We are reporting L–alanine as inhibitor for carbon steel in well water was studied using weight loss technique. The results indicate that the L-alanine functioned as a good corrosion inhibitor for the tested system. The inhibition efficiency increases with increasing L-alanine concentration. Synergistic effects increased the inhibition efficiency in the presence of zinc ions. Tafel results indicated that L-alanine is an anodic inhibitor. Adsorption of the used inhibitor led to a reduction in the double layer capacitance and an increase in the charge transfer resistance. Fluorescence spectral analysis was used in detecting the presence of an iron – inhibitor complex and the coordination sites of the metal inhibitor with iron were determined by the FT-IR spectra. Scanning electron microscopy (SEM) study confirmed that the inhibition of corrosion of carbon steel is through adsorption of the Inhibitors molecule on the surface of the metal. Energy dispersive analysis of X-rays (EDAX) shows that in the presence of inhibitors the suppression of Fe peaks, additional line of N and Zn signal & enhancement in ‘C’ and ‘O’ signal. These data show that metal surface is covered by adsorbed layer of Inhibitors molecule that protects carbon steel against corrosion. The surface morphology of the protective film (nano film) on the metal surface was characterized by using atomic force microscopy (AFM). A suitable mechanism of corrosion inhibition is proposed based on the results obtained from weight loss study, electrochemical study and surface analysis technique. The eco-friendly inhibitor L - alanine -Zn²⁺ system may find application in cooling water system.
Keywords: Green Inhibitor; L-alanine; Synergistic Effect; Fluorescence Spectra; Nano Film; Spectral Characterizations