B. Hammouti

3,5-Diaryl-4-amino-1,2,4-triazole derivatives as effective corrosion inhibitors for mild steel in hydrochloric acid solution: Correlation between anti-corrosion activity and chemical structure

The corrosion inhibition efficiency of newly synthesized 3,5-diaryl-4-amino-1,2,4-triazole derivatives was investigated for mild steel corrosion in 1.0 M HCl medium using weight loss quantum chemical calculations and Monte Carlo simulations. It was found that the studied compounds exhibit a very good performance as inhibitors for mild steel corrosion in 1.0 M HCl. The results show that the inhibition efficiency increases with decreasing temperature and increasing concentration of inhibitors. The kinetic parameters such as Ea, ΔHa, and ΔSa were evaluated. It was found that the adsorption for these inhibitors on the mild surface obeys the Langmuir adsorption isotherm at all studied temperatures and the adsorption isotherm parameters (Kads, ΔGads°, ΔHads°, and ΔSads°) were determined and discussed. The values of inhibition efficiency for all triazoles followed the order 3-APAT < 4-APAT < 4-DTAT < 4-MAT < 3,4-MAT. The 3,4-methoxyphenyl substituted triazole (3,4-MAT) exhibited the highest inhibition efficiency of 98.5% at concentration of 1 × 10–4 M. Quantum chemical calculations using the Density Functional Theory (DFT) were performed on the 3,5-diaryl-4-amino-1,2,4-triazole derivatives in an attempt to correlate the corrosion inhibition properties of these 1,2,4-triazole derivatives with their calculated quantum chemical parameters. Furthermore, Monte Carlo (MC) simulations were applied to search for the most stable configuration and adsorption energy for the interaction of inhibitors on Fe (110)/30 H2O interface. A good correlation was observed between the Monte Carlo calculations and experimentally inhibition efficiency data.

Chitosan polymer as a green corrosion inhibitor for copper in sulfide-containing synthetic seawater

The influence of chitosan on the copper corrosion in sulfide polluted synthetic seawater (SSW) containing 20 ppm of sulfide has been investigated for the first time. Potentiodynamic polarization measurements, electrochemical impedance spectroscopy at the open circuit potential and weight loss measurements were employed to assess the corrosion inhibition ability of chitosan. The impedance studies revealed that in the presence of chitosan at various concentrations, the charge transfer resistance increases. At a concentration of 800 ppm, chitosan exhibited a corrosion inhibition efficiency of 89% following physical adsorption. The influence of temperature and immersion time was studied in sulfide-contaminated synthetic seawater and significant inhibition was observed even after 90 days. SEM-EDS studies confirm the absence of the deterioration products on copper surface.