Electrochemical, thermodynamic and theoretical studies of some imidazole derivatives compounds as acid corrosion inhibitors for mild steel

Enhancing corrosion resistance of mild steel in hydrochloric acid with Chiquita banana sap extract

The corrosion of metals is still a huge challenge for various industries, and the pursuit of effective treatments ensures environmental sustainability. In this study, we utilized Chiquita banana sap-water extract (BSWE) to prevent mild steel from electrochemical corrosion in a 0.1 M HCl at room temperature. Corrosion resistance was assessed using various electrochemical methodologies, combining with surface characterization techniques. The results showed a high level of effectiveness when the corrosion current density decreased from 3292.67 μA cm-2 (for the sample immerged in the blank solution) to 187.33 μA cm-2 after 24 hours of immersion in the solution containing BSWE at a 2000 ppm concentration, equivalent to corrosion efficiency of 94.32%. Surface characterization revealed diminished corrosion on the inhibited steel surface due to the formation of a protective layer. X-ray photoelectron spectroscopy results demonstrated the presence of BSWE ingredients combining with iron oxides and hydroxides to form a smooth protective layer. Furthermore, theoretical calculations also indicated that the addition of BSWE can reduce steel surface damage when exposing to corrosive environment. The inhibitor based on banana sap extract can be referred to as a sustainable protective coating since it is biodegradable, abundantly available in banana plants and free of other harmful substances.

Frontiers and advances in N-heterocycle compounds as corrosion inhibitors in acid medium: Recent advances

The acid solution is widely used in chemical cleaning, oil well acidifying, and other fields, which also brings the problem of metal corrosion that cannot be underestimated. However, adding an inhibitor is one of the most convenient and effective ways to slow down metal corrosion. N-heterocyclic compounds with high stability and durability, in line with the strategy of sustainable development, have been widely studied in an acidic environment. Imidazole, pyridine, and quinoline compounds, as the most commonly used corrosion inhibitors, can form a compact protective film via π electron cloud shifting towards the N atoms to generate coordination function. In particular, flexible modifiability makes N-heterocyclic compounds adapt to different corrosion environments readily, conducive to the formation of chemical bonds between compounds with metal surfaces to be better adsorption, so as to avoid the blemish of traditional inhibitors (such as inorganic salt and organic amines inhibitors) due to excessive usage, surface roughness of metal or environmental factor (for instance, temperature, pH and metallic) causing loose bonding between film and metal surface. More importantly, the efficient corrosion inhibition and toxicity of N-heterocyclic compounds have close to do with their own functional groups. Combined with the latest research achievement, the effects of different substituents on the corrosion inhibition and corrosion inhibition mechanisms were systematically reviewed in the acid-corrosive solution of imidazole, pyridine, and quinoline and their derivatives in this review article, respectively. In addition, the application and function of density functional theory in predicting the corrosion inhibition effect of corrosion inhibitors are also discussed. The future development trend was prospected according to the summarized research results.

Novel biphenylidene-thiopyrimidine derivatives as corrosion inhibitors for carbon-steel in oilfield produced water

The inhibiting efficiency of three newly synthesized organic compounds:5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1228), 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1227) and 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1226) in oilfield produced water on the corrosion of carbon steel has been examined via electrochemical measurements; potentiodynamic polarization (PDP) and electrochemical impedance (EIS) techniques. The adsorption of these compounds on the surface of carbon steel followed Langmuir isotherm. In addition, the surface morphology of uninhibited and inhibited carbon steel was examined by Atomic Force Microscopy (AFM), observing surface improvement when carbon steel samples exposed to the inhibited corrosive solutions. The average surface roughness (Ra) in oilfield produced water solution in the presence of 0.5 mM of HM-1228 inhibitor was 138.28 nm compared to the uninhibited surface 571.62 nm. To explore the corrosion inhibition mechanism, quantum chemical calculations and Monte Carlo simulations were utilized. The HM-1228 inhibitor demonstrated the highest corrosion inhibition efficiency at 94.8% by PDP measurements. The higher corrosion inhibition of compound HM-1228 can be attributed to the presence of di-N-ethyl groups that enhance both electron donating ability and lipophilic properties.

A comprehensive assessment of carbon steel corrosion inhibition by 1,10-phenanthroline in the acidic environment: insights from experimental and computational studies

1,10-Phenanthroline (PHN) is a nitrogen-containing heterocyclic organic compound that is widely used in a variety of applications, including chemosensors, biological studies, and pharmaceuticals, which promotes its use as an organic inhibitor to reduce corrosion of steel in acidic solution. In this regard, the inhibition ability of PHN was examined for carbon steel (C48) in a 1.0 M HCl environment by performing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), mass loss, and thermometric/kinetic. Additionally, scanning electron microscopy (SEM) was used to examine the surface morphology of C48 immersed in 1.0 M HCl protected with our inhibitor. According to the PDP tests, increasing the PHN concentration resulted in an improvement in corrosion inhibition efficiency. Besides, the maximum corrosion inhibition efficiency is about 90% at 328 K. Furthermore, the PDP assessments demonstrated that PHN functions as a mixed-type inhibitor. The adsorption analysis reveals that our title molecule mechanism is due to physical-chemical adsorption, as predicted by the Frumkin, Temkin, Freundlich, and Langmuir isotherms. The SEM technique exhibited that the corrosion barrier occurs due to the adsorption of the PHN compound through the metal/1.0 M HCl interface. In addition, the computational investigations based on a quantum calculation using density functional theory (DFT), reactivity (QTAIM, ELF, and LOL), and molecular-scale by Monte Carlo (MC) simulations confirmed the experimental results by providing further insight into the mode of adsorption of PHN on the metal surface, thus forming a protective film against corrosion on the C48 surface.

Developing novel imidazoline-modified glucose derivatives as eco-friendly corrosion inhibitors for Q235 steel

Many natural compounds and imidazoline derivatives have been previously evaluated as eco-friendly corrosion inhibitors for application in the food, pharmaceutical and chemical industries. Herein, a novel alkyl glycoside cationic imaginary ammonium salt (FATG) was designed via the grafting of imidazoline molecules into the skeleton of a glucose derivative, and its effects on the electrochemical corrosion behavior of Q235 steel in 1 M HCl were systemically investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves (PDP), and gravimetric measurements. The results indicated that its maximum inhibition efficiency (IE) was 96.81% at a concentration as low as 500 ppm. The adsorption of FATG on the Q235 steel surface followed the Langmuir adsorption isotherm. The scanning electron microscopy (SEM) and diffraction X-ray (XRD) results suggested the formation of inhibitor film on the metal surface, which significantly impeded the corrosion of Q235 steel. Additionally, FATG showed a high biodegradability efficiency (98.4%), which had great potential as a green corrosion inhibitor based on concepts of greenness and biocompatibility.

Inhibitory Capabilities of Sweet Yellow Capsicum Extract toward the Rusting of Steel Rebars in Cement Pore Solution

The inhibitory capabilities of the sweet yellow capsicum extract (SYCE) toward the rusting of steel rebars in cement pore solution (CPS) were tested employing the electrochemical and mass loss methods. Gallic acid, caffeic acid, p-coumaric acid, ferulic acid, luteolin, and cinnamic acid are the most important constituents in the SYCE extract. By adsorbing them on steel bars, the organic compounds in the CSA extract enable them with an effective mixed-type inhibition, suppressing both anodic and cathodic procedures. At 300 ppm, the highest performances were 95.3 and 97.5% utilizing mass loss and electrochemical approaches, respectively. The activation energy for the corrosion process is greatly increased by the addition of the SYCE extract, going from 13.2 kJ mol^-1 (blank solution) to 30.0 kJ mol^-1 (300 ppm SYCE extract). The physical adsorption actions of the SYCE extract are described by the Freundlich equilibrium constant's smallest value, which is 0.074 ppm^-1. Many future investigators will be attracted by these discoveries to work relentlessly to uncover the anti-corrosion characteristics of novel plant extracts in the area of concrete additives.

Adsorption, thermodynamic, and quantum chemical investigations of an ionic liquid that inhibits corrosion of carbon steel in chloride solutions

The purpose of this work lies in the use of ionic liquids as corrosion inhibitors due to the difficulty in some oil fields with the solubility of corrosion inhibitors and these materials can be miscible with water and thus provide a solution to such problems in the industry. The second purpose is concerned with the lower toxicity of these compounds compared with the most common corrosion inhibitors. The study covered the corrosion inhibition performance of the ionic liquid 1-butyl-3-methylimidazolium trifluoromethyl sulfonate ([BMIm]TfO) for carbon steel in 3.5% NaCl solutions. The study comprised electrochemical, adsorption, and quantum chemical investigations. The results manifested that [BMIm]TfO can be considered a promising corrosion inhibitor and the inhibition efficacy intensifies as the concentration rises. The observed inhibitive effect can be correlated to the adsorption of the ionic liquid species and the creation of protecting films on the surface. The mode of adsorption follows the Langmuir adsorption isotherm. The polarization results showed that the ionic liquid [BMIm]TfO functions as a mixed inhibitor. Reliance of the corrosion influence on the temperature in the existence and absence of [BMIm]TfO was demonstrated in the temperature range of 303-333 K using polarization data. Activation parameters were determined and discussed. The observed inhibition performance of [BMIm]TfO was correlated with the electronic properties of the ionic liquid using a quantum chemical study.

In Silico Approaches for Some Sulfa Drugs as Eco-Friendly Corrosion Inhibitors of Iron in Aqueous Medium

This paper addresses the prediction of the adsorption behavior as well as the inhibition capacity of non-toxic sulfonamide-based molecules, also called sulfa drugs, on the surface of mild steel. The study of the electronic structure was investigated through quantum chemical calculations using the density functional theory method (DFT) and the direct interaction of inhibitors with the iron (Fe) metal surface was predicted using the multiple probability Monte Carlo simulations (MC). Then, the examination of the solubility and the environmental toxicity was confirmed using a chemical database modeling environment website. It was shown that the presence of substituents containing heteroatoms able to release electrons consequently increased the electron density in the lowest unoccupied and highest occupied molecular orbitals (LUMO and HOMO), which allowed a good interaction between the inhibitors and the steel surface. The high values of EHOMO imply an ability to donate electrons while the low values of ELUMO are related to the ability to accept electrons thus allowing good adsorption of the inhibitor molecules on the steel surface. Molecular dynamics simulations revealed that all sulfonamide molecules adsorb flat on the metal surface conforming to the highly protective Fe (1 1 0) surface. The results obtained from the quantum chemistry and molecular dynamics studies are consistent and reveal that the order of effectiveness of the sulfonamide compounds is P7 > P5 > P6 > P1 > P2 > P3 > P4.

Novel triazole derivatives as ecological corrosion inhibitors for mild steel in 1.0 M HCl: experimental & theoretical approach

The present paper illustrates the investigation of two novel ecological triazole derivative corrosion inhibitors, namely ethyl 2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetate [Tria-CO₂Et], and 2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetohydrazide [Tria-CONHNH₂].