The corrosion inhibition of carbon steel (CS) using the “green” inhibitor, L-alanine (L-Ala) was investigated. This study was conducted at pH 7.6. The effect caused by Zn²⁺ additive also was investigated. The study was done over a range of concentrations. Gravimetric method and electrochemical methods were applied. It was found that the L-alanine acts as a good inhibitor at pH 7.6. The inhibition efficiency increases with increasing L-Ala concentrations. The addition of Zn²⁺ to L-alanine significantly increased the inhibition efficiency. Tafel results indicated that decrease the corrosion current (I_corr) value. The influence of biocide SDS on the inhibition efficiency of L-alanine – Zn²⁺ system has been investigated. Also it is evident that at minimum concentration of biocides added to the inhibitor system, 100 % biocidal efficiency is noticed. The protective film formed on the metal surface has been analyzed by UV-visible, Fluorescence and FT-IR spectra. It is found that the protective film consists of Fe²⁺ - L-alanine complex and Zn(OH)₂.
Keywords: Green Inhibitor; L-Alanine; SDS; Biocidal Efficiency; FT-IR; UV-Visible