Inhibition Efficiency of Some Amino Acids in the Presence of Vanillin for the Corrosion of Mild Steel in HCl Solution

The inhibition of corrosion of mild steel in HCl in the presence of vanillin (van) coexisting with some amino acids, i.e., valine (val), cysteine (cys), methylcysteine hydrochloride (m-cys) and methionine (meth) are compared. The possible synergistic inhibition of the corrosion by these amino acids using vanillin are also examined. It has been found that the inhibition efficiency of the studied amino acids in HCl is arranged as follows; meth < m-cys