A detailed investigation on the corrosion inhibition effect of by newly synthesized pyran derivative on mild steel in 1.0 M HCl: Experimental, surface morphological (SEM-EDS, DRX& AFM) and computational analysis (DFT & MD simulation)

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.

Effect of Adsorption and Interactions of New Triazole-Thione-Schiff Bases on the Corrosion Rate of Carbon Steel in 1 M HCl Solution: Theoretical and Experimental Evaluation

Due to the unique properties of steel, including its hardness, durability, and superconductivity, which make it an essential material in many industries, it lacks corrosion resistance. Herewith, two novel triazole-thione Schiff bases, namely, (E)-5-methyl-4-((thiophen-2-ylmethylene)amino)-2,4-dihydro-3H-1,2,4-triazole-3-thione (TMAT) and (E)-4-(((5-(dimethylamino)thiophen-2-yl)methylene)amino)-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (DMTMAT), were synthesized and characterized. The corrosion inhibition (CI) ability of these two molecules on carbon steel in an aqueous solution of 1 M HCl as well as their interaction with its surface was studied using a number of different techniques. The results confirmed that the CI capability of these organic molecules depends on their strong adsorption on the metal surface and the formation of a protective anticorrosion film. Weight loss tests revealed that the inhibition efficiencies of TMAT and DMTMAT were 91.1 and 94.0%, respectively, at 1 × 10-3 M concentrations. The results of electrochemical impedance spectroscopy (EIS) indicated that there was a direct relationship between the inhibitor concentration and the transfer resistance. Potentiodynamic polarization (PDP) experiments have proven to be mixed-type inhibitors of C-steel in aqueous hydrochloric acid solution and follow the Langmuir adsorption isotherm model. Several thermodynamic and kinetic parameters were calculated. The negative values of the adsorption-free energy are -36.7 and -38.5 kJ/mol for TMAT and DMTMAT, respectively, confirming the spontaneity of the adsorption process. The MD simulation study's findings show that the inhibitor molecules are nearly parallel to the metal surface. The interaction energy calculated by the MD simulation and the inhibitory trend are the same. The practical implementation is consistent with what the computer models predicted.

Unraveling the Adsorption Mechanism and Anti-Corrosion Functionality of Dextrin and Inulin as Eco-Friendly Biopolymers for the Corrosion of Reinforced Steel in 1.0 M HCl: A Thermodynamic and Kinetic Approach

Reinforcing steel (RS) is mainly used in building construction and many industries, but it suffers from corrosion problems, especially in acidic environments. Biopolymers are characterized by their unique chemical composition, as they contain a variety of functional groups that are capable of binding strongly to the metal surface and forming a protective layer on it. Herewith, two biopolymers, viz. dextrin (Dex) and inulin (Inu), were tested as eco-friendly inhibitors for the corrosion of RS in 1.0 M HCl medium at different temperatures. Various experimental tools were utilized in this research. The inhibition efficiencies (% IEs) of the tested polymeric compounds were improved by increasing their doses while reducing with rising temperature. The % IEs of Dex and Inu at a dose of 500 mg/L reached 85% and 93%, respectively. The examined biopolymers displayed cathodic/anodic behavior (mixed type) with a foremost anodic one. The acquired higher % IEs were demonstrated by intense adsorption of Dex and Inu on the RS surface fitting the Langmuir isotherm. The influence of rising temperature in the range of 288-318 K on the corrosion behavior was examined, and the evaluated thermodynamic and kinetic parameters sustained the mechanism of physical adsorption of the polymeric inhibitors. Additionally, the kinetics of corrosion, as well as its inhibition by Dex and Inu, were also investigated. The SEM micrographs of the RS surfaces were accorded with all utilized experimental tools. The results gained from all used tools were discovered to be in good agreement with each other.

Investigating the Inhibitory Properties of Cupressus sempervirens Extract against Copper Corrosion in 0.5 M H2SO4: Combining Quantum (Density Functional Theory Calculation-Monte Carlo Simulation) and Electrochemical-Surface Studies

The study investigates the potential of Cupressus sempervirens (EO) as a sustainable and eco-friendly inhibitor of copper corrosion in a 0.5 M sulfuric acid medium. The electrochemical impedance spectroscopy analysis shows that the effectiveness of corrosion inhibition rises with increasing inhibitor concentrations, reaching 94% with the application of 2 g/L of EO, and potentiodynamic polarization (PDP) studies reveal that EO functions as a mixed-type corrosion inhibitor. In addition, the Langmuir adsorption isotherm is an effective descriptor of its adsorption. Scanning electron microscopy/energy-dispersive X-ray spectroscopy, atomic force microscopy surface examination, and contact angle measurement indicate that EO may form a barrier layer on the metal surface. Density functional theory calculations, Monte Carlo simulation models, and the radial distribution function were also used to provide a more detailed understanding of the corrosion protection mechanism. Overall, the findings suggest that Cupressus sempervirens (EO) has the potential to serve as an effective and sustainable corrosion inhibitor for copper in a sulfuric acid medium, contributing to the development of green corrosion inhibitors for environmentally friendly industrial processes.

Inhibition performance of halogen-substituted benzaldehyde thiosemicarbazones as corrosion inhibitors for mild steel in hydrochloric acid solution

Halogen-substituted benzaldehyde thiosemicarbazone derivatives were synthesized and their inhibition performance for mild steel in hydrochloric acid solution were investigated systematically using weight loss measurements, electrochemical techniques, scanning electron microscopy and quantum chemical calculations. Results of weight loss measurements indicated that all these compounds exhibited excellent inhibition performance and the inhibition efficiency increased with increasing inhibitor concentrations. Polarization results revealed that the synthesized benzaldehyde thiosemicarbazone derivatives were mixed-type inhibitors. Adsorption of these compounds onto a mild steel surface was mainly chemisorption and complied with the Langmuir adsorption isotherms. Both theoretical calculations and experimental measurements suggested that the inhibition efficiency of these compounds followed the order of Br-BT > Cl-BT > F-BT > H-BT.