Eco-friendly approach to corrosion inhibition of AA5083 aluminum alloy in HCl solution by the expired Vitamin B1 drugs

Effects of Vitamins as Green Inhibitors on the Surface of Steel Bars in Chloride-Polluted Simulated Concrete Pore Solution: Experimental, Characteristic Analysis, and Theoretical Calculation

This study evaluates the effects of vitamins B1 (VB1), B6 (VB6), B3 (VB3), and C (VC) as green corrosion inhibitors for steel bars in a chloride-polluted simulated concrete pore (SCP) solution. Electrochemical tests demonstrated that VB6 achieves the highest corrosion inhibition efficiency (IE%) of 92.86%, and the IE% of VB1 and VC are 91.96 and 91.51%, respectively, while VB3 shows the least effectiveness of 83.49% at their respective optimum concentrations. Scanning electron microscopy revealed that vitamin treatment significantly improves the surface morphology, enhancing smoothness. Energy dispersive X-ray spectroscopy confirmed the presence of protective molecular layers and precipitated calcium (Ca) on the steel surface, indicating effective adsorption. X-ray photoelectron spectroscopy revealed that vitamin interacts with iron (Fe) through chemisorption and physisorption, contributing to the formation of protective FeOOH compounds. Moreover, it also suggests that the main component of precipitated Ca is protective calcium carbonate (CaCO3). Density functional theory calculations showed that vitamins adhere to the surface of γ-FeOOH through hydrogen bonds. These findings underscore the potential of vitamins as effective green inhibitors in corrosion prevention applications.

In-Depth Insight into Corrosion Inhibition Performance of Sweet Potato Leaf Extract as a Green and Efficient Inhibitor for 6N01 Al Alloy in the Seawater: Experimental and Theoretical Perspectives

Corrosion protection of metal has become an important and urgent topic, which requires the development of an inexpensive, environmentally friendly, and highly efficient corrosion inhibitor. Herein, a sweet potato leaf extract (SPL) was obtained by a simple water-based extraction method and then as a green corrosion inhibitor for 6N01 Al alloy in the seawater was well investigated by the weight loss method and various electrochemical tests. Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopies were carried out to investigate the compositions of SPL. The findings from the potentiodynamic polarization (PDP) curves suggest that SPL functions as a typical mixed-type corrosion inhibitor. Notably, the maximum corrosion inhibition efficiency reaches 94.6% following a 36 h immersion period at 25 °C. The adsorption behavior of SPL on the Al alloy surface belongs to the Langmuir adsorption isotherm. The Gibbs free energy value illustrates that the adsorption of SPL contains both physisorption and chemisorption. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) indicate that SPL is firmly attached to the Al alloy surface by making a protective layer, which can effectively inhibit the corrosion of the Al alloy in the seawater. Furthermore, quantum chemical calculations were applied to validate the chemical adsorption and elucidate the relationship between the electronic structure of the active components in SPL and their effectiveness in corrosion inhibition.

Experimental Studies on the Effect of Expired Amiodarone Drug (EAD) as a Corrosion Inhibitor on Mild Steel in 1 M HCl

In the present investigation, the corrosion tendency of mild steel under acidic pH was studied by employing unused expired amiodarone (EAD) drug as a potential corrosion inhibitor by adopting the weight loss measurement method. The corrosion inhibition efficiency (IE) of the formed protective film (EAD) on the steel surface was analyzed using potentiodynamic polarization and AC-impedance spectroscopy studies. The surface morphology of the mild steel before and after corrosion (in 1.0 M HCl) was analyzed via scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDAX), atomic force microscopy (AFM), and thermodynamic studies. The weight loss measurement under different concentrations of EAD indicated that an excellent inhibition was displayed at a concentration of 0.001 M, and the IE was found to depend on both the concentration and molecular structure of EAD. A potentiodynamic polarization study revealed that EAD predominantly acted as a cathode inhibitor, and electrochemical impedance spectroscopy (EIS) confirmed the adsorption of EAD on the surface of mild steel, which obeyed Temkin's adsorption isotherm model. The calculated thermodynamic parameters revealed that adsorption was spontaneous and exothermic.

Experimental and theoretical studies of the efficiency of metal-organic frameworks (MOFs) in preventing aluminum corrosion in hydrochloric acid solution

Aluminum corrosion inhibitors "{[CuI (CN)2(phen) CuII (CN)2(phen)]5H2O},(MOF1) and {[CuI(CN)2(phen)CuII(CN)2(phen)]5H2O}@TiO2 (MOF1@TiO2) were studied in one molar HCl solution". The ML results for three different temperatures (25-45 °C) were compared with the results of PDP and EIS analyses. The adsorption of inhibitors on Al surfaces has been calculated and discussed by a Langmuir isotherm. The inhibitors that were created showed great effectiveness, with a noticeable increase in their inhibitory efficiency as the dosage was raised and the temperature was lowered. Inhibition efficiency each amounted to 88.6%, 84.5% at 400 ppm and 25 °C for MOF1@TiO2 and MOF1, respectively. Analyzing the polarization curves of synthesized inhibitors revealed that they were mixed-type inhibitors. Al was found to be surface inhibited when coated with a thin film of inhibitors, and "Al's surface morphology was assessed by different techniques such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM)". "Theoretical models like quantum chemical and molecular dynamics simulation authenticated the experimental observation". The MOFs exhibit exceptional corrosion resistance against Al when exposed to acidic environments, according to several tests.

Efficiency of Expired Drugs Used as Corrosion Inhibitors: A Review

Corrosion inhibitors represent one of the most commonly used methods for significantly reducing the corrosion rate of metals and alloys. Adsorption inhibitors have a wide range of applications in cooling water systems, deicing solutions for aircrafts, airports and ways, etching and degreasing solutions, oil pipelines, paints and coatings and metal processing solutions. Adsorption corrosion inhibitors of metals and alloys are generally organic compounds that contain structures with heteroatoms (N, P, S, As, O) in their molecules, having lone pair electrons or π electrons in aromatic rings or multiple bonds. They enable relatively strong interactions between the metal atoms and organic molecules, resulting in a protective layer of organic molecules adsorbed at the metal-corrosive solution interface. Most molecules of active substances from drugs contain similar structures, which is why many drugs have been already tested as corrosion inhibitors. One of the major disadvantages of using drugs for this purpose is their particularly high price. To overcome this impediment, the possibility of using expired drugs as corrosion inhibitors has been investigated since 2009. The present paper is an exhaustive compilation of the scientific published papers devoted to the use of expired drugs as corrosion inhibitors in various aggressive solutions. The inhibitory efficiencies of expired drugs are presented as a function of the studied metal or alloy and the nature of the aggressive solution, as well as the concentration of the inhibitor in such a solution. Research has especially been focused on mild and carbon steel and less on stainless steel, as well as on some metals such as copper, zinc, nickel, tin and aluminum and its alloys. The experimental methods used to assess the inhibitory efficiencies of expired drugs are briefly discussed. Also, the available information on the stability of the active substances in the drugs is presented, although most authors were not concerned with this aspect. Finally, several actions are revealed that must be undertaken by researchers so that the results obtained in the study of the anticorrosive action of expired drugs can be applied at the industrial level and not remain only an academic concern.

Electrochemical and theoretical investigations of favipiravir drug performance as ecologically benign corrosion inhibitor for aluminum alloy in acid solution

Aluminum-silicon alloys have become a preferred option in the automotive and aerospace industries thanks to their fault-tolerant process ability and reasonable static characteristics at relatively affordable costs. This study aimed to investigate the use of favipiravir (FAV) drug as a biocompatible and eco-friendly inhibitor to protect aluminum alloy (AlSi) surface in an aggressive acid environment (1.0 M HCl). The electrochemical measurements declare that FAV is categorized as an inhibitor of mixed type with a cathodic effect. At 100 ppm, FAV had the highest inhibitory efficiency (96.45%). FAV is associated with lower double-layer capacitance values and more excellent charge-transfer resistance. These results show that AlSi corrosion in 1.0 M HCl is reduced in the presence of FAV. The Langmuir model is well-suited to the FAV adsorption behavior (R² ≈ 1). Chemisorption is the primary adsorption in this environment. The theoretical calculation studies corrosion inhibitors' molecular structure and behavior. Different quantum chemical properties of the FAV have been calculated, including energy difference (ΔE), softness, global hardness, and energy of back-donation depending on the highest occupied and lowest unoccupied molecular orbitals. In addition, Mulliken and Fukui's population analysis and the Molecular Electrostatic Potential map represent the electron distribution and the molecule's active centers. Experimental findings and quantum chemical computations matched, and FAV is recommended as a green corrosion inhibitor.