Green Corrosion Inhibitor Research Articles

Trifolium repens extracts as a green corrosion inhibitor for carbon steel in a 3.5% NaCl solution

BackgroundMaterial degradation is a major issue that has been the subject of intense research and investigation by the scientific community. It has harmful consequences that require serious and careful intervention. However, restrictions on the use of inhibitors containing toxic compounds pose a significant challenge to the implementation of effective corrosion treatments. This has necessitated a continuous search for new and innovative ways to protect against material damage. Plant-derived natural inhibitors offer several advantages, including potent inhibitory effects, lack of toxicity, biodegradability, and environmentally sustainable origins. The purpose of this research was to evaluate the corrosion resistance of API5LX60 carbon steel in a 3.5 % NaCl environment using Trifolium repens as an environmentally friendly inhibitor. MethodsThe inhibitor extract was analysed using Fourier Transform Infrared (FTIR) spectroscopy. However, gravimetry and electrochemical methods (potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)) were used to investigate the corrosion behaviour. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to examine the surface morphology. Significant findingsAfter testing a range of concentrations in a 3.5 % NaCl medium, the highest level of inhibition (98 %) was obtained at 20 ppm, confirming the mixed action of the inhibitor with predominantly cathodic action. The inhibition mechanism involved physical adsorption on metal surfaces according to the Langmuir model, which enhances the corrosion-inhibiting ability; the extract forms a protective layer that successfully inhibits corrosion, as confirmed through electrochemical and surface analysis. These results demonstrate that the extract acts as a potent anticorrosive agent.

Corrosion inhibition of AZ31 magnesium alloy in 3.5 % NaCl by green corrosion inhibitor: Maleic hydrazide derivative

A novel maleic hydrazide derivative containing multiple active groups (NOMAM) has been synthetized and characterized. Electrochemical tests revealed that it can provide effective protection for AZ31 magnesium alloys in 3.5 % NaCl. The best inhibition was achieved at 0.2 g·L−1. The observation results of the surface morphology also confirmed its excellent corrosion inhibition performance. Density functional theory (DFT) calculations and molecular dynamics simulations (MDS) revealed that maleic hydrazide derivative molecules adsorb onto magnesium alloy surfaces via a combination of physisorption and chemisorption with heteroatoms as active sites. The complexes formed by derivative molecules with Mg2+, together with the deposited Mg(OH)2, form protective barriers at the interface. The synthesized derivative has many advantages, such as low cost, simple processing and low toxicity. This study can contribute to the search for green corrosion inhibitors for magnesium alloys.

A comprehensive electrochemical evaluation of the corrosion inhibition by sodium silicate on carbon steel

Sodium silicate (SS) is investigated as a sustainable green corrosion inhibitor for carbon steel in saline environment under both static and dynamic flow conditions. Potentiodynamic scans and Electrochemical Impedance Spectroscopy revealed that silica is both highly efficient in static and flowing water conditions (up to 98 and 99% resp.). An increased inhibition efficiency (IE) is seen as a function of silica concentration as a result of decreased defects in the resulting silica film (Mott–Schottky). The film forming behaviour changes at increasing flow speed, producing a more defect-rich structure at both low and high silica concentration, although showing improved IE at intermediate flow speed for low SS concentrations.

Electrochemical, thermodynamic and DFT studies of Fomitopsis pinicola as green corrosion inhibitor for carbon steel in sulfuric acid

In this work, the methanolic extract of Fomitopsis pinicola has been evaluated as a green corrosion inhibitor for the dissolution of 1018 carbon steel in 0.5 M sulfuric acid. For this, gravimetric tests and electrochemical methods such as potentiodynamic polarization curves, linear polarization resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS) techniques were used. These tests were aided with Infrared and GC–MS analytical techniques. In addition to this, theoretical calculation with the use of the density functional theory (DFT) technique has been used to correlate the electronic extract properties and its inhibitory capacity. Weight loss results have shown an inhibitor efficiency of 85 % with the addition of 400 ppm. Thermodynamic parameters have shown that Fomitopsis pinicola extract is physically adsorbed onto the steel following a Langmuir adsorption isotherm. Potentiodynamic polarization curves showed that the extract behaves as a mixed type of corrosion inhibitor inducing the formation of a protective film onto the steel surface. In the presence of the Fomitopsis pinicola extract, a more resistive film obtained the highest polarization resistance value when 400 ppm of extract was used. In addition to this, as the concentration of the extract increased the charge transfer resistance and the double electrochemical layer capacitance decreased. GC–MS results indicated that main compounds contained in the Fomitopsis pinicola extract were Dehydrergosterol, Hydrazino-acetic acid ethyl ester, and Phthalic acid, di (2-propylpentyl) ester, whereas theoretical calculations showed that the highest EHOMO and lowest ELUMO values correspond to Dehydrergosterol and the Phthalic acid, which are the responsible for the extract inhibitory properties.

Assessment of Warionia saharea Essential Oil as a Green Corrosion Inhibitor for Mild Steel in HCl: Experimental and Computational Studies

The objective of this research work is the study of the inhibitory effect of Warionia saharea essential oil (WSEO) on the corrosion of mild steel (MS) in molar HCl solution, employing both experimental and theoretical methods. This inhibitory effect (IE) has been evaluated by using a combination of weight loss measurements (LW) and various electrochemical methods, such as open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) experiments. The LW results indicated that IE increased with inhibitor concentration, reaching 83.34% at 3.00 g/L. The PDP analysis suggested that WSEO functions as a mixed inhibitor, while in the EIS results the Rct values increased with inhibitor concentration to reach 165.8 Ω cm2 at 2.00 g/L, suggesting a defensive film formation by WSEO molecules over the metallic surface. The thermodynamic study demonstrated that the WSEO molecules adsorption on the MS surface followed a Langmuir isotherm, involving mixed physical and chemical (physicochemical) adsorption on the MS surface. Theoretical methods, including density functional theory (DFT) and molecular dynamics (MD) simulations, were employed to elucidate the inhibition mechanisms of the three main components of WSEO. The quantum chemical analysis, using density functional theory (DFT) and molecular dynamics (MD) simulations, showed a low ΔEgap value of 6.30 eV and a low adsorption energy (Eads) value on an Fe (110) substrate of −258 Kcal/mol for (E)-Nerolidol, indicating the significant contribution of this molecule to the overall corrosion inhibition effect of WSEO. The scanning electron microscope (SEM) analysis verified the presence of a protective film formed by the inhibitor on the MS surface. This study highlights the potential of WSEO as a sustainable and green corrosion inhibitor in acidic environments.

Fatty Imidazolines as a Green Corrosion Inhibitor of Bronze Exposed to Acid Rain

Acid rain is one of the primary corrosive agents on bronze exposed to the atmosphere. Bronze naturally forms a layer of oxides on its surface called patina, protecting it from corrosion. However, when exposed to acid rain, this layer dissolves, making it necessary to use a corrosion inhibitor or stabilize the patina. This study investigated fatty imidazolines derived from agro-industrial waste bran as a corrosion inhibitor of SAE-62 bronze in simulated acid rain (pH of 4.16 ± 0.1). Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements were used to evaluate corrosion inhibition efficiency, which was 90% for an inhibitor concentration of 50 ppm. The EIS measurements showed that the fatty imidazolines formed a protective film that stabilized the patina on the bronze surface to a certain extent by hindering the charge transfer process. SEM–EDS analyzed the morphology and composition of the protective oxide layer. The results were complemented by Raman spectroscopy and XRD analysis, indicating cuprite, tenorite, cassiterite, and covellite in the patina layer formed on the bronze surface. The SEM analysis showed that the protective coating on the bronze surface was homogeneous using a 50-ppm inhibitor concentration. The XRD analysis suggested the presence of an organic complex that stabilizes the corrosion products formed on the bronze surface.

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.

Experimental and Quantum Chemical Studies of a Green Corrosion Inhibitor for Mild Steel in Acidic Chloride Solution

AbstractA green corrosion inhibitor was prepared from the bio‐based platform compound 5‐hydroxymethylfurfural through a green synthetic route, which avoid the use of toxic reagent. The inhibition performance and mechanism of this compound for the corrosion of mild steel in 0.1 M HCl was investigated by using the weight loss experiments, polarization measurements, EIS measurements and quantum chemical calculations. The corrosion inhibition efficiency by weight loss measurement (ηWLM%) of this inhibitor can reach up to 90.3 % at 303 K with 1.2 mM concentration. Moreover, the electrochemical experiments revealed that this corrosion inhibitor acts as a mixed‐type inhibitor. Thermodynamic studies gave the values of the standard Gibbs free energy , fall within the range of −20 kJ/mol to −40 kJ/mol, suggested the adsorption of this compound is a spontaneous process involving both physisorption and chemisorption. In addition, quantum chemical calculations were conducted to further validate the formation of an effective absorption layer by this inhibitor on metal surfaces, which showed that the electron density iso‐surfaces of HOMO was mainly distributed on chloride ions, while LUMO tended to be distributed on furan rings and aldehyde groups. Besides, the other quantum chemical parameters of this inhibitor were also calculated to explore the molecular activity, such as, the molecular volume (ν, 333.105 Å), global hardness (η, 4.706 eV), global softness (σ, 0.2125 eV), electronegativity (χ, 4.93 eV), dipolemoment (μ, 13.1429 D) and vertical ionization energy (VIE, 7.2646 eV).

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.

Gleditsia sinensic extract as green corrosion inhibitor for N80 steel in 1 M HCl

The inhibition efficiency of gleditsia sinensic extract (GSE) as green corrosion inhibitor for N80 steel has been evaluated by weightlessness test, electrochemical impedance spectroscopy (EIS) study, Potentiodynamic polarization (PDP) measurement and Density Functional Theory (DFT) calculations in 1M HCl solution. Consequently, the inhibition efficiency of GSE is increased with the concentrations, immersion time and corrosion temperature (except 60 °C). After 144 h of immersion at 30 °C, the inhibition efficiency of GSE at a concentration of 500 mg/L was as high as 92.34 %. The adsorption process was spontaneous exothermic and conformed to Langmuir's law of adsorption, while Tafel's analysis showed that GSE is a mixed type of inhibitor. In addition, the corrosion products have been examined by scanning electron microscopy (SEM) analysis, X-Ray Diffractomer (XRD) testing, Fourier transform infrared spectroscopy (FTIR-ATR), UV-Vis spectroscopy and contact angle (CA) measurements. Furthermore, the corrosion inhibition mechanism has also been investigated.

WITHDRAWN: Moroccan Cannabis sativa L plant extract as green corrosion inhibitor for mild steel in 1 M HCl solution

Cannabis Sativa L Extract (CSLE) action on the electrochemical properties of mild steel in 1M HCl solution was studied, using potentiodynamic polarization and electrochemical impedance spectroscopy. The findings revealed an improvement in corrosion inhibition efficiency when extracts concentrations increase, achieving an inhibitory efficiency of 96.68% at 10% (v/v) of CSLE. Moreover, the temperature influence on the effectiveness of the extract has been studied over a range of 293-338K and findings proved the inhibitor adsorption according to mono-layer barrier film conformed to Langmuir isotherm. Corrosion kinetics and thermodynamic factors were calculated and discussed. Furthermore, the DFT method has been exploited to describe the corrosion inhibitory mechanism.

Carbon Steel Corrosion Induced by Sulfate-Reducing Bacteria: A Review of Electrochemical Mechanisms and Pathways in Biofilms

Microbial metal corrosion has become an important topic in metal research, which is one of the main causes of equipment damage, energy loss, and economic loss. At present, the research on microbial metal corrosion focuses on the characteristics of corrosion products, the environmental conditions affecting corrosion, and the measures and means of corrosion prevention, etc. In contrast, the main microbial taxa involved in metal corrosion, their specific role in the corrosion process, and the electron transfer pathway research are relatively small. This paper summarizes the mechanism of microbial carbon steel corrosion caused by SRB, including the cathodic depolarization theory, acid metabolite corrosion theory, and the biocatalytic cathodic sulfate reduction mechanism. Based on the reversible nature of electron transfer in biofilms and the fact that electrons must pass through the extracellular polymers layer between the solid electrode and the cell, this paper focuses on three types of electrochemical mechanisms and electron transfer modes of extracellular electron transfer occurring in microbial fuel cells, including direct-contact electron transfer, electron transfer by conductive bacterial hair proteins or nanowires, and electron shuttling mediated by the use of soluble electron mediators. Finally, a more complete pathway of electron transfer in microbial carbon steel corrosion due to SRB is presented: an electron goes from the metal anode, through the extracellular polymer layer, the extracellular membrane, the periplasm, and the intracellular membrane, to reach the cytoplasm for sulfate allosteric reduction. This article also focuses on a variety of complex components in the extracellular polymer layer, such as extracellular DNA, quinoline humic acid, iron sulfide (FeSX), Fe3+, etc., which may act as an extracellular electron donor to provide electrons for the SRB intracellular electron transfer chain; the bioinduced mineralization that occurs in the SRB biofilm can inhibit metal corrosion, and it can be used for the development of green corrosion inhibitors. This provides theoretical guidance for the diagnosis, prediction, and prevention of microbial metal corrosion.

Insight into the corrosion resistance of mild steel in an acidic environment in the presence of an organic extract: Experimental and computational approach

Green corrosion inhibitors are crucial in lowering the rate at which metals corrode as well as the negative environmental effects of hazardous substances. Considering this, Curcuma longa (CL) root extract was used as an effective and safe corrosion inhibitor in this study. The inhibitory efficacy was thoroughly investigated using the weight loss (WL), open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) techniques, respectively. The inhibitor was found to be effective at impeding the rate of deterioration of mild steel in 1 M HCl and 0.5 M H2SO4 environments. In a mixed-type mode, the CL reduced the anodic and cathodic reactions. However, in a 0.5 M H2SO4 environment, CL proved to be slightly more effective compared to a 1 M HCl environment. Inhibition efficiency values of 91.8 % (0.5 M H2SO4) and 89.6 % (1 M HCl) were obtained. The Langmuir adsorption isotherm (LAI) was used to validate the results. Some surface probe analysis such as scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FR-IR), and X-ray photoelectron spectroscopy (XPS), were used to complement the electrochemical results. Quantum chemical computations confirmed some active sites on the molecular structures of a few selected active constituents of the CL extract.

Effect of spinach (Spinacia oleracea) leaf extract on the aluminum (Al) as a green corrosion inhibitor in HCl medium

Green corrosion inhibitors have recently attracted much attention due to their non-toxic properties, especially plant extracts. This study used spinach leaf extract (Spinacia oleracea) as a corrosion inhibitor on aluminum in an HCl medium. Spinach leaf extract (Spinacia oleracea) was obtained by maceration method, using ethanol as the solvent, which was then distilled to purify the extract. The corrosion inhibition properties were studied by the gravimetric method. The results showed that spinach leaf extract (Spinacia oleracea) can efficiently decrease the corrosion rate of aluminum in an HCl medium, achieving a maximum efficiency of 96.7742 %. Spinach leaf extract (Spinacia oleracea) formed a protective layer on the aluminum surface via adsorption and chemisorption, thus increasing surface coverage and blocking mass transfers. As the inhibitor concentration increases, the corrosion rate decreases, and the corrosion inhibition efficiency increases. This study shows that spinach leaf extract (Spinacia oleracea) is a viable organic corrosion inhibitor option with high efficiency.

Polymeric carboxylic acid functionalized ionic liquid as a green corrosion inhibitor: Insights into the synergistic effect with KI

A poly ionic liquid, poly(3-(3-carboxypropyl)-1-vinyl-1H-imidazolium chloride) (P[CPVI]Cl), was synthesized and demonstrated to be effective as an inhibitor for carbon steel corrosion. The structure of P[CPVI]Cl contains a carboxylic acid group and N- heterocyclic ring, which serve as multiple adsorption sites and facilitate the formation of multi-anchored adsorption. The P[CPVI]Cl can be adsorbed onto the metal surface, resulting in a larger surface area coverage, leading to a higher inhibition efficiency of 88.27 %. The synergistic effect of P[CPVI]Cl and KI further enhanced inhibition efficiency up to 98.83 %. Various surface characterizations and molecular simulations have been performed, and a possible corrosion inhibitor mechanism has been proposed.

Green Corrosion Inhibitors for Metal and Alloys Protection in Contact with Aqueous Saline.

Corrosion is an inevitable and persistent issue that affects various metallic infrastructures, leading to significant economic losses and safety concerns, particularly in areas near or in contact with saline solutions such as seawater. Green corrosion inhibitors are compounds derived from natural sources that are biodegradable in various environments, offering a promising alternative to their conventional counterparts. Despite their potential, green corrosion inhibitors still face several limitations and challenges when exposed to NaCl environments. This comprehensive review delves into these limitations and associated challenges, shedding light on the progress made in addressing these issues and potential future developments as tools in corrosion management. Explicitly the following aspects are covered: (1) attributes of corrosion inhibitors, (2) general corrosion mechanism, (3) mechanism of corrosion inhibition in NaCl, (4) typical electrochemical and surface characterization techniques, (5) theoretical simulations by Density Functional Theory, and (6) corrosion testing standards and general guidelines for corrosion inhibitor selection. This review is expected to advance the knowledge of green corrosion inhibitors and promote further research and applications.

Investigation of the energy gap and anti-corrosion activities of triethanolamine lauryl sulfate for carbon steel in 1.0 M HCl using DFT theory and electrochemical studies

Corrosion inhibition is a critical strategy in the industry to mitigate the detrimental effects of corrosion. Green inhibitors are a concern and are encouraged to apply in various ways. Triethanolamine lauryl sulfate (TLS) investigates as a green corrosion inhibition for carbon steel in 1 M HCl using weight loss and electrochemical measurements. A weight loss study revealed that 100 μM of TLS had the highest inhibition effectiveness of 95.7 %. Tafel estimations from the polarization profiles showed that 100 μM had an optimal inhibition effectiveness of about 96.3 %. The physical adsorption of TLS on the carbon steel surface, which followed the Langmuir adsorption isotherm, was ascribed to the inhibitive effect. The results declare that TLS functioned as an inhibitor of mixed types. For TLS, the adsorption Gibb's free energy is −19.6 kJ mol−1, indicating spontaneous and physisorption-based. The energy gap of TLS is evaluated theoretically using density functional theory (DFT), and a lower value indicates its great donation ability of electron’s to the carbon steel. The mechanism of adsorption of TLS onto the metal surfaces is illustrated in terms of experimental and theoretical calculations.

Inhibition Potentials of Solanum macrocarpon Leave Extract as a Green Corrosion Inhibitor of Mild Steel in an Acidic Solution

Inhibition Potentials of Solanum macrocarpon Leave Extract as a Green Corrosion Inhibitor of Mild Steel in an Acidic Solution

Sodium humate as green corrosion inhibition for enhanced corrosion resistance of EH40 ship plate steel

A new green corrosion inhibitor was extracted and prepared from available and inexpensive natural humic plant humus for the corrosion inhibition of EH40 steel in a 15 % HCl medium. The corrosion inhibition properties of SH were evaluated using weight loss, cyclic voltammetry, potentiodynamic polarization and electrochemical impedance spectroscopy. The morphology of EH40 steel was characterized using scanning electron microscopy, atomic force spectroscopy and x-ray photoelectron spectroscopy. It was found that, the optimum concentration of sodium humate was 1.0 gL−1 with an inhibition efficiency of above 95 %. The corresponding corrosion inhibition mechanism was proposed, in which the corrosion inhibitor formed a film on the surface of EH40 steel as a result of the synergistic adsorption effect of chemistry and physics, improving its corrosion retention in the strong acid medium.

Turning Waste into Treasure: Invasive Plant Ambrosia trifida L Leaves as a High-Efficiency Inhibitor for Steel in Simulated Pickling Solutions.

High toxicity is the main reason for the limited application of traditional corrosion inhibitors. Herein, it is critical to find a green, efficient, and long-term stable alternative substitute for the hazardous and conventional corrosion inhibitor. Ambrosia trifida L is widely distributed in fields and riverside wetlands as an invasive plant in China. According to the concept of turning waste into treasure, the extract of Ambrosia trifida L leaves (ATL) has the potential to address this issue due to its natural origin and abundant presence of heterocyclic organics. Therefore, ATL, as a green corrosion inhibitor, is prepared for the first time via a simple water-based extraction method. FT-IR (Fourier transform infrared spectroscopy) and UV-Vis (UV-visible) indicate that ATL extract contains abundant heterocyclic organics with conjugated structures, which exhibit the potential to become a high-efficiency inhibitor. Notably, the active sites of ATL molecules and their interaction with Q235 steel at the molecular/atomic level are revealed via theoretical calculations. The highest Ebinding value observed for the major components in the ATL extract is 259.66 kcal/mol, implying a significant adsorption capacity. The electrochemical results verify that microdose ATL extract can prominently inhibit steel corrosion, and the highest inhibition efficiency (η) is 97.5% (1000 mg/L). Following immersion for 24 h, the η value is enhanced to 99.0%, indicating a reliable and long-term ATL extract protection film is formed on the steel surface in harsh acidic solutions. The results of the weight loss, SEM (scanning electron microscope), and LSCM (laser scanning confocal microscopy) are consistent with the above conclusions. Finally, this study anticipates providing theoretical support for developing novel green plant extract inhibitors and aiding in their application in industrial pickling environments.