Schiff's Base Performance in Preventing Corrosion on Mild Steel in Acidic Conditions

Many industries, particularly the oil and gas industry, extensively use metallic materials. However, steel is negatively impacted by corrosion, which decreases the functioning of its surfaces. Therefore, finding a solution to the corrosion challenge is imperative. To prevent mild steel from corroding in a 1 M hydrochloric acid medium, a Schiff base named methyl 5-(((((2-hydroxynaphthalen-1-yl)methylene)amino))-1-methyl-1H-pyrazole-4-carboxylate (MMPC) was utilized. Weight loss measurements and theoretical calculations were conducted to explore the effectiveness and mechanism of corrosion protection. MMPC adsorbs onto mild steel, blocking active sites, and the adsorption follows the Langmuir adsorption isotherm model. Based on a free energy ( ) value of -37.25 KJmol-1, physical adsorption and chemical adsorption are two separate adsorption modes. At a concentration of 0.5 mM and 303 K, the findings demonstrate that MMPC showed an excellent inhibitor effectiveness of 97.13 %. The acid reaction site is blocked by the inhibitor adsorbed onto the mild steel surface. Density Functional Theory (DFT) at the B3LYP/6-311 G++ basis set was also used to determine the effectiveness of the inhibitor, and the results demonstrated that MMPC is an effective inhibitor.