Green Corrosion Inhibition of Mild Steel by Hydrazone Derivatives in 1.0 M HCl

An Exploratory Experimental Analysis Backed by Quantum Mechanical Modeling, Spectroscopic, and Surface Study for C-Steel Surface in the Presence of Hydrazone-Based Schiff Bases to Fix Corrosion Defects in Acidic Media

This work focuses on developing corrosion control and protecting the environment by creating affordable, sustainable, environmentally friendly, and efficient corrosion resistance chemicals. That is, through synthesized three hydrazone Schiff bases E-2-(1-hydrazonoethyl)thiazole (HTZ), 2-((E)-(((Z)-1-(thiazol-2-yl)ethylidene)hydrazono)methyl)phenol (HTZS), and 2-((E)-(((Z)-1-(pyridin-2-yl)ethylidene)hydrazono)methyl)phenol (HPYS) and corrosion inhibitors for C-steel in 8 M H3PO4 solution that were studied. The chemicals were analyzed by using 1H NMR and 13C NMR spectroscopy to learn more about them. Predominantly, the hydrazone-based Schiff bases have been considered powerful inhibitors due to their ability to be adsorbed with very low concentrations through their reactive sites (N, O, and S). Maximum surface (θmax) coverage and inhibition efficiency of 83.33% were sufficiently found at 99.00 × 10-3 mol/L concentration of HTZS at 293 K. Galvanostatic experiments demonstrated that raising the concentration of hydrazones improved mass transfer resistance. To study microstructure, scanning, reflectance, and energy-dispersive X-rays were used. Roughness and qualitative adhesion of the adsorbed layer were estimated by an atomic force microscope. After adding 99.00 × 10-3 mol/L of HTZS, the degree of surface brightness and reflectance increases to 137.20, relative to the corroded electrolyte-free solution 27.70. The roughness (Ra) decreased from 0.468 to 0.088 μm by adding HTZS. A surface morphology study confirmed that adding hydrazones to the C-steel dissolution bath greatly improves the surface's look and texture quality. The atomic absorption spectroscopy technique was used to compare the concentration of the iron ions that remained in the solution after galvanostatic analysis in the absence and presence of the hydrazones under different conditions; it was found that the inhibited solution contained lower concentrations of iron ions as compared to the uninhibited solution. The DFT theoretical analysis verified the observation of hydrazone physical adsorption through bonding electrons that obey kinetic adsorption isotherms. It is based on examining the highest occupied molecular orbital-lowest occupied molecular orbital (HOMO-LUMO), the Fukui functions, and the Mulliken atomic charge. Overall, the results suggest that HTZS is a good corrosion inhibitor with a large surface area due to the presence of S, N, and O atoms, allowing for creating a larger surface due to the large molecular volume of atoms protecting against the corrosion process.

Investigation of olive leaf extract as a potential environmentally-friendly corrosion inhibitor for carbon steel

Corrosion constitutes a significant issue in industries that handle metals. Corrosion inhibitors with a low impact on the environment provide a significant economic benefit in various engineering applications. In this work, the effectiveness of olive leaves extract is evaluated as a cost-effective and environmentally-friendly corrosion inhibitor. The corrosion of carbon steel in different concentrations of hydrochloric acid (0.1, 1.0, and 2.0 M) when protected by an aqueous solution of olive leaf extract of concentrations ranging from 10 to 60 ppm is investigated. A green extraction process based upon water extraction is used to ensure minimum impact on the environment. Results show that the corrosion inhibition efficiency increased as the concentration of the olive leaf extract increased. An analysis of variance showed a significant effect of acidic molarity, temperature, and inhibitor concentration on the corrosion rate. A significant statistical model indicates that the inhibitor exhibits higher efficiencies at higher acidic molarity. Results of SEM and EDX also demonstrated that a protective film of the inhibitor on the specimen surface plays a role in corrosion inhibition, suggesting that the inhibitor molecules are adsorbed at the interface between the carbon steel and the acid solution. The study provides an insight on the corrosion mechanism and highlights the potential of olive oil extract as an eco-friendly alternative to traditional corrosion inhibitors.

Some Brassicaceae Extracts as Potential Antioxidants and Green Corrosion Inhibitors

Glucosinolates-rich extracts of some Brassicaceae sources, such as broccoli, cabbage, black radish, rapeseed, and cauliflower, were obtained using an eco-friendly extraction method, in a microwave field, with 70% ethanol, and evaluated in order to establish their in vitro antioxidant activities and anticorrosion effects on steel material. The DPPH method and Folin-Ciocâlteu assay proved good antioxidant activity (remaining DPPH, 9.54-22.03%) and the content of total phenolics between 1008-1713 mg GAE/L for all tested extracts. The electrochemical measurements in 0.5 M H₂SO₄ showed that the extracts act as mixed-type inhibitors proving their ability to inhibit corrosion in a concentration-dependent manner, with a remarkable inhibition efficiency (92.05-98.33%) achieved for concentrated extracts of broccoli, cauliflower, and black radish. The weight loss experiments revealed that the inhibition efficiency decreased with an increase in temperature and time of exposure. The apparent activation energies, enthalpies, and entropies of the dissolution process were determined and discussed, and an inhibition mechanism was proposed. An SEM/EDX surface examination shows that the compounds from extracts may attach to the steel surface and produce a barrier layer. Meanwhile, the FT-IR spectra confirm bond formation between functional groups and the steel substrate.

Flower-like Superhydrophobic Surfaces Fabricated on Stainless Steel as a Barrier against Corrosion in Simulated Acid Rain

Functionalisation of the metal surface of low-carbon ferritic stainless steel (from hydrophilic to hydrophobic properties) was achieved by flower-like hierarchical structures on a steel substrate prepared by a low-cost immersion method. The flower-like structured hydrophobic layers on the steel substrate were obtained by immersing the samples in an ethanolic solution of stearic acid with the addition of various concentrations of expired vitamin E ((+)α-tocopherol). The stability and corrosion-inhibiting effect of the hierarchically structured (such as natural cornflower) hydrophobic layers were studied systematically during short and long immersion tests, 120 h (five days) in an acidic environment (pH = 3) using potentiodynamic measurements, electrochemical impedance spectroscopy and chronopotentiometry. The surfaces of the samples, their wettability, surface morphology and chemical composition were characterised by contact angle measurements, SEM, ATR-FTIR and EDAX. After 120 h of immersion, the inhibition efficiency of the flower-like structured hydrophobic layers on the steel substrate in the selected corrosion medium remained above 99%, and the hierarchical structure (flower-like structure) was also retained on the surface.

Formamidine-Based Thiuram Disulfides as Efficient Inhibitors of Acid Corrosion of Mild Steel: Electrochemical, Surface, and Density Functional Theory/Monte Carlo Simulation Studies

Electrochemical, surface, and density functional theory (DFT)/Monte Carlo (MC) simulation studies were used in investigating the characteristics of N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-bis(2,6-dimethylphenyl)formimidamide) (DS1), N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-bis(2,6-diisopropylphenyl)formimidamide) (DS2), N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-dimesitylformimidamide) (DS3), and N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-bis(2,6-dichlorophenyl)formimidamide) (DS4) as inhibitors of acid corrosion of mild steel. The inhibitors were found to effectively reduce the rates of steel dissolution at the anode as well as cathodic hydrogen evolution. The order of inhibition efficiencies of studied compounds is DS1 (PDP/LPR/EIS: 98.60/97.98/96.94%) > DS2 (PDP/LPR/EIS: 98.36/96.86/96.90%) > DS3 (PDP/LPR/EIS: 94.66/87.44/94.30%) > DS4 (PDP/LPR/EIS: 83.57/77.02/75.17%) at 1.00 mM, and the overall efficiencies appeared to depend on the molecular and electronic structures of the compounds. The compounds offered high resistance to charge transfer across the electrode/electrolyte system by forming adsorbed film whose resistance increased with an increase in concentration. Findings suggested that the adsorption process involved combined chemisorption and physisorption. DFT calculations and MC simulations provided theoretical justifications for the experimental results.

Corrosion Inhibition of Mild Steel in Hydrochloric Acid Environment Using Terephthaldehyde Based on Schiff Base: Gravimetric, Thermodynamic, and Computational Studies

Using traditional weight-loss tests, as well as different electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy), we investigated the corrosion-inhibition performance of 2,2′-(1,4-phenylenebis(methanylylidene)) bis(N-(3-methoxyphenyl) hydrazinecarbothioamide) (PMBMH) as an inhibitor for mild steel in a 1 M hydrochloric acid solution. The maximum protection efficacy of 0.0005 M of PMBMH was 95%. Due to the creation of a protective adsorption layer instead of the adsorbed H2O molecules and acidic chloride ions, the existence of the investigated inhibitor reduced the corrosion rate and increased the inhibitory efficacy. The inhibition efficiency increased as the inhibitor concentration increased, but it decreased as the temperature increased. The PMBMH adsorption mode followed the Langmuir adsorption isotherm, with high adsorption-inhibition activity. Furthermore, the value of the ∆Gadso indicated that PMBMH contributed to the physical and chemical adsorption onto the mild-steel surface. Moreover, density functional theory (DFT) helped in the calculation of the quantum chemical parameters for finding the correlation between the inhibition activity and the molecular structure. The experimental and theoretical findings in this investigation are in good agreement.

Review on the Recent Development of Fatty Hydrazide as Corrosion Inhibitor in Acidic Medium: Experimental and Theoretical Approaches

In recent years, numerous research work has been conducted in order to find the most practical and cost-effective solution for corrosion issues in the oil and gas industry. Several studies have revealed that fatty hydrazide derivatives are the most suitable corrosion inhibitor for the application in the said industry. These compounds can also act as effective corrosion inhibitors in acidic medium with inhibition efficiency greater than 95%. This review summarizes and discusses the recent corrosion inhibitor development in acidic media from 2017 until 2021, focusing on fatty hydrazide derivatives. The significant findings and mechanisms of inhibition have been elucidated. In addition, intake on the computer simulation studies of fatty hydrazide inhibition properties is also included in this review. Finally, some suggestions for future research on corrosion inhibitors have been recommended.

Synthesis and Characterization of Zn-Organic Frameworks Containing Chitosan as a Low-Cost Inhibitor for Sulfuric-Acid-Induced Steel Corrosion: Practical and Computational Exploration

In this work, a Zn-benzenetricarboxylic acid (Zn@H3BTC) organic framework coated with a dispersed layer of chitosan (CH/Zn@H3BTC) was synthesized using a solvothermal approach. The synthesized CH/Zn@H3BTC was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), thermal gravimetric analysis (TGA), and Brunauer, Emmett, and Teller (BET) surface area. The microscopic observation and the analysis of the BET surface area of CH/Zn@H3BTC nanocomposites indicated that chitosan plays an important role in controlling the surface morphology and surface properties of the Zn@H3BTC. The obtained findings showed that the surface area and particle size diameter were in the range of 80 m2 g-1 and 800 nm, respectively. The corrosion protection characteristics of the CH/Zn@H3BTC composite in comparison to pristine chitosan on duplex steel in 2.0 M H2SO4 medium determined by electrochemical (E vs. time, PDP, and EIS) approaches exhibited that the entire charge transfer resistance of the chitosan- and CH/Zn@H3BTC-composite-protected films on the duplex steel substrate was comparatively large, at 252.4 and 364.8 Ω cm2 with protection capacities of 94.1% and 97.8%, respectively, in comparison to the unprotected metal surface (Rp = 20.6 Ω cm2), indicating the films efficiently protected the metal from corrosion. After dipping the uninhabited and protected systems, the surface topographies of the duplex steel were inspected by FESEM. We found the adsorption of the CH/Zn@H3BTC composite on the metal interface obeys the model of the Langmuir isotherm. The CH/Zn@H3BTC composite revealed outstanding adsorption on the metal interface as established by MD simulations and DFT calculations. Consequently, we found that the designed CH/Zn@H3BTC composite shows potential as an applicant inhibitor for steel protection.

Inhibitory Potential of New Phenolic Hydrazide-Hydrazones with a Decoy Substrate Fragment towards Laccase from a Phytopathogenic Fungus: SAR and Molecular Docking Studies

Laccase from pathogenic fungi participates in both the delignification and neutralization of phytoantibiotics. Furthermore, it interferes with the hormone signaling in plants and catalyzes melanization. Infections of these pathogens contribute to loss in forestry, agriculture, and horticulture. As there is still a need to expand knowledge on efficient defense strategies against phytopathogenic fungi, the present study aimed to reveal more information on the molecular mechanisms of laccase inhibition with natural and natural-like carboxylic acid semi-synthetic derivatives. A set of hydrazide-hydrazones derived from carboxylic acids, generally including electron-rich arene units that serve as a decoy substrate, was synthesized and tested with laccase from Trametes versicolor. The classic synthesis of the title inhibitors proceeded with good to almost quantitative yield. Ninety percent of the tested molecules were active in the range of K_I = 8–233 µM and showed different types of action. Such magnitude of inhibition constants qualified the hydrazide-hydrazones as strong laccase inhibitors. Molecular docking studies supporting the experimental data explained the selected derivatives’ interactions with the enzyme. The results are promising in developing new potential antifungal agents mitigating the damage scale in the plant cultivation, gardening, and horticulture sectors.

Impediment of Iron Corrosion by N,N′-Bis[2-hydroxynaphthylidene]amino]oxamide in 3.5% NaCl Solution

Hydrazone [N,N′-bis[2-hydroxynaphthylidene]amino]oxamide] derived from the condensation of ethanedihydrazide with 2-hydroxynaphthalene-1-carbaldehyde was synthesized and assessed on the basis of elemental analysis (CHN) and spectral (IR, mass, 13C/1H NMR and UV-Vis) measurements. The influence of N,N-bis([2-hydroxynaphthylidene]amino)oxamide (HAO) in terms of the inhibition of iron corrosion in concentrated sodium chloride solution (3.5 wt.% NaCl) after various exposure periods was assessed. Numerous electrochemical and spectroscopic assessment techniques were performed. Cyclic potentiodynamic polarization experiments indicated that the presence of HAO and its increased concentration decreased the corrosion of iron in NaCl solution by decreasing the corrosion values, anodic and cathodic currents, and corrosion rate. The electrochemical impedance spectroscopy results showed that HAO molecules greatly increased the corrosion resistance. The chronoamperometric experiments performed at −475 mV (Ag/AgCl) revealed that the HAO molecules decreased the absolute currents and reduced the probability of the occurrence of pitting corrosion. The effect of HAO on the inhibition of iron corrosion was also confirmed through scanning electron microscopy micrographs and energy-dispersive X-ray profile analyses, which proved that the surface of the iron sample exposed to chloride solution alone was pitted, while the presence of HAO molecules reduced the severity of the pitting corrosion. The results confirmed that the presence of HAO molecules inhibits the corrosion of iron and this impact increased when the exposure time was increased to 48 h.

Experimental, DFT and MD Assessments of Bark Extract of Tamarix aphylla as Corrosion Inhibitor for Carbon Steel Used in Desalination Plants

This study aimed to examine the extract of barks of Tamarix aphylla as a corrosion inhibitor. The methodology briefly includes plant sample collection, extraction of the corrosion inhibitor, gravimetric analysis, plotting potentiodynamic polarization plots, electrochemical impedance spectroscopic measurements, optimization of conditions, and preparation of the inhibitor products. The results show that the values of inhibition efficiency (IE%) increased as the concentrations of the inhibitor increased, with a maximum achievable inhibition efficiency of 85.0%. Potentiodynamic polarization (PP) tests revealed that the extract acts as a dual-type inhibitor. The results obtained from electrochemical impedance spectroscopy (EIS) measurements indicate an increase in polarisation resistance, confirming the inhibitive capacity of the tested inhibitor. The adsorption of the inhibitor on the steel surface follows the Langmuir adsorption isotherm model and involves competitive physio-sorption and chemisorption mechanisms. The EIS technique was utilized to investigate the effect of temperature on corrosion inhibition within the 298–328 K temperature range. Results confirm that the inhibition efficiency (IE%) of the inhibitor decreased slightly as the temperature increased. Lastly, the thermodynamic parameters for the inhibitor were calculated.

Thiocarbohydrazones Based on Adamantane and Ferrocene as Efficient Corrosion Inhibitors for Hydrochloric Acid Pickling of C-Steel

N′-(adamantan-2-ylidene)hydrazinecarbothiohydrazide and 2-(ferrocenyl-1-ylidene) hydrazinecarbothiohydrazide are used in coordination and organometallic complexes. The important idea of the research in this paper is the principal to prepare thiocarbohydrazones from the reaction of 2-acetylferrocene (Fe-Th) or 2-adamantanone (Ad-Th) with carbonothioic dihydrazide. The materials were elucidated by elemental analysis and spectral data. The as-prepared compounds were applied as effective corrosion inhibitors for HCl pickling of C-steel. Detailed investigations on electrochemical (open circuit potential (OCP) vs. time, potentiodynamic polarization (PDP), and impedance spectroscopy (EIS)) techniques and surface morphology studies are introduced in this work. Results indicated that Fe-Th could deliver greater inhibition performance than Ad-Th, and the highest protection capacity values of 93.6% (Ad-Th) and 97.9% (Fe-Th) were accomplished at 200 ppm. The adsorption of Ad-Th or Fe-Th additives followed the Langmuir isotherm with both the chemical and the physical adsorption with chemisorption predominance. EIS measurements supported a betterment in the capacitive behavior with the corrosion inhibitors. The inhibitors exhibited a mixed-type behavior as observed from the PDP studies. Field emission scanning electron microscopy (FESEM) and Fourier-transform infrared spectroscopy (FTIR) studies emphasize the occurrence of a protective layer of the as-synthesized organic inhibitors on the C-steel interface. Theoretical studies (density functional theory (DFT) calculations and Monte Carlo (MC) simulations) provide appropriate support for the experimental findings. The existing report provides very significant consequences in formulating and designing novel thiocarbohydrazone inhibitors with high protection efficacy.

Green Synthesis, SC-XRD, Non-Covalent Interactive Potential and Electronic Communication via DFT Exploration of Pyridine-Based Hydrazone

Ultrasound-based synthesis at room temperature produces valuable compounds greener and safer than most other methods. This study presents the sonochemical fabrication and characterization of a pyridine-based halogenated hydrazone, (E)-2-((6-chloropyridin-2-yl)oxy)-N′-(2-hydroxybenzylidene) acetohydrazide (HBPAH). The NMR spectroscopic technique was used to determine the structure, while SC-XRD confirmed its crystalline nature. Our structural studies revealed that strong, inter-molecular attractive forces stabilize this crystalline organic compound. Moreover, the compound was optimized at the B3LYP/6-311G(d,p) level using the Crystallographic Information File (CIF). Natural bonding orbital (NBO) and natural population analysis (NPA) were performed at the same level using optimized geometry. Time-dependent density functional theory (DFT) was performed at the B3LYP/6-311G (d,p) method to calculate the frontier molecular orbitals (FMOs) and molecular electrostatic potential (MEP). The global reactivity descriptors were determined using HOMO and LUMO energy gaps. Theoretical calculations based on the Quantum Theory of Atoms in Molecules (QT-AIM) and Hirshfeld analyses identified the non-covalent and covalent interactions of the HBPAH compound. Consequently, QT-AIM and Hirshfeld analyses agree with experimental results.