Adsorption behavior and corrosion inhibitive characteristics of newly synthesized cyano-benzylidene xanthenes on copper/sodium hydroxide interface: Electrochemical, X-ray photoelectron spectroscopy and theoretical studies

Inhibition Effect of Triphenylmethane Dyes for the Corrosion of Carbon Steel in CO2-Saturated NaCl Corrosion Medium

Carbon dioxide corrosion presents a significant challenge in the oil and gas field. This study simulates the corrosive environment characteristics of oil and gas fields to investigate the corrosion inhibition properties of three triphenylmethane dyes. The inhibitive performance and mechanisms of these dyes were analyzed through weight loss and electrochemical testing, revealing that crystal violet (CV) exhibited a superior inhibition effectiveness over malachite green (MG) and Fuchsine basic (FB). At a concentration of 150 ppm in a CO2-saturated 5% NaCl solution at 25 °C, CV achieved an impressive maximum inhibition efficiency of 94.89%. With the increase in temperature, the corrosion rate slightly decreased, and the corrosion rate was 92.94% at 60 °C. The investigated CV acted as a mixed-type corrosion inhibitor and its protection obeyed the Langmuir adsorption isotherm. The corrosion morphology was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and confocal laser scanning microscopy (CLMS). Quantum chemical calculations and molecular dynamics simulations were employed to validate the corrosion inhibition mechanisms, providing guidance for the further application of these dyes in corrosion control.

Colloidal and interface aqueous chemistry of dyes: Past, present and future scenarios in corrosion mitigation

The most effective corrosion inhibitors are organic compounds, especially heterocyclic ones with a certain balance of hydrophilicity, hydrophobicity, and conjugation. Most dyes develop the critical characteristics of a substance that can be utilized as an effective corrosion inhibitor. These include the presence of polar functional groups, nonbonding electrons and multiple bonds of the aromatic ring(s) and side chains. In aqueous electrolytes, dyes efficiently bind to metal surfaces through their electron-rich spots, known as adsorption centers. Literature studies show that many dye series have excellent anticorrosive properties for many metal/electrolyte combinations. They contain many electron-donating sites and behave as polydentate and chelating ligands. The polar functional for instance -OH, -CONH₂, -NH₂, -OR, -SO₃H, -COOH, -NMe₂, -N=N-, -CHO, -N=C < etc. also help in solubilizing relatively complex dye molecules in aqueous electrolytes. This review work seeks to explain the interfacial adsorption of dye molecules and how that negatively affects metallic corrosion. Through their adsorption, dye molecules block the active sites. They mainly achieved this by employing the Langmuir isotherm model. Additionally, the mechanism of corrosion inhibition is investigated, with a special emphasis on dyes.

Solvothermal synthesis of functionalized carbon dots from amino acid as an eco-friendly corrosion inhibitor for copper in sulfuric acid solution

In this work, novel N-doped carbon dots (N-CDs) were synthesized from citric acid and l-serine. The results of fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) show that there are many unsaturated bonds and polar groups in the N-CDs. The inhibition performance of the concerned zero-dimensional nanomaterial for copper was investigated by electrochemical, combining FT-IR, XPS and Raman to investigate the corrosion products. Results indicate that the N-CDs were found to be effective inhibitor with the suppression efficiency as high as 98.5% means after immersed for 24 h, and they interacted with copper substrate by chemical & physical adsorption. Moreover, the related anticorrosion mechanism was explored and elucidated in detail. The purpose of this work is to explore eco-friendly and efficient corrosion inhibitor materials for metal protection.

Benzimidazole loaded β-cyclodextrin as a novel anti-corrosion system; coupled experimental/computational assessments

HYPOTHESIS

Silane (sol-gel)-based coatings have been introduced as an eco-friendly system for reducing the metals' corrosion in NaCl solutions. However, due to the lack of active protection property for this type of coatings, their modification is totally recommended for achieving durable protection properties. The present study introduces Beta-cyclodextrin (β-CD) as a novel/effective organic nano-container for Benzimidazole (BM) encapsulation to obtain reliable active protection property via a controlled-release property.

EXPERIMENTS

The chemical structure of the β-CD-BM macromolecule was explored by Fourier-transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD), and Ultraviolet-visible spectroscopy (UV-Vis). Besides, the Electrochemical Impedance Spectroscopy (EIS) and polarization (potentiodynamic) tests were carried out for investigating the inhibition impacts of the constructed containers. The exposed and unexposed samples' surfaces were analyzed by Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive Spectroscopy (EDS)/mapping, and Grazing incidence X-ray diffraction (GIXRD) experiments. Also, the EIS test was conducted over the Silane-based composite film (SCF) for analyzing the anti-corrosion performance of the constructed composites.

FINDINGS

The EIS achievements demonstrated that by the addition of β-CD-BM complexes to the saline solution, the mild steel corrosion was mitigated by about 84%. The EIS results also displayed that the total resistance of the modified composite was enhanced from 5540 Ω.cm² to 10967 Ω.cm² and the intact coating provided a total resistance of 80254 Ω.cm². The dispersion-corrected Density Functional Theory (DFT)-D explorations ascertained the inclusion capacity of benzimidazole inside the β-CD. The Monte Carlo/Molecular Dynamics (MC/MD) calculations strongly affirmed the adsorption of BM and β-CD-BM over the substrate.