Inhibition of carbon steel corrosion in HCl solution using N-oleyl-1,3-propanediamine based formulation

Novel synthesized triazole derivatives as effective corrosion inhibitors for carbon steel in 1M HCl solution: experimental and computational studies

This article outlines the synthesis of two derivatives of 4-amino-5-hydrazineyl-4H-1,2,4-triazole-3-thiol for the prevention of carbon steel corrosion in 1M HCl solution. These derivatives are (Z)-3-(1-(2-(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)hydrazono)ethyl)-2H-chromen-2-one (TZ1) and 5-(2-(9H-fluoren-9-ylidene)hydrazineyl)-4-amino-4H-1,2,4-triazole-3-thiol (TZ2). Weight loss, electrochemical experiments, surface examinations, and theoretical computation are used to evaluate the effectiveness of the two compounds to be used as corrosion inhibitors. Weight loss and electrochemical studies demonstrate that these derivatives reduce the corrosion rate of carbon steel. To examine the morphology and constitution of the carbon steel surface submerged in HCl solution as well as after adding inhibitors, surface examination tests are performed. Analysis of the test solution via UV-visible spectroscopy is employed to check the possibility of complex formation between inhibitor molecules and Fe2+ ions released during the corrosion process. In order to explore their biological activity, the antibacterial activity was investigated against (E. coli and Bacillus subtilis). Finally, theoretical confirmation of the experimental findings is provided by quantum chemical (DFT) and Monte Carlo (MC) simulation studies. More adsorption sites are present in the derivatives of 4-amino-5-hydrazineyl-4H-1,2,4-triazole-3-thiol, which offer a novel perspective for developing new classes of corrosion inhibitors with substantial protective efficacy, especially at high temperatures.

Recycling Unused Midazolam Drug as Efficient Corrosion Inhibitor for Copper in Nitric Acid Solution

The current work explores the potential for recycling unused or expired Midazolam (MID) drug, a benzodiazepine derivative, as an efficient corrosion inhibitor for copper in nitric acid solution. The technical advantage of recycling expired MID drug relates to the avoidance of organic inhibitor production costs and the reduction of disposal costs of the expired medication. A combination of electrochemical methods (potentiodynamic polarization and electrochemical impedance spectroscopy), weight loss, and quantum chemical calculation were used to assess the inhibition mechanism and efficiency of MID. It was found that inhibition efficiency increases with inhibitor concentration, reaching a highest value of 92.9% for a concentration of 10⁻⁴ M MID. MID was classified as a mixed-type inhibitor, showing a preferential cathodic suppression mechanism. The obtained values of −45.89 kJ mol⁻¹ for the standard free energy of adsorption indicate that the inhibition mechanism is based on chemisorption of MID molecules on the copper surface, which obeys the Langmuir isotherm. Surface analysis using scanning electronic microscopy revealed that MID offers high protection against corrosion during both immersion and polarization tests. Molecular modelling and quantum chemical calculations indicated chemical interactions between MID molecules and the copper surface, as well as electrostatic interactions. The results obtained using the different techniques were in good agreement and highlight the effectiveness of MID in the corrosion inhibition of copper.

Insight into the anti-corrosion performance of two food flavors as eco-friendly and ultra-high performance inhibitors for copper in sulfuric acid medium

2,5-dihydroxy-1,4-dithiane (DDD) and 2,5-dimethy- [1.4] dithiane-2,5-diol (DTDD) two food flavors as environmentally-friendly inhibitors for Cu in 0.5 mol/L H₂SO₄ media were researched via theoretical calculation and experimental ways. Electrochemical measurement data showed that DDD and DTDD can exhibit high level anti-corrosion feature. The anti-corrosion efficiency of DDD and DTDD were as high as 99.6% and 98.9%, respectively. The atomic force microscope (AFM) and scanning electron microscope (SEM) tests showed that the Cu specimens were immersed in the H₂SO₄ with 5 mM DDD and DTDD for 30 h at the 298 K, and the Cu specimen surface was still smooth. Besides, the adsorption of DDD and DTDD at the interface of Cu/solution was comply with Langmuir adsorption. Theoretical calculation data showed that DDD exhibit more ascendant anti-corrosion feature than DTDD.