Asian Journal of Chemical Sciences

Corrosion of aluminum in acidic environments remains a significant challenge in industrial processes, necessitating the development of efficient and environmentally acceptable organic inhibitors. Several compounds have been used as inhibitors to combat this phenomenon. However, some of these compounds, such as inorganic compounds, have a negative impact on the environment and humans. In this study, the inhibitory effect of (E)-3-(2-chloroimidazo[1,2-a]pyridin-3-yl)-1-phenylprop-2-en-1-one on the corrosion of aluminum in 1M sulfuric acid medium was evaluated using the weight mass loss technique in a temperature range of 298 to 323 K, as well as through theoretical approaches based on quantum chemistry. The results reveal that the inhibition efficiency varies with concentration and temperature. At a concentration of 0.35 mM and a temperature of 298 K, the inhibition efficiency reaches 97%.

Thermodynamic adsorption parameters (\(\Delta G^0_{ads}, \Delta H^0_{ads}, \Delta S^0_{ads}\)) were determined and analyzed. This analysis indicates that the adsorption process is spontaneous and that a strong interaction exists between the inhibitor and the aluminum surface. Several adsorption isotherms, including those of Langmuir, Temkin, and El-Awady, were tested. These tests show this compound adsorbs onto aluminum according to the modified Langmuir adsorption isotherm. The Adejo-Ekwenchi isotherm indicated that the adsorption process of the molecule onto the metal surface is dominated by physisorption. Furthermore, the key quantum chemical descriptors related to the molecule's potential efficacy as a corrosion inhibitor were evaluated using DFT calculations at the B3LYP level with the 6-31G(d,p) basis set. These include the energy of the highest occupied molecular orbital (E_HOMO), the energy of the lowest unoccupied molecular orbital (E_LUMO), the energy gap (\(\Delta E\)), the dipole moment (\(\mu\)), and the fraction of electrons transferred. Fukui indices were also calculated and analyzed. Overall, the combined results demonstrate that E-CPP is a highly effective corrosion inhibitor in acidic media. However, the absence of surface characterization techniques (e.g., scanning electron microscopy or X-ray photoelectron spectroscopy) limits direct validation of the adsorption mechanism. Future work should incorporate such techniques to provide detailed insight into the inhibitor film and strengthen the correlation between experimental and theoretical findings.