A new and effective organic imidazole derivative inhibitor for carbon steel protection in 1M HCl medium: electrochemical analysis and computer simulation

A novel imidazole derivative organic compound was employed as a corrosion inhibitor for carbon steel in a 1M hydrochloric acid medium. Several methods, including electrochemical impedance spectroscopy, potentiodynamic polarisation, surface characterisations (SEM/EDX), and UV-vis spectroscopy at 303 K, were used to study this. At a concentration of 10-3 M, the inhibitory effect of TOPI reached a high of 95.5%. The differences in corrosion potential reported indicate that this inhibitor chemical inhibits in a mixed fashion. The adsorption of TOPI derivatives onto the surface of carbon steel follows the Langmuir adsorption model and requires strong chemical bonding (chemisorption). In Bode diagrams, the electrochemical impedance spectra are shown primarily as a slightly flattened semicircle, corresponding to a single time constant. Furthermore, thermodynamic parameters such as $\Delta G_{{\rm ads}}\comma \; \; \; \Delta S_{\rm a}\comma \; \; \Delta H_{\rm a}$Delta Gads,Delta Sa,Delta Ha and $E_{\rm a}$Ea were calculated and discussed. Finally, a combination of DFT and MD simulation was used to determine which regions of the TOPI molecule interact with the steel surface.