adsorption on carbon steel promoted a compact protective layer, as verified by SEM, AFM, and XPS. This work presents a magnetic field-assisted adsorption strategy that combines pH-responsive release and magnetic targeting for stimuli-responsive corrosion protection, which has potential applications in industrial acid cleaning and pipeline maintenance.

Highlights Lotus leaf extract-based green corrosion inhibitor was developed for copper. The inhibitor effectively suppressed both cathodic and anodic corrosion processes. The inhibitor adsorption followed the Langmuir adsorption isotherm.Abstract The objective of this study is to develop and assess the feasibility of utilizing lotus (Nelumbo nucifera Gaertn.) leaf extract as a green corrosion inhibitor for copper in a sulfuric acid environment. The inhibitory efficacy was comprehensively evaluated using a multi-technique approach, incorporating electrochemical measurements, weight loss analysis, theoretical analysis, and surface morphological characterization. The experimental results demonstrate that the lotus leaf extract functions as an efficient corrosion inhibitor for copper, achieving an inhibition efficiency of 88.07% at 700 mg/L by effectively suppressing both cathodic and anodic corrosion processes. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the protective effect, whereas X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) identified functional groups and surface interaction between metal and inhibitor. Theoretical calculations further confirmed the involvement of nitrogen (N) and oxygen (O) as the key active sites. Adsorption behavior adheres to the Langmuir isotherm model, involving both physical and chemical adsorption processes that inhibit the Cu+-> Cu2+ oxidation reaction. This study demonstrates acid-resistant protection of copper using lotus leaf extract.

Biowaste has become a serious problem that can lead to serious environmental pollution and waste of resources if not handled properly. Waste materials are often high in proteins, which are easily extracted and hydrolyzed to provide an adequate quantity of amino acids. This indicates that biowastes can be used as green and efficient corrosion inhibitors (CIs). This work aimed to prepare fish waste extract (FWE) by acid hydrolysis with alkaline leaching using fish waste as the raw material. The results of the characterization analysis identified the presence of 17 amino acids, with Leucine, Phenylalanine, Methionine, and Alanine being the most abundant. FWE was then tested as a corrosion inhibitor (CI) for carbon steel in 0.5 mol/L H2SO4. Further, the effect of KI on the corrosion inhibition performance of FWE for carbon steel in 0.5 mol/L H2SO4 was systematically investigated by the weight loss method, electrochemical method, and surface analysis. The maximum corrosion inhibition efficiencies were 88.7 % and 63.9 % for the FWE and KI alone, and 97.10 % for the combination of FWE and KI. The synergistic coefficient study confirmed that the synergistic coefficients of the FWE and KI exceeded 1 across all concentration conditions, indicating a synergistic effect between them. The surface analysis results showed that the deterioration of carbon steel after adding the compounded CI was mild, and pitting and crevice corrosion was not observed. Theoretical calculations revealed the active reaction sites of four major amino acid molecules via quantum chemical and molecular dynamics simulations. The effect of different types of side chains and heteroatoms of amino acid molecules on their corrosion inhibition performance was elucidated to provide theoretical guidance for designing biowaste CIs.

The inhibitory potential of an alcoholic extract derived from Canarium strictum leaves (CSL) was evaluated as a corrosion inhibitor for mild steel (MS) in 15% HCl solution. Furthermore, to enhance its inhibition effectiveness, the influence of potassium iodide (KI) was also examined. The corrosion inhibition and adsorption characteristics of CSL were comprehensively analysed through weight loss measurement, electrochemical impedance measurement (EIS), potentiodynamic polarization (PP), UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy and energy dispersive spectroscopy (SEM–EDS). The effect of temperature and immersion time on corrosion inhibition was also investigated. The studied CSL extract exhibited maximum inhibition efficiency of 92.2% at 700 ppm alone, while adding 5 ppm KI 96.8% inhibition efficiency was observed. Moreover, with KI, an efficiency of 98% was observed at extended immersion of 48 h. The PP results showed that CSL and CSL + KI were good mixed-type inhibitor system. Adsorption data was best fitted to the Langmuir isotherm model, and thermodynamic, kinetic, and surface analyses shed light on the inhibitory mechanism.

This work investigates the corrosion protective characteristics of graphene oxide functionalized with an ionic liquid, namely choline hexanoate, abbreviated as Ch-Hex/GO nanohybrid, for mild steel in 5% HCl solution. The performance of this nanohybrid was evaluated using a range of analytical methods, including weight loss measurement, electrochemical method, contact angle measurement, XPS, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). Using Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and Raman analysis, the synthesis of Ch-Hex/GO was verified. An inhibitory efficiency reaching 85.75 % at a 100 ppm inhibitor concentration at 298 K was observed, which was further increased with increasing temperature, reaching 97.48 % at 323 K, suggesting a chemisorption mechanism. Assessments of inhibition performance throughout a range of immersion times, up to 144 hr, revealed a steady rise in efficiency up to 96 hr, followed by a minor decline while maintaining efficiencies above 85 %. The pronounced increases in polarization resistance (Rp) and reductions in corrosion current density (Icorr) indicated the strong adsorption of inhibitor molecules onto metal surface. In addition, the values of open circuit potential (OCP) and corrosion potential (Ecorr) were further evidence of a mixed inhibition mechanism. XPS and AFM/SEM analyses confirmed and supported these results, indicating the formation of protective layer on the steel surface.

This study the synthesis of undoped and Zn,N-doped carbon quantum dots (Zn,N-BCDs) utilizing banana peel biowaste via a hydrothermal method. The graphitic structure, size distribution, surface characteristics, and fluorescence properties of CDs were characterized by various techniques. Further, their efficacy in mitigating MS corrosion in a 15% HCl solution was analyzed using methods such as weight loss, OCP, EIS, and PDP measurements. Results revealed that both types of CDs exhibited inhibition properties against MS corrosion, with Zn,N-CDs demonstrating superior effectiveness, particularly at lower concentrations. Undoped and Zn,N-BCDs displayed inhibition efficiencies of 96.1% at 400 ppm and 98.7% at 200 ppm at 313 K, respectively, with temperature influencing their performance. XPS and FTIR studies confirmed the adsorption of CDs on the MS surface.

Corrosion is a significant challenge in maintaining material performance and longevity, particularly in harsh environments, necessitating the development of innovative protective materials. In this study, a novel composite was developed by combining tannic acid-benzoxazine (TA-BZ), epoxy resin, and zinc oxide (ZnO) nanoparticles, named Epoxy-TA-BZ-1-C, Epoxy-TA-BZ-2-C, and Epoxy-TA-BZ-4-C. These composites were cured at 200°C, with and without ZnO, to investigate the effect of ZnO addition on enhancing anticorrosion, mechanical, and thermal properties. The bio-based TA-BZ matrix, synthesized via Mannich condensation, demonstrated inherent thermal stability and corrosion resistance. Epoxy improved structural integrity, while ZnO nanoparticles enhanced barrier properties and antimicrobial activity. Comprehensive analyses, including FTIR, NMR, TGA, SEM, TEM, electrochemical, and mechanical studies, confirmed improved cross-linking density and structural optimization. Potentiodynamic polarization studies revealed a corrosion rate of 0.069 mm/year for Epoxy-TA-BZ-4-ZnO-C, highlighting its superior performance. These findings underscore its potential for advanced applications in demanding environments.

The objective of this study is to develop novel and sustainable corrosion inhibitors, which is an important and challenging task in corrosion management. This study reports the fabrication of a novel nanocomposite (NC) through the functionalization of an iron metal-organic framework (MOF) using cumin-derived carbon dots (CD). The MOF@CD NC was tested as a novel corrosion inhibitor for Q235B steel in 1.0 M HCl solution. The corrosion inhibition potential was significantly improved through the functionalization process and gravimetric tests showed an inhibition efficiency of about 98 % after 72 h immersion at 25 degrees C with an inhibitor concentration of 100 mg/L. FT-IR and XPS analysis indicated that binding and adsorption were achieved through functional groups of MOF@CD NC. SEM and AFM studies showed significant surface damage reduction and supported the formation of a powerful protective layer in the presence of inhibitor. This research represents a significant step forward in corrosion protection technology by introducing a new class of materials with excellent performance at low concentrations, offering a promising solution for industrial applications.

The present study describes the anti-corrosive properties of tyrosine and leucine functionalized glucose-derived carbon dots, abbreviated as CDTyr and CDLeu, respectively, for Q235B steel in a 5 % HCl solution. 1H-NMR, FT-IR, UV-vis, zeta potential, XRD and TEM analysis confirmed the preparation of functionalized CDs. The inhibition efficiencies and corrosion rates were calculated using mass loss and electrochemical methods. The inhibition effectiveness calculated for CDTyr and CDLeu were, i.e., 96.8 % and 93.6 %, respectively, at 303 K at a very low concentration of both CDs, i.e., at 80 ppm. On increasing temperature from 303 to 313 K, corrosion rates decreased to 0.303 mm/y for CDTyr and 1.11 mm/y for CDLeu, with %IE values of 97.84 % and 92.10 %, respectively. The experimental data from the immersion time test indicated that the CDs demonstrated consistently stable performance under static and dynamic conditions. Adsorption studies confirmed the spontaneous interaction and followed the Langmuir adsorption isotherm. The XPS analysis revealed the composition of the inhibitors' layer on the metals surface. AFM and SEM studies demonstrated reduced surface roughness. CDTyr outperformed CDLeu due to the phenolic group enabling stronger hydrogen bonding and improved protective layer stability. DFT and MD simulations provided insights into CDs' electronic structure and stability derived from glucose and amino acid precursors, revealing distinct electronic characteristics.

The special configuration and elongated geometrical appearance of the helical strand give it properties of tensile-torsion-bending coupling as well as macroscopic geometrical nonlinearity. Simulating small-scale strands using solid elements in finite element software reproduces these properties but is time-consuming. Current methods of modeling large-scale strands using cable elements or beam elements can account for geometric nonlinearities, but often fail to adequately consider the tensile-torsion-bending coupling characteristics of the strand cross-section. This study presents a new finite element method for modeling strand structures. This analysis method adopts the rigid body rule to handle the geometric nonlinearity of strand structures, considering the tensile-torsion-bending coupling characteristics of the strand cross-section, while remaining acceptable in terms of analysis time. The analytical method can provide the strand structure's displacement and the parameters of the tension-torsion-bending coupling characteristics of the strand element. The results obtained from the proposed analytical method were compared with those from numerical modeling and experimental testing, confirming the validity of the analytical method.